Patent Grant
8652221
Typically, compression candles are made from wax that has been formed into prills, which prills are compressed in a mold to make a candle. The candle industry has traditionally relied on prilled paraffin waxes to make compression candles.
Some attempts to formulate waxes from bio-based, renewable materials suitable for making compression candles have suffered from a variety of problems, including poor compressive strength, poor cohesive strength, slump at elevated temps, flashing, tooling, and fat bloom associated with triglycerides. The term cohesive strength is used herein to refer to the bulk strength of a compressed wax article (i.e., load to failure of a test specimen).
A desirable characteristic for prilled waxes is to compress evenly in the compression mold and for the resulting compressed wax article to exhibit sufficient strength to resist chipping or crumbling when subjected to rough handling or dropping. Natural oil-based waxes may be mixed with paraffin wax to create hybrid waxes with improved properties. However, hybrid waxes with greater than 50% weight natural oil-based wax, when compressed, typically fail to exhibit bulk strengths that are comparable to paraffin systems. Consequently, the resulting candles are more susceptible to damage during processing and handling. They can also be more susceptible to damage while being ejected from the compression mold, resulting in defects such as surface scarring, erosion, pitting and/or filming. The strength issues become more problematic as the size of the candle that is being manufactured increases. For example, it is particularly challenging to make bio-based compression candles that are freestanding and/or that are larger than about 2.5 inches wide by about 2.5 inches tall.
While paraffin-based compression candles exhibit good strength properties, paraffin wax does have some disadvantages, such as being a non-renewable resource; exhibiting visible emissions; and having a low fragrance holding ability (about 1% maximum by weight) in freestanding and/or larger-size compression candles.
Hence, there is continuing interest in the development of new wax compositions and candle products based on bio-based materials, such as natural oils, that have a high compressive and a high cohesive strength.
Hybrid wax compositions that are suitable for use in manufacturing wax articles (e.g., candles) by compression molding are disclosed here. The combination of a hydrogenated natural oil-based wax and a paraffin wax having a select distribution of hydrocarbon chain lengths provides the hybrid wax compositions with improved properties, such as improved compressive strength and improved de-molding characteristics, for example, as evidenced by reduced scarring and/or flashing. The hybrid wax compositions comprise: (a) a wax comprising a hydrogenated natural oil; and (b) a paraffin wax, wherein the paraffin wax comprises less than about 50% by weight of the hybrid wax composition, and wherein about 52% or greater of hydrocarbons in the paraffin wax have carbon chain lengths ranging from C25 to C29.
Wax articles incorporating the hybrid wax compositions may be formed from prilled wax particles by compressing the prilled wax particles to form the wax article.
The invention will be described further in connection with the attached drawings, wherein like reference numbers have been used to indicate like parts and wherein:
As used herein, a “fully hydrogenated” refers to a natural oil that has been hydrogenated to achieve an iodine value (IV) of about 5 or less.
As used herein the term “partially hydrogenated” refers to a natural oil that has been hydrogenated to achieve an Iodine Value of about 5 to about 50.
As used herein, the term “natural oil” is intended to mean any oil derived from a plant or animal source, and includes any chemically modified oils from plant or animal sources.
As used herein, the term “relative density” is intended to mean the density, typically measured in g/ml, of the compressed candle or portion of a compressed candle, as the case may be, divided by the density of the individual particles making up the compressed candle or portion. As will be described below, the term “relative density” is one measure of the extent to which the prilled particles have been compressed to eliminate interstitial space therebetween.
As used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a substituent” encompasses a single substituent as well as two or more substituents, and the like.
As used in the specification and the appended claims, the terms “for example,” “for instance,” “such as,” or “including” are meant to introduce examples that further clarify more general subject matter. Unless otherwise specified, these examples are provided only as an aid for understanding the applications illustrated in the present disclosure, and are not meant to be limiting in any fashion.
The term “alkyl” as used herein refers to a linear, branched, or cyclic saturated hydrocarbon group typically although not necessarily containing 1 to about 24 carbon atoms, preferably 1 to about 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl, decyl, and the like, as well as cycloalkyl groups such as cyclopentyl, cyclohexyl and the like. Generally, although again not necessarily, alkyl groups herein contain 1 to about 12 carbon atoms. The term “lower alkyl” intends an alkyl group of 1 to 6 carbon atoms, and the specific term “cycloalkyl” intends a cyclic alkyl group, typically having 4 to 8, preferably 5 to 7, carbon atoms. The term “substituted alkyl” refers to alkyl substituted with one or more substituent groups, and the terms “heteroatom-containing alkyl” and “heteroalkyl” refer to alkyl in which at least one carbon atom is replaced with a heteroatom. If not otherwise indicated, the terms “alkyl” and “lower alkyl” include linear, branched, cyclic, unsubstituted, substituted, and/or heteroatom-containing alkyl and lower alkyl, respectively.
The term “alkylene” as used herein refers to a difunctional linear, branched, or cyclic alkyl group, where “alkyl” is as defined above.
The term “alkenyl” as used herein refers to a linear, branched, or cyclic hydrocarbon group of 2 to about 24 carbon atoms containing at least one double bond, such as ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, octenyl, decenyl, tetradecenyl, hexadecenyl, eicosenyl, tetracosenyl, and the like. Preferred alkenyl groups herein contain 2 to about 12 carbon atoms. The term “lower alkenyl” intends an alkenyl group of 2 to 6 carbon atoms, and the specific term “cycloalkenyl” intends a cyclic alkenyl group, preferably having 5 to 8 carbon atoms. The term “substituted alkenyl” refers to alkenyl substituted with one or more substituent groups, and the terms “heteroatom-containing alkenyl” and “heteroalkenyl” refer to alkenyl in which at least one carbon atom is replaced with a heteroatom. If not otherwise indicated, the terms “alkenyl” and “lower alkenyl” include linear, branched, cyclic, unsubstituted, substituted, and/or heteroatom-containing alkenyl and lower alkenyl, respectively.
The term “alkenylene” as used herein refers to a difunctional linear, branched, or cyclic alkenyl group, where “alkenyl” is as defined above.
The term “alkynyl” as used herein refers to a linear or branched hydrocarbon group of 2 to about 24 carbon atoms containing at least one triple bond, such as ethynyl, n-propynyl, and the like. Preferred alkynyl groups herein contain 2 to about 12 carbon atoms. The term “lower alkynyl” intends an alkynyl group of 2 to 6 carbon atoms. The term “substituted alkynyl” refers to alkynyl substituted with one or more substituent groups, and the terms “heteroatom-containing alkynyl” and “heteroalkynyl” refer to alkynyl in which at least one carbon atom is replaced with a heteroatom. If not otherwise indicated, the terms “alkynyl” and “lower alkynyl” include linear, branched, unsubstituted, substituted, and/or heteroatom-containing alkynyl and lower alkynyl, respectively.
The term “alkynylene” as used herein refers to a difunctional alkynyl group, where “alkynyl” is as defined above.
The term “alkoxy” as used herein intends an alkyl group bound through a single, terminal ether linkage; that is, an “alkoxy” group may be represented as —O-alkyl where alkyl is as defined above. A “lower alkoxy” group intends an alkoxy group containing 1 to 6 carbon atoms. Analogously, “alkenyloxy” and “lower alkenyloxy” respectively refer to an alkenyl and lower alkenyl group bound through a single, terminal ether linkage, and “alkynyloxy” and “lower alkynyloxy” respectively refer to an alkynyl and lower alkynyl group bound through a single, terminal ether linkage.
The term “aryl” as used herein, and unless otherwise specified, refers to an aromatic substituent containing a single aromatic ring or multiple aromatic rings that are fused together, directly linked, or indirectly linked (such that the different aromatic rings are bound to a common group such as a methylene or ethylene moiety). Preferred aryl groups contain 5 to 24 carbon atoms, and particularly preferred aryl groups contain 5 to 14 carbon atoms. Exemplary aryl groups contain one aromatic ring or two fused or linked aromatic rings, e.g., phenyl, naphthyl, biphenyl, diphenylether, diphenylamine, benzophenone, and the like. “Substituted aryl” refers to an aryl moiety substituted with one or more substituent groups, and the terms “heteroatom-containing aryl” and “heteroaryl” refer to aryl substituents in which at least one carbon atom is replaced with a heteroatom, as will be described in further detail infra.
The term “aryloxy” as used herein refers to an aryl group bound through a single, terminal ether linkage, wherein “aryl” is as defined above. An “aryloxy” group may be represented as —O-aryl where aryl is as defined above. Preferred aryloxy groups contain 5 to 24 carbon atoms, and particularly preferred aryloxy groups contain 5 to 14 carbon atoms. Examples of aryloxy groups include, without limitation, phenoxy, o-halo-phenoxy, m-halo-phenoxy, p-halo-phenoxy, o-methoxy-phenoxy, m-methoxy-phenoxy, p-methoxy-phenoxy, 2,4-dimethoxy-phenoxy, 3,4,5-trimethoxy-phenoxy, and the like.
The term “alkaryl” refers to an aryl group with an alkyl substituent, and the term “aralkyl” refers to an alkyl group with an aryl substituent, wherein “aryl” and “alkyl” are as defined above. Preferred alkaryl and aralkyl groups contain 6 to 24 carbon atoms, and particularly preferred alkaryl and aralkyl groups contain 6 to 16 carbon atoms. Alkaryl groups include, for example, p-methylphenyl, 2,4-dimethylphenyl, p-cyclohexylphenyl, 2,7-dimethylnaphthyl, 7-cyclooctylnaphthyl, 3-ethyl-cyclopenta-1,4-diene, and the like. Examples of aralkyl groups include, without limitation, benzyl, 2-phenyl-ethyl, 3-phenyl-propyl, 4-phenyl-butyl, 5-phenyl-pentyl, 4-phenylcyclohexyl, 4-benzylcyclohexyl, 4-phenylcyclohexylmethyl, 4-benzylcyclohexylmethyl, and the like. The terms “alkaryloxy” and “aralkyloxy” refer to substituents of the formula —OR wherein R is alkaryl or aralkyl, respectively, as just defined.
The term “acyl” refers to substituents having the formula —(CO)-alkyl, —(CO)-aryl, or —(CO)-aralkyl, and the term “acyloxy” refers to substituents having the formula —O(CO)-alkyl, —O(CO)-aryl, or —O(CO)-aralkyl, wherein “alkyl,” “aryl, and “aralkyl” are as defined above.
The terms “cyclic” and “ring” refer to alicyclic or aromatic groups that may or may not be substituted and/or heteroatom containing, and that may be monocyclic, bicyclic, or polycyclic. The term “alicyclic” is used in the conventional sense to refer to an aliphatic cyclic moiety, as opposed to an aromatic cyclic moiety, and may be monocyclic, bicyclic or polycyclic.
The terms “halo” and “halogen” are used in the conventional sense to refer to a chloro, bromo, fluoro or iodo substituent.
“Hydrocarbyl” refers to univalent hydrocarbyl radicals containing 1 to about 30 carbon atoms, preferably 1 to about 24 carbon atoms, most preferably 1 to about 12 carbon atoms, including linear, branched, cyclic, saturated and unsaturated species, such as alkyl groups, alkenyl groups, aryl groups, and the like. The term “lower hydrocarbyl” intends a hydrocarbyl group of 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and the term “hydrocarbylene” intends a divalent hydrocarbyl moiety containing 1 to about 30 carbon atoms, preferably 1 to about 24 carbon atoms, most preferably 1 to about 12 carbon atoms, including linear, branched, cyclic, saturated and unsaturated species. The term “lower hydrocarbylene” intends a hydrocarbylene group of 1 to 6 carbon atoms. “Substituted hydrocarbyl” refers to hydrocarbyl substituted with one or more substituent groups, and the terms “heteroatom-containing hydrocarbyl” and “heterohydrocarbyl” refer to hydrocarbyl in which at least one carbon atom is replaced with a heteroatom. Similarly, “substituted hydrocarbylene” refers to hydrocarbylene substituted with one or more substituent groups, and the terms “heteroatom-containing hydrocarbylene” and heterohydrocarbylene” refer to hydrocarbylene in which at least one carbon atom is replaced with a heteroatom. Unless otherwise indicated, the term “hydrocarbyl” and “hydrocarbylene” are to be interpreted as including substituted and/or heteroatom-containing hydrocarbyl and hydrocarbylene moieties, respectively.
The term “heteroatom-containing” as in a “heteroatom-containing hydrocarbyl group” refers to a hydrocarbon molecule or a hydrocarbyl molecular fragment in which one or more carbon atoms is replaced with an atom other than carbon, e.g., nitrogen, oxygen, sulfur, phosphorus or silicon, typically nitrogen, oxygen or sulfur. Similarly, the term “heteroalkyl” refers to an alkyl substituent that is heteroatom-containing, the term “heterocyclic” refers to a cyclic substituent that is heteroatom-containing, the terms “heteroaryl” and “heteroaromatic” respectively refer to “aryl” and “aromatic” substituents that are heteroatom-containing, and the like. It should be noted that a “heterocyclic” group or compound may or may not be aromatic, and further that “heterocycles” may be monocyclic, bicyclic, or polycyclic as described above with respect to the term “aryl.” Examples of heteroalkyl groups include alkoxyaryl, alkylsulfanyl-substituted alkyl, N-alkylated amino alkyl, and the like. Examples of heteroaryl substituents include pyrrolyl, pyrrolidinyl, pyridinyl, quinolinyl, indolyl, pyrimidinyl, imidazolyl, 1,2,4-triazolyl, tetrazolyl, etc., and examples of heteroatom-containing alicyclic groups are pyrrolidino, morpholino, piperazino, piperidino, etc.
The term “heterocyclic carbene” refers to a neutral electron donor ligand comprising a carbene molecule, where the carbenic carbon atom is contained within a cyclic structure and where the cyclic structure also contains at least one heteroatom. Examples of heterocylic carbenes include “N-heterocyclic carbenes” wherein the heteroatom is nitrogen and “P-heterocyclic carbenes” wherein the heteroatom is phosphorus.
By “substituted” as in “substituted hydrocarbyl,” “substituted alkyl,” “substituted aryl,” and the like, as alluded to in some of the aforementioned definitions, is meant that in the hydrocarbyl, alkyl, aryl, or other moiety, at least one hydrogen atom bound to a carbon (or other) atom is replaced with one or more non-hydrogen substituents. Examples of such substituents include, without limitation: functional groups referred to herein as “Fn,” such as halo, hydroxyl, sulfhydryl, C1-C24 alkoxy, C2-C24 alkenyloxy, C2-C24 alkynyloxy, C5-C24 aryloxy, C6-C24 aralkyloxy, C6-C24 alkaryloxy, acyl (including C2-C24 alkylcarbonyl (—CO-alkyl) and C6-C24 arylcarbonyl (—CO-aryl)), acyloxy (—O-acyl, including C2-C24 alkylcarbonyloxy (—O—CO-alkyl) and C6-C24 arylcarbonyloxy (—O—CO-aryl)), C2-C24 alkoxycarbonyl (—(CO)—O-alkyl), C6-C24 aryloxycarbonyl (—(CO)—O-aryl), halocarbonyl (—CO)—X where X is halo), C2-C24 alkylcarbonato (—O—(CO)—O-alkyl), C6-C24 arylcarbonato (—O—(CO)—O-aryl), carboxy (—COOH), carboxylato (—COO−), carbamoyl (—(CO)—NH2), mono-(C1-C24 alkyl)-substituted carbamoyl (—(CO)—NH(C1-C24 alkyl)), di-(C1-C24 alkyl)-substituted carbamoyl (—(CO)—N(C1-C24 alkyl)2), mono-(C5-C24 aryl)-substituted carbamoyl (—(CO)—NH-aryl), di-(C5-C24 aryl)-substituted carbamoyl (—(CO)—N(C5-C24 aryl)2), di-N—(C1-C24 alkyl), N—(C5-C24 aryl)-substituted carbamoyl, thiocarbamoyl (—(CS)—NH2), mono-(C1-C24 alkyl)-substituted thiocarbamoyl (—(CO)—NH(C1-C24 alkyl)), di-(C1-C24 alkyl)-substituted thiocarbamoyl (—(CO)—N(C1-C24 alkyl)2), mono-(C5-C24 aryl)-substituted thiocarbamoyl (—(CO)—NH-aryl), di-(C5-C24 aryl)-substituted thiocarbamoyl (—(CO)—N(C5-C24 aryl)2), di-N—(C1-C24 alkyl), N—(C5-C24 aryl)-substituted thiocarbamoyl, carbamido (—NH—(CO)—NH2), cyano (—C≡N), cyanato (—O—C≡N), thiocyanato (—S—C≡N), formyl (—(CO)—H), thioformyl (—(CS)—H), amino (—NH2), mono-(C1-C24 alkyl)-substituted amino, di-(C1-C24 alkyl)-substituted amino, mono-(C5-C24 aryl)-substituted amino, di-(C5-C24 aryl)-substituted amino, C2-C24 alkylamido (—NH—(CO)-alkyl), C6-C24 arylamido (—NH—(CO)-aryl), imino (—CR═NH where R=hydrogen, C1-C24 alkyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), C2-C20 alkylimino (—CR═N(alkyl), where R=hydrogen, C1-C24 alkyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), arylimino (—CR═N(aryl), where R=hydrogen, C1-C20 alkyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), nitro (—NO2), nitroso (—NO), sulfo (—SO2—OH), sulfonato (—SO2—O−), C1-C24 alkylsulfanyl (—S-alkyl; also termed “alkylthio”), C5-C24 arylsulfanyl (—S-aryl; also termed “arylthio”), C1-C24 alkylsulfinyl (—(SO)-alkyl), C5-C24 arylsulfinyl (—(SO)-aryl), C1-C24 alkylsulfonyl (—SO2-alkyl), C5-C24 arylsulfonyl (—SO2-aryl), boryl (—BH2), borono (—B(OH)2), boronato (—B(OR)2 where R is alkyl or other hydrocarbyl), phosphono (—P(O)(OH)2), phosphonato (—P(O)(O−)2), phosphinato (—P(O)(O−)), phospho (—PO2), phosphino (—PH2), silyl (—SiR3 wherein R is hydrogen or hydrocarbyl), and silyloxy (—O-silyl); and the hydrocarbyl moieties C1-C24 alkyl (preferably C1-C12 alkyl, more preferably C1-C6 alkyl), C2-C24 alkenyl (preferably C2-C12 alkenyl, more preferably C2-C6 alkenyl), C2-C24 alkynyl (preferably C2-C12 alkynyl, more preferably C2-C6 alkynyl), C5-C24 aryl (preferably C5-C14 aryl), C6-C24 alkaryl (preferably C6-C16 alkaryl), and C6-C24 aralkyl (preferably C6-C16 aralkyl).
In addition, the aforementioned functional groups may, if a particular group permits, be further substituted with one or more additional functional groups or with one or more hydrocarbyl moieties such as those specifically enumerated above. Analogously, the above-mentioned hydrocarbyl moieties may be further substituted with one or more functional groups or additional hydrocarbyl moieties such as those specifically enumerated.
“Optional” or “optionally” means that the subsequently described circumstance may or may not occur, so that the description includes instances where the circumstance occurs and instances where it does not. For example, the phrase “optionally substituted” means that a non-hydrogen substituent may or may not be present on a given atom, and, thus, the description includes structures wherein a non-hydrogen substituent is present and structures wherein a non-hydrogen substituent is not present.
In the molecular structures herein, the use of bold and dashed lines to denote particular conformation of groups follows the IUPAC convention. A bond indicated by a broken line indicates that the group in question is below the general plane of the molecule as drawn, and a bond indicated by a bold line indicates that the group at the position in question is above the general plane of the molecule as drawn.
Hydrogenated Natural Oil-Based Wax
As disclosed here, hybrid wax compositions comprise a hydrogenated natural oil-based wax. Natural oils include, for example, vegetable oils and animal fats. Representative examples of vegetable oils include canola oil, jatropha oil, rapeseed oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, safflower oil, sesame oil, soybean oil, sunflower oil, linseed oil, palm kernel oil, tung oil, castor oil, and the like. Of these, soybean oil, canola oil, rapeseed, palm, and jatropha are preferred. Soybean oil is most preferred. Representative examples of useful animal fats include lard, tallow, chicken fat (yellow grease), and fish oil. Natural oils derived from algae also may be used.
In accordance with the invention, the natural oil is hydrogenated to modify the physical properties of the oil such that it forms a wax. Representative techniques for hydrogenating natural oils are known in the art. For example, hydrogenation of certain vegetable oils is reported in Chapter 11 of Bailey, A. E.; Baileys Industrial Oil and Fat Products; Volume 2: Edible Oil & Fat Products: Oils and Oil Seeds; 5th Edition (1996) edited by Y. H. Hui (ISBN 0-471-59426-1).
The hydrogenated natural oil-based waxes may be fully hydrogenated or partially hydrogenated. In an exemplary embodiment, the hydrogenated natural oil-based wax is fully hydrogenated, refined, bleached, and deodorized soybean oil (i.e., fully hydrogenated RBD soybean oil). Suitable fully hydrogenated RBD soybean oil can be obtained commercially from Cargill, Incorporated. (Minneapolis, Minn.).
In some embodiments, the hybrid wax may comprise a mixture of two or more natural oil-based waxes. For example, in some embodiments, the hydrogenated natural oil may comprise a mixture of fully hydrogenated soybean oil and partially hydrogenated soybean oil.
In many embodiments, the hydrogenated natural oil-based wax is present in the hybrid wax in an amount ranging from about 50% to about 99% wax weight of the hybrid wax composition. By “wax weight” it is meant that the weight percentage is calculated on the basis of the wax component only, and is exclusive of additives such as fragrance, colorants, anti-oxidants, UV stabilizers, oxidizers, and the like. Preferably, the hydrogenated natural oil-based wax is present in the hybrid wax in an amount ranging from about 50% to about 65% wax weight.
Paraffin Wax
The candle wax compositions described here include a paraffin wax. The paraffin wax is chosen to provide the wax composition of the invention with a desirable balance of properties. The paraffin wax is present in the composition at less than about 50% wax weight of the wax composition.
Generally, paraffin wax comprises primarily straight chain hydrocarbons having carbon chain lengths that range from about C20 to about C40, with the remainder of the wax comprising isoalkanes and cycloalkanes. Useful paraffin waxes are characterized by having a relatively narrow distribution of hydrocarbon carbon chain lengths. Preferably, the paraffin waxes useful in the hybrid wax compositions described here are characterized by having a relatively narrow distribution of predominantly straight chain hydrocarbons. In many embodiments, the paraffin wax has a hydrocarbon chain length distribution that is centered (i.e., has a maximum content) at about C25 to C29. That is, the maximum weight percentage of hydrocarbon in the paraffin wax has a carbon chain length that ranges from C25 to C29.
For example, in many embodiments, about 52% or greater of the hydrocarbons in the paraffin wax have carbon chain lengths that range from C25 to C29. In other embodiments, about 65% or greater of the hydrocarbons in the paraffin wax have carbon chain lengths ranging from about C25 to C29. In exemplary embodiments, about 70% or greater of the hydrocarbons in the paraffin wax have chain lengths ranging from about C25 to C29. In some embodiments, some of the paraffin wax has a hydrocarbon carbon chain length distribution that is centered at C25 to C27. For example,
Useful paraffin waxes also are characterized by having two distinct endotherms of melting as shown by differential scanning calorimetry (DSC); a dominant endotherm in the temperature range 46-62° C. and a minor endotherm of melting in the range 25-45° C., preferably in the range of 30-45° C. This minor endotherm also is present in the blended hybrid wax. It is believed that the lower melting endotherms may be the result of a percentage of branched hydrocarbon species being present in the paraffin wax, and the melting range is influenced by their molecular weight and specific branching structure. In some embodiments, about 15% or less of the hydrocarbons in the paraffin wax is branched. In other embodiments, about 10% or less of the hydrocarbons in the paraffin wax is branched. For example, about 7% to about 10% of the hydrocarbons in the paraffin wax may be branched.
The lower temperature melting peak is considered advantageous for improving the bulk strength of compressed prills of the hybrid wax compositions, particularly at relative densities less than 0.95. The desired fraction of the minor endotherm melting below 45° C. is about 10% of the hybrid wax. A significantly higher fraction of paraffin wax melting below 45° C. may impact the ability to pass the slump test of the compressed candle made from the hybrid wax formulations.
The melting point of the paraffin wax typically ranges from about 130° F. to about 140° F., more typically ranging from about 130° F. to 135° F., and most typically ranging from about 132° F. to 134° F. Melting point can be measured, for example, according to ASTM D87. Unless otherwise noted, the melting points referred to herein and the appended claims are determined by ASTM D87 (also referred to as the Mettler drop point).
One suitable paraffin wax is commercially available under the trade designation “PACEMAKER 37 (PM 37)” (from Citgo Petroleum Corp., Tulsa Okla.). This paraffin wax is characterized in having a melting point of about 132° F. to about 134° F. (55.55 to 56.66° C.); an oil content of about 0.50 weight % or less; a needle penetration @77° F. (25° C.) of about 14; @100° F. (37.77° C.) of about 43; and @110° F. (43.33° C.) of about 96. Another suitable paraffin wax is commercially available under the trade designation “PACEMAKER 35” (from Citgo). This paraffin wax is characterized in having a melting point of about 130° F. to about 132° F. (54.44 to 55.55° C.); an oil content of about 0.50 weight % or less; a needle penetration @77° F. (25° C.) of about 14; @100° F. (37.33° C.) of about 57; and @110° F. of about 98. Yet another paraffin wax that may be suitable is commercially available under the trade designation “PACEMAKER 42” (PM 42) (from Citgo). This paraffin wax is characterized in having a melting point of about 134° F. to about 139° F. (56.66-59.44° C.); an oil content of about 0.50 weight % or less; a needle penetration @77° F. (25° C.) of about 13; @100° F. (37.77° C.) of about 21; and @110° F. (37.77° C.) of about 58.
In many embodiments, the paraffin wax is present in the wax composition of the invention in a minor amount, for example, less than about 50% wax weight of the hybrid wax composition. In more typical embodiments, the paraffin wax is present in an amount ranging from about 20% to about 49% wax weight of the hybrid wax composition. In a preferred embodiment, the paraffin wax is present in an amount ranging from about 40% to about 49% wax weight, for example 45% wax weight.
Fat Bloom Inhibitor
Fat bloom is an undersireable phenomena that occurs frequently in wax articles that contain high levels natural oils (i.e. greater than 50% wax weight). It typically occurs in one of two modes:
The hybrid wax compositions may include a fat bloom inhibitor. The fat bloom inhibitor functions to reduce or prevent polymorphic behaviors that may lead to visual defects in the form of haze and surface whiteness. When the wax article is a compression candle, polymorphic behavior may lead to cauliflower type crystal formation that can rise out of the melt pool of the compression candle (e.g. after burning the candle and then extinguishing the flame and allowing the melt pool to re-solidify). Representative examples of fat bloom inhibitors that may be used to retard polymorphic transformation in natural oil-based wax candles include monoglycerides, diglycerides, sorbitan esters, polyglycerol polyricinoleate, lecithin, high-molecular weight paraffins (such as polyalphaolefins and microcrystalline waxes), paraffin waxes at high levels of incorporation, and other surface-active ingredients. The fat bloom inhibitor may be added to the wax composition in an amount up to about 35% weight.
Hydrogenated Metathesized Natural Oil-Based Wax
In some embodiments, the wax compositions include a hydrogenated metathesized natural oil-based wax. The hydrogenated metathesized natural oil-based wax comes from a renewable resource (a natural oil), is naturally fat bloom resistant and functions to control fat bloom in the hybrid wax. Hydrogenated metathesized natural oil-based wax is typically fat bloom resistant by itself, allowing it to be used as a bulk natural oil-based ingredient in formulations. In many embodiments, it is used at lower levels to control the fat bloom of other natural oil-based ingredients, such as hydrogenated soybean oil.
A metathesized natural oil-based wax refers to the product obtained when one or more unsaturated polyol ester ingredient(s) are subjected to a metathesis reaction. Metathesis is a catalytic reaction that involves the interchange of alkylidene units among compounds containing one or more double bonds (i.e., olefinic compounds) via the formation and cleavage of the carbon-carbon double bonds. Metathesis may occur between two of the same molecules (often referred to as self-metathesis) and/or it may occur between two different molecules (often referred to as cross-metathesis). Self-metathesis may be represented schematically as shown in Equation I.
R1—CH═CH—R2+R1—CH═CH—R2R1—CH═CH—R1+R2—CH═CH—R2 (I)
Cross-metathesis may be represented schematically as shown in Equation II.
R1—CH═CH—R2+R3—CH═CH—R4R1—CH═CH—R3+R1—CH═CH—R4+R2—CH═CH—R3+R2—CH═CH—R4+R1—CH═CH—R1+R2—CH═CH—R2+R3—CH═CH—R3+R4—CH═CH—R4 (II)
When the unsaturated polyol ester comprises molecules such that there is more than one carbon-carbon double bond in the polyol ester (i.e., a polyunsaturated polyol ester), self-metathesis results in oligomerization of the unsaturated polyol ester. The self-metathesis reaction results in the formation of metathesis dimers, metathesis trimers, and metathesis tetramers. Higher order metathesis oligomers, such as metathesis pentamers and metathesis hexamers, also may be formed by continued self-metathesis.
A metathesized natural oil can be prepared from one or more unsaturated polyol esters. As used herein, the term “unsaturated polyol ester” refers to a compound having two or more hydroxyl groups wherein at least one of the hydroxyl groups has been esterified to a fatty acid chain and wherein the resulting ester has an organic group including at least one carbon-carbon double bond. In many embodiments, the unsaturated polyol ester can be represented by the general structure (I):
In many embodiments of the invention, the unsaturated polyol ester is an unsaturated polyol ester of glycerol. Unsaturated polyol esters of glycerol have the general structure (II):
In some embodiments, R′ is a straight or branched chain hydrocarbon having about 50 or less carbon atoms (e.g., about 36 or less carbon atoms or about 26 or less carbon atoms) and at least one carbon-carbon double bond in its chain. In some embodiments, R′ is a straight or branched chain hydrocarbon having about 6 carbon atoms or greater (e.g., about 10 carbon atoms or greater or about 12 carbon atoms or greater) and at least one carbon-carbon double bond in its chain. In some embodiments, R′ may have two or more carbon-carbon double bonds in its chain. In other embodiments, R′ may have three or more double bonds in its chain. In exemplary embodiments, R′ has 17 carbon atoms and 1 to 3 carbon-carbon double bonds in its chain. Representative examples of R′ include:
—(CH2)7CH═CH—(CH2)7—CH3;
—(CH2)7CH═CH—CH2—CH═CH—(CH2)4—CH3; and
—(CH2)7CH═CH—CH2—CH═CH—CH2—CH═CH—CH2—CH3.
In some embodiments, R″ is a saturated straight or branched chain hydrocarbon having about 50 or less carbon atoms (e.g., about 36 or less carbon atoms or about 26 or less carbon atoms). In some embodiments, R″ is a saturated straight or branched chain hydrocarbon having about 6 carbon atoms or greater (e.g., about 10 carbon atoms or greater or about 12 carbon atoms or greater. In exemplary embodiments, R″ has 15 carbon atoms or 17 carbon atoms.
Sources of unsaturated polyol esters of glycerol include synthesized oils, natural oils (e.g., vegetable oils, algae oils, and animal fats), combinations of these, and the like. Representative examples of vegetable oils include canola oil, rapeseed oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, safflower oil, sesame oil, soybean oil, sunflower oil, linseed oil, palm kernel oil, tung oil, castor oil, jatropha oil, tall oil, combinations of these, and the like. Representative examples of animal fats include lard, tallow, chicken fat, yellow grease, fish oil, combinations of these, and the like.
In the preferred embodiment, the vegetable oil is soybean oil, for example, refined, bleached, and deodorized soybean oil (i.e., RBD soybean oil). Soybean oil is an unsaturated polyol ester of glycerol that typically comprises about 95% weight or greater (e.g., 99% weight or greater) triglycerides of fatty acids. Major fatty acids in the polyol esters of soybean oil include saturated fatty acids, for example, palmitic acid (hexadecanoic acid) and stearic acid (octadecanoic acid), and unsaturated fatty acids, for example, oleic acid (9-octadecenoic acid), linoleic acid (9,12-octadecadienoic acid), and linolenic acid (9,12,15-octadecatrienoic acid). Soybean oil is a highly unsaturated vegetable oil with many of the triglyceride molecules having at least two unsaturated fatty acids (i.e., a polyunsaturated triglyceride).
In exemplary embodiments, an unsaturated polyol ester is self-metathesized in the presence of a metathesis catalyst to form a metathesized composition. In many embodiments, the metathesized composition comprises one or more of: metathesis monomers, metathesis dimers, metathesis trimers, metathesis tetramers, metathesis pentamers, and higher order metathesis oligomers (e.g., metathesis hexamers).
A metathesis dimer refers to a compound formed when two unsaturated polyol ester molecules are covalently bonded to one another by a self-metathesis reaction. In many embodiments, the molecular weight of the metathesis dimer is greater than the molecular weight of the individual unsaturated polyol ester molecules from which the dimer is formed. A metathesis trimer refers to a compound formed when three unsaturated polyol ester molecules are covalently bonded together by metathesis reactions. In many embodiments, a metathesis trimer is formed by the cross-metathesis of a metathesis dimer with an unsaturated polyol ester. A metathesis tetramer refers to a compound formed when four unsaturated polyol ester molecules are covalently bonded together by metathesis reactions. In many embodiments, a metathesis tetramer is formed by the cross-metathesis of a metathesis trimer with an unsaturated polyol ester. Metathesis tetramers also may be formed, for example, by the cross-metathesis of two metathesis dimers. Higher order metathesis products also may be formed. For example, metathesis pentamers and metathesis hexamers also may be formed.
An exemplary metathesis reaction scheme is shown in
The self-metathesis reaction also results in the formation of internal olefin compounds that may be linear or cyclic.
The relative amounts of monomers, dimers, trimers, tetramers, pentamers, and higher unit oligomers may be determined by chemical analysis of the metathesized polyol ester including, for example, by liquid chromatography, specifically gel permeation chromatography (GPC). For example, the relative amount of monomers, dimers, trimers, tetramers and higher unit oligomers may be characterized, for example, in terms of “area %” or weight %. That is, an area percentage of a GPC chromatograph can be correlated to weight percentage.
In some embodiments, the metathesized unsaturated polyol ester comprises at least about 30 area % or weight % tetramers and/or other higher unit oligomers or at least about 40 area % or weight % tetramers and/or other higher unit oligomers. In some embodiments, the metathesized unsaturated polyol ester comprises no more than about 60 area % or weight % tetramers and/or other higher unit oligomers or no more than about 50 area % or weight % tetramers and/or other higher unit oligomers. In other embodiments, the metathesized unsaturated polyol ester comprises no more than about 1 area % or weight % tetramers and/or other higher unit oligomers. In some embodiments, the metathesized unsaturated polyol ester comprises at least about 5 area % or weight % dimers or at least about 15 area % or weight % dimers. In some embodiments, the metathesized unsaturated polyol ester comprises no more than about 25 area % or weight % dimers. In some of these embodiments, the metathesized unsaturated polyol ester comprises no more than about 20 area % or weight % dimers or no more than about 10 area % or weight % dimers. In some embodiments, the metathesized unsaturated polyol ester comprises at least 1 area % or weight % trimers. In some of these embodiments, the metathesized unsaturated polyol ester comprises at least about 10 area % or weight % trimers. In some embodiments, the metathesized unsaturated polyol ester comprises no more than about 20 area % or weight % trimers or no more than about 10 area % or weight % trimers. According to some of these embodiments, the metathesized unsaturated polyol ester comprises no more than 1 area % or weight % timers. However, in some embodiments, dimmers, trimers, tetramers, pentamers, and higher unit oligomers may be present at greater levels.
In some embodiments, the unsaturated polyol ester is partially hydrogenated before being metathesized. For example, the soybean oil is partially hydrogenated to achieve an iodine value (IV) of about 120 or less before subjecting the partially hydrogenated soybean oil to metathesis. In some embodiments, the hydrogenated metathesized polyol ester has an iodine value (IV) of about 100 or less, for example, about 90 or less, about 80 or less, about 70 or less, about 60 or less, about 50 or less, about 40 or less, about 30 or less, about 20 or less, about 10 or less or about 5 or less.
The self-metathesis of unsaturated polyol esters is typically conducted in the presence of a catalytically effective amount of a metathesis catalyst. The term “metathesis catalyst” includes any catalyst or catalyst system that catalyzes a metathesis reaction. Any known or future-developed metathesis catalyst may be used, alone or in combination with one or more additional catalysts. Exemplary metathesis catalysts include metal carbene catalysts based upon transition metals, for example, ruthenium, molybdenum, osmium, chromium, rhenium, and tungsten. The olefin metathesis catalyst for carrying out the cross-metathesis reactions of the disclosure is preferably a Group 8 transition metal complex having the structure of formula (Ill)
wherein any two or more of X1, X2, L1, L2, L3, R1, and R2 can be taken together to form a cyclic group, and further wherein any one or more of X1, X2, L1, L2, L3, R1, and R2 may be attached to a support.
Preferred catalysts contain Ru or Os as the Group 8 transition metal, with Ru particularly preferred.
Numerous embodiments of the catalysts useful in the reactions of the disclosure are described in more detail infra. For the sake of convenience, the catalysts are described in groups, but it should be emphasized that these groups are not meant to be limiting in any way. That is, any of the catalysts useful in the disclosure may fit the description of more than one of the groups described herein.
A first group of catalysts, then, are commonly referred to as 1st Generation Grubbs-type catalysts, and have the structure of formula (III). For the first group of catalysts, M and m are as described above, and n, X1, X2, L1, L2, L3, R1, and R2 are described as follows.
For the first group of catalysts, n is 0, and L1 and L2 are independently selected from phosphine, sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine, stibine, ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl, pyridine, substituted pyridine, imidazole, substituted imidazole, pyrazine, and thioether. Exemplary ligands are trisubstituted phosphines.
X1 and X2 are anionic ligands, and may be the same or different, or are linked together to form a cyclic group, typically although not necessarily a five- to eight-membered ring. In preferred embodiments, X1 and X2 are each independently hydrogen, halide, or one of the following groups: C1-C20 alkyl, C5-C24 aryl, C1-C20 alkoxy, C5-C24 aryloxy, C2-C20 alkoxycarbonyl, C6-C24 aryloxycarbonyl, C2-C24 acyl, C2-C24 acyloxy, C1-C20 alkylsulfonato, C5-C24 arylsulfonato, C1-C20 alkylsulfanyl, C5-C24 arylsulfanyl, C1-C20 alkylsulfinyl, or C5-C24 arylsulfinyl. Optionally, X1 and X2 may be substituted with one or more moieties selected from C1-C12 alkyl, C1-C12 alkoxy, C5-C24 aryl, and halide, which may, in turn, with the exception of halide, be further substituted with one or more groups selected from halide, C1-C6 alkyl, C1-C6 alkoxy, and phenyl. In more preferred embodiments, X1 and X2 are halide, benzoate, C2-C6 acyl, C2-C6 alkoxycarbonyl, C1-C6 alkyl, phenoxy, C1-C6 alkoxy, C1-C6 alkylsulfanyl, aryl, or C1-C6 alkylsulfonyl. In even more preferred embodiments, X1 and X2 are each halide, CF3CO2, CH3CO2, CFH2CO2, (CH3)3CO, (CF3)2(CH3)CO, (CF3)(CH3)2CO, PhO, MeO, EtO, tosylate, mesylate, or trifluoromethane-sulfonate. In the most preferred embodiments, X1 and X2 are each chloride.
R1 and R2 are independently selected from hydrogen, hydrocarbyl (e.g., C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), substituted hydrocarbyl (e.g., substituted C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), heteroatom-containing hydrocarbyl (e.g., heteroatom-containing C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), and substituted heteroatom-containing hydrocarbyl (e.g., substituted heteroatom-containing C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), and functional groups. R1 and R2 may also be linked to form a cyclic group, which may be aliphatic or aromatic, and may contain substituents and/or heteroatoms. Generally, such a cyclic group will contain 4 to 12, preferably 5, 6, 7, or 8 ring atoms.
In preferred catalysts, R1 is hydrogen and R2 is selected from C1-C20 alkyl, C2-C20 alkenyl, and C5-C24 aryl, more preferably C1-C6 alkyl, C2-C6 alkenyl, and C5-C14 aryl. Still more preferably, R2 is phenyl, vinyl, methyl, isopropyl, or t-butyl, optionally substituted with one or more moieties selected from C1-C6 alkyl, C1-C6 alkoxy, phenyl, and a functional group Fn as defined earlier herein. Most preferably, R2 is phenyl or vinyl substituted with one or more moieties selected from methyl, ethyl, chloro, bromo, iodo, fluoro, nitro, dimethylamino, methyl, methoxy, and phenyl. Optimally, R2 is phenyl or —C═C(CH3)2.
Any two or more (typically two, three, or four) of X1, X2, L1, L2, L3, R1, and R2 can be taken together to form a cyclic group, as disclosed, for example, in U.S. Pat. No. 5,312,940 to Grubbs et al. When any of X1, X2, L1, L2, L3, R1, and R2 are linked to form cyclic groups, those cyclic groups may contain 4 to 12, preferably 4, 5, 6, 7 or 8 atoms, or may comprise two or three of such rings, which may be either fused or linked. The cyclic groups may be aliphatic or aromatic, and may be heteroatom-containing and/or substituted. The cyclic group may, in some cases, form a bidentate ligand or a tridentate ligand. Examples of bidentate ligands include, but are not limited to, bisphosphines, dialkoxides, alkyldiketonates, and aryldiketonates.
A second group of catalysts, commonly referred to as 2nd Generation Grubbs-type catalysts, have the structure of formula (III), wherein L1 is a carbene ligand having the structure of formula (IV)
such that the complex may have the structure of formula (V)
X and Y are heteroatoms typically selected from N, O, S, and P. Since O and S are divalent, p is necessarily zero when X is O or S, and q is necessarily zero when Y is O or S. However, when X is N or P, then p is 1, and when Y is N or P, then q is 1. In a preferred embodiment, both X and Y are N.
Q1, Q2, Q3, and Q4 are linkers, e.g., hydrocarbylene (including substituted hydrocarbylene, heteroatom-containing hydrocarbylene, and substituted heteroatom-containing hydrocarbylene, such as substituted and/or heteroatom-containing alkylene) or —(CO)—, and w, x, y, and z are independently zero or 1, meaning that each linker is optional. Preferably, w, x, y, and z are all zero. Further, two or more substituents on adjacent atoms within Q1, Q2, Q3, and Q4 may be linked to form an additional cyclic group.
R3, R3A, R4, and R4A are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl.
In addition, any two or more of X1, X2, L1, L2, L3, R1, R2, R3, R3A, R4, and R4A can be taken together to form a cyclic group, and any one or more of X1, X2, L1, L2, L3, R1, R2, R3, R3A, R4, and R4A may be attached to a support.
Preferably, R3A and R4A are linked to form a cyclic group so that the carbene ligand is an heterocyclic carbene and preferably an N-heterocyclic carbene, such as the N-heterocylic carbene having the structure of formula (VI)
where R3 and R4 are defined above, with preferably at least one of R3 and R4, and more preferably both R3 and R4, being alicyclic or aromatic of one to about five rings, and optionally containing one or more heteroatoms and/or substituents. Q is a linker, typically a hydrocarbylene linker, including substituted hydrocarbylene, heteroatom-containing hydrocarbylene, and substituted heteroatom-containing hydrocarbylene linkers, wherein two or more substituents on adjacent atoms within Q may also be linked to form an additional cyclic structure, which may be similarly substituted to provide a fused polycyclic structure of two to about five cyclic groups. Q is often, although again not necessarily, a two-atom linkage or a three-atom linkage.
Examples of N-heterocyclic carbene ligands suitable as L1 thus include, but are not limited to, the following:
When M is ruthenium, then, the preferred complexes have the structure of formula (VII).
In a more preferred embodiment, Q is a two-atom linkage having the structure —CR11R12—CR13R14— or —CR11═CR13—, preferably —CR11R12—CR13R14—, wherein R11, R12, R13, and R14 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups. Examples of functional groups here include carboxyl, C1-C20 alkoxy, C5-C24 aryloxy, C2-C20 alkoxycarbonyl, C5-C24 alkoxycarbonyl, C2-C24 acyloxy, C1-C20 alkylthio, C5-C24 arylthio, C1-C20 alkylsulfonyl, and C1-C20 alkylsulfinyl, optionally substituted with one or more moieties selected from C1-C12 alkyl, C1-C12 alkoxy, C5-C14 aryl, hydroxyl, sulfhydryl, formyl, and halide. R11, R12, R13, and R14 are preferably independently selected from hydrogen, C1-C12 alkyl, substituted C1-C12 alkyl, C1-C12 heteroalkyl, substituted C1-C12 heteroalkyl, phenyl, and substituted phenyl. Alternatively, any two of R11, R12, R13, and R14 may be linked together to form a substituted or unsubstituted, saturated or unsaturated ring structure, e.g., a C4-C12 alicyclic group or a C5 or C6 aryl group, which may itself be substituted, e.g., with linked or fused alicyclic or aromatic groups, or with other substituents.
When R3 and R4 are aromatic, they are typically although not necessarily composed of one or two aromatic rings, which may or may not be substituted, e.g., R3 and R4 may be phenyl, substituted phenyl, biphenyl, substituted biphenyl, or the like. In one preferred embodiment, R3 and R4 are the same and are each unsubstituted phenyl or phenyl substituted with up to three substituents selected from C1-C20 alkyl, substituted C1-C20 alkyl, C1-C20 heteroalkyl, substituted C1-C20 heteroalkyl, C5-C24 aryl, substituted C5-C24 aryl, C5-C24 heteroaryl, C6-C24 aralkyl, C6-C24 alkaryl, or halide. Preferably, any substituents present are hydrogen, C1-C12 alkyl, C1-C12 alkoxy, C5-C14 aryl, substituted C5-C14 aryl, or halide. As an example, R3 and R4 are mesityl.
In a third group of catalysts having the structure of formula (III), M, m, n, X1, X2, R1, and R2 are as defined for the first group of catalysts, L1 is a strongly coordinating neutral electron donor ligand such as any of those described for the first and second groups of catalysts, and L2 and L3 are weakly coordinating neutral electron donor ligands in the form of optionally substituted heterocyclic groups. Again, n is zero or 1, such that L3 may or may not be present. Generally, in the third group of catalysts, L2 and L3 are optionally substituted five- or six-membered monocyclic groups containing 1 to 4, preferably 1 to 3, most preferably 1 to 2 heteroatoms, or are optionally substituted bicyclic or polycyclic structures composed of 2 to 5 such five- or six-membered monocyclic groups. If the heterocyclic group is substituted, it should not be substituted on a coordinating heteroatom, and any one cyclic moiety within a heterocyclic group will generally not be substituted with more than 3 substituents.
For the third group of catalysts, examples of L2 and L3 include, without limitation, heterocycles containing nitrogen, sulfur, oxygen, or a mixture thereof.
Examples of nitrogen-containing heterocycles appropriate for L2 and L3 include pyridine, bipyridine, pyridazine, pyrimidine, bipyridamine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, pyrrole, 2H-pyrrole, 3H-pyrrole, pyrazole, 2H-imidazole, 1,2,3-triazole, 1,2,4-triazole, indole, 3H-indole, 1H-isoindole, cyclopenta(b)pyridine, indazole, quinoline, bisquinoline, isoquinoline, bisisoquinoline, cinnoline, quinazoline, naphthyridine, piperidine, piperazine, pyrrolidine, pyrazolidine, quinuclidine, imidazolidine, picolylimine, purine, benzimidazole, bisimidazole, phenazine, acridine, and carbazole.
Examples of sulfur-containing heterocycles appropriate for L2 and L3 include thiophene, 1,2-dithiole, 1,3-dithiole, thiepin, benzo(b)thiophene, benzo(c)thiophene, thionaphthene, dibenzothiophene, 2H-thiopyran, 4H-thiopyran, and thioanthrene.
Examples of oxygen-containing heterocycles appropriate for L2 and L3 include 2H-pyran, 4H-pyran, 2-pyrone, 4-pyrone, 1,2-dioxin, 1,3-dioxin, oxepin, furan, 2H-1-benzopyran, coumarin, coumarone, chromene, chroman-4-one, isochromen-1-one, isochromen-3-one, xanthene, tetrahydrofuran, 1,4-dioxan, and dibenzofuran.
Examples of mixed heterocycles appropriate for L2 and L3 include isoxazole, oxazole, thiazole, isothiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,3,4-oxadiazole, 1,2,3,4-oxatriazole, 1,2,3,5-oxatriazole, 3H-1,2,3-dioxazole, 3H-1,2-oxathiole, 1,3-oxathiole, 4H-1,2-oxazine, 2H-1,3-oxazine, 1,4-oxazine, 1,2,5-oxathiazine, o-isooxazine, phenoxazine, phenothiazine, pyrano[3,4-b]pyrrole, indoxazine, benzoxazole, anthranil, and morpholine.
Preferred L2 and L3 ligands are aromatic nitrogen-containing and oxygen-containing heterocycles, and particularly preferred L2 and L3 ligands are monocyclic N-heteroaryl ligands that are optionally substituted with 1 to 3, preferably 1 or 2, substituents. Specific examples of particularly preferred L2 and L3 ligands are pyridine and substituted pyridines, such as 3-bromopyridine, 4-bromopyridine, 3,5-dibromopyridine, 2,4,6-tribromopyridine, 2,6-dibromopyridine, 3-chloropyridine, 4-chloropyridine, 3,5-dichloropyridine, 2,4,6-trichloropyridine, 2,6-dichloropyridine, 4-iodopyridine, 3,5-diiodopyridine, 3,5-dibromo-4-methylpyridine, 3,5-dichloro-4-methylpyridine, 3,5-dimethyl-4-bromopyridine, 3,5-dimethylpyridine, 4-methylpyridine, 3,5-diisopropylpyridine, 2,4,6-trimethylpyridine, 2,4,6-triisopropylpyridine, 4-(tert-butyl)pyridine, 4-phenylpyridine, 3,5-diphenylpyridine, 3,5-dichloro-4-phenylpyridine, and the like.
In general, any substituents present on L2 and/or L3 are selected from halo, C1-C20 alkyl, substituted C1-C20 alkyl, C1-C20 heteroalkyl, substituted C1-C20 heteroalkyl, C5-C24 aryl, substituted C5-C24 aryl, C5-C24 heteroaryl, substituted C5-C24 heteroaryl, C6-C24 alkaryl, substituted C6-C24 alkaryl, C6-C24 heteroalkaryl, substituted C6-C24 heteroalkaryl, C6-C24 aralkyl, substituted C6-C24 aralkyl, C6-C24 heteroaralkyl, substituted C6-C24 heteroaralkyl, and functional groups, with suitable functional groups including, without limitation, C1-C20 alkoxy, C5-C24 aryloxy, C2-C20 alkylcarbonyl, C6-C24 arylcarbonyl, C2-C20 alkylcarbonyloxy, C6-C24 arylcarbonyloxy, C2-C20 alkoxycarbonyl, C6-C24 aryloxycarbonyl, halocarbonyl, C2-C20 alkylcarbonato, C6-C24 arylcarbonato, carboxy, carboxylato, carbamoyl, mono-(C1-C20 alkyl)-substituted carbamoyl, di-(C1-C20 alkyl)-substituted carbamoyl, di-N—(C1-C20 alkyl), N—(C5-C24 aryl)-substituted carbamoyl, mono-(C5-C24 aryl)-substituted carbamoyl, di-(C6-C24 aryl)-substituted carbamoyl, thiocarbamoyl, mono-(C1-C20 alkyl)-substituted thiocarbamoyl, di-(C1-C20 alkyl)-substituted thiocarbamoyl, di-N—(C1-C20 alkyl)-N—(C6-C24 aryl)-substituted thiocarbamoyl, mono-(C6-C24 aryl)-substituted thiocarbamoyl, di-(C6-C24 aryl)-substituted thiocarbamoyl, carbamido, formyl, thioformyl, amino, mono-(C1-C20 alkyl)-substituted amino, di-(C1-C20 alkyl)-substituted amino, mono-(C5-C24 aryl)-substituted amino, di-(C5-C24 aryl)-substituted amino, di-N—(C1-C20 alkyl), N—(C5-C24 aryl)-substituted amino, C2-C20 alkylamido, C6-C24 arylamido, imino, C1-C20 alkylimino, C5-C24 arylimino, nitro, and nitroso. In addition, two adjacent substituents may be taken together to form a ring, generally a five- or six-membered alicyclic or aryl ring, optionally containing 1 to 3 heteroatoms and 1 to 3 substituents as above.
Preferred substituents on L2 and L3 include, without limitation, halo, C1-C12 alkyl, substituted C1-C12 alkyl, C1-C12 heteroalkyl, substituted C1-C12 heteroalkyl, C5-C14 aryl, substituted C5-C14 aryl, C5-C14 heteroaryl, substituted C5-C14 heteroaryl, C6-C16 alkaryl, substituted C6-C16 alkaryl, C6-C16 heteroalkaryl, substituted C6-C16 heteroalkaryl, C6-C16 aralkyl, substituted C6-C16 aralkyl, C6-C16 heteroaralkyl, substituted C6-C16 heteroaralkyl, C1-C12 alkoxy, C5-C14 aryloxy, C2-C12 alkylcarbonyl, C6-C14 arylcarbonyl, C2-C12 alkylcarbonyloxy, C6-C14 arylcarbonyloxy, C2-C12 alkoxycarbonyl, C6-C14 aryloxycarbonyl, halocarbonyl, formyl, amino, mono-(C1-C12 alkyl)-substituted amino, di-(C1-C12 alkyl)-substituted amino, mono-(C5-C14 aryl)-substituted amino, di-(C5-C14 aryl)-substituted amino, and nitro.
Of the foregoing, the most preferred substituents are halo, C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy, phenyl, substituted phenyl, formyl, N,N-diC1-C6 alkyl)amino, nitro, and nitrogen heterocycles as described above (including, for example, pyrrolidine, piperidine, piperazine, pyrazine, pyrimidine, pyridine, pyridazine, etc.).
L2 and L3 may also be taken together to form a bidentate or multidentate ligand containing two or more, generally two, coordinating heteroatoms such as N, O, S, or P, with preferred such ligands being diimine ligands of the Brookhart type. One representative bidentate ligand has the structure of formula (VIII)
In a fourth group of catalysts that have the structure of formula (III), two of the substituents are taken together to form a bidentate ligand or a tridentate ligand. Examples of bidentate ligands include, but are not limited to, bisphosphines, dialkoxides, alkyldiketonates, and aryldiketonates. Specific examples include —P(Ph)2CH2CH2P(Ph)2-, —As(Ph)2CH2CH2As(Ph2)-, —P(Ph)2CH2CH2C(CF3)2O—, binaphtholate dianions, pinacolate dianions, —P(CH3)2(CH2)2P(CH3)2—, and —OC(CH3)2(CH3)2CO—. Preferred bidentate ligands are —P(Ph)2CH2CH2P(Ph)2- and —P(CH3)2(CH2)2P(CH3)2—. Tridentate ligands include, but are not limited to, (CH3)2NCH2CH2P(Ph)CH2CH2N(CH3)2. Other preferred tridentate ligands are those in which any three of X1, X2, L1, L2, L3, R1, and R2 (e.g., X1, L1, and L2) are taken together to be cyclopentadienyl, indenyl, or fluorenyl, each optionally substituted with C2-C20 alkenyl, C2-C20 alkynyl, C1-C20 alkyl, C5-C20 aryl, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, C5-C20 aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl, or C1-C20 alkylsulfinyl, each of which may be further substituted with C1-C6 alkyl, halide, C1-C6 alkoxy or with a phenyl group optionally substituted with halide, C1-C6 alkyl, or C1-C6 alkoxy. More preferably, in compounds of this type, X, L1, and L2 are taken together to be cyclopentadienyl or indenyl, each optionally substituted with vinyl, C1-C10 alkyl, C5-C20 aryl, C1-C10 carboxylate, C2-C10 alkoxycarbonyl, C1-C10 alkoxy, or C5-C20 aryloxy, each optionally substituted with C1-C6 alkyl, halide, C1-C6 alkoxy or with a phenyl group optionally substituted with halide, C1-C6 alkyl or C1-C6 alkoxy. Most preferably, X, L1 and L2 may be taken together to be cyclopentadienyl, optionally substituted with vinyl, hydrogen, methyl, or phenyl. Tetradentate ligands include, but are not limited to O2C(CH2)2P(Ph)(CH2)2P(Ph)(CH2)2CO2, phthalocyanines, and porphyrins.
Complexes wherein L2 and R2 are linked are examples of the fourth group of catalysts, and are commonly called “Grubbs-Hoveyda” catalysts. Examples of Grubbs-Hoveyda-type catalysts include the following:
wherein L1, X1, X2, and M are as described for any of the other groups of catalysts.
In addition to the catalysts that have the structure of formula (III), as described above, other transition metal carbene complexes include, but are not limited to:
wherein: X1, X2, L1, L2, n, L3, R1, and R2 are as defined for any of the previously defined four groups of catalysts; r and s are independently zero or 1; t is an integer in the range of zero to 5;
Y is any non-coordinating anion (e.g., a halide ion, BF4−, etc.); Z1 and Z2 are independently selected from —O—, —S—, —NR2—, —PR2—, —P(═O)R2—, —P(OR2)—, —P(═O)(OR2)—, —C(═O)—, —C(═O)O—, —OC(═O)—, —OC(═O)O—, —S(═O)—, and —S(═O)2—; Z3 is any cationic moiety such as —P(R2)3+ or —N(R2)3+; and
any two or more of X1, X2, L1, L2, L3, n, Z1, Z2, Z3, R1, and R2 may be taken together to form a cyclic group, e.g., a multidentate ligand, and
wherein any one or more of X1, X2, L1, L2, n, L3, Z1, Z2, Z3, R1, and R2 may be attached to a support.
Other suitable complexes include Group 8 transition metal carbenes bearing a cationic substituent, such as are disclosed in U.S. Pat. No. 7,365,140 (Piers et al.) having the general structure (XIII):
wherein:
M is a Group 8 transition metal;
L1 and L2 are neutral electron donor ligands;
X1 and X2 are anionic ligands;
R1 is hydrogen, C1-C12 hydrocarbyl, or substituted C1-C12 hydrocarbyl;
W is an optionally substituted and/or heteroatom-containing C1-C20 hydrocarbylene linkage;
Y is a positively charged Group 15 or Group 16 element substituted with hydrogen, C1-C12 hydrocarbyl, substituted C1-C12 hydrocarbyl; heteroatom-containing C1-C12 hydrocarbyl, or substituted heteroatom-containing hydrocarbyl;
Z− is a negatively charged counterion;
m is zero or 1; and
n is zero or 1;
wherein any two or more of L1, L2, X1, X2, R1, W, and Y can be taken together to form a cyclic group.
Each of M, L1, L2, X1, and X2 in structure (XIII) may be as previously defined herein.
W is an optionally substituted and/or heteroatom-containing C1-C20 hydrocarbylene linkage, typically an optionally substituted C1-C12 alkylene linkage, e.g., —(CH2)i— where i is an integer in the range of 1 to 12 inclusive and any of the hydrogen atoms may be replaced with a non-hydrogen substituent as described earlier herein with regard to the definition of the term “substituted.” The subscript n is zero or 1, meaning that W may or may not be present. In a preferred embodiment, n is zero.
Y is a positively charged Group 15 or Group 16 element substituted with hydrogen, C1-C12 hydrocarbyl, substituted C1-C12 hydrocarbyl, heteroatom-containing C1-C12 hydrocarbyl, or substituted heteroatom-containing hydrocarbyl. Preferably, Y is a C1-C12 hydrocarbyl-substituted, positively charged Group 15 or Group 16 element. Representative Y groups include P(R2)3, P(R2)3, As(R2)3, S(R2)2, O(R2)2, where the R2 are independently selected from C1-C12 hydrocarbyl; within these, preferred Y groups are phosphines of the structure P(R2)3 wherein the R2 are independently selected from C1-C12 alkyl and aryl, and thus include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, cyclopentyl, cyclohexyl, and phenyl. Y can also be a heterocyclic group containing the positively charged Group 15 or Group 16 element. For instance, when the Group 15 or Group 16 element is nitrogen, Y may be an optionally substituted pyridinyl, pyrazinyl, or imidazolyl group.
Z− is a negatively charged counterion associated with the cationic complex, and may be virtually any anion, so long as the anion is inert with respect to the components of the complex and the reactants and reagents used in the metathesis reaction catalyzed. Preferred Z− moieties are weakly coordinating anions, such as, for instance, [B(C6F5)4]−, [BF4]−, [B(C6H6)4]−, [CF3S(O)3]−, [PF6]−, [SbF6]−, [AlCl4]−, [FSO3]−, [CB11H6Cl6]−, [CB11H6Br6]−, and [SO3F:SbF5]−. Preferred anions suitable as Z− are formula B(R15)4− where R15 is fluoro, aryl, or perfluorinated aryl, typically fluoro or perfluorinated aryl. Most preferred anions suitable as Z− are BF4− and B(C6F5)−, optimally the latter.
It should be emphasized that any two or more of X1, X2, L1, L2, R1, W, and Y can be taken together to form a cyclic group, as disclosed, for example, in U.S. Pat. No. 5,312,940 to Grubbs et al. When any of X1, X2, L1, L2, R1, W, and Y are linked to form cyclic groups, those cyclic groups may be five- or six-membered rings, or may comprise two or three five- or six-membered rings, which may be either fused or linked. The cyclic groups may be aliphatic or aromatic, and may be heteroatom-containing and/or substituted, as explained in part (I) of this section.
One group of exemplary catalysts encompassed by the structure of formula (XIII) are those wherein m and n are zero, such that the complex has the structure of formula (XIV)
Possible and preferred X1, X2, and L1 ligands are as described earlier with respect to complexes of formula (I), as are possible and preferred Y+ and Z− moieties. M is Ru or Os, preferably Ru, and R1 is hydrogen or C1-C12 alkyl, preferably hydrogen.
In formula (XIV)-type catalysts, L1 is preferably a heteroatom-containing carbene ligand having the structure of formula (XV)
such that complex (XIV) has the structure of formula (XVI)
wherein X1, X2, R1, R2, Y, and Z are as defined previously, and the remaining substituents are as follows:
Z1 and Z2 are heteroatoms typically selected from N, O, S, and P. Since O and S are divalent, j is necessarily zero when Z1 is O or S, and k is necessarily zero when Z2 is O or S. However, when Z1 is N or P, then j is 1, and when Z2 is N or P, then k is 1. In a preferred embodiment, both Z1 and Z2 are N.
Q1, Q2, Q3, and Q4 are linkers, e.g., C1-C12 hydrocarbylene, substituted C1-C12 hydrocarbylene, heteroatom-containing C1-C12 hydrocarbylene, substituted heteroatom-containing C1-C12 hydrocarbylene, or —(CO)—, and w, x, y, and z are independently zero or 1, meaning that each linker is optional. Preferably, w, x, y, and z are all zero.
R3, R3A, R4, and R4A are independently selected from hydrogen, hydrogen, C1-C20 hydrocarbyl, substituted C1-C20 hydrocarbyl, heteroatom-containing C1-C20 hydrocarbyl, and substituted heteroatom-containing C1-C20 hydrocarbyl.
Preferably, w, x, y, and z are zero, Z1 and Z1 are N, and R3A and R4A are linked to form -Q-, such that the complex has the structure of formula (XVII)
wherein R3 and R4 are defined above, with preferably at least one of R3 and R4, and more preferably both R3 and R4, being alicyclic or aromatic of one to about five rings, and optionally containing one or more heteroatoms and/or substituents. Q is a linker, typically a hydrocarbylene linker, including C1-C12 hydrocarbylene, substituted C1-C12 hydrocarbylene, heteroatom-containing C1-C12 hydrocarbylene, or substituted heteroatom-containing C1-C12 hydrocarbylene linker, wherein two or more substituents on adjacent atoms within Q may be linked to form an additional cyclic structure, which may be similarly substituted to provide a fused polycyclic structure of two to about five cyclic groups. Q is often, although not necessarily, a two-atom linkage or a three-atom linkage, e.g., —CH2—CH2—, —CH(Ph)-CH(Ph)- where Ph is phenyl; ═CR—N═, giving rise to an unsubstituted (when R═H) or substituted (R═ other than H) triazolyl group; or —CH2— SiR2—CH2— (where R is H, alkyl, alkoxy, etc.).
In a more preferred embodiment, Q is a two-atom linkage having the structure —CR8R9—CR10R11— or —CR8═CR10—, preferably —CR8R9—CR10R11—, wherein R8, R9, R10, and R11 are independently selected from hydrogen, C1-C12 hydrocarbyl, substituted C1-C12 hydrocarbyl, heteroatom-containing C1-C12 hydrocarbyl, substituted heteroatom-containing C1-C12 hydrocarbyl, and functional groups as defined in part (I) of this section. Examples of functional groups here include carboxyl. C1-C20 alkoxy, C5-C20 aryloxy, C2-C20 alkoxycarbonyl, C2-C20 alkoxycarbonyl, C2-C20 acyloxy, C1-C20 alkylthio, C5-C20 arylthio, C1-C20 alkylsulfonyl, and C1-C20 alkylsulfinyl, optionally substituted with one or more moieties selected from C1-C10 alkyl, C1-C10 alkoxy, C5-C20 aryl, hydroxyl, sulfhydryl, formyl, and halide. Alternatively, any two of R9, R9, R10, and R11 may be linked together to form a substituted or unsubstituted, saturated or unsaturated ring structure, e.g., a C4-C12 alicyclic group or a C5 or C6 aryl group, which may itself be substituted, e.g., with linked or fused alicyclic or aromatic groups, or with other substituents.
Further details concerning such formula (XIII) complexes, as well as associated preparation methods, may be obtained from U.S. Pat. No. 7,365,140.
As is understood in the field of catalysis, suitable solid supports for any of the catalysts described herein may be of synthetic, semi-synthetic, or naturally occurring materials, which may be organic or inorganic, e.g., polymeric, ceramic, or metallic. Attachment to the support will generally, although not necessarily, be covalent, and the covalent linkage may be direct or indirect, if indirect, typically through a functional group on a support surface.
Non-limiting examples of catalysts that may be used in the reactions of the disclosure include the following, some of which for convenience are identified throughout this disclosure by reference to their molecular weight:
In the foregoing molecular structures and formulae, Ph represents phenyl, Cy represents cyclohexane, Me represents methyl, nBu represents n-butyl, i-Pr represents isopropyl, py represents pyridine (coordinated through the N atom), and Mes represents mesityl (i.e., 2,4,6-trimethylphenyl).
Further examples of catalysts useful in the reactions of the present disclosure include the following: ruthenium (II) dichloro (3-methyl-1,2-butenylidene)bis(tricyclopentylphosphine) (C716); ruthenium (II) dichloro (3-methyl-1,2-butenylidene)bis(tricyclohexylphosphine) (C801); ruthenium (II) dichloro(phenylmethylene)bis(tricyclohexylphosphine) (C823); ruthenium (II) [1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(triphenylphosphine) (C830), and ruthenium (II) dichloro(vinyl phenylmethylene)bis(tricyclohexylphosphine) (C835); ruthenium (II) dichloro(tricyclohexylphosphine)(o-isopropoxyphenylmethylene) (C601), and ruthenium (II) (1,3-bis-(2,4,6,-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(bis 3-bromopyridine (C884)).
Referring to
Techniques for using the metathesis catalysts are known in the art (see, for example, U.S. Pat. Nos. 7,102,047; 6,794,534; 6,696,597; 6,414,097; 6,306,988; 5,922,863; 5,750,815; and metathesis catalysts with ligands in U.S. Publication No. 2007/0004917 A1), all incorporated by reference herein in their entireties. Metathesis catalysts as shown, for example, in
Additional exemplary metathesis catalysts include, without limitation, metal carbene complexes selected from the group consisting of molybdenum, osmium, chromium, rhenium, and tungsten. The term “complex” refers to a metal atom, such as a transition metal atom, with at least one ligand or complexing agent coordinated or bound thereto. Such a ligand typically is a Lewis base in metal carbene complexes useful for alkyne- or alkene-metathesis. Typical examples of such ligands include phosphines, halides and stabilized carbenes. Some metathesis catalysts may employ plural metals or metal co-catalysts (e.g., a catalyst comprising a tungsten halide, a tetraalkyl tin compound, and an organoaluminum compound).
An immobilized catalyst can be used for the metathesis process. An immobilized catalyst is a system comprising a catalyst and a support, the catalyst associated with the support. Exemplary associations between the catalyst and the support may occur by way of chemical bonds or weak interactions (e.g. hydrogen bonds, donor acceptor interactions) between the catalyst, or any portions thereof, and the support or any portions thereof. Support is intended to include any material suitable to support the catalyst. Typically, immobilized catalysts are solid phase catalysts that act on liquid or gas phase reactants and products. Exemplary supports are polymers, silica or alumina. Such an immobilized catalyst may be used in a flow process. An immobilized catalyst can simplify purification of products and recovery of the catalyst so that recycling the catalyst may be more convenient.
The metathesis process can be conducted under any conditions adequate to produce the desired metathesis products. For example, stoichiometry, atmosphere, solvent, temperature and pressure can be selected to produce a desired product and to minimize undesirable byproducts. The metathesis process may be conducted under an inert atmosphere. Similarly, if a reagent is supplied as a gas, an inert gaseous diluent can be used. The inert atmosphere or inert gaseous diluent typically is an inert gas, meaning that the gas does not interact with the metathesis catalyst to substantially impede catalysis. For example, particular inert gases are selected from the group consisting of helium, neon, argon, nitrogen and combinations thereof.
Similarly, if a solvent is used, the solvent chosen may be selected to be substantially inert with respect to the metathesis catalyst. For example, substantially inert solvents include, without limitation, aromatic hydrocarbons, such as benzene, toluene, xylenes, etc.; halogenated aromatic hydrocarbons, such as chlorobenzene and dichlorobenzene; aliphatic solvents, including pentane, hexane, heptane, cyclohexane, etc.; and chlorinated alkanes, such as dichloromethane, chloroform, dichloroethane, etc.
In certain embodiments, a ligand may be added to the metathesis reaction mixture. In many embodiments using a ligand, the ligand is selected to be a molecule that stabilizes the catalyst, and may thus provide an increased turnover number for the catalyst. In some cases the ligand can alter reaction selectivity and product distribution. Examples of ligands that can be used include Lewis base ligands, such as, without limitation, trialkylphosphines, for example tricyclohexylphosphine and tributyl phosphine; triarylphosphines, such as triphenylphosphine; diarylalkylphosphines, such as, diphenylcyclohexylphosphine; pyridines, such as 2,6-dimethylpyridine, 2,4,6-trimethylpyridine; as well as other Lewis basic ligands, such as phosphine oxides and phosphinites. Additives also may be present during metathesis that increase catalyst lifetime.
Any useful amount of the selected metathesis catalyst can be used in the process. For example, the molar ratio of the unsaturated polyol ester to catalyst may range from about 5:1 to about 10,000,000:1 or from about 50:1 to 500,000:1. In some embodiments, an amount of about 1 to about 10 ppm, or about 2 ppm to about 5 ppm, of the metathesis catalyst per double bond of the starting composition (i.e., on a mole/mole basis) is used.
The metathesis reaction temperature may be a rate-controlling variable where the temperature is selected to provide a desired product at an acceptable rate. The metathesis temperature may be greater than −40° C., may be greater than about −20° C., and is typically greater than about 0° C. or greater than about 20° C. Typically, the metathesis reaction temperature is less than about 150° C., typically less than about 120° C. An exemplary temperature range for the metathesis reaction ranges from about 20° C. to about 120° C.
The metathesis reaction can be run under any desired pressure. Typically, it will be desirable to maintain a total pressure that is high enough to keep the cross-metathesis reagent in solution. Therefore, as the molecular weight of the cross-metathesis reagent increases, the lower pressure range typically decreases since the boiling point of the cross-metathesis reagent increases. The total pressure may be selected to be greater than about 10 kPa, in some embodiments greater than about 30 kP, or greater than about 100 kPa. Typically, the reaction pressure is no more than about 7000 kPa, in some embodiments no more than about 3000 kPa. An exemplary pressure range for the metathesis reaction is from about 100 kPa to about 3000 kPa.
In some embodiments, the metathesis reaction is catalyzed by a system containing both a transition and a non-transition metal component. The most active and largest number of catalyst systems are derived from Group VI A transition metals, for example, tungsten and molybdenum.
In some embodiments, the unsaturated polyol ester is partially hydrogenated before it is subjected to the metathesis reaction. Partial hydrogenation of the unsaturated polyol ester reduces the number of double bonds that are available for in the subsequent metathesis reaction. In some embodiments, the unsaturated polyol ester is metathesized to form a metathesized unsaturated polyol ester, and the metathesized unsaturated polyol ester is then hydrogenated (e.g., partially or fully hydrogenated) to form a hydrogenated metathesized unsaturated polyol ester.
Hydrogenation may be conducted according to any known method for hydrogenating double bond-containing compounds such as vegetable oils. In some embodiments, the unsaturated polyol ester or metathesized unsaturated polyol ester is hydrogenated in the presence of a nickel catalyst that has been chemically reduced with hydrogen to an active state. Commercial examples of supported nickel hydrogenation catalysts include those available under the trade designations “NYSOFACT”, “NYSOSEL”, and “NI 5248 D” (from Englehard Corporation, Iselin, N.H.). Additional supported nickel hydrogenation catalysts include those commercially available under the trade designations “PRICAT 9910”, “PRICAT 9920”, “PRICAT 9908”, “PRICAT 9936” (from Johnson Matthey Catalysts, Ward Hill, Mass.).
The hydrogenation catalyst may comprise, for example, nickel, copper, palladium, platinum, molybdenum, iron, ruthenium, osmium, rhodium, or iridium. Combinations of metals also may be used. Useful catalyst may be heterogeneous or homogeneous. In some embodiments, the catalysts are supported nickel or sponge nickel type catalysts.
In some embodiments, the hydrogenation catalyst comprises nickel that has been chemically reduced with hydrogen to an active state (i.e., reduced nickel) provided on a support. The support may comprise porous silica (e.g., kieselguhr, infusorial, diatomaceous, or siliceous earth) or alumina. The catalysts are characterized by a high nickel surface area per gram of nickel.
The particles of supported nickel catalyst may be dispersed in a protective medium comprising hardened triacylglyceride, edible oil, or tallow. In an exemplary embodiment, the supported nickel catalyst is dispersed in the protective medium at a level of about 22 weight % nickel.
The supported nickel catalysts may be of the type descibed in U.S. Pat. No. 3,351,566 (Taylor et al.), and incorporated by reference herein. These catalysts comprise solid nickel-silica having a stabilized high nickel surface area of 45 to 60 sq. meters per gram and a total surface area of 225 to 300 sq. meters per gram. The catalysts are prepared by precipitating the nickel and silicate ions from solution such as nickel hydrosilicate onto porous silica particles in such proportions that the activated catalyst contains 25 weight % to 50 weight % nickel and a total silica content of 30 weight % to 90 weight %. The particles are activated by calcining in air at 600° F. to 900° F., then reducing with hydrogen.
Useful catalysts having a high nickel content are described in EP 0 168 091 (incorporated by reference herein), wherein the catalyst is made by precipitation of a nickel compound. A soluble aluminum compound is added to the slurry of the precipitated nickel compound while the precipitate is maturing. After reduction of the resultant catalyst precursor, the reduced catalyst typically has a nickel surface area of the order of 90 to 150 sq. m per gram of total nickel. The catalysts have a nickel/aluminum atomic ratio in the range of 2 to 10 and have a total nickel content of more than about 66 weight %.
Useful high activity nickel/alumina/silica catalysts are described in EP 0 167 201 (incorporated by reference herein). The reduced catalysts have a high nickel surface area per gram of total nickel in the catalyst. Useful nickel/silica hydrogenation catalysts are described in U.S. Pat. No. 6,846,772. The catalysts are produced by heating a slurry of particulate silica (e.g. kieselguhr) in an aqueous nickel amine carbonate solution for a total period of at least 200 minutes at a pH above 7.5, followed by filtration, washing, drying, and optionally calcination. The nickel/silica hydrogenation catalysts are reported to have improved filtration properties. U.S. Pat. No. 4,490,480 reports high surface area nickel/alumina hydrogenation catalysts having a total nickel content of 5% to 40% weight.
Commercial examples of supported nickel hydrogenation catalysts include those available under the trade designations “NYSOFACT”, “NYSOSEL”, and “NI 5248 D” (from Englehard Corporation, Iselin, N.H.). Additional supported nickel hydrogenation catalysts include those commercially available under the trade designations “PRICAT 9910”, “PRICAT 9920”, “PRICAT 9908”, “PRICAT 9936” (from Johnson Matthey Catalysts, Ward Hill, Mass.).
Hydrogenation may be carried out in a batch or in a continuous process and may be partial hydrogenation or complete hydrogenation. In a representative batch process, a vacuum is pulled on the headspace of a stirred reaction vessel and the reaction vessel is charged with the material to be hydrogenated (e.g., RBD soybean oil or metathesized RBD soybean oil). The material is then heated to a desired temperature. Typically, the temperature ranges from about 50° C. to 350° C., for example, about 100° C. to 300° C. or about 150° C. to 250° C. The desired temperature may vary, for example, with hydrogen gas pressure. Typically, a higher gas pressure will require a lower temperature. In a separate container, the hydrogenation catalyst is weighed into a mixing vessel and is slurried in a small amount of the material to be hydrogenated (e.g., RBD soybean oil or metathesized RBD soybean oil). When the material to be hydrogenated reaches the desired temperature, the slurry of hydrogenation catalyst is added to the reaction vessel. Hydrogen gas is then pumped into the reaction vessel to achieve a desired pressure of H2 gas. Typically, the H2 gas pressure ranges from about 15 to 3000 psig, for example, about 15 psig to 90 psig. As the gas pressure increases, more specialized high-pressure processing equipment may be required. Under these conditions the hydrogenation reaction begins and the temperature is allowed to increase to the desired hydrogenation temperature (e.g., about 120° C. to 200° C.) where it is maintained by cooling the reaction mass, for example, with cooling coils. When the desired degree of hydrogenation is reached, the reaction mass is cooled to the desired filtration temperature.
The amount of hydrogenation catalyst is typically selected in view of a number of factors including, for example, the type of hydrogenation catalyst used, the amount of hydrogenation catalyst used, the degree of unsaturation in the material to be hydrogenated, the desired rate of hydrogenation, the desired degree of hydrogenation (e.g., as measure by iodine value (IV)), the purity of the reagent, and the H2 gas pressure. In some embodiments, the hydrogenation catalyst is used in an amount of about 10 weight % or less, for example, about 5 weight % or less or about 1 weight % or less.
After hydrogenation, the hydrogenation catalyst may be removed from the hydrogenated product using known techniques, for example, by filtration. In some embodiments, the hydrogenation catalyst is removed using a plate and frame filter such as those commercially available from Sparkler Filters, Inc., Conroe Tex. In some embodiments, the filtration is performed with the assistance of pressure or a vacuum. In order to improve filtering performance, a filter aid may be used. A filter aid may be added to the metathesized product directly or it may be applied to the filter. Representative examples of filtering aids include diatomaceous earth, silica, alumina, and carbon. Typically, the filtering aid is used in an amount of about 10 weight % or less, for example, about 5 weight % or less or about 1 weight % or less. Other filtering techniques and filtering aids also may be employed to remove the used hydrogenation catalyst. In other embodiments the hydrogenation catalyst is removed using centrifugation followed by decantation of the product.
When present, the hydrogenated metathesized natural oil-based wax is typically present in a minor amount as compared to the hydrogenated natural oil-based wax. For example, the hydrogenated metathesized natural oil-based wax is typically present in an amount ranging from about 5% to about 80% wax weight of the hybrid wax composition, more typically from about 5% to about 30% wax weight. In many embodiments, the ratio of hydrogenated vegetable oil wax to hydrogenated metathesized natural oil-based wax ranges from about 10:1 to about 1:2.
Wax Prillinq
Hybrid wax compositions of the invention are often prilled to form prilled waxes that comprise a plurality of typically spherical and/or flat particles. Prilled wax particles of the invention may be formed conventionally by first melting a wax composition of the invention in a vat or similar vessel. Optionally, additives such as coloring agents, scenting agents, UV stabilizers, and antioxidants may be added to the melted wax composition so they become incorporated into the prilled wax. The molten wax composition is then sprayed through a nozzle and into a cooling chamber. The finely dispersed liquid solidifies as it falls through the relatively cooler air in the chamber and forms prilled wax particles that, to the naked eye, appear to be spherical and/or flat particles (i.e., flakes) about the size of a grain of sand (e.g., about 600 μm to about 2000 μm).
Prilled waxes of the invention may be formed into wax articles (e.g., candles) using compression molding techniques that are known in the art. The particles may be introduced into a mold using a gravity flow tank. The mold is typically made from steel although other material also may be used. A physical press then applies between about 400-4000 pounds per square inch of pressure at ambient room temperature (i.e., generally about 65° F. to 85° F.). The pressure may be applied from the top or the bottom of the mold or both. The formed wax article (e.g., candle) can then be pushed out or ejected from the mold. In general, candles formed by this method do not tend to have even appearing sides and may be overdipped with hot liquid wax to give the candle a smooth appearance.
Hybrid Wax Properties
In order to survive abuse that is typical during handling, it is desirable for wax articles (e.g., compression candles) to have good cohesive strength. In commercial practice, compression candles do not typically have a uniform density throughout. That is, compression candles usually have a density gradient from one portion of the candle to another. The lower density regions are often responsible for certain types of defects. For example, in uniaxial compression, it is often difficult to get the longitudinal center of a tall candle to compress to the same density as the top and/or the bottom regions of the candle. The lower density regions may be more prone to breakage by snapping actions, surface erosion, and the like. As a result, compression waxes that exhibit good cohesive strength at low relative density (e.g. at relative densities less than 0.96; in some cases less than 0.90; sometimes even below 0.87) are desired since they may resist these type of defects. A high level of cohesiveness at lower relative density also allows the production of lighter compression candles, which may potentially improve the yield per candle and, thus, reduce raw material costs.
Advantageously, in many embodiments, the hybrid wax compositions of the invention display improved cohesive strength. This allows prilled wax compositions of the invention to be compressed to form wax articles (e.g., candles) that have improved compressive strength. Hybrid wax compositions of the invention typically comprise greater than about 50% wax weight natural oil-based wax, yet compare favorably in terms of maximum crush force to pure paraffin wax compositions, when evaluated using Test Procedure 2, as defined herein.
In some embodiments, the wax articles have improved cohesive strength as compared to prior hybrid waxes, particularly where the natural-oil based content was more than 50% wax weight. Cohesive strength can be measured, for example, by crushing a wax article comprising the wax of the invention and measuring the force necessary to crush the article (i.e., maximum crush force). It is useful to report cohesive strength on a relative basis, for example, comparing the strength of a particular wax against the strength of a paraffin control. As used herein the term “paraffin control wax” refers to the paraffin compression wax that is described in detail in the Example section of the application. When both the control and the test sample are pilled on the same prilling system, this relative strength comparison is expected to be reproducible. A relative strength of 1 means that the maximum crush force of a hybrid wax article is equal to the maximum crush force of the paraffin control when both articles are measured using Test Procedure 2.
In some embodiments, the wax article has a relative strength that is equal to or greater than 0.80 as compared to the paraffin control wax when measured at a relative density of 0.93 using Test Procedure 2. In yet other embodiments, the wax article has a relative strength that is equal to or greater than 0.90 as compared to the paraffin control wax when measured at a relative density of 0.93 using Test Procedure 2. In yet other embodiments, the wax article has a relative strength that is equal to or greater than 1.0 as compared to the paraffin control wax when measured at a relative density of 0.93 using Test Procedure 2. In yet other embodiments, the wax article has a relative strength that is equal to or greater than 0.88, when measured at a relative density of 0.95 using Test Procedure 2. In yet other embodiments, the wax article has a relative strength that is equal to or greater than 0.98, when measured at a relative density of 0.95 using Test Procedure 2.
The compressive strength may be specific to the thermal history that is imparted to the wax during prilling. For example, it has been observed that compressed prills of the same composition taken from different prilling configurations may have different maximum crush force as measured by Test Procedure 2. The order ranking of different compositions max crush strength appears to remain constant even if the absolute values measured change proportionally. For this reason, a standard paraffin control is included as a comparison.
The candle wax compositions described here also may display improved de-molding characteristics. In particular, the waxes resist damage that can occur as a result of the wax sticking to the compression mold during the ejection cycle. In some instances, the ejection of the wax article (e.g., candle) may cause “tooling marks” to be imparted to the surface of the candle. Tooling marks include, for example, scars on the surface of the candle, which may give the candle an unacceptable visual appearance. In some instances, “flashing” also may be a problem with candle wax compositions that display high adhesion to a mold. “Flashing” refers to thin layers of candle wax (i.e., thin shavings) that may form when the candle is ejected from a compression mold. After ejection, the shavings may stick to the candle (e.g., by static electricity or other means) causing the candle to be covered in a film (often a white film). Although not wishing to be bound by theory, it is believed that the improved de-molding characteristics for the candle wax compositions of the present invention may be due to the cohesive strength of the hybrid wax being greater than the adhesion forces between the wax prills and the wall of the compression mold during de-molding.
One test that is useful for characterizing hybrid wax compositions for use in freestanding compression candles is the slump test. Passing the slump test indicates that candles stacked on top of each other in a hot warehouse will retain their shape. Typically, refined paraffin waxes with Mettler drop points below 144° F. (e.g., Pacemaker 45, Pacemaker 37, and Pacemaker 35 from Citgo) do not retain enough crystallinity and rigidity to pass the slump test at 120° F. (49° C.). Pure paraffin compression waxes usually contain higher-melting-point wax components in order to provide a composition that passes the slump test. Hybrid wax compositions of the invention combine natural oil-based waxes with specific paraffin waxes that, by themselves, do not pass the slump test, in order to provide a hybrid wax that passes the slump test. The slump test is described in detail in Test Procedure 5 herein and in Example 5. In many embodiments, the hybrid wax of the invention has a Mettler drop point that ranges from about 120° F. to about 160° F.
Optional Ingredients
A variety of optional ingredients may be added to the wax compositions of the invention. Examples of optional ingredients include colorants, dyes, fragrances, UV stabilizers, and anti-oxidants. A variety of pigments and dyes suitable for candle making are listed in U.S. Pat. No. 4,614,625
The colorant is an optional ingredient and is commonly made up of one or more pigments and dyes. Colorants are typically added in a quantity of about 0.001 to 2 weight % of the wax base composition. If a pigment is employed, it is typically an organic toner in the form of a fine powder suspended in a liquid medium, such as a mineral oil. It may be advantageous to use a pigment that is in the form of fine particles suspended in a vegetable oil, e.g., a natural oil derived from an oilseed source such as soybean or corn oil. The pigment is typically a finely ground, organic toner so that the wick of a candle formed eventually from pigment-covered wax particles does not clog as the wax is burned. Pigments, even in finely ground toner forms, are generally in colloidal suspension in a carrier.
Candles often are designed to appeal to the olfactory as well as the visual sense. This type of candle usually incorporates a fragrance oil in the waxy body material. As the waxy material is melted in a lighted candle, there is a release of the fragrance oil from the liquefied wax pool. The scenting agent may be an air freshener, an insect repellent or serve more than one of such functions.
The air freshener ingredient commonly is a liquid fragrance comprising one or more volatile organic compounds which are available from perfumery suppliers such IFF, Firmenich Inc., Takasago Inc., Belmay, Noville Inc., Quest Co., and Givaudan-Roure Corp. Most conventional fragrance materials are volatile essential oils. The fragrance can be a synthetically formed material, or a naturally derived oil such as oil of Bergamot, Bitter Orange, Lemon, Mandarin, Caraway, Cedar Leaf, Clove Leaf, Cedar Wood, Geranium, Lavender, Orange, Origanum, Petitgrain, White Cedar, Patchouli, Lavandin, Neroli, Rose and the like.
A wide variety of chemicals are known for perfumery such as aldehydes, ketones, esters, alcohols, terpenes, and the like. A fragrance can be relatively simple in composition, or can be a complex mixture of natural and synthetic chemical components. A typical scented oil can comprise woody/earthy bases containing exotic constituents such as sandalwood oil, civet, patchouli oil, and the like. Scented oil can have a light floral fragrance, such as rose extract or violet extract. Scented oil also can be formulated to provide desirable fruity odors, such as lime, lemon or orange.
Synthetic types of fragrance compositions either alone or in combination with natural oils such as described in U.S. Pat. Nos. 4,314,915; 4,411,829; and 4,434,306; incorporated herein by reference. Other artificial liquid fragrances include geraniol, geranyl acetate, eugenol, isoeugenol, linalool, linalyl acetate, phenethyl alcohol, methyl ethyl ketone, methylionone, isobomyl acetate, and the like. The scenting agent can also be a liquid formulation containing an insect repellent such as citronellal, or a therapeutic agent such as eucalyptus or menthol. Once the coloring and scenting agents have been formulated, the desired quantities are combined with waxy material which will be used to form the body of the candle. For example, the coloring and/or scenting agents can be added to the waxy materials in the form of pilled wax granules.
When both coloring and scenting agents are employed, it is generally preferable to combine the agents together and then add the resulting mixture to the wax. It also is possible, however, to add the agents separately to the waxy material. Having added the agent or agents to the wax, the granules are coated by agitating the wax particles and the coloring and/or scenting agents together. The agitating step commonly consists of tumbling and/or rubbing the particles and agent(s) together. Preferably, the agent or agents are distributed substantially uniformly among the particles of wax, although it is entirely possible, if desired, to have a more random pattern of distribution. The coating step may be accomplished by hand, or with the aid of mechanical tumblers and agitators when relatively large quantities of prilled wax are being colored and/or scented.
Other optional additives include but are not limited to UV stabilizers and anti-oxidants.
The following materials were used in the Examples:
The following test procedures are used in the various examples.
Test Procedure 1: Determination of Hydrocarbon Components by GC
This method determines the hydrocarbon (HC) components in candles containing paraffin by capillary gas chromatography with cool on-column injection and flame ionization detection (GC/FID). The hydrocarbon components, while themselves not needing to be derivatized, are exposed to silylation treatment using bis-(trimethylsilyl)-trifluoroacetamide+1% trimethylchlorosilane (BSTFA+1% TMCS) for the sake of other potential functional groups present that might require such conditions for proper GC introduction without risk to column disruption. Pyridine is added during derivatization and is thought to act as a catalyst by facilitating removal of active hydrogen.
This method may be done either qualitatively to determine which hydrocarbon compounds are present or quantitatively to determine the concentration of those hydrocarbons present. Heptadecane (17:0) is used as an internal standard (IS) and added via the solubilizing solvent, dichloromethane(methylene chloride).
This method incorporates the use of Theoretical Correction Factors (TCFs), which account for the differences in the detector response for all of the different hydrocarbons relative to heptadecane. The amount of each hydrocarbon is determined by comparison to the IS and multiplied by the appropriate TCF. Results are reported as total hydrocarbons on a weight percent basis.
It is useful to understand the difference (and hence the relationship) between TCF and Theoretical Response Factor (TRF) for a Flame Ionization Detector (FID). The TRF is actually the proportion (with respect to the total weight, which is the molecular weight) of the total amount of carbon atoms that are responding to the FID. Since the FID response depends on the proportion of active carbon atoms, to determine the actual weight of a hydrocarbon, the experimental measured area (or the weight) needs to be corrected. This factor is termed as TCF and it is equal to 1/TRF. The use of TCF should allow for reduced method variation compared to Empirical Correction Factors (ECFs) (if the GC system is operating properly). In essence, the standards do not need to be run to determine the RF. Thus TCFs can be used where the TCF of heptadecane is set to equal 1.000 and is the only TCF used in the calculation. In an effort to minimize and expedite processing (e.g., integrate all hydrocarbon peaks as one peak) the TCF of heptadecane was chosen since most of the other TCFs ranged from 1.0154 to 0.9939 for 6:0 to 54:0 hydrocarbons, respectively, when normalized to 17:0.
This method determines percent paraffin on a weight/weight percent basis. In order to calculate the percent detected paraffin in a given size range (say C25 to C29), the w/w % for the straight chain paraffins in that size range are summed and placed over the w/w % for the straight chain sum of the total (C6-C54) and multiplied by 100 to obtain a percent of the total paraffins detected by this method that fall in the C25 to C29 chain length window.
To determine the percent branched material a similar exercise is performed. This time the w/w % of the branched chains (minor components eluting between the straight chain paraffins) is summed and placed over the w/w % sum of both branched and straight chains over the C6-C54 range which encompasses all paraffins detected.
Test Procedure 2: Compression Testing of Wax Article
Test Procedure 2 tests the compressive strength of the wax article under compression (load to failure). The test has two parts. Part A, a constrained compression test, is used to form a compressed wax article under precisely controlled conditions. Depending on the test conditions (i.e. the physical properties of the wax composition being subjected to the test and the amount of force/pressure being applied during the text), the wax article will be produced with a certain relative density. Part B, an unconstrained compression test, takes the wax article formed in Part A and does a destructive test to measure its compressive strength. By comparing compressive strengths for samples with different wax compositions but comparable (i.e. similar) relative densities, it is possible to get a ranking of cohesive strength between different wax compositions. At the same relative density, a higher compressive strength indicates that one wax composition is more cohesive than other wax composition.
Equipment:
All testing is performed at 22° C. and 50% relative humidity. First, 10±0.1 grams of the prilled wax to be tested is weighed out and placed in a compression mold 10, such as that shown in
The compression speed is set at 5 mm/sec until a trigger force of 100 grams is reached. At this point, the speed is reduced to 0.5 mm/sec. The prills are compressed until a force of 190 Kg (695 psi) is reached. The amount of force and the psi exerted are directly proportional to each other. The force is maintained for 5 seconds (All samples are run in duplicate). A typical stress/strain curve that results from the constrained compression test is shown in
In order to obtain results that are comparable across different degrees of compression, additional compressed articles may be formed using the procedure described above at forces of 163 Kg (596 psi), 231 Kg (845 psi), and 273.4 Kg (1000 psi). These pressures span a range that is similar to that reached in industrial candle compression molding equipment. The multiple pressures are used so that relative densities in the range of interest can be attained and there need not be extrapolation of crush values and relative densities significantly outside the range of those measured. When complete, the compressed article is removed from the compression mold by inverting the mold and by applying a slow steady force to the plunger by hand.
The intrinsic density of the prill is determined using TEST PROCEDURE 3. The bulk density of the plug is then determined by measuring the height, diameter, and weight of the plug, and calculating the density of the compressed article from this data. The relative density of the plug is calculated by dividing the bulk density of the plug by the intrinsic density of the prill. For example, a 10 gram plug made up of prills with an intrinsic density of 0.9523 pressed to a volume of 10.5 mL would have a relative density of 1. If those same 10 grams of prills were compressed to 11 mL its relative density would be 0.9545.
Maximum Crush Force
Height and Maximum Crush Force Determination
This test involves the unconstrained compression of the compressed article that is formed as described above. The expelled candle plug is placed on a piece of paper under a disk that is parallel to the surface below. When the article crumbles it can be conveniently collected and disposed of. The height of the plug is determined during the crush via a 100 g trigger force (0.01 mm accuracy). This is detected when parallel plates converge to crush the plug. The height of the article is used along with the max crush force to generate subsequent plots of relative density vs. max crush force. The parallel plates converge at 5 mm/second until a 100 g trigger force is reached and at this point the rate of convergence slows to 0.5 mm·second for the act of crushing. A typical unconstrained compression curve is shown in
Article integrity as measured by this test is dependent on the degree to which the sample is compressed in constrained compression. For this reason, multiple wax samples are typically compressed to different relative densities. The article integrity tends to increase with increasing relative density. The effect of composition on article integrity can then be compared across a range of compression pressures and relative densities. Using the procedure described above, wax compositions of the invention may be compared to a control paraffin wax.
Test Procedure 3: Determination of Density or Specific Gravity of a Solid Fat or Wax Sample
Equipment/Reagents/Software
The method is used to measure the density of the most dense (i.e. those not containing air voids) particles in the solid sample. IT is a modification of AOCS Official Method Cc 10b-25 Reapproved 1997, Sampling and Analysis of Commercial Fats and Oils.
When the sample particles float on the surface or distribute in the medium solution (i.e., suspended with no particles at the bottom of the medium solution), the sample particles have the same density as the medium solution. By measuring the density of the medium solution, the density of the most dense particles can be known.
Differential scanning calorimetry, DSC, measures changes in heat flow that occurs due to phase changes such as crystal formation or melting and the glassy to rubbery transitions. It reveals melting and crystallization temperature. The enthalpy of the transitions (J/g) relate to the amount of crystallinity. All temperature and heats of fusion were calibrated with indium.
The DSC method is used to examine (a) melt profiles on heating and (b) crystallization profiles on cooling. The heating/cooling program used was as follows. First, beginning at room temperature the sample is cooled at 10° C./min to −30° C. The sample is then heated at 10° C./min from −30° C. to 90° C. The sample is then cooled at a rate of 10° C./min from 90° C. to −30° C. This is followed by a second heat cycle at where the sample is heated at 10° C./min from −30° C. to 90° C.
The percent crystallinity can be determined by using the integrated heats of fusion and dividing by the theoretical heat of fusion for a 100% polyethylene crystallinity of 290 J/g.
Test Procedure 5: Slump Test
Purpose:
The slump test is used to test the strength of a candle under heat and weight conditions. It is meant to replicate the conditions a candle could undergo while being stored or shipped.
Procedure:
3 inch by 3 inch cylindrical candles were tested as follows. First, the height and diameter of the candle is measured and recorded. Next, the candle is placed on a tray with a rigid plate placed on top of the candle. The rigid plate is designed to evenly distribute the weight across the entire top of the candle. Next a 5 pound weight is placed on top of the rigid plate. Following this, the weighted candle is placed in an oven at a temperature of 49° C. for a period of 4 hours. After the 4 hour period, the weight and plate are removed and the height and diameter are again measured and recorded. All candles are then evaluated as a pass or a fail. A candle is considered to fail the slump test if the height and/or the diameter has changed by ± 1/16 inch or more. Preferably, the wax articles of the present invention pass the slump test.
Characterization of Paraffin Control Wax:
The “paraffin control wax” used herein is a paraffin compression wax of the type that is suitable for use in forming candles by compression. A detailed chemical analysis of the paraffin control wax is provided in
The melting profile, which is provided in
Gas Chromatograph of Paraffin Control Wax
The straight chain carbon number distribution for the paraffin control wax is shown in
Wax compositions as shown in TABLE 1-1 were prepared and were used in a compression molding operation to produce wax articles. The articles were visually examined for tooling marks and flashing. The results are provided in TABLE 1-2.
As noted in TABLE 1-2, the de-molding characteristics for Example 1, a wax representative of those covered by the present invention, are improved over the de-molding characteristics of other hybrid wax compositions.
Wax compositions having the formulations listed in TABLE 2-1 were prepared and were tested for compressive strength using Test Procedure 2. The relative density for each sample was measured using Test Procedure 3. The results are graphically depicted in
Wax compositions having the formulations listed in TABLE 2-2 were prepared and were tested for compressive strength using Test Procedure 2. The relative density for each sample was measured using Test Procedure 3. The results are graphically depicted in
The curves in Example 2 demonstrate how cohesive one wax is versus another at a given relative density. At a given relative density, a wax with a higher crush force represents a wax with higher cohesive strength. The crush strength data is method specific, that is, the measured crush values are specific to the geometry, method of manufacture, and size of the samples that is tested. However, the relative trends in cohesive strength should be independent of scale and geometry for a given relative density.
Regression fits were applied to each sample set on the aforementioned plots. The regressed lines were then used to estimate values of strength at relative densities of 0.93 and 0.95. This allowed the sets to be ranked according to cohesive strength on a comparable basis.
Data for crush strength at relative densities of 0.93 and 0.95 are presented in TABLE 2-3. At 0.93, the hybrid waxes using PM37 and PM35 exhibited strengths similar to paraffin (i.e. strengths around 43,000-50,000 grams). At 0.95 relative density, the same hybrid waxes also exhibited strengths similar to paraffin (i.e., strengths around 53,000-63,000 grams). Hybrid waxes made with bio-based wax in combination with standard paraffin compression wax (PRL97) (Sample 97 in Table 2-3) performed poorly. Hybrid waxes made with high levels of PM30, PM45 or PM53 also performed noticeably worse than the paraffin benchmark.
The carbon distribution profile for various paraffin waxes and paraffin wax blends was determined using Test Procedure 1. The results are shown in
As set forth above, the paraffin waxes used in the hybrid compositions here typically have a narrow distribution of carbon chain lengths, concentrated in the range of C25-C29. As can be seen in Graph 3-2, these same examples also have a small shoulder on the gas chromatogram, in the range of C32-C35 carbon chain lengths. The size of this shoulder varies as a percentage of the total hydrocarbon content and may affect the properties (e.g. cohesive strength) of the hybrid wax. The shoulder is typically less than 10% of the hydrocarbon content, more typically less than 7%, sometimes even less than 4%.
The percent branching for certain paraffin waxes was determined using Test Procedure 1. The results are reported in TABLE 3-2. This data in the table was derived by summing the w/w % of the total paraffin over the range from C18-C54 and summing the branched paraffin over the same range. The branched w/w % is divided by the total to get the percent of branched paraffin that is detected.
Waxes were characterized using differential scanning calorimetry (DSC).
Table 4-2 was generated by making limits of integration at 25, 30, 35 45 and 55 the values listed show the percent of the enthalpy of melting that exists below that temperature limit of integration. It gives quantitative comparative values on how much of the sample is melted at a given temperature.
Candles having the wax formulations shown in TABLE 5-1 were tested according the Slump Test of Test Procedure 5. The results are shown in TABLE 5-1.
Sample candles PRL70-4, PRL71-3, PRL68-2, and PRL72-7, made in accordance with the present invention, maintained both their pre-oven height and diameter and, hence, passed the slump test. Control candle 1 lost 1/16 inch of its pre-oven height and control candle 2 lost % inch, and hence, failed the slump test.
It is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.
This application is a continuation of International Application No. PCT/US2008/067025, filed Jun. 13, 2008, which claims the benefit of U.S. Provisional Application having Ser. No. 60/934,753, filed Jun. 15, 2007, and entitled HYBRID WAX COMPOSITIONS FOR USE IN COMPRESSION MOLDED WAX ARTICLES SUCH AS CANDLES, the disclosures of which are incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20100205851 A1 | Aug 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60934753 | Jun 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2008/067025 | Jun 2008 | US |
| Child | 12637123 | US |
