Patent Application
20240327231
The present disclosure relates to molecular sieve compositions, methods of making the same, and uses thereof.
Molecular sieve materials, both natural and synthetic, may be used as adsorbents and have catalytic properties for hydrocarbon conversion reactions. Certain molecular sieves, such as zeolites, AlPOs, and mesoporous materials, are ordered, porous crystalline materials having a definite crystalline structure as determined by X-ray diffraction (XRD). Certain molecular sieves are ordered and produce specific identifiable XRD patterns. Within certain molecular sieve materials there may be a large number of cavities, which may be interconnected by a number of channels or pores. These cavities and pores are uniform in size within a specific molecular sieve material. Because the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as “molecular sieves” and are utilized in a variety of industrial processes, e.g., cracking, hydrocracking, disproportionation, alkylation, oligomerization, and isomerization.
Molecular sieves that find application in catalysis and adsorption include any of the naturally occurring or synthetic crystalline molecular sieves. These zeolites and their isotypes are classified by the Structure Commission of the International Zeolite Association according to the rules of the IUPAC Commission on Zeolite Nomenclature. According to this classification, framework type zeolites and other crystalline microporous molecular sieves, for which a structure has been established, are assigned a three letter code and are described in the “Atlas of Zeolite Framework Types”, eds. Ch. Baerlocher, L. B. McCusker, and D. H. Olson, Elsevier, Sixth Edition, 2007, which is hereby incorporated by reference. These zeolites and their isotypes are also described in http://America.iza-structure.org/IZA-SC/ftc_table.php.
The idealized inorganic framework structure of zeolites is a framework of silicate in which all tetrahedral atoms are connected by oxygen atoms with the four next-nearest tetrahedral atoms. The term “silicate”, as used herein, refers to a substance containing at least silicon and oxygen atoms that are alternately bonded to each other (i.e., —O—Si—O—Si—), and optionally including other atoms within the inorganic framework structure, including atoms such as boron, aluminum, or other metals (e.g., transition metals, such as titanium, vanadium, or zinc). Atoms other than silicon and oxygen in the framework silicate occupy a portion of the lattice sites otherwise occupied by silicon atoms in an ‘all-silica’ framework silicate. Thus, the term “framework silicate” as used herein refers to an atomic lattice comprising any of a silicate, borosilicate, gallosilicate, ferrisilicate, aluminosilicate, titanosilicate, zincosilicate, vanadosilicate, or the like.
The structure of the framework silicate within a given zeolite determines the size of the pores or channels that are present therein. The pore or channel size may determine the types of processes for which a given zeolite is applicable. Currently, greater than 200 unique zeolite framework silicate structures are known and recognized by the Structure Commission of the International Zeolite Association, thereby defining a range of pore geometries and orientations.
The framework silicates of zeolites or molecular sieves are commonly characterized in terms of their ring size, wherein the ring size refers to the number of silicon atoms (or alternative atoms, such as those listed above) that are tetrahedrally coordinated with oxygen atoms in a loop to define a pore or channel within the interior of the zeolite. For example, an “8-ring” zeolite refers to a zeolite having pores or channels defined by 8 alternating tetrahedral atoms and 8 oxygen atoms in a loop. The pores or channels defined within a given zeolite may be symmetrical or asymmetrical depending upon various structural constrains that are present in the particular framework silicate.
Zeolites can be classified as having small, medium, large, and extra-large pore structures for pore windows delimited by 8, 10, 12, and more than 12 T-atoms, respectively. Extra-large pore zeolites (>12R) include, for example, AET (14R, e.g., ALPO-8), SFN (14R, e.g., SSZ-59), VFI (18R, e.g., VPI-5), CLO (20R, e.g., cloverite), and ITV (30R, e.g., ITQ-37) framework type zeolites. Extra-large pore zeolites generally have a free pore diameter of larger than about 0.8 nm. Large pore zeolites (12R) include, for example, LTL, MAZ, FAU, EMT, OFF, *BEA, MOR, and SFS framework type zeolites, e.g., mazzite, offretite, zeolite L, zeolite Y, zeolite X, omega, ZSM-2, zeolite T, Beta, and SSZ-56. Large pore zeolites generally have a free pore diameter of 0.6 to 0.8 nm. Medium (or intermediate) pore size zeolites (10R) include, for example, MFI, MEL, EUO, MTT, MFS, AEL, AFO, HEU, FER, MWW, and TON framework type zeolites, e.g., ZSM-5, ZSM-11, ZSM-22, MCM-22, silicalite-1, and silicalite-2. Medium pore size zeolites generally have a free pore diameter of 0.45 to 0.6 nm. Small pore size zeolites (8R) include, for example, CHA, RTH, ERI, KFI, LEV, and LTA framework type zeolites, e.g., ZK-4, SAPO-34, SAPO-35, ZK-14, SAPO-42, ZK-21, ZK-22, ZK-5, ZK-20, zeolite A, chabazite, and ALPO-17. Small pore size zeolites generally have a free pore diameter of 0.3 to 0.45 nm.
Synthesis of molecular sieve materials typically involves hydrothermal crystallization from a synthesis mixture comprising sources of all the elements present in the molecular sieve (or zeolite) such as sources of silica but also of alumina etc. In many cases a structure directing agent (SDA) is also present. Structure directing agents are compounds which are believed to promote the formation of molecular sieves and which are thought to act as templates around which certain molecular sieve structures can form and which thereby promote the formation of the desired molecular sieve. Various compounds have been used as structure directing agents including various types of quaternary ammonium cations. Typically, molecular sieve (or zeolite) crystals form around structure directing agents with the structure directing agent occupying pores in the molecular sieve once crystallization is complete. The “as-synthesized” (or “as-made”) molecular sieve will therefore contain the structure directing agent in its pores so that, following crystallization, the “as-synthesized” molecular sieve is usually subjected to a treatment step such as a calcination step to remove the structure directing agent.
Although many different molecular sieves have been discovered there is a continuing need for new molecular sieves (or zeolites) with desirable properties for gas separation and drying, organic conversion reactions, and other applications. New molecular sieves can contain novel internal pore architectures, providing enhanced selectivities in these processes. It is also important to identify new structure directing agents and more efficient methods for the synthesis of molecular sieves to facilitate the preparation of new molecular sieves and/or to reduce the cost of making known molecular sieves.
The present disclosure relates to molecular sieves, methods of making the same, and uses thereof.
In a first aspect, the present disclosure relates to a molecular sieve having, in its calcined form (e.g., where at least part of the SDA has been removed), an X-ray diffraction pattern including at least 14, or at least 15, or at least 16, or at least 17, such as all of the peaks in degree 2-theta in Table 1:
In a second aspect, the present disclosure relates to a molecular sieve having, in its as-synthesized form (e.g., where the SDA has not been removed), an X-ray diffraction pattern including at least 9, or at least 10, or at least 11, or at least 12, such as all of the peaks in degree 2-theta in Table 2:
In a third aspect, the present disclosure relates to a method of making a molecular sieve, in particular a molecular sieve as defined in the first and/or second aspects of the present disclosure, comprising the steps of (a) preparing a synthesis mixture comprising water, a source of an oxide of tetravalent element (Y), a source of an oxide of trivalent element (X), a structure directing agent (Q) comprising a 2-ethyl-1,3-dimethylbenzimidazolium cation of Formula I, a source of fluoride ions (F), and optionally a source of hydroxide ions (OH),
(b) heating said synthesis mixture under crystallization conditions including a temperature of from 100° C. to 200° C. for a time sufficient to form crystals of said molecular sieve; (c) recovering at least a portion of the molecular sieve from step (b); and (d) optionally treating the molecular sieve recovered in step (c) to remove at least part of the structure directing agent (Q).
In a fourth aspect, the present disclosure relates to a process of converting an organic compound to a conversion product, which comprises contacting the organic compound with the molecular sieve according to the first or second aspect of the present disclosure, or prepared according to the process of the third aspect of the present disclosure.
These and other features and attributes of the present disclosure and their advantageous applications and/or uses will be apparent from the detailed description which follows. It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. In particular, any two or more of the features described in this specification, including in this summary section, can be combined to form combinations of features not specifically described herein.
The present disclosure relates to molecular sieve compositions, methods of making the same, and uses thereof. Said molecular sieves may be designated as EMM-75 molecular sieves, or EMM-75 zeolites, or EMM-75 materials.
In a first aspect, the present disclosure relates to a molecular sieve having, in its calcined form (e.g., where at least part of the SDA has been removed), an X-ray diffraction pattern including at least 14, or at least 15, or at least 16, or at least 17, such as all of the peaks in degree 2-theta in Table 1:
In a further embodiment, said molecular sieve, in its calcined form, may have an X-ray diffraction pattern including at least 14, or at least 15, or at least 16, or at least 17, such as all of the peaks in Table 1A, wherein the d-spacing values have a deviation determined based on the corresponding deviation±0.20 degree 2-theta when converted to the corresponding values for d-spacing using Bragg's law:
In yet a further embodiment, the X-ray diffraction pattern of said molecular sieve, in its calcined form, may include at least 10, such as at least 11, or at least 12, or at least 14, or all of the peaks in degree 2-theta in Table 1 or 1A that have a relative intensity of minimum 10-30, for instance the 10 peaks in degree 2-theta in Table 1 or 1A that have a relative intensity of minimum of minimum 20-40.
The XRD patterns with the XRD peaks described herein use Cu(Kα) radiation.
In one or more further embodiments, said molecular sieve, in its calcined form, may have a micropore volume of 0.02 to 0.2 cm3/g, such as 0.05 to 0.1 cm3/g, e.g., 0.07 cm3/g.
In one or more further embodiments, said molecular sieve, in its calcined form, may have a micropore surface area of 75 to 500 m2/g, such as from 100 to 300 m2/g, e.g., around 150 to 180 m2/g, and/or an external surface area of 10 to 300 m2/g, such as from 30 to 200 m2/g, e.g., 45 to 155 m2/g.
In one or more further embodiments, said molecular sieve, in its calcined form, may be optionally represented by the molecular formula of Formula II:
(m)X2O3:YO2 Formula II,
wherein 0.01≤m≤0.1, X is a trivalent element, and Y is a tetravalent element. Y may comprise or be Si and/or Ge, for example, Y may comprise or be Si. X may comprise or be Al and/or B, for instance X may comprise or be Al. In embodiments where Y is Si and X is Al, the molecular sieve is an aluminosilicate. In embodiments where Y is Si and X is B, the molecular sieve is a borosilicate. The oxygen atoms in Formula II may be replaced by carbon atoms (e.g., in the form of CH2), which can come from sources of the components used to prepare the as-made molecular sieve. The oxygen atoms in Formula II can also be replaced by nitrogen atoms, e.g., after the SDA has been removed. Formula II can represent the framework of a typical molecular sieve as defined in the present disclosure, in its calcined form, and is not meant to be the sole representation of said molecular sieve. Said molecular sieve, in its calcined form, may contain SDA and/or impurities after appropriate treatments to remove the SDA and impurities, which are not accounted for in Formula II. Further, Formula II does not include the protons and charge compensating ions that may be present in the calcined molecular sieve.
The variable m represents the molar ratio relationship of X2O3 to YO2 in Formula II. For example, when m is 0.025, the molar ratio of YO2 to X2O3 is 40 and the molar ratio of Y to X is 20 (e.g., the molar ratio of Si/Al is 20). m may vary from 0.01 to 0.1, such as at least 0.01, or at least 0.0125, preferably more than 0.0125, or at least 0.017 to at most 0.1, or at most 0.07, or at most 0.05, e.g., around 0.025 or 0.03 or 0.04. The molar ratio of Y to X may be 5 to 50, such as at least 5, or at least 7.5 or at least 10, and up to 50, or up to 40, preferably up to less than 40, or up to 30, e.g., around 12.5 or 15 or 20.
In a second aspect, the present disclosure relates to a molecular sieve, in particular a molecular sieve as defined in the first aspect, having in its as-synthesized form (e.g., where the SDA has not been removed) an X-ray diffraction pattern including at least 9, or at least 10, or at least 11, or at least 12, such as all of the peaks in degree 2-theta in Table 2:
In a further embodiment, said molecular sieve, in its as-synthesized form, may have an X-ray diffraction pattern including at least 9, or at least 10, or at least 11, or at least 12, such as all of the peaks in Table 2A, wherein the d-spacing values have a deviation determined based on the corresponding deviation±0.20 degree 2-theta when converted to the corresponding values for d-spacing using Bragg's law:
In yet a further embodiment, the X-ray diffraction pattern of said molecular sieve, in its as-synthesized form, may include at least 6, such as at least 7, or at least 8, or all of the peaks in degree 2-theta in Table 2 or 2A that have a relative intensity of minimum 10-20, for instance the 9 peaks in degree 2-theta in Table 2 or 2A that have a relative intensity of minimum of minimum 10-40 or 20-40.
The XRD patterns with the XRD peaks described herein use Cu(Kα) radiation.
In one or more further embodiments, said molecular sieve, in its as-synthesized form, may be optionally represented by the molecular formula of Formula III:
(q)Q:(m)X2O3:YO2 Formula III,
wherein 0<q≤0.7, 0.01≤m≤0.1, X is a trivalent element as defined for Formula II, Y is a tetravalent element as defined for Formula II, and Q comprises a 2-ethyl-1,3-dimethylbenzimidazolium cation of Formula I
Formula III can represent the framework of a typical molecular sieve as defined in the present disclosure, in its as-synthesized form, therefore containing structure directing agent (Q), and is not meant to be the sole representation of such material. Said molecular sieve, in its as-synthesized form, may contain impurities which are not accounted for in Formula III. Further, Formula III does not include the protons and charge compensating ions that may be present in said as-synthesized molecular sieve.
The variable m represents the molar ratio relationship of X2O3 to YO2 in Formula III. The values for variable m in Formula III are the same as those described herein for Formula II.
The variable q represents the molar relationship of Q to YO2 in Formula III. For example, when q is 0.1, the molar ratio of Q to YO2 is 0.1. The molar ratio of Q to YO2 may be from more than 0 to 0.7, such as from 0.1 to 0.6, e.g., 0.1 to 0.5.
In a further embodiment, the as-synthesized molecular sieve of the second aspect of the present disclosure is a layer phase with monoclinic symmetry [e.g., unit cell dimensions a=7.3±0.30 Å, b 17.7±0.30 Å, and c=25.0±0.30 Å, β: ˜95.0°] containing silanol defects, e.g., about 17% silanol defects. In a still further embodiment, upon calcination, the molecular sieve of the first aspect of the present disclosure becomes more symmetric with orthorhombic cell [e.g., unit cell dimensions a=7.6±0.30 Å, b=17.9±0.30 Å, and c=22.4±0.30 Å] and the defects are at least partially healed. The calcined molecular sieve of the first aspect of the present disclosure has 48 Si atoms in one unit cell and shares similar structure as MOR zeolite, with one 12-ring dimension that is more elliptical (12MR: 6.5±0.30 Å by 8.3±0.30 Å as compared to 6.5±0.30 Å by 7±0.30 Å for MOR), and a narrower 8-ring dimension (8MR: 5.7±0.30 Å by 2.3±0.30 Å as compared to 5.7±0.30 Å by 2.6±0.30 Å for MOR).
In still a further embodiment, at least a portion of the molecular sieve crystals of the present disclosure (whether in as-synthesized or calcined form) can have a plate-like morphology, in particular a thin plate-like morphology. By “at least a portion” of the molecular sieve crystals can have a (thin) plate-like morphology is meant at least about 50% of the molecular sieve crystals can have a (thin) plate-like morphology, such as at least 60%, at least 75%, or at least 85%. By “(thin) plate-like morphology” is meant crystals that are substantially in the form of (thin) platelets, for instance of discs or rectangular plates, having first and second major dimensions that can be referred to as the length (1) and the breadth (b) of the platelet (i.e., the longest dimension of the biggest face of the platelet and the dimension of said biggest face measured at the middle and perpendicular to said longest dimension) and a minor third dimension that can be referred to as the thickness (t) of the platelet (i.e., smallest dimension measured at the middle of the longest dimension, perpendicular to said biggest face). The morphology as well as the percentage (as vol %) of crystals having said morphology can be determined by image analysis, for example, of scanning electron microscopy (SEM) micrographs, e.g., using ImageJ software.
The molecular sieve crystals having a (thin) plate-like morphology according to the present disclosure may for instance have a thickness as small as about 1 nm, such as at least about 5 or 10 nm and up to about 100 nm, such as up to 50 or 25 nm.
In a third aspect, the present disclosure relates to a method of making a molecular sieve, in particular a molecular sieve as defined in the first and/or second aspects of the present disclosure, comprising the following steps:
The structure directing agent (Q) comprises a 2-ethyl-1,3-dimethylbenzimidazolium cation of Formula I as defined above. The structure directing agent (Q) may be present in any suitable form, for example as a halide, such as a fluoride, a chloride, an iodide or a bromide, as a hydroxide or as a nitrate, for instance in its hydroxide form. The structure directing agent (Q) may be present in the synthesis mixture in a Q/Y molar ratio of 0.05 to 1.0, such as 0.1 to 0.8, or 0.2 to 0.7, or 0.3 to 0.6, e.g., 0.5.
The synthesis mixture comprises at least one source of an oxide of tetravalent element Y which may be selected from Si and/or Ge, preferably Si. Suitable sources of tetravalent element Y that can be used to prepare the synthesis mixture depend on the element Y that is selected. In embodiments where Y is silicon, Si sources (e.g., silicon oxide sources) suitable for use in the method include silicates, e.g., tetraalkyl orthosilicates such as tetramethylorthosilicate (TMOS) and tetraethylorthosilicate (TEOS), fumed silica such as Aerosil® (available from Evonik), Cabosperse® (available from Cabot) and CabO—O-Sil® (available from DMS), precipitated silica such as Ultrasil® and Sipernat® 340 (available from Evonik) or Hi-Sil®, alkali metal silicates such as potassium silicate and sodium silicate, and aqueous colloidal suspensions of silica, for example, that sold by E.I. du Pont de Nemours under the tradename Ludox® or that sold by Evonik under the tradename Aerodisp®; preferably silicates, fumed silica, colloidal silica, precipitated silica, alkali metal silicates, and in particular silicates. In embodiments where Y is germanium, suitable Ge sources include germanium oxide.
The synthesis mixture comprises at least one source of an oxide of trivalent element X which may be selected from Al and/or B, in particular Al. Suitable sources of trivalent element X that can be used to prepare the synthesis mixture depend on the element X that is selected. In embodiments where X is aluminum, Al sources (e.g., aluminum oxide sources) suitable for use in the method include aluminum hydroxide, aluminum salts, especially water-soluble salts, such as aluminum sulfate, aluminum nitrate, alkali metal aluminates such as sodium aluminate, and aluminum alkoxides such as aluminum isopropoxide, as well as hydrated aluminum oxides, such as boehmite, gibbsite, and pseudoboehmite, and mixtures thereof. Other aluminum sources include, but are not limited to, other water-soluble aluminum salts, or aluminum metal, such as aluminum in the form of chips. Especially suitable sources of alumina are aluminum hydroxide and aluminum alkoxides. In embodiments where X is boron, suitable B sources include boric acid and borate salts such as sodium tetraborate or borax and potassium tetraborate. Sources of boron tend to be more soluble than sources of aluminum in hydroxide-mediated synthesis systems.
Alternatively or in addition to previously mentioned sources of Y and X, sources containing both Y and X elements can also be used, such as sources of Si and Al. Examples of suitable sources containing both Si and Al elements include amorphous silica-alumina gels or dried silica alumina powders, silica aluminas, clays, such as kaolin, metakaolin, and zeolites, in particular aluminosilicates such as synthetic faujasite and ultrastable faujasite, for instance Y-Type Zeolite, Ultrastable Y (USY), beta or other large to medium pore molecular sieves or zeolites.
The synthesis mixture may have a Y/X molar ratio of from 5 to 50, such as from 7.5 to 40 or less than 40, for instance from 10 or 12 to 35 or 30 or 25, e.g., 12.5, 15 or 20.
In preferred embodiment of this aspect of the invention, Y is Si, X is Al or B, and the molecular sieve is an aluminosilicate or a borosilicate, in particular Y is Si, X is Al and the molecular sieve is an aluminosilicate.
The synthesis mixture comprises at least one source of fluoride ions (F). The source of fluoride ions (F) may be any compound capable of releasing fluoride ions in the molecular sieve synthesis mixture. For instance, fluoride ions can be present as a counter ion of the structure directing agent (Q). Non-limiting examples of sources of fluoride ions (F) include hydrogen fluoride (HF); salts containing one or several fluoride ions, such as metal fluoride, preferably where the metal is an alkali or alkaline earth metal such as sodium, potassium, calcium, magnesium, strontium or barium, or a metal such as aluminum (AlF3, Al2F6) or tin (SnF2); ammonium fluoride (NH4F); and ammonium bifluoride (NH4HF2). Especially convenient sources of fluoride ions are HF, NH4F, and NH4HF2, in particular HF. Small amounts of fluoride ions (F) may also be present as impurities, for instance in the optional source of alkali or alkaline earth metal cation (M). The fluoride ions (F) may be present in a F/Y molar ratio of 0.05 to 1.0, for instance 0.1 to 0.8, such as 0.15 to 0.7 or 0.2 to 0.6, e.g., 0.5.
The synthesis mixture may optionally contain at least one source of halide ions (W), different from fluoride ions, which may be selected from the group consisting of chloride, bromide or iodide. The source of halide ions (W) may be any compound capable of releasing halide ions in the molecular sieve synthesis mixture. For instance, halide ions can be present as a counter ion of the structure directing agent (Q). Non-limiting examples of sources of halide ions include hydrogen chloride, ammonium chloride, hydrogen bromide, ammonium bromide, hydrogen iodide, and ammonium iodide; salts containing one or several halide ions, such as metal halides, preferably where the metal is an alkali or alkaline earth metal such as sodium, potassium, calcium, magnesium, strontium or barium; or tetraalkylammonium halides such as tetramethylammonium halides or tetraethylammonium halides. Small amounts of halide ions (W) may also be present as impurities, for instance in the optional source of alkali or alkaline earth metal cation (M). The halide ions (W) may be present in a W/Y molar ratio of 0 to 0.2, such as 0 to 0.1, for instance less than 0.1 or even 0. Alternatively, the synthesis mixture may be substantially free from halide ions (W).
Optionally, the synthesis mixture may comprise at least one source of hydroxide ions (OH). For example, hydroxide ions can be present as a counter ion of the structure directing agent (Q) or by the use of aluminum hydroxide or sodium aluminate as a source of Al. Suitable sources of hydroxide ions can also be selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxide, and mixtures thereof; such as from sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, calcium hydroxide, magnesium hydroxide, ammonium hydroxide, and mixtures thereof; more often sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, and mixtures thereof; most often sodium hydroxide and/or potassium hydroxide. The synthesis mixture may comprise the hydroxide ions source in an OH/Y molar ratio of from 0 to 1.0, such as 0.01 to 0.8, or 0.1 to 0.7, e.g., 0.5. Alternatively, the synthesis mixture may be substantially free from a hydroxide source.
When the synthesis mixture comprises a source of hydroxide ions, the source of fluoride ions will neutralize at least partly the hydroxide ions. In a preferred embodiment, the relative amounts of fluoride ions and hydroxide ions may be adjusted so that the synthesis mixture has a pH of less than 10, in particular of at most 9, for instance around 7, 8 or 9. For instance, the pH of the synthesis mixture may be around 7 when the source of fluoride ions is HF and around 8 to 9 when the source of fluoride ions is NH4F. There is no particular lower limit for the pH of the synthesis mixture. Typically, the synthesis mixture has a pH of at least 3, for instance at least 4, such as at least 5 or 6. In the context of the present disclosure, the pH of the synthesis mixture is measured using a pH-meter at 20° C., and is determined to an accuracy of ±0.05 in accordance with the IUPAC Recommendations 2002 (R. P. Buck et al. (2002) Pure Appl. Chem., v. 74(11), pp. 2169-2200). A suitable and commercially available instrument for pH measurement is the Mettler Toledo FE20 pH meter. The pH calibration is carried out as 3-point calibration using pH=4.0, pH=7.0 and pH=10.00 standard buffer solutions. The resolutions are: 0.01 pH; 1 mV; and 0.1° C. The limits of error are: ±0.01 pH; ±1 mV; and ±0.5° C.
Optionally, the synthesis mixture may comprise one or more sources of alkali or alkaline earth metal cation (M). If present, M is preferably selected from the group consisting of sodium, potassium, lithium, rubidium, calcium, magnesium, strontium, barium, and mixtures thereof, preferably sodium and/or potassium, more preferably sodium. The sodium source, when present, may be sodium hydroxide, sodium aluminate, sodium silicate, or sodium salts such as NaCl, NaBr or sodium nitrate. The potassium source, when present, may be potassium hydroxide, potassium aluminate, potassium silicate, a potassium salt such as KCl or KBr or potassium nitrate. The lithium source, when present, may be lithium hydroxide or lithium salts such as LiCl, LiBr, LiI, lithium nitrate, or lithium sulfate. The rubidium source, when present, may be rubidium hydroxide or rubidium salts such as RbCl, RbBr, RbI, or rubidium nitrate. The calcium source, when present, may be calcium hydroxide. The magnesium source, when present, may be magnesium hydroxide. The strontium source, when present, may be strontium hydroxide. The barium source, when present, may be barium hydroxide. The alkali or alkaline earth metal cation M may also be present in the one or more sources of a trivalent element X, such as sodium aluminate, sodium tetraborate, potassium tetraborate, and/or in the one or more sources of tetravalent element Y, such as potassium silicate and/or sodium silicate. The source of alkali or alkaline earth metal cation (M) is advantageously soluble in water. The synthesis mixture may comprise the alkali or alkaline earth metal cation (M) source in a M/Y molar ratio of 0 to 1.0, such as 0.01 to 0.5, for instance 0.01 to 0.2 or 0.15, e.g., 0 or 0.01 to 0.1 or even to less than 0.1. Alternatively, the synthesis mixture may be substantially free from alkali or alkaline earth metal cation (M).
The synthesis may be performed with or without added nucleating seeds. If nucleating seeds are added to the synthesis mixture, the seeds may be of the same or of a different structure than the molecular sieve of the present disclosure, for instance molecular sieves EMM-75 obtained from a previous synthesis, and may suitably present in an amount from about 0.01 ppm by weight to about 10,000 ppm by weight, based on the synthesis mixture, such as from about 100 ppm by weight to about 5,000 ppm by weight of the synthesis mixture.
The synthesis mixture typically comprises water in a H2O/Y molar ratio of from 1 to 50, such as 5 to 40 or 5 to 30, for instance 5 or 10 to 15. Depending on the nature of the components in the base mixture, the amount of solvent (e.g., water from the hydroxide solution, and optionally methanol and ethanol from the hydrolysis of silica sources) of the base mixture may be removed such that a desired solvent to Y molar ratio is achieved for the synthesis mixture. Suitable methods for reducing the solvent content may include evaporation under a static or flowing atmosphere such as ambient air, dry nitrogen, dry air, or by spray drying or freeze drying. Water may also be added to the resulting mixture to achieve the desired H2O/Y molar ratio when too much water is removed during the solvent removal process. In some examples, water removal is not necessary when the preparation have sufficient H2O/Y molar ratio.
Carbon in the form of CH2 may be present in the various sources of components used to prepare the molecular sieve of the present disclosure, e.g., tetravalent element source (silica source) or trivalent element source (alumina source), and incorporated into the resulting molecular sieve framework as bridging atoms. Nitrogen atoms may be incorporated into the framework of the molecular sieve material as bridging atoms after the SDA has been removed.
In one or more aspects, the synthesis mixture after solvent adjustment (e.g., where the desired water to silica ratio is achieved) may be mixed by a mechanical process such as stirring or high shear blending to assure suitable homogenization of the base mixture, for example, using dual asymmetric centrifugal mixing (e.g., a FlackTek speedmixer) with a mixing speed of 1000 rpm to 3000 rpm (e.g., 2000 rpm).
The synthesis mixture is then subject to crystallization conditions suitable for the molecular sieve material to form. Crystallization of the molecular sieve material may be carried out under static or stirred conditions in a suitable reactor vessel, such as for example, Teflon® lined or stainless steel autoclaves placed in a convection oven maintained at an appropriate temperature.
The crystallization in step (b) of the method is typically carried out at a temperature of 100° C. to 200° C., such as 120° C. to 180° C., e.g., 120° C. to 150° C., for a time sufficient for crystallization to occur at the temperature used. For instance, at higher temperatures, the crystallization time may be reduced. For instance, the crystallization conditions in step (b) of the method may include heating for a period of from 1 day to 100 days, such as from 1 day to 50 days, for example from 1 day to 30 days, e.g., at least 1 day or at least 5 days up to 40 days or 30 days. The crystallization time can be established by methods known in the art such as by sampling the synthesis mixture at various times and determining the yield and X-ray crystallinity of precipitated solid. Unless indicated otherwise herein, the temperature measured is the temperature of the surrounding environment of the material being heated, for example the temperature of the atmosphere in which the material is heated.
Typically, the molecular sieve is formed in solution and can be recovered by standard means, such as by centrifugation or filtration. The separated molecular sieve can also be washed, recovered by centrifugation or filtration and dried.
The molecular sieve of the present disclosure, when employed either as an adsorbent or as a catalyst in an organic compound conversion process may be dehydrated (e.g., dried) at least partially. This can be done by heating to a temperature in the range of 80° C. to 500° C., such as 90° C. to 370° C. in an atmosphere such as air, nitrogen, etc., and at atmospheric, subatmospheric or superatmospheric pressures for between 30 minutes and 48 hours. Dehydration may also be performed at room temperature merely by placing the molecular sieve in a vacuum, but a longer time is required to obtain a sufficient amount of dehydration.
As a result of the crystallization process, the recovered product contains within its pores at least a portion of the structure directing agent used in the synthesis. The as-synthesized molecular sieve recovered from step (c) may thus be subjected to thermal treatment or other treatment to remove part or all of the SDA incorporated into its pores during the synthesis. Thermal treatment (e.g., calcination) of the as-synthesized molecular sieve typically exposes the materials to high temperatures sufficient to remove part or all of the SDA, in an atmosphere selected from air, nitrogen, ozone or a mixture thereof in a furnace. While subatmospheric pressure may be employed for the thermal treatment, atmospheric pressure is desired for reasons of convenience. The thermal treatment may be performed at a temperature up to 925° C. e.g., 300° C. to 700° C. or 400° C. to 600° C. The temperature measured is the temperature of the surrounding environment of the sample. The thermal treatment (e.g., calcination) may be carried out in a box furnace in dry air, which has been exposed to a drying tube containing drying agents that remove water from the air. The heating is usually calcined for at least 1 minute and generally no longer than 1 day or at most a few days. The heating may first be carried out under a nitrogen atmosphere and then the atmosphere may be switched to air and/or ozone.
The molecular sieve may also be subjected to an ion-exchange treatment, for example, with aqueous ammonium salts, such as ammonium nitrates, ammonium chlorides, and ammonium acetates, in order to remove remaining alkali metal cations and/or alkaline earth metal cations, if present in the synthesis mixture, and to replace them with protons thereby producing the acid form of the molecular sieve. To the extent desired, the original cations of the as-synthesized material, such as alkali metal cations, can be replaced by ion exchange with other cations. Preferred replacing cations can include hydrogen ions, hydrogen precursor, e.g., ammonium ions and mixtures thereof. The ion exchange step may take place after the as-made molecular sieve is dried. The ion-exchange step may take place either before or after a calcination step.
The molecular sieve may also be subjected to other treatments such as steaming and/or washing with solvent. Such treatments are well-known to the skilled person and are carried out in order to modify the properties of the molecular sieve as desired.
The molecular sieve of the present disclosure, where part or all of the SDA has been removed, may be used as an adsorbent or as a catalyst or support for catalyst in a wide variety of hydrocarbon conversions, e.g., conversion of organic compounds to a converted product. In a fourth aspect, the present disclosure therefore relates to a process of converting an organic compound to a conversion product, which comprises contacting the organic compound with the molecular sieve according to the first or second aspect of the present disclosure or prepared according to the process of the third aspect of the present disclosure.
The molecular sieve materials of the present disclosure (where part or all of the SDA is removed) may be used as an adsorbent, such as for separating at least one component from a mixture of components in the vapor or liquid phase having differential sorption characteristics with respect to the material. Therefore, at least one component can be partially or substantially totally separated from a mixture of components having differential sorption characteristics with respect to the molecular sieve by contacting the mixture with said molecular sieve to selectively sorb the one component. For instance, in a process for selectively separating one or more desired components of a feedstock from remaining components of the feedstock, the feedstock may be contacted with a sorbent that comprises the molecular sieve of the present disclosure at effective sorption conditions, thereby forming a sorbed product and an effluent product. One or more of the desired components are recovered from either the sorbed product or the effluent product.
The molecular sieve of the present disclosure (where part or all of the SDA is removed) may also be used as a catalyst to catalyze a wide variety of organic compound conversion processes. Examples of chemical conversion processes, which are effectively catalyzed by the molecular sieve described herein, either alone or in combination with one or more other catalytically active substances including other crystalline catalysts, include those requiring a catalyst with acid activity. Examples of organic conversion processes, which may be catalyzed by the molecular sieve described herein, either alone or in combination with one or more other catalytically active substances, including other crystalline catalysts, include cracking, hydrocracking, isomerization, polymerisation, reforming, hydrogenation, dehydrogenation, dewaxing, hydrodewaxing, adsorption, alkylation, transalkylation, dealkylation, hydrodecylization, disproportionation, oligomerization, dehydrocyclization, conversion of methanol to olefins, deNOx applications, and combinations thereof. The conversion of hydrocarbon feeds can take place in any convenient mode, for example in fluidized bed, moving bed, or fixed bed reactors depending on the types of process desired.
The molecular sieve of the present disclosure may be formulated into product compositions by combination with other materials, such as binders and/or matrix materials that provide additional hardness to the finished product. These other materials can be inert or catalytically active materials.
For instance, it may be desirable to incorporate the molecular sieve of the present disclosure with another material that is resistant to the temperatures and other conditions employed during use. Such materials include synthetic or naturally occurring zeolites as well as inorganic materials such as clays, silica and/or metal oxides such as alumina and mixtures thereof. The metal oxides may be either naturally occurring or in the form of gelatinous precipitates or gels including mixtures of silica and metal oxides. Use of a resistant material in conjunction with the molecular sieve of the present disclosure, i.e., combined therewith or present during synthesis of the as-made molecular sieve, which crystal is active, tends to change the conversion and/or selectivity of the catalyst in certain organic conversion processes. Inactive resistant materials suitably serve as diluents to control the amount of conversion in a given process so that products can be obtained in an economic and orderly manner without employing other means for controlling the rate of reaction. These materials may be incorporated into naturally occurring clays, e.g., bentonite and kaolin, to improve the crush strength of the product under commercial operating conditions. Said inactive resistant materials, i.e., clays, oxides, etc., function as binders for the catalyst. A catalyst having good crush strength can be beneficial because in commercial use, it is desirable to prevent the catalyst from breaking down into powder-like materials.
Naturally occurring clays which may be used include the montmorillonite and kaolin family, which families include the subbentonites, and the kaolins commonly known as Dixie, McNamee, Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite, or anauxite. Such clays can be used in the raw state as originally mined or after being subjected to calcination, acid treatment or chemical modification. Binders useful for compositing with the molecular sieve of the present disclosure also include inorganic oxides selected from silica, zirconia, titania, magnesia, beryllia, alumina, yttria, gallium oxide, zinc oxide and mixtures thereof.
In addition to the foregoing materials, the molecular sieve of the present disclosure may be composited with a porous matrix material such as silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, silica-titania as well as ternary compositions such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesia-zirconia.
These binder materials are resistant to the temperatures and other conditions, e.g., mechanical attrition, which occur in various hydrocarbon separation processes. Thus the molecular sieve of the present disclosure may be used in the form of an extrudate with a binder. They are typically bound by forming a pill, sphere, or extrudate. The extrudate is usually formed by extruding the molecular sieve, optionally in the presence of a binder, and drying and calcining the resulting extrudate. Further treatments such as steaming, and/or ion exchange may be carried out as required. The molecular sieve may optionally be bound with a binder having a surface area of at least 100 m2/g, for instance at least 200 m2/g, optionally at least 300 m2/g.
The relative proportions of molecular sieve and inorganic oxide matrix may vary widely, with the molecular sieve content ranging from about 1% to about 100% by weight and more usually, particularly when the composite is prepared in the form of extrudates, in the range of about 2 to about 95, optionally from about 20 to about 90 weight percent of the composite.
The molecular sieve of the present disclosure may also be used in intimate combination with a hydrogenating component such as tungsten, vanadium, molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noble metal such as platinum or palladium where a hydrogenation-dehydrogenation function is to be performed. Such hydrogenating components may be incorporated in the composition by way of one or more of the following processes: cocrystallization; exchanged into the composition to the extent a Group IIIA element, e.g., aluminum, is in the structure; or intimately physically admixed therewith. Such components can also be impregnated in or onto the molecular sieve, for example, by treating the molecular sieve with a hydrogenating metal-containing ion. For instance, in the case of platinum, suitable platinum compounds for this purpose include chloroplatinic acid, platinous chloride and various compounds containing a platinum amine complex. Combinations of metals and methods for their introduction can also be used.
It will be understood by a person skilled in the art that the molecular sieve of the present disclosure may contain impurities, such as amorphous materials, unit cells having different topologies (e.g., quartz or molecular sieves of different framework type or of different layer phase, that may or may not impact the performance of the resulting catalyst), and/or other impurities (e.g., heavy metals and/or organic hydrocarbons). Typical examples of molecular sieves of different framework type co-existing with the molecular sieve of the present disclosure are e.g., molecular sieves of IWV framework type, such as ITQ-27. The molecular sieve of the present disclosure is preferably substantially free of impurities. The term “substantially free of impurities” (or in the alternative “substantially pure”) used herein means the molecular sieve material contains a minor proportion (less than 50 wt %), preferably less than 20 wt %, more preferably less than 10 wt %, even more preferably less than 5 wt % and most preferably less than 1 wt % (e.g., less than 0.5 wt % or 0.1 wt %), of such impurities (or “non-EMM-75” material), which weight percent (wt %) values are based on the combined weight of impurities and pure molecular sieve. The amount of impurities can be appropriately determined by powder XRD, rotating electron diffraction, and/or SEM/TEM (e.g., different crystal morphologies).
The molecular sieve described herein is substantially crystalline. As used herein, the term “crystalline” refers to a crystalline solid form of a material, including, but not limited to, a single-component or multiple-component crystal form, e.g., including solvates, hydrates, and a co-crystal. Crystalline can mean having a regularly repeating and/or ordered arrangement of molecules, and possessing a distinguishable crystal lattice. For example, the molecular sieve can have different water or solvent content. The different crystalline lattices can be identified by solid state characterization methods such as by XRD (e.g., powder XRD). Other characterization methods known to a person of ordinary skill in the relevant art can further help identify the crystalline form as well as help determine stability and solvent/water content. As used herein, the term “substantially crystalline” means a majority (greater than 50 wt %) of the weight of a sample of a material described is crystalline and the remainder of the sample is a non-crystalline form. In one or more aspects, a substantially crystalline sample has at least 95% crystallinity (e.g., 5% of the non-crystalline form), at least 96% crystallinity (e.g., 4% of the non-crystalline form), at least 97% crystallinity (e.g., 3% of the non-crystalline form), at least 98% crystallinity (e.g., about 2% of the non-crystalline form), at least 99% crystallinity (e.g., 1% of the non-crystalline form), and 100% crystallinity (e.g., 0% of the non-crystalline form).
Aspects of the disclosure are described in greater detail by way of specific examples. The following examples are offered for illustrative purposes and are not intended to limit the disclosure in any manner. Those of skill in the relevant art will readily recognize a variety of parameters can be changed or modified to yield essentially the same results.
The present invention is further illustrated below without limiting the scope thereto.
In these examples, the X-ray diffraction (XRD) patterns of the as-synthesized and calcined materials were recorded on an X-Ray Powder Diffractometer (Bruker DaVinci D8 Discovery instrument) in continuous mode using a Cu Kα radiation, Bragg-Bentano geometry with Vantec 500 detector, in the 20 range of 4 to 36 degrees. The interplanar spacings, d-spacings, were calculated in Angstrom units, and the relative intensities of the lines, I/IO is the ratio of the peak intensity to that of the intensity of the strongest line, above background. The intensities are uncorrected for Lorentz and polarization effects. The location of the diffraction peaks in 2-theta, and the relative peak area intensities of the lines, I/I(o), where Io is the intensity of the strongest line, above background, were determined with the MDI Jade peak search algorithm. It should be understood that diffraction data listed as single lines may consist of multiple overlapping lines which under certain conditions, such as differences in crystallographic changes, may appear as resolved or partially resolved lines. Typically, crystallographic changes can include minor changes in unit cell parameters and/or a change in crystal symmetry, without a change in the framework connectivity. These minor effects, including changes in relative intensities, can also occur as a result of differences in cation content, framework composition, nature and degree of pore filling, crystal size and shape, preferred orientation and thermal and/or hydrothermal history.
The scanning electron microscopy (SEM) images of the as-synthesized materials were obtained on a Hitachi 4800 Scanning Electron Microscope. SEM images were used to aid assessment of product purity. The presence of obviously different crystal morphologies in a SEM image can be an indication of impurities in the form of other crystalline materials. Such an approximate analysis can be especially useful in identifying the presence of formation of relatively minor amounts of crystalline impurities which may not be identifiable on product XRD patterns.
The overall BET surface area (SBET) of the materials was determined by the BET method as described by S. Brunauer, P. H. Emmett and E. Teller, J. Am. Chem. Soc., 1938, v. 60, pg. 309, incorporated herein by reference, using nitrogen adsorption-desorption at liquid nitrogen temperature. The external surface area (Sext) of the material was obtained from the t-plot method, and the micropore surface area (Smicro) of the material was calculated by subtracting the external surface area (Sext) from the overall BET surface area (SBET).
The micropore volume (Vmicro) and total pore volume (Vtot) of the materials can be determined using methods known in the relevant art. For example, the micropore and total pore volumes of the materials can be measured with nitrogen physisorption, and the data can be analyzed by the t-plot method described in Lippens, B. C. et al., “Studies on pore system in catalysts: V. The t method”, J. Catal., v. 4, pg. 319 (1965), which describes micropore and total pore volume methods and is incorporated herein by reference.
The molar ratios and conditions used for the syntheses of Examples 2 to 6, as well as the resulting products, are detailed below and summarized in Table 3.
A mixture of 15 g of 2-ethyl-benzimidazole, 21 g potassium carbonate (K2CO3), and 58.3 g of iodomethane in 170 mL of acetonitrile (CH3CN) was heated to 60° C. overnight. The reaction mixture was cooled to room temperature, potassium carbonate was filtered out from the solution, and the acetonitrile in the filtrate was removed via rotavap. Chloroform was added to the flask to precipitate the residual potassium salts, then the solution was filtered again. The filtrate in chloroform was rotavaped to obtain pure 2-ethyl-1,3-dimethyl-1H-benzo[d]imidazole-3-ium iodide.
The iodide salt of 2-ethyl-1,5-dimethylbenzimidazolium was then ion-exchanged with ion-exchange resin Amberlite® IRN78 OH hydroxide form, with a iodide: resin: water weight ratio of 1:3.5:5, to its hydroxide form. The exchange was performed at room temperature overnight.
A mixture of 1.2 g tetraethylorthosilicate (TEOS, >99 wt %) and 0.035 g Al(OH)3 (Sigma, 54 wt % Al2O3) was hydrolyzed at room temperature in 13.5 mL of 2-ethyl-1,3-dimethylbenzimidazolium hydroxide (QOH) solution (4 wt %) for about 2 hours to 3 hours and then 0.12 mL HF (48 wt % solution) was added to the mixture. The gel was left at room temperature for a few days to remove the ethanol and water, to produce a synthesis mixture having the following composition in terms of molar ratios:
10H2O:1SiO2:0.033Al2O3:0.5QOH:0.5HF
This thick paste was homogenized by hand in a PTFE container and transferred to a 23 mL PTFE-lined stainless steel Parr autoclave. The autoclave was kept at 135° C. with rotation (about 40 rpm) for 28 days in a convection oven. The product was isolated by filtration, rinsed with deionized water and dried at 90° C. in a vented drying oven. The as-synthesized material was then calcined to 580° C. in air within a box furnace with a ramping rate of 3° C./minute. The temperature remained at 580° C. for 8 hours and then the box furnace was allowed to cool.
XRD analysis of the as-synthesized and calcined products showed the material to have unique powder XRD patterns which could not be matched with any known molecular sieve or zeolite and were designated as pure as-synthesized and calcined EMM-75 products.
The as-made EMM-75 material was shown to be a layer phase with monoclinic symmetry (a:7.3000(15) A; b:17.7000(40) A; c:25.0000(50) A; J: 95.000(30)°) containing about 17% silanol defects, while upon calcination, it became more symmetric with orthorhombic cell (a:7.5900(15) A; b:17.8700(40) A; c:22.3500(50) A) and the defects were healed. The calcined EMM-75 material has 48 Si atoms in one unit cell. Calcined EMM-75 material shares similar structure as MOR zeolite, with one 12-ring dimension is more elliptical (12R: 6.5 Å by 8.3 Å for EMM-75 as compared to 6.5 Å by 7 Å for MOR), and a narrower 8-ring (8R: 5.7 Å by 2.3 Å for EMM-75 as compared to 5.7 Å by 2.6 Å for MOR).
The micropore surface area (Smicro) of the calcined version of the EMM-75 material of Example 2 was 174 m2/g, its external surface area (Sext) was 45 m2/g, its total volume (Vtot) was 0.23 cm3/g and its micropore volume (Vmicro) was 0.074 c cm3/g.
This example was conducted in similar conditions as Example 2 except that the Si/Al ratio was decreased to 12.5, resulting in a synthesis mixture having the following composition in terms of molar ratios:
10H2O:1SiO2:0.04Al2O3:0.5QOH:0.5HF.
After 28 days of heating at 135° C., pure EMM-75 product was obtained, as identified by its XRD pattern.
This example was conducted in similar conditions as Example 2, from a synthesis mixture having the following composition in terms of molar ratios:
10H2O:1SiO2:0.033Al2O3:0.5QOH:0.5HF
except that aluminum isopropoxide (Al(OiPr)3, 98 wt %, Sigma) was used as the Al source. After 28 days of heating at 135° C., pure EMM-75 product was obtained, as identified by its XRD pattern (
The micropore surface area (Smicro) of the calcined version of the EMM-75 material of Example 3 was 155 m2/g, its external surface area (Sext) was 147 m2/g, its total volume (Vtot) was 0.73 cm3/g and its micropore volume (Vmicro) was 0.069 cm3/g.
This example was conducted in similar conditions as Example 4 except that the Si/Al ratio was increased to 20, resulting in a synthesis mixture having the following composition in terms of molar ratios:
10H2O:1SiO2:0.025Al2O3:0.5QOH:0.5HF.
After 28 days of heating at 135° C., pure EMM-75 product was obtained, as identified by its XRD pattern.
This example was conducted in similar conditions as Example 4 except that the Si/Al ratio was increased to 20, resulting in a synthesis mixture having the following composition in terms of molar ratios:
10H2O:1SiO2:0.0125Al2O3:0.5QOH:0.5HF.
After 28 days of heating at 135° C., XRD pattern indicated that EMM-75 product was obtained with another layer phase impurity.
While the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different alterations, modifications, and variations not specifically illustrated herein. It will also be apparent to those skilled in the art that when numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated. Also, all numerical values within the detailed description herein are modified by “about” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.
Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.
Additionally or alternately, the invention relates to:
Embodiment 1. A molecular sieve having, in its calcined form, an X-ray diffraction pattern including at least 14 of the peaks in Table 1.
Embodiment 2. The molecular sieve of embodiment 1 having, in its calcined form, an X-ray diffraction pattern including at least 15, preferably at least 16, more preferably at least 17, most preferably all of the peaks selected from Table 1.
Embodiment 3. The molecular sieve of embodiment 1 or 2 having a molecular formula of Formula II:
(m)X2O3:YO2 Formula II,
wherein 0.01≤m≤0.1, X is a trivalent element, and Y is a tetravalent element.
Embodiment 4. The molecular sieve of embodiment 3, wherein X comprises or is aluminum and/or boron, preferably X comprises or is aluminum.
Embodiment 5. The molecular sieve of embodiment 3 or 4, wherein Y comprises or is silicon and/or germanium, preferably Y comprises or is silicon.
Embodiment 6. A molecular sieve having, in its as-synthesized form, an X-ray diffraction pattern including at least 9 of the peaks in Table 2.
Embodiment 7. The molecular sieve of embodiment 6 having, in its as-synthesized form, an X-ray diffraction pattern including at least 10, preferably at least 11, more preferably at least 12, most preferably all of the peaks selected from Table 2.
Embodiment 8. The molecular sieve of embodiment 6 or 7 having a molecular formula of Formula III:
(q)Q:(m)X2O3:YO2 Formula III,
wherein 0<q≤0.7, 0.01≤m≤0.1, X is a trivalent element, Y is a tetravalent element, and Q comprises a 2-ethyl-1,3-dimethylbenzimidazolium cation of Formula I
Embodiment 9. The molecular sieve of embodiment 8, wherein X comprises or is aluminum and/or boron, preferably X comprises or is aluminum.
Embodiment 10. The molecular sieve of embodiment 8 or 9, wherein Y comprises or is silicon and/or germanium, preferably Y comprises or is silicon.
Embodiment 11. The molecular sieve of any one of embodiments 1 to 10, wherein at least a portion of the molecular sieve crystals have a plate-like morphology.
Embodiment 12. The molecular sieve of any one of embodiments 1 to 11, which is an aluminosilicate or a borosilicate, preferably an aluminosilicate having a Si/Al molar ratio of 5 to 50.
Embodiment 13. A method of making a molecular sieve of any one of embodiments 1 to 12, comprising: (a) preparing a synthesis mixture comprising water, a source of an oxide of tetravalent element (Y), a source of an oxide of trivalent element (X), a structure directing agent (Q) comprising a 2-ethyl-1,3-dimethylbenzimidazolium cation of Formula I, a source of fluoride ions (F), and optionally a source of hydroxide ions (OH),
(b) heating said synthesis mixture under crystallization conditions including a temperature of from 100° C. to 200° C. for a time sufficient to form crystals of said molecular sieve; (c) recovering at least a portion of the molecular sieve from step (b); and (d) optionally treating the molecular sieve recovered in step (c) to remove at least part of the structure directing agent (Q).
Embodiment 14. The method of embodiment 13, wherein the structure directing agent (Q) is in the form of a halide, hydroxide or nitrate, preferably wherein the structure directing agent (Q) is in its hydroxide form.
Embodiment 15. The method of embodiment 13 or 14, wherein the tetravalent element (Y) comprises silicon and/or germanium, preferably wherein the tetravalent element (Y) is silicon and/or germanium, more preferably silicon.
Embodiment 16. The method of any one of embodiments 13 to 15, wherein the trivalent element (X) comprises aluminum and/or boron, more preferably wherein the trivalent element (X) is aluminum and/or boron, in particular aluminum.
Embodiment 17. The method of any one of embodiments 13 to 16, wherein the synthesis mixture has the following composition in terms of molar ratios:
Embodiment 18. The method of any one of embodiments 13 to 17, wherein the synthesis mixture is substantially free from alkali or alkaline earth metal cation (M) or, if some alkali or alkaline earth metal cation (M) is present, the molar ratio M/Y is at most 1.0, preferably at most 0.5, in particular at most 0.2, more particularly less than 0.1.
Embodiment 19. The method of any one of embodiments 13 to 18, wherein the synthesis mixture has a pH of less than 10, preferably at most 9.
Embodiment 20. The method of any one of embodiments 13 to 19, wherein the synthesis mixture has a pH of at least 3, preferably at least 4.
Embodiment 21. A process of converting an organic compound to a conversion product comprises contacting the organic compound with the molecular sieve of any one of embodiments 1 to 12.
The present application claims priority to and the benefit of U.S. Provisional Application No. 63/492,292 filed on Mar. 27, 2023, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63492292 | Mar 2023 | US |
