Patent Application
20060100127
This invention relates to surfactants. More particularly, it relates to N,N-dialkylpolyhydroxyalkylamines, their use as surfactants, and methods for making them.
The ability to reduce the surface tension of water is of great importance in the application of water-based formulations because decreased surface tension translates to enhanced substrate wetting during use. Examples of water-based compositions requiring good wetting include coatings, inks, adhesives, fountain solutions for lithographic printing, cleaning compositions, metalworking fluids, agricultural formulations, electronics cleaning and semiconductor processing compositions, personal care products, and formulations for textile processing and oilfield applications. Surface tension reduction in water-based systems is generally achieved through the addition of surfactants, resulting in enhanced surface coverage, fewer defects, and more uniform distribution. Equilibrium surface tension (EST) is important when the system is at rest, while dynamic surface tension (DST) provides a measure of the ability of a surfactant to reduce surface tension and provide wetting under high speed application conditions.
The importance of the ability of a surfactant to achieve low surface tension at low use levels, the ability to affect foaming performance, and the surfactant's ability to provide efficient emulsification and solubilization are all of considerable industrial importance, as is well-appreciated in the art. And, although equilibrium surface tension reduction efficiency is important for some applications, other applications may require both equilibrium and dynamic surface tension reduction.
The foaming characteristics of a surfactant are also important because they can help define applications for which the surfactant might be suitable. For example, foam can be desirable for applications such as ore flotation and cleaning. On the other hand, in coatings, graphic arts and adhesive applications, foam is undesirable because it can complicate application and lead to defect formation. Thus foaming characteristics are frequently an important performance parameter.
The wide variety of applications for which surfactants are used, and the resultant variation in performance requirements, results in a need for a correspondingly large number of surfactants adapted to these various performance demands, and a need for suitable methods for making them.
In a first aspect, the invention provides compounds according to formula (I):
wherein n is an integer from 0 to 2; R1 and R2 are independently selected from the group consisting of C2-C30 linear alkyl, cyclic alkyl, branched alkyl, alkenyl, aryl, aralkyl, alkaryl, alkoxyalkyl, and dialkylaminoalkyl; and R3 is selected from the group consisting of hydrogen, α-D-glucopyranosyl, β-D-glucopyranosyl, and β-D-galactopyranosyl.
In a second aspect, the invention provides a method of making a compound according to formula (I) above. The method includes contacting an N-alkylpolyhydroxyalkylamine with a carbonyl equivalent compound selected from the group consisting of nitriles, ketones, aldehydes, acetals, and hemiacetals. The contacting is performed in the presence of hydrogen and a transition metal catalyst in a reaction solvent comprising at least 30 wt % of an organic solvent selected from the group consisting of methanol, isopropanol, tetrahydrofuran, ethylene glycol, propylene glycol, 1,2-dimethoxyethane, and mixtures of these.
In a third aspect, the invention provides a formulation containing between 0.1 and 99.9 wt % in total of one or more ingredients selected from the group consisting of surfactants and wetting agents other than according to formula (I) as shown above; solvents; alkali metal hydroxides; water-borne, water-dispersible, or water-soluble resins; flow agents; leveling agents; pigments; processing aids; defoamers; solubilizing agents; pesticides; plant growth modifying agents; water-soluble film-forming macromolecules; water-soluble alcohols, glycols, or polyols; water-soluble acids or salts thereof; tetramethylammonium hydroxide; emulsifying agents; alkanolamines; organic monoacids; biocides; chelants; detergent builders; detergent co-builders; dyes; fragrances; anti-redeposition aids; sunscreen agents; solubilizing agents; polymers; oligomers; functional cement additives; sodium chloride; sodium bromide; calcium chloride; calcium bromide; zinc chloride; zinc bromide; cesium formate; hydrochloric acid; hydrofluoric acid; acetic acid; formic acid; and water. The formulation also contains between 0.001 and 45 wt % of one or more compounds according to formula (I).
In a fourth aspect, the invention provides a fluid for drilling, completing, cementing, stimulating, fracturing, acidizing, or working over a subterranean gas or oil well, or for treating or enhancing the production of oil or gas from an oil or gas bearing formation. The fluid includes between 5 and 99.85 wt % in total of at least one of an organic liquid and water and further contains between 0.1 and 80 wt % in total of one or more ingredients selected from the group consisting of weighting agents, viscosifiers, dispersants, drilling mud base oils, emulsifiers, soluble salts, cements, proppants, mineral acids, organic acids, biocides, defoamers, demulsifiers, corrosion inhibitors, friction reducers, gas hydrate inhibitors, hydrogen sulfide removal or control additives, asphaltene control additives, paraffin control additives, and scale control additives, wherein the one or more ingredients does, not include any component of a pre- or post-preparation synthesis reaction mixture for preparation of any of the one or more compounds according to formula (I) as shown above. The fluid also contains between 0.05 and 10 wt % of one or more compounds according to formula (I).
In a fifth aspect, the invention provides a method for drilling, completing, cementing, stimulating, fracturing, acidizing, working over, or treating a subterranean well. The method includes injecting into the well a fluid containing one or more compounds according to formula (I) as shown above.
In a sixth aspect; the invention provides a method for treating a produced stream of oil or gas from an oil and gas bearing formation. The improvement includes injecting into the produced stream a fluid comprising one or more compounds according to formula (I) as shown above.
In a seventh aspect, the invention provides a formulation including:
i) a first component consisting of one or more compounds according to formula (I) as shown above; and
ii) a second component consisting of one or more materials selected from the group consisting of nonvolatile organic and nonvolatile inorganic materials and mixtures of these. The second component does not including any component of a pre- or post-preparation synthesis reaction mixture for preparation of any of the one or more compounds according to formula (I), and the formulation is fluid at 25° C.
This invention relates to N,N-dialkylpolyhydroxyalkylamines according to formula (I), and methods of making and using them.
In formula (I), n is an integer from 0 to 2, and R1 and R2 are independently selected from the group consisting of C2-C30 linear, cyclic, and branched alkyl, alkenyl, aryl, aralkyl, and alkaryl groups, or from the group consisting of C2-C30 alkoxyalkyl and dialkylaminoalkyl groups. Typically, R3═H, for example when the compound according to formula (I) is derived from a monosaccharide. The compound of formula (I) may however instead be derived from a disaccharide, in which case R3 is selected from the group consisting of α-D-glucopyranosyl, β-b-glucopyranosyl, and β-D-galactopyranosyl.
Although any of a variety of polyhydroxyalkyl groups may be incorporated in compounds according to the invention, they most typically will be derived from the open-chain forms of reducing sugars, for example glucose. Therefore, for simplicity of explanation, these compounds are exemplified herein as glucose derivatives such as may be obtained by the reaction of an N-(1-deoxyglucityl)alkylamine with an aldehyde or ketone, combined with a reduction employing a transition metal catalyst and hydrogen, as will be discussed below. Thus, exemplary glucose-derived compounds made according to the invention are of formula (I), wherein R1 and R2 are as defined above, n is 2, and R3 is hydrogen.
The N-alkylpolyhydroxyalkylamine with which a carbonyl compound (or its equivalent) is reacted can be prepared by reductive amination of a polyhydroxyalkyl compound, such as a glucose or other suitable mono- or disaccharide, with the desired amine. One way of doing this is shown in U.S. Pat. No. 5,449,770, Example 1, where glucose reacts with R1—NH2 (where R1 may for example be methyl) to give an N-alkylpolyhydroxyalkylamine according to formula (II), where n is 2 and R3 is H.
In general, the polyhydroxyalkyl groups of N-alkylpolyhydroxyalkylamines useful for making N,N-dialkylpolyhydroxyalkylamines according to the invention may be derived from any of the group of reducing sugars consisting of glucose, fructose, maltose, lactose, galactose, mannose, and xylose. Typically, the reducing sugar will be an aldose, although ketoses may also be used, and both monosaccharides and disaccharides may be used, with convenient sources of the latter including high dextrose corn syrup, high fructose corn syrup, and high maltose corn syrup. Other useful polyhydroxyalkyl groups may be derived from glyceraldehydes. In one embodiment, the polyhydroxyalkyl group is derived from glucose; i.e. the group is 1-deoxyglucityl.
The alkylamine with which the reducing sugar or other polyhydroxyalkyl group precursor is reacted may be represented by the formula R1—NH2. The group R1 is as defined above. It may contain from 2 to 30 carbon atoms, preferably from 2 to about 18 carbon atoms, and more preferably from 2 to about 14 carbon atoms. Examples of suitable alkylamines include, but are not limited to, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, n-pentylamine, isopentylamine, cyclopentylamine, n-hexylamine, cyclohexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, isooctylamine, n-decylamine, n-dodecylamine, 3-methoxypropylamine, 3-ethoxypropylamine, 3-n-propoxypropylamine, 3-isopropoxypropylamine, 3-n-hexyloxypropylamine, 3-isohexyloxypropylamine, 3-[(2-ethyl)hexyloxy]propylamine, 3-isodecyloxypropylamine, 3-isotridecyloxypropylamine, 3-dodecyloxypropylamine, 3-isododecyloxypropylamine, 3-tetradecyloxypropylamine, mixed octyloxy-decyloxypropylamines (Tomah PA-1214, available from Tomah Products, Inc. of Milton, Wis.), mixed tetradecyloxy-dodecyloxypropylamines (Tomah PA-1816), mixed dodecyloxy-tetradecyloxypropylamines (Tomah PA-1618), mixed dodecyloxy-pentadecyloxypropylamines (Tomah PA-19), mixed octadecyloxy-hexadecyloxypropylamines (Tomah PA-2220), 3-dimethylaminopropylamine, 3-diethylaminopropylamine, 3-di-n-hexylpropylamine, stearylamine, and mixtures of amines derived from natural sources such as cocoalkylamine, oleylamine, and tallowamine. More preferred amines are ethylamine, butylamine, n-hexylamine, and n-octylamine. As used herein, the meaning of “alkylamine” as used in the terms “N-(1-deoxyglucityl)alkylamine” and “N-alkylpolyhydroxyalkylamine” is to be understood to include amines where the alkyl group is either substituted or unsubstituted, non-limiting examples of which are set forth in the foregoing part of this paragraph.
The carbonyl equivalent compound with which the intermediate N-alkyl-1-(deoxyglucityl)amine of formula (II) is reacted may be an aldehyde or a ketone, represented by formula (III).
If the carbonyl equivalent compound is an aldehyde, R4 is H and R5 may be a linear, cyclic, or branched alkyl, alkoxylalkyl, dialkylaminoalkyl, alkenyl, aryl, aralkyl, or alkaryl group having from 1 to about 30 carbon atoms, preferably from about 1 to about 18 carbon atoms, and more preferably from about 1 to about 14 carbon atoms. Examples of suitable aldehydes include, but are not limited to, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexanal, cyclopentane carboxaldehyde, heptanal, cyclohexane carboxaldehyde, heptanal, octanal, nonanal, and decanal. Acetals and hemiacetals may also or instead be used in place of aldehydes, an nitriles may also be used, according to the invention. As used herein, the term “carbonyl equivalent compound” includes aldehydes, ketones, acetals, hemiacetals, and nitriles. For example, acetaldehyde dimethyl acetal and dimethylaminoacetaldehyde dimethyl acetal may be used.
If the carbonyl equivalent compound is a ketone, R4 and R5 may be independently selected from the group consisting of linear, cyclic, or branched alkyl, alkoxylalkyl, dialkylaminoalkyl, alkenyl, aryl, aralkyl, or alkaryl group having from 1 to about 30 carbon atoms, preferably from about 2 to about 18 carbon atoms, and more preferably from about 4 to about 14 carbon atoms. Examples of suitable ketones include, but are not limited to, acetone, methoxyacetone, 2-butanone, diethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, 2-octanone, 4-octanone, 2-nonanone, and 2-decanone.
Although compounds (I) of this invention may be made by reductive alkylation of an N-1-(deoxyglucityl)alkylamine with either an aldehyde or ketone, those made by reaction of the deoxyglucitylalkylamine with an aldehyde are preferred. More preferred are those derived from linear aldehydes such as acetaldehyde, butyraldehyde, valeraldehyde, or hexanal.
The preferred compounds (I) of the present invention are N-ethyl-N-pentyl-1-(deoxyglucityl)amine, N-ethyl-N-hexyl-1-(deoxyglucityl)amine, N-ethyl-N-octyl-1-(deoxyglucityl)amine, N,N-dibutyl-1-(deoxyglucityl)amine, N-butyl-N-pentyl-1-(deoxyglucityl)amine, N-butyl-N-hexyl-1-(deoxyglucityl)amine, and N-butyl-N-octyl-1-(deoxyglucityl)amine. The more preferred compounds are N-ethyl-N-hexyl-1-(deoxyglucityl)amine, N,N-dibutyl-1-(deoxyglucityl)amine, N-butyl-N-pentyl-1-(deoxyglucityl)amine, and N-butyl-N-hexyl-1-(deoxyglucityl)amine.
Preparation of Compounds of Formula (I)
In one exemplary preparative procedure, compounds according to the invention may be prepared by the reductive alkylation of an N-alkylpolyhydroxyalkylamine with an aldehyde or ketone, typically in the presence of a solvent, at a temperature sufficiently high so as to provide a convenient reaction rate and sufficiently low so as to prevent significant by-product formation. Functional equivalents of aldehydes and ketones, such as acetals/ketals (especially the dimethyl or diethyl acetals/ketals), hemiacetals/hemiketals, or nitrites may also be used. If acetals or ketals are used, it may be necessary to add a small amount of water to the reaction mixture, allow formation of the corresponding carbonyl compound. The reaction temperatures may be in the range from about 50° C. to about 175° C., typically from about 50° C. to about 150° C., and more typically from about 60° C. to about 125° C. The optimum conditions will depend upon the reactor configuration, the solvents employed, and other variables. The N-alkylpolyhydroxyalkylamines may be prepared using procedures such as those described in U.S. Pat. No. 5,449,770 to Shumate et al.
The linking of the N-alkylpolyhydroxyalkylamine with an aldehyde or ketone to form the corresponding compound (I) requires the presence of a catalyst and hydrogen. The catalyst is typically a metal chosen from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum. Typically, the catalyst is selected from the group consisting of ruthenium, rhodium, palladium, or platinum, and more typically is either palladium or platinum. To maximize productivity, the catalyst is typically dispersed on a support. Such a support may be organic, such as carbon, or inorganic. Examples of the latter class of supports include alumina, silica, titania, magnesia, zirconia, and aluminosilicates. The preferred support for the catalyst is carbon. The hydrogen pressure may be in the range from about 250 psig to 1500 psig, typically from about 500 psig to about 1250 psig, and more typically from about 750 psig to about 1100 psig.
A variety of solvents may be used in the reaction medium for the reductive alkylation of the N-alkylpolyhydroxyalkylamine. The inventors have found that the use of organic solvents for this purpose may result in suitably high reaction rates, reaction specificity, and ease of reaction mixture workup to isolate the desired product. Additionally, it has been found that reducing the concentration of water in the reaction medium may be beneficial to improving reaction rates and specificity. In many cases, however, reducing the amount of water in the reaction mixture to a sufficiently low level solely by increasing the concentration of reactants results in low solubility of starting materials and/or products, as well as excessively high reaction mixture viscosities. The latter condition may give rise to less-than-optimal heat transfer and/or hydrogen mass transfer, and thus is undesirable. The inventors have found that use of certain organic solvents in certain amounts allows such problems to be overcome or at least greatly diminished, while keeping the concentration of water sufficiently low that conversion rates and reaction specificity are good. Thus the term “reaction solvent”, as that term is used herein, may mean one or more organic solvents, either with or without admixture with water.
In many cases, it is convenient to use, as starting material, an N-alkylpolyhydroxyalkylamine that has been generated in situ in the reaction equipment in which it will subsequently be coupled with an aldehyde or ketone to form the final product. Such an in situ preparation is typically performed by reductive reaction of a mono- or disaccharide with an amine, as noted herein above, and typically involves the use of significant water in the reaction medium to provide solubility for the saccharide and/or the product. This introduces a significant amount of water into the reaction mixture for the subsequent reductive alkylation reaction. However, especially when using aldehydes or ketones that contain four or more carbon atoms in their structures, solubility in an all-aqueous medium may be poor, resulting in slow reaction rates. Fortunately, the use of a significant proportion of organic solvent for the reasons described above typically helps to solubilize the starting material, thus providing an additional benefit.
Examples of suitable organic solvents and organic solvent mixtures include, but may not be limited to, methanol, ethanol, ethylene glycol, propylene glycol, tetrahydrofuran, isopropanol, 1,2-dimethoxyethane, and mixtures thereof. The most preferred organic solvent is methanol. The reductive alkylation to form N,N-dialkylpolyhydroxyalkylamines according to the invention may be performed in any of these solvents, or mixtures thereof with water, provided that the reaction solvent comprises at least 30 wt %, preferably at least 50 wt %, more preferably at least 70 wt %, and most preferably at least 80 wt % of an organic solvent or mixture thereof. The amount of water in the reaction solvent is thereby limited accordingly. In some cases, the reaction solvent is water-free, i.e. it contains only such small amounts of water as may have been adventitiously introduced with the organic solvent.
Uses of Compounds of Formula (I)
Compositions according to the invention may also include a variety of other ingredients adapted to complement the utility of compounds of formula (I) in a number of applications. The performance properties of such products may be optimized for a specific application by appropriate modification of the structure of the amine and the choice of the substituents R1, R2, and R3. Such optimization is routine, and within the ability of the person of ordinary skill in the art in the particular application area. Thus manipulation of these variables yields compounds which may be useful as emulsifiers or detergents, wetting agents, foaming agents, defoamers, rheology modifiers or associative thickeners, dispersants, and the like. As such, these compounds may be useful in applications such as coatings, inks, adhesives, agricultural formulations, fountain solutions, photoresist strippers and developers, shampoos, and detergents and other cleaning compositions. The compounds may also find use in oil-field exploration, development, and production applications such as enhanced oil recovery, fracturing and stimulation processes, and drilling and cementing operations, and may also be useful in various wet-processing textile operations, such as dyeing of fibers and fiber scouring and kier boiling. The general formulation principles governing each of these applications are well known in the respective arts, and a detailed description of the numerous application areas and methods for incorporating the compounds of this invention into such formulations is not necessary to their effective incorporation therein. However, as an indication of the wide scope of possible uses for compounds according to the invention, exemplary but nonlimiting formulations are set forth below for a number of application areas.
The terms “water-based”, “waterborne”, “aqueous”, or “aqueous medium”, or “aqueous carrier” as used herein refer to systems in which the solvent or liquid dispersing medium comprises at least 50 wt % water, preferably at least 90 wt %, and more preferably at least 95 wt % water. The dispersing medium may consist essentially of water, i.e. it may have no added solvents, or it may also contain solvents.
In broad terms, compounds according to formula (I) may be used in a wide range of formulations that include a second component, such that the application of the second component benefits from the surface active properties provided by the formula (I) material. It is to be understood that, although components of a pre- or post-preparation synthesis reaction mixture for preparation of the compounds according to formula (I) may be present, these do not count as part of the second component for purposes of this invention. Such materials might for example include simple salts, solvents, catalysts, organic precursors, reagents, side products, and byproducts related to the preparation of the compound of formula (I), are not part of the second component. Typically, but not necessarily, the amount by weight of the second component in a formulation will be greater than that of the compound(s) of formula (I).
Formulations containing compounds according to formula (I) according to the invention are typically constructed so as to be fluid at 25° C. They are typically aqueous, but they need not be. The second component may consist of one or more materials selected from nonvolatile organic and nonvolatile inorganic materials, and mixtures of these. As used herein, the term “nonvolatile” means that the indicated material either cannot boil, or it boils at a temperature of at least 150° C. at a pressure of 760 Torr. Thus, although typical low-boiling solvents may be included in the formulation, they do not constitute a part of the second component.
Typical non-limiting examples of nonvolatile materials are given in the exemplary formulations provided hereinafter. Formulations according to the invention may include ready-to-use formulations, or concentrates. Either of these may be further diluted in use. Thus the concentration of the one or more compounds of formula (I) in a composition according to the invention may vary over a wide range. Typically it will be between 0.001 and 45 wt % of the formulation, although in some cases the amount may be as low as 0.00001 wt %. In many cases compositions at the higher end of this concentration range will be diluted during or before use in the intended application, although this is not required in all applications.
By using compounds of formula (I), it is possible to reduce surface tension in a waterborne composition or an industrial process. Thus the invention provides aqueous compositions comprising such compounds, wherein the surfactant provides good wetting properties when used in a surfactant effective amount. For example, the amount of surfactant that is effective to provide enhanced wetting properties of a water-based, organic compound containing composition may range from 0.00001 to 5 wt %, preferably from 0.0001 to 3 wt %, and most preferably from 0.001 to 3 wt %, based on total weight of the formulation. The most favorable amount will vary from one application to another, depending upon the amount and type of other species present in the formulation that are capable of affecting foam properties and wetting performance, for example latex polymers.
A typical water-based coating formulation that includes the surfactants of the invention may include the following components in an aqueous medium, typically at 30 to 80% solids:
A typical water-based ink composition that includes the surfactants of the invention may include the following components in an aqueous medium at a 20 to 60% solids content (i.e. not including the coalescing solvent):
A typical water-based agricultural composition that includes the surfactants of the invention may include the following components in an aqueous medium at 0.01 to 80% of the following ingredients:
A typical fountain solution composition for planographic printing that includes the surfactants of the invention may include the following components:
A typical hard surface cleaner that includes the surfactants of the invention may include the following components:
*To total, in combination, between 0.1 and 99 wt %.
A typical water-based photoresist developer or electronic cleaning composition that includes the surfactants of the invention may include the following components:
A typical metalworking fluid that includes the surfactants of the invention may include the following components:
Surfactants are also used in a wide variety of products in the areas of personal care and household and industrial cleaning. The surfactants of the present invention may be used in any of these formulations to provide one or more benefits, with the exact structure of the surfactant compound depending upon the specific performance features required for a particular application. Typical formulations used in these markets are described in Louis Ho Tan Tai's book, Formulating Detergents and Personal Care Products: A Complete Guide to Product Development (Champaign, Ill.: AOCS Press, 2000) as well as in other books, literature, product formularies, etc. familiar to those skilled in the art. A few representative example formulations are described here as illustrations. For example, a rinse aid for use in household-automatic dishwashing or in industrial and institutional warewashing may have the ingredients described below.
Cement admixtures may be of any of several types, including superplasticizing, plasticizing, accelerating, set retarding, air entraining, water-resisting, corrosion inhibiting, and other types. Such admixtures are used to control the workability, settling and end properties (strength, impermeability, durability and frost/deicing salt resistance, etc.) of cementitious products like concretes, mortars, etc. The admixtures are usually provided as aqueous solutions and they can, be added to the cementitious system at some point during its formulation. Surfactants of this invention may provide wetting, foam control, flow and leveling, water reduction, corrosion inhibition, high ionic strength tolerance and compatibility, and other benefits when used in such systems.
*To total, in combination, between 0.1 and 20 wt %.
Surfactants of this invention, used alone or as a component in formulations, may provide surface tension reduction, foam control, and improved wetting in a variety, of applications within the Oil and Gas industry. These may include, for example, formulations for the following uses.
In drilling applications, the surfactants may be used in formulations for dispersion of clays and drill cuttings, ROP (rate of penetration) enhancement, emulsification and de-emulsification, surface wetting and surface tension reduction, shale stabilization, and enhancement of hydration or dissolution of solid additives.
In cementing, stimulation and workover applications uses may include formulations for spacers, cement dispersion, controlled air content in cements, cement retardation, fracturing fluids, stimulation of coal bed methane, surface or interfacial tension reduction, oil/water wetting, and cleaning fluids.
In oil and gas production, uses may include rig wash formulations, defoaming of crude, water flooding/injection, defoaming for acid gas sweetening, oil/water separation, enhanced oil recovery, and inhibition or dispersion of asphaltenes, hydrates, scale and waxes.
Exemplary fluids for drilling, completing, cementing, stimulating, fracturing, acidizing, working over, or other treating of subterranean wells, or for enhancing production from an oil- or gas-bearing formation or treating the produced oil or gas, typically include from 0.05 to 10 wt % of a surfactant of this invention in a fluid containing water and/or an organic liquid, which typically constitutes from 5 to 99.85 wt % of the fluid. The organic liquid is typically a petroleum product, although it need not be, and may for example include crude oil or any of the drilling mud base oils described below. If water is included, it may be from a freshwater, sea water, or brine source, or it may be provided by inclusion of an aqueous mineral acid such as hydrochloric acid, hydrofluoric acid, sulfuric acid, etc. Fluids for such applications usually also include between 0.1 and 80 wt % in total of one or more ingredients-selected from weighting agents, viscosifiers, dispersants, drilling mud base oils, emulsifiers, soluble salts, cements, proppants, mineral acids, organic acids, biocides, defoamers, demulsifiers, corrosion inhibitors, friction reducers, gas hydrate inhibitors, hydrogen sulfide removal or control additives, asphaltene control additives, paraffin control additives, and scale control additives. A variety of specific materials are known in the art for performing these functions. Suitable nonlimiting examples of some of these materials follow, and others will be apparent to those of skill in the art.
The foregoing classes of materials may find application, when used in combination with the surfactants of this invention, in a variety of oilfield applications. Depending upon the exact application and desired effect, compositions may be injected into a well or added to the stream of oil or gas produced by the well, all according to methods well known in the art.
Typical applications, and the ingredients commonly (although not necessarily) used in making formulations for these purposes, are shown immediately below. Other ingredients may also be present. It will be understood that each of these formulations will also contain a surfactant according to the invention.
Fluids for stimulating or enhancing production from a gas or oil bearing formation, may contain ingredients similar to those found in fracturing fluids, except for proppants. Finally, fluids for treating oil or gas produced in the above ways may include one or more of biocides, defoamers, demulsifiers, corrosion inhibitors, friction reducers, gas hydrate inhibitors, hydrogen sulfide removal or control additives, asphaltene control additives, paraffin control additives, and scale control additives.
Compounds according to formula (I) may have utility in preventing or slowing the formation of gas hydrates in petroleum-bearing formations or during transport of crude petroleums, where lower hydrocarbons such as methane, ethane, propane, n-butane, and iso-butane are commonly found. Water is also typically present in such formations and, under conditions of elevated pressure and reduced temperature, mixtures of the water and lower hydrocarbons tend to form clathrate hydrates. Such hydrates are water crystals that have formed a cage structure around a guest molecule such as the lower hydrocarbon. For example, at a pressure of about 1 MPa, ethane can form gas hydrates with water at temperatures below 4° C.; at a pressure of 3 MPa, it can form gas hydrates with water at temperatures below 14° C. Temperatures and pressures such as these are commonly encountered for many environments in which natural gas and crude petroleum are produced and transported. The resulting hydrates frequently cause pipeline blockages due to growth and agglomeration of crystals inside pipes, conduits, valves, and other equipment, resulting in reduced flow and even equipment damage.
Compounds according to formula (I) may be used to reduce the nucleation, growth, and/or agglomeration of gas hydrates by including them in petroleum streams, thereby minimizing unscheduled shutdowns, maintenance and repair. The amount of compound of formula (I) used for such an application may vary over a wide range, and may depend inter alia upon the relative proportions of the various lower hydrocarbons present in the crude petroleum, the temperature and pressure conditions to which the petroleum will be exposed, and the amount of water present. An appropriate amount for any given situation can easily be determined by routine experimentation, but typically the amount will be at least about 0.05 wt % relative to the amount of water present, more typically at least about 0.1 wt %, and most typically at least about 0.3 wt %. While there need be no upper limit to the amount of compound of formula (I) used, it may be most economical to limit it to at most about 5 wt % relative to water and typically at most 2 wt % relative to water. In one embodiment of the invention, a compound of formula (I) in which n is 2, R3 is H, R1 is n-butyl, and R2 is n-pentyl is used as a gas hydrate inhibitor.
As will be appreciated in light of the foregoing discussion, the compounds of this invention may find utility in a wide variety of applications. The present invention is further illustrated by the following examples, which are presented for purposes of demonstrating, but not limiting, the methods and compositions of this invention.
Examples 1-12c illustrate a preferred process of this invention, reacting a 1-deoxy-1-(alkylamino)-D-glucitol with an aldehyde or ketone in the presence of a catalyst at elevated temperature and pressure of hydrogen. This transformation is illustrated by the following schematic equations for reaction of a 1-deoxy-1-(alkylamino)-D-glucitol with an aldehyde (where R4═H) or a ketone:
A 300 mL Autoclave Engineers stainless steel reactor was charged with 47.4 g (0.20 mole) 1-deoxy-1-(butylamino)-D-glucitol, 17.9 g (0.21 mole; 1.05 equivalent) of valeraldehyde, 1.28 g (dry weight basis) 5% palladium on carbon, and 100 g of methanol. The reactor was closed, purged with nitrogen and hydrogen, and pressurized to ca 600 psig with hydrogen. The mixture was heated with stirring (1000 rpm) to 100° C. and pressurized with hydrogen to 1000 psig. The reaction was maintained at this temperature; pressure was maintained at 1000 psig via regulated hydrogen feed. After 10 hr, the mixture was cooled to 50° C., and the product removed from the reactor by filtration through an internal 0.5 μm sintered metal element. Upon cooling, the product precipitated as a white-cream colored solid. After trimethylsilylation, analysis of the product by gas chromatography (GC) and GC-MS (gas chromatography-mass spectrometry) indicated that it consisted of >95% N-butyl-N-pentyl-1-(deoxyglucityl)amine, and minor amounts of byproducts. 13C NMR (CDCl3): 13.67, 13.71 (2C, CH3); 20.02, 20.20 (1C, CH2); 22.05, 22.22 (1C, CH2); 25.78 (1C, CH2); 28.28 (1C, CH2); 29.23 (1C, CH2); 53.44, 53.73 (2C, NCH2CH2—); 56.48 (1C, NCH2CHOH—); 63.91 (1C, CH2OH); 69.77, 70.89, 71.20 (3C, CHOH); 73.24 (1C, HOCH2CHOH—) ppm.
Additional N,N-dialkyl-1-(deoxyglucityl)amines were prepared and characterized using procedures similar to that above. Details of the reactants used in these preparations are shown in Table 1 as sample Nos. 1-12c. Reaction conditions used for the runs in Table 1 are shown in Table 2.
Notes to table:
aSamples were isolated typically by precipitation and filtration. Compositions refer to the solid products. Complete mass balances were not done.
bRatio by weight.
cGC analyses are area percent.
dAldol reaction of aldehyde with itself, sometimes with reductive dehydration of the aldol product, followed by reductive alkylation of the alkylglucamine.
eNone detected.
fNot identified.
gMixture of C8, C10, C12, C14, C16, and C18 species, centered on C12.
aWt % starting materials (alkylglucamine and aldehyde) in reaction mixture.
bCatalyst loading (dry weight basis), based on total reactants (alkylglucamine and aldehyde).
A series of preparations, labeled A-N, were made of N-butyl-N-pentylglucamine. The procedures used were as follows, with the results tabulated below in Table 3.
Butylglucamine (11.85 g; 0.05 mole) and 5% Pd/C (0.32 g, dry weight basis; 2 wt %, based on total organic feed) were charged to a 100 mL Parr reactor bowl, followed by pentanal (4.5 g; 0.0523 mole; 1.036 eq.). If appropriate, solvent components were mixed prior to addition to the reactor. In all cases, a total of 30 g of (mixed) solvent was added to the reactor. Subsequently, the reactor was assembled, pressurized with nitrogen to 1000 psig, and vented to ca 5-10 psig. After two more nitrogen pressurization-vent cycles, the reactor was pressurized to 1000 psig with hydrogen, and the contents stirred at 1000 rpm until the pressure stabilized. (Typically, an initial drop of ca 40-80 psig was noted owing to solution of hydrogen in the reaction mixture.) The stirrer was turned off, and the reactor was leak checked. The reactor was vented to ca 5-10 psig, the hydrogen pressurization-vent cycle was repeated two more times, and the reactor was then pressurized to 600 psig. The stirrer was then turned onto 1000 rpm again, and the reactor heated to 100° C. At 100° C., the pressure was adjusted to 1000 psig and maintained at that level via regulated hydrogen feed for the course of the reaction. The reaction was maintained at 100° C./1000 psig for 5 hr, after which time heating was stopped and the reaction mixture was cooled to ambient. The following morning, the reactor was opened. Reaction mixtures where the desired product was essentially fully soluble were filtered to remove catalyst, the filtrate was evaporated to dryness, and the product was trimethylsilylated and analyzed by GC. Reaction mixtures where the desired product was partially soluble were mixed with additional methanol to dissolve the product, and then filtered and treated as above.
The above procedure was followed, but using 40 g of water and a reaction time of 10 hr. (See Note d, Table 3.)
The procedure of Example 6, DE 4307163 was followed on the 0.445× scale, with substitution of 6.885 g (0.08008 mole; 1.067 eq.; the same ratio as used in that patent) of pentanal for aqueous formaldehyde. After being weighed in a pycnometer, the Raney® 2800 catalyst was washed with deionized water three times and transferred to the reactor with the butylglucamine-pentanal-water solution. The sequence of nitrogen and hydrogen pressurization-vent cycles was analogous to that immediately above, with the exception that the reactor was leak checked at 500 psig, pressurized to 250 psig prior to heating, and the final pressure adjusted to 440 psig at 10° C. The reaction was maintained at 100° C./440 psig for 10 hours, after which heating was stopped and the reaction cooled to ambient. The following morning, the semi-solid product was dissolved in added methanol, filtered, and the filtrate was evaporated to dryness. After trimethylsilylation, the product was analyzed by GC.
Table 3 shows the results of the above Examples A-N.
Notes to table:
aWeight ratios of organic solvent:water.
bConversion based on starting alkylglucamine.
cGC analyses by area percent; the entire reaction mixture was evaporated, and a portion analyzed.
dRun A used 40 g of water, run B used 30 g of water.
eNot detected.
fUnknown material.
gAldol reaction side products present at 0.2-0.3%.
The results shown in Table 3 indicate that minimization of water concentration in the reaction mixture favored rapid and selective formation of the desired dialkylglucamine. For example, runs A and B both used only water as the reaction medium, but run A used 40 mL of water and run B used only 30 mL, i.e. run B had a lower molar concentration of water in the reaction mixture, and exhibited more complete conversion of the butylglucamine starting material to desired product, despite a reaction time of only 5 hours for run B vs. 10 hours for run A. The effects of water concentration on conversion were distinct from effects of reactant concentration, as seen by comparing runs A and F. In both cases, a similar volume of reaction medium was used (40 g=40 mL of water in run A, 30 g=38 mL of methanol in run F), but considerably better conversion was obtained in run F, where no water was included in preparing the reaction medium. In particular, reaction media containing methanol showed particularly good conversions and selectivities, as seen by comparing run D with runs G-K.
Equilibrium surface tensions obtained using N,N-dialkylpolyhydroxyalkylamines, and comparison runs using the corresponding N-alkylglucamine precursors, were determined using a Kruss K-12 tensiometer with a platinum Wilhelmy plate, maintaining the temperature at 25±1° C. by means of a constant temperature circulating bath. The results, reported in Table 4, are averages of 10 measurements over a 10-minute period, and have a standard deviation of less than 0.01 dyne/cm.
Some of the practical benefits of a low equilibrium surface tension values are that less surfactant is required to reduce the surface tension of a formulation (enhancing its wetting properties) and less surfactant will be needed to stabilize emulsions. For the examples in Table 4, surfactants of the invention demonstrated low equilibrium surface tension values, which will enhance the ability of formulations containing them to wet out a given surface.
An additional benefit that the surfactants of the invention offer is the reduction of dynamic surface tension. Solutions of the surfactants of the invention were prepared in distilled and deionized water. Their dynamic surface tensions were measured using the maximum bubble pressure method, and the resulting data are provided in Table 5. The maximum bubble pressure method of measuring surface tension is described in Langmuir 1986, 2, 428-432. These data provide information about the performance of a surfactant at conditions close to equilibrium (0.1 bubbles/sec) through high surface creation rates or dynamic conditions (10 bubbles/sec). In a practical sense, high surface creation rates refer to rapid processes such as a spray or roller-applied coating, a high speed printing operation, or the rapid application of an agricultural product or a cleaner.
The data of Table 5 indicate that a wide range of dynamic surface tension reduction levels is possible with this family of molecules, providing different surfactants for strong (Examples 30, 31 and 36 at low bubble rates), and moderate to low (Example 29, 34 and 35) surface tension reduction of an aqueous solution or a formulation. Depending upon the mode of application of a formulation, the solubility of the surfactant in the formulation and the substrate to be wetted (brush application of an industrial coating, spray application of an industrial cleaner, roller application of an adhesive), surfactants that provide such a range of dynamic surface tension reduction may find significant commercial utility.
The foaming characteristics of surfactants according to formula (I) were determined using a slight modification of the Ross-Miles foam test (Am. Soc. For Testing Materials, Method D1173-53, Philadelphia, Pa., 1953) for solutions of 0.1 wt % surfactant in water. Foam data for surfactants of the invention as well as the N-alkylglucamine precursors (comparative examples) are shown in Table 6.
For the N-alkylglucamine precursors to the invention, little change in initial foam height was observed with an increase in hydrophobe length (Comparative Examples 39, 40, and 41). The surfactants of the invention showed an increase in initial foam height and foam stability with an increase in alkyl chain length (compare Example 43 with 42, 45 and 46 with 44, and 50 with 49). These data demonstrate that a range of foam performance may be obtained, depending upon the alkyl group attached to the amine. While applications such as coatings, inks, and adhesives require low foam or foam that dissipates quickly, other applications such as cleaning or ore floatation require a controlled amount of foam to be present and to persist. Therefore, the surfactants of the invention will likely be of use in a wide range of applications where manipulation of foaming performance is important.
In this example, 100 mL of deionized water is charged to a 500-cc stainless steel autoclave equipped with a turbine agitator. The system is pressurized to 6.5 MPa with methane, and the pressure is maintained by the gas supply. The autoclave temperature is reduced at a rate of approximately 5° C. per hour, to a temperature of 15° C. The temperature is then further reduced slowly in controlled fashion at a rate of 1° C. per hour. Significant hydrate formation occurs at 9° C.
The operation is the same as in Example 52, but 0.5 wt % (with respect to water) of a compound according to formula (I) is added to the autoclave prior to pressurization with methane. Significantly less nucleation, growth, and/or agglomeration of gas hydrates is observed than in the control experiment.
The invention provides novel surfactants with properties that make suitable for use in a wide range of industrial and commercial applications. Such applications include water-based coatings, inks, adhesives, agricultural formulations, aqueous and non-aqueous cleaning compositions, personal care applications, and formulations for textile processing and oilfield applications.
Although the invention is illustrated and described herein with reference to specific embodiments, it is not intended that the subjoined claims be limited to the details shown. Rather, it is expected that various modifications may be made in these details by those skilled in the art, which modifications may still be within the spirit and scope of the claimed subject matter and it is intended that these claims be construed accordingly.
