阅读说明：本技术 用于转化芳烃的催化剂和方法 (Catalyst and process for conversion of aromatic hydrocarbons ) 是由 M·皮尔拉切古拉比 J·E·加蒂 P·卡马科蒂 W·J·克奈伯 W·F·莱 P·波迪斯阿德 于 2020-03-26 设计创作，主要内容包括：本公开提供了用于转化含有C-(8+)芳烃(特别是C-(9+)芳烃)的芳烃进料以形成包含例如苯和/或二甲苯的转化产物混合物的方法和相应的催化剂。所述芳族进料可以被在催化剂存在下转化,所述催化剂包括具有MEL骨架的第一沸石如ZSM-11和具有MOR骨架的第二沸石如丝光沸石(特别是使用TEA或者MTEA作为结构导向剂合成的丝光沸石)的混合物。在所述催化剂中第一沸石与第二沸石的重量比可以在0.3-1.2的范围内,或者在0.3-1.1的范围内,或者在0.3-1.0的范围内。所述催化剂可以还包括负载在所述催化剂上的一种或多种金属,例如多种金属的组合。(The present disclosure provides methods for converting a catalyst containing C 8+ Aromatic hydrocarbons (especially C) 9+ Aromatics) to form a conversion product mixture comprising, for example, benzene and/or xylene, and a corresponding catalyst. The aromatic feed may be converted in the presence of a catalyst comprising a mixture of a first zeolite having a MEL framework, such as ZSM-11, and a second zeolite having a MOR framework, such as mordenite (particularly mordenite synthesized using TEA or MTEA as a structure directing agent). The weight ratio of the first zeolite to the second zeolite in the catalyst may be in the range of 0.3 to 1.2, or in the range of 0.3 to 1.1, or in the range of 0.3 to 1.0. The catalyst may further comprise one or more metals, for example a combination of metals, supported on the catalyst.)

1. For transforming a protein comprising C₈₊A process for the feed of aromatics, the process comprising:

contacting a feedstock and optionally hydrogen with a catalyst composition in a reactor containing at least one fixed catalyst bed of said catalyst composition under conversion conditions to produce a converted product mixture,

wherein the catalyst composition comprises:

(i) a mixture of a first zeolite having a MEL framework and a second zeolite having a MOR framework having a weight ratio of the first zeolite to the second zeolite in the range of 0.3 to 1.2; and

(ii) a combination of a first metal from group 10 of the periodic table and a second metal from groups 11 to 15 of the periodic table, the combination having a second metal to first metal molar ratio in the range of 1.0 to 10.

2. The process of claim 1 wherein the first zeolite comprises ZSM-11.

3. The process of claim 2 wherein the second zeolite consists essentially of ZSM-11.

4. The process of any of the preceding claims, wherein the weight ratio of the first zeolite to the second zeolite is in the range of from 0.3 to 1.0.

5. The process of any of the preceding claims, wherein the weight ratio of the first zeolite to the second zeolite is in the range of from 0.5 to 1.0.

6. The method of any of the preceding claims, wherein the second zeolite has a size greater than 30m²Mesopore surface area in g.

7. The process of any of the preceding claims, wherein the catalyst composition comprises 0.005 wt% to 0.1 wt% Pt as the first metal, based on the total weight of the catalyst composition.

8. The process of any of the preceding claims, wherein the catalyst composition comprises 0.005 wt% to 0.02 wt% Pt as the first metal, based on the total weight of the catalyst composition.

9. The process of claim 7 or claim 8, wherein the catalyst composition comprises tin as the second metal.

10. The method of any of the preceding claims, wherein the catalyst composition further comprises a binder.

11. The method of claim 5, wherein the binder comprises silica.

12. The process of any of the preceding claims, wherein the feedstock comprises C₉₊Aromatic hydrocarbons and at least one of benzene and toluene, and the product mixture of the conversion comprises xylenes.

13. The process of claim 12, wherein the step of contacting the feedstock with the catalyst composition is conducted in the presence of hydrogen.

14. The process of any preceding claim, wherein the conversion conditions include a temperature of 340 ℃ to 515 ℃, a pressure of 380kPa-a (55psia) to 4240kPa-a (615psia), and a pressure of 1 to 100hr, based on the weight of the feedstock^-1Within the range ofWeight Hourly Space Velocity (WHSV).

15. A catalyst composition comprising:

(i) a mixture of a first zeolite having a MEL framework and a second zeolite having a MOR framework having a weight ratio of the first zeolite to the second zeolite in the range of 0.3 to 1.2; and

(ii) a combination of a first metal from group 10 of the periodic table and a second metal from groups 11 to 15 of the periodic table, the combination having a second metal to first metal molar ratio in the range of 1.0 to 10.

16. The catalyst composition of claim 15, wherein the first zeolite comprises ZSM-11.

17. The catalyst composition of claim 16, wherein the first zeolite consists essentially of ZSM-11.

18. The catalyst composition of any of claims 15-17, wherein the weight ratio of the first zeolite to the second zeolite is in the range of 0.3 to 1.0.

19. The catalyst composition of any of claims 15-18, wherein the weight ratio of the first zeolite to the second zeolite is in the range of 0.5 to 1.0.

20. The catalyst composition of any one of claims 15-19, wherein the catalyst composition comprises 0.005 wt% to 0.1 wt% Pt as the first metal, based on the total weight of the catalyst composition.

21. The catalyst composition of any one of claims 15-20, wherein the catalyst composition comprises 0.005 wt% to 0.02 wt% Pt as the first metal, based on the total weight of the catalyst composition.

22. The catalyst composition of claim 21 or claim 22, wherein the catalyst composition further comprises tin as the second metal.

23. The catalyst composition of any of claims 15-22, wherein the second zeolite has a zeolite greater than 30m²A mesopore surface area per gram, and the second zeolite comprises agglomerates of primary crystals, and the primary crystals have an average primary crystal size as determined by TEM of less than 80nm and an aspect ratio of less than 2.

24. The catalyst composition of any one of claims 15-23, wherein the catalyst composition further comprises a binder.

25. The catalyst composition of claim 24, wherein the binder comprises silica.

Technical Field

The present disclosure provides catalysts and corresponding catalytic processes for transalkylation of aromatic hydrocarbons to more valuable products, such as heavy aromatics, to produce xylenes.

Background

One source of benzene and xylenes is the catalytic reformate, which is prepared by contacting a mixture of naphtha and hydrogen with a strong hydrogenation/dehydrogenation catalyst such as platinum on a moderately acidic support such as halogen-treated alumina. In general, C₆-C₈A distillate is separated from the reformate and extracted with a solvent selective for aromatic or aliphatic compounds to produce an aromatic mixture that is relatively free of aliphatic compounds. This mixture of aromatics usually contains BTX (benzene, toluene and xylene) and ethylbenzene.

Refineries also focus on passing lower value C₉The transalkylation of + aromatics with benzene or toluene to produce xylenes to produce benzene and xylenes is an increasingly important process. Chemical plants theoretically wish to process as much heavy C as possible₉+ aromatics while minimizing and possibly removing toluene/benzene co-feed. Both transalkylation activity and dealkylation activity are important for a successful catalyst system. Transalkylation is the ability to transalkylate a methyl group to form xylenes. The dealkylation activity is such that₉The ability to dealkylate the ethyl and propyl groups on the + aromatics to allow the formation of lower methyl/cyclic species that can be transalkylated with higher methyl/cyclic species to form xylenes. The metal function is required to saturate the olefins formed during dealkylation while maintaining the integrity of the aromatics saturation. Increasing amount of C in the feed as the plant turns₉Acceptable activity and catalyst life become challenging.

For C₉₊Aromatic hydrocarbons with C₆-C₇Catalyst systems for the transalkylation of aromatic hydrocarbons are disclosed in U.S. patent No. 7,663,010. The catalyst system described therein comprises (a) a first catalyst comprising a molecular sieve having a constraint index of 3 to 12 (e.g., a 10MR molecular sieve, such as ZSM-5, ZSM-11, ZSM-22 and ZSM-23) and a metal that catalyzes the saturation reaction of olefins formed by the dealkylation reaction and (b) a second catalyst comprising a molecular sieve having a constraint index of less than 3 (e.g., a 12MR molecular sieve, such as ZSM-12, MOR, zeolite beta, MCM-22 family molecular sieves) and optionally a metal (which may be the same or different from the metal on the first catalyst). U.S. Pat. Nos. 8,163,966 and 9,034,780 describe additional catalyst systems and processes for transalkylation of mixed aromatic feeds.

U.S. Pat. Nos. 8,183,424, 8,481,443 and 9,006,125 disclose the improved performance of using a packed bed system in a process for producing xylenes by C₉+ aromatic hydrocarbon feedstock and C₆And/or C₇Aromatic hydrocarbons and hydrogen and a first catalyst effective in dealkylating aromatic hydrocarbons and in forming C₂+ olefin saturation conditions to trigger transalkylation to produce a first effluent, the first catalyst comprising (i) a first molecular sieve having a constraint index of from 3 to 12 and (ii) at least first and second different IUPAC periodic table group 6 to 12 metals or compounds thereof. At least a portion of the first effluent is then contacted with a second catalyst comprising a second molecular sieve having a constraint index of less than 3 in an amount effective to reduce the amount of C₉+ aromatic hydrocarbons with C₆/C₇The aromatic hydrocarbons are subjected to transalkylation conditions to form a second effluent comprising xylenes.

U.S. patent 10,118,165 describes catalyst compositions and their use in heavy aromatics conversion processes. The catalyst composition includes a first zeolite having a constraint index of 3 to 12, a second zeolite corresponding to a mordenite synthesized from tetraethylammonium cations (TEA) or methyl tetraethylammonium cations (MTEA), a mixture of a group 10 metal and a group 11 to 15 metal. Examples of zeolites comprising a constraint index of 3 to 12 include ZSM-5 and ZSM-11.

Summary of The Invention

It has been found in a surprising manner that a catalyst composition comprising a mixture of a MEL framework zeolite, such as ZSM-11, and a MOR framework zeolite, such as mordenite, a metal, such as Pt, exhibits superior performance in terms of at least aromatics selectivity, ethyl substituted aromatics, xylene yield and in aromatics conversion processes such as C, as compared to a similar catalyst composition not containing the MEL framework zeolite but comprising a replacement zeolite, such as ZSM-5, in place thereof₉₊One or more of the aging rates in the transalkylation of aromatics with benzene/toluene.

In a first aspect, the present disclosure provides methods for converting a polypeptide comprising C₈₊A process for the feed of aromatics, the process comprising: contacting the feedstock and optionally hydrogen with a catalyst composition at conversion conditions in a reactor comprising at least one fixed catalyst bed of the catalyst composition to produce a converted product mixture, wherein the catalyst composition comprises: (i) a mixture of a first zeolite having a MEL framework and a second zeolite having a MOR framework, the mixture having a weight ratio of the first zeolite to the second zeolite of from 0.3 to 1.2; and (ii) a combination of a first metal from group 10 of the periodic Table of the elements and a second metal from groups 11 to 15 of the periodic Table of the elements, the combination having a second metal to first metal molar ratio of from 1.0 to 10.

In a second aspect, the present disclosure provides a catalyst composition comprising: (i) a mixture of a first zeolite having a MEL framework and a second zeolite having a MOR framework, the mixture having a weight ratio of the first zeolite to the second zeolite of from 0.3 to 1.2; and (ii) a combination of a first metal from group 10 of the periodic Table of the elements and a second metal from groups 11 to 15 of the periodic Table of the elements, the combination having a second metal to first metal molar ratio of from 1.0 to 10.

Brief description of the drawings

Figure 1 shows the various reaction pathways that may exist during the conversion of a heavy aromatic feed.

Figure 2 shows the aromatics selectivity versus ethyl aromatics conversion for various catalysts.

Detailed Description

SUMMARY

In various aspects and embodiments, methods for converting a feedstock containing C are provided₈₊Aromatic hydrocarbons (especially containing C)₉₊Heavy aromatics of aromatics) to form benzene and/or xylene and corresponding catalysts. The aromatic feed may be converted in the presence of a catalyst comprising a mixture of a first zeolite having a MEL framework, such as ZSM-11, and a second zeolite having a MOR framework, such as mordenite (particularly mordenite synthesized using TEA or MTEA as a structure directing agent). The weight ratio of the first zeolite to the second zeolite in the catalyst may be in the range of 0.3 to 1.2, alternatively in the range of 0.3 to 1.1, alternatively in the range of 0.3 to 1.0. The catalyst may further comprise one or more metals, for example a combination of metals, supported on the catalyst. 0.

It has been found that catalysts comprising a mixture of MEL framework zeolite and MOR framework zeolite (e.g., mordenite, particularly mordenite synthesized using TEA or MTEA) in the desired weight ratios can provide an unexpectedly beneficial combination of properties. For example, the aromatics selectivity of the catalyst can be unexpectedly high relative to the amount of ethyl-substituted aromatics converted. Ethyl substituted aromatics, such as ethylbenzene, are less desirable components in product mixtures that include xylenes, in part because it is difficult to separate such ethyl substituted aromatics from other desired products. However, the conversion of ethyl substituted aromatics by the ring opening reaction of saturated and/or aromatic rings represents a net loss of potential products, as such saturated and/or open aromatic rings can no longer be readily recycled for use in the production of additional desired aromatic products. Thus, the ability to reduce or minimize aromatics loss (i.e., high aromatics selectivity) while providing increased amounts of ethyl-substituted aromatics conversion is beneficial for the commercial production of aromatic products such as benzene, toluene, and/or xylene.

It has also been found that the use of a silica binder can unexpectedly reduce or minimize the rate of aging of a catalyst comprising a mixture of MEL framework zeolite and mordenite synthesised using TEA or MTEA. This may facilitate the use of, for example, MEL framework zeolites having a lower silica to alumina ratio, while providing improved catalyst lifetime.

Comprising C₈₊(particularly C)₉₊) Conversion of aromatic feeds of aromatics may require balancing various reaction mechanisms to achieve the desired products. FIG. 1 shows the reaction in a transalkylation reactor between toluene and C₉Aromatic hydrocarbons (from two exemplary C's)₉Aromatic hydrocarbons 1,3, 5-trimethylbenzene and 1-methyl-4-ethylbenzene). One desirable reaction is C₉Transalkylation between aromatic hydrocarbons (e.g., 1,3, 5-trimethylbenzene) and toluene to produce high value xylenes catalyzed by acids such as zeolites. Another desirable reaction is the deethylation of an aromatic hydrocarbon containing ethyl groups (e.g., 1-methyl-4-ethylbenzene) in the presence of an acid such as a zeolite to form toluene/benzene and an olefin (e.g., ethylene). It is highly desirable to hydrogenate the olefin (ethylene) to ethane in the presence of a hydrogenation metal catalyst to prevent it from ethylating aromatics. On the other hand, it is highly undesirable to allow an aromatic hydrocarbon (e.g., toluene) to undergo hydrogenation in the presence of a hydrogenation metal catalyst to form non-aromatics, which results in loss of aromatic rings ("ring loss"). Aromatic compounds, including benzene, toluene, xylene, and the like, are considered to be more valuable molecules than non-aromatic hydrocarbons. Therefore, it is highly desirable to reduce ring loss and increase deethylation in aromatic conversion processes such as transalkylation processes. The ability to balance the reaction train shown in fig. 1 is of high commercial value, as the ability to selectively remove ethyl substituted aromatics while reducing or minimizing aromatic ring loss may allow for an increase in the net yield obtained from conversion of the feed, while simplifying the separation process required to separate xylenes from other components of the conversion effluent.

In general, some types of catalysts or catalyst systems used to convert heavy aromatic effluents may involve the use of some combinations of mordenite with zeolites such as ZSM-5 and Pt with another metal supported on the catalyst. For catalysts comprising mordenite and ZSM-5, the use of a combination of Pt and Sn may seem less advantageous than a combination of Pt and Ga. This is due in part to the lower activity of catalysts comprising a combination of Pt and Sn for the conversion of ethyl substituted aromatics. However, it has been found that the combination of Pt and Sn as catalytic metals can provide an unexpectedly beneficial combination of aromatics selectivity (i.e., retention of aromatic rings in the conversion effluent) with a given or targeted level of ethyl-substituted aromatics conversion when using a combination of ZSM-11 and mordenite synthesized using TEA or MTEA.

The term "Framework type" as used in this specification is used in the sense described in the "Atlas of Zeolite Framework Types" (2001) published in 2001.

The term "arene" as used herein is to be understood in accordance with its art-recognized scope, which includes alkyl substituted and unsubstituted mononuclear and polynuclear compounds. The term "ethyl substituted aromatic hydrocarbon" refers to an aromatic hydrocarbon that includes at least one ethyl group as a substituent for an aromatic ring, such as ethylbenzene.

The term "hydrocarbon" refers to (i) any compound consisting of hydrogen and carbon atoms or (ii) any mixture of two or more such compounds in (i). The term "C_nHydrocarbon "(where n is a positive integer) refers to (i) any hydrocarbon compound containing a total number n of carbon atoms in its molecule or (ii) any mixture of two or more such hydrocarbon compounds in (i). Thus, C₂The hydrocarbon may be ethane, ethylene, acetylene or a mixture of at least two of them in any proportion. "C_mTo C_nHydrocarbon "or" C_m-C_nHydrocarbons "(where m and n are positive integers and m is<n) is C_m、C_m+1、C_m+2、…、C_n-1、C_nAny one of the hydrocarbons or any mixture of two or more thereof. Thus, "C₂To C₃Hydrocarbon "or" C₂-C₃The hydrocarbon "may be any of ethane, ethylene, acetylene, propane, propylene, propyne, propadiene, cyclopropane and any mixture of two or more thereof in any inter-component ratio. "saturated C₂-C₃The hydrocarbon "may be ethane, propane, cyclopropane or any proportion of two or more thereofAny mixture thereof. "C_n+By hydrocarbon is meant (i) any hydrocarbon compound containing a total number of carbon atoms of at least n in its molecule or (ii) any mixture of two or more such hydrocarbon compounds of (i). "C_n-By hydrocarbon is meant (i) any hydrocarbon compound containing in its molecule a total number of carbon atoms of at most n or (ii) any mixture of two or more such hydrocarbon compounds of (i). "C_mBy "hydrocarbon stream" is meant a stream consisting essentially of C_mA hydrocarbon stream of hydrocarbons. "C_m-C_nBy "hydrocarbon stream" is meant a stream consisting essentially of C_m-C_nA hydrocarbon stream of hydrocarbons.

Unless otherwise indicated, the phrase "consisting essentially of …" does not exclude the presence of other steps, elements, or materials, whether or not specifically mentioned in the specification, so long as such steps, elements, or materials do not affect the basic and novel features of the disclosure. In addition, they do not exclude impurities and differences normally associated with the elements and materials used. In the present disclosure, "consisting essentially of a certain component" may mean, for example, that at least 80 wt% of a given material is contained by weight, based on the total weight of the composition containing the component.

In the present discussion, references to groups of elements correspond to groups according to the IUPAC periodic table. Thus, the group 10 metals include Ni, Pt and Pd.

The term "mesoporous mordenite" as used herein means having a pore size greater than 30m²Mordenite zeolite with a mesopore surface area per gram. The mesoporous mordenite may be synthesized from TEA or MTEA and may comprise agglomerates composed of primary crystals having an average primary crystal size as determined by TEM of less than 80nm and an aspect ratio of less than 2, as disclosed in U.S. patent 10,017,394, which is incorporated herein by reference for the limited purpose of describing the synthesis of such mordenite.

The term "medium pore zeolite" as used herein refers to a zeolite having a constraint index of from 3 to 12. The term "constraint index" as used herein is defined in U.S. Pat. nos. 3,972,832 and 4,016,218, both incorporated herein by reference.

The term "TEA" as used herein refers to the tetraethylammonium cation. The term "MTEA" as used herein refers to the methyltriethylammonium cation. The term "aspect ratio" when used in reference to a primary crystal is defined as the longest dimension of a crystallite divided by the width of the crystallite, wherein the width of a crystallite is defined as the dimension of the crystallite in a direction orthogonal to the longest dimension, midway between the longest dimensions, which is relatively low, e.g., less than 2.0, as measured by TEM. Typically, the primary crystals are not elongated crystals or platelets with aspect ratios greater than 2.0.

The term "primary crystals" as used herein means individual, indivisible crystals as opposed to agglomerates. The primary crystals are typically adhered together by weak physical interactions (rather than chemical bonds) to form agglomerates. The words "crystalline" and "microcrystalline" are used interchangeably herein.

Catalyst composition

The catalyst composition employed in the process of the present invention comprises a first zeolite having a MEL framework type, a second zeolite comprising a MOR framework zeolite (e.g., a mordenite zeolite, particularly a mordenite zeolite synthesized from TEA or MTEA), at least one first metal of group 10 of the IUPAC periodic table and at least one second metal of groups 11-15 of the IUPAC periodic table, wherein the MOR framework zeolite may be a zeolite having a structure of greater than 30m²A mesoporous zeolite with a mesopore surface area per gram. The MOR framework zeolite may comprise agglomerates composed of primary crystals, and wherein the primary crystals have an average primary crystal size of less than 80nm as determined by TEM and an aspect ratio of less than 2. Preferably, the group 10 metal may be Pt and the group 11-15 metal may be Sn. The MOR framework zeolite may be a mesoporous mordenite zeolite.

ZSM-11 is an example of a MEL framework type zeolite. ZSM-11 has a constraint index of 3 to 12. ZSM-11 is described in U.S. Pat. No. 3,709,979, incorporated herein by reference. The constraint index and its method of determination are described in U.S. Pat. No. 4,016,218, the description of which is incorporated herein by reference with respect to the constraint index and its method of determination. Preferably, the first zeolite consists essentially of ZSM-11, such as containing ZSM-11 in a concentration of at least, for example, 85, 90, 95, 98, 99, or even 100 wt%, based on the total weight of the first zeolite.

Additional examples of MEL framework type Zeolites are SSZ-46 (described in U.S. Pat. No. 5,968,474), TS-2 (described in Reddy, J.S. and Kumar, R., Crystallization kinetics of a new titanium silicate with MEL structure (TS-2), Zeolite, 12,95-100(1992)), which may be used in the first zeolite of the zeolite mixture of the catalyst composition of the present disclosure. The contents of these references are incorporated herein by reference in their entirety. These alternative MEL framework zeolites and ZSM-11 may be used alone or in combination in or as the first zeolite.

The second zeolite comprises a MOR framework zeolite, such as mordenite, particularly a mordenite synthesized from TEA or MTEA structure directing agents. Desirably, the MOR framework zeolite has a structure of greater than 30m²Mesopore surface area in g. The MOR framework zeolite may comprise agglomerates of primary crystals, wherein the primary crystals have an average primary crystal size of less than 80nm as determined by TEM (transmission electron microscopy) and an aspect ratio of less than 2. Preferably, the second zeolite consists essentially of mordenite, for example comprising mordenite in a concentration of at least, for example, 85, 90, 95, 98, 99, or even 100 wt%, based on the total weight of the second zeolite. Preferably, the second zeolite consists essentially of, e.g., comprises, mesoporous mordenite in a concentration of at least, e.g., 85, 90, 95, 98, 99, or even 100 wt%, based on the total weight of the second zeolite.

Other examples of zeolites having a MOR framework include: RMA1- (described in Itabashi, K., Matsumoto, A., Ikeda, T., Kato, M.and Tsutsumi, K., Synthesis and chromatography properties of Rb-mordenite, Microporous mat.,101,57-65 (2007)); Ga-Si-O-MOR, described in Eaven, M.J., Reddy, K.S.N., Joshi, P.N.and Shiralkar, V.P., Synthesis of a Gallosilicate analog of High Silica, Large Port Mordenite, J.Incl.Phenom.,14,119-129 (1992); LZ-211 (described in U.S. patent No. 4,503,023); large and small open cell mordenite zeolites are described in Sand, L.B., Synthesis of large-and small-port zeolites, Molecular Sieves, pp.71-77 (1968). The contents of all of these references are incorporated herein by reference in their entirety. These MOR framework type zeolites and ZSM-11 may be used alone or in combination in the second zeolite of the catalyst composition of the present disclosure.

The mesoporous mordenite may contain agglomerates, typically irregular agglomerates. The agglomerates consist of primary crystals having an average primary crystal size as determined by TEM of less than 80nm, preferably less than 70nm, more preferably less than 60nm, for example less than 50 nm. The primary crystals may have an average primary crystal size, as determined by TEM, of, for example, greater than 20nm, optionally greater than 30 nm.

Optionally, the primary crystals of the mesoporous mordenite have an average primary crystal size at each of the a, b and c crystal vectors of less than 80nm, preferably less than 70nm, and in some cases less than 60nm, as determined by X-ray diffraction. The primary crystals may optionally have an average primary crystal size at each of the a, b and c crystal vectors of greater than 20nm, optionally greater than 30nm, as determined by X-ray diffraction.

The mesoporous mordenite will typically contain a mixture of agglomerates of the primary crystals with some unagglomerated primary crystals. A substantial portion, such as greater than 80 wt% or greater than 90 wt%, of the mesoporous mordenite will be present in the form of agglomerates of primary crystals. The agglomerates are typically in an irregular form. For more information on the Agglomerates see Walter, D. (2013) Primary Particles-Aggregates, in Nanomaterials (ed. Deutsche Forschungsgemeinschaft (DFG)), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany. doi: 10.1002/97527673919, pages 1-24. Usefully, the mesoporous mordenite is not an aggregate.

Optionally, the mesoporous mordenite comprises at least 50 wt%, preferably at least 70 wt%, advantageously at least 80 wt%, more preferably at least 90 wt% of irregular agglomerates consisting of primary crystals having a primary crystal size of less than 80nm, preferably less than 70nm, more preferably less than 60nm, for example less than 50nm, optionally consisting essentially of irregular agglomerates consisting of primary crystals having a primary crystal size of less than 80nm, preferably less than 70nm, more preferably less than 60nm, for example less than 50 nm. Preferably, the mesoporous mordenite of the present invention comprises less than 10% by weight of primary crystals having a size in excess of 80nm as assessed by TEM. Preferably, the mesoporous mordenite of the present invention is comprised of said irregular agglomerates comprised of crystallites having a crystal size of less than 80nm as determined by TEM. Preferably, the mesoporous mordenite of the present invention is substantially free of acicular or platelet crystals, e.g. contains less than 10% by number of acicular or platelet crystals as assessed by TEM.

Preferably, said primary crystals of the inventive porous mordenite have an aspect ratio of less than 3.0, more preferably less than 2.0, wherein said aspect ratio is defined as the longest dimension of the crystallite divided by the width of the crystallite, wherein the width of the crystallite is defined as the dimension of the crystallite in a direction orthogonal to said longest dimension midway between said longest dimension, measured by TEM.

The agglomerates of primary crystals are typically in irregular form and may be referred to as "secondary" particles because they are formed from agglomerates of crystallites, which are "primary" particles.

The primary crystals may have a narrow particle size distribution such that at least 90% by number of the primary crystals have a primary crystal size in the range of 20-80nm, preferably in the range of 20-60nm, as determined by TEM.

The mesoporous mordenite has a very small crystal size and a high mesoporous surface area, particularly by selecting the composition of the synthesis mixture. The very small primary crystal size promotes access of the reactant compounds to the active sites within the pores of the mordenite, thereby increasing catalytic efficiency.

Said mesoporous mordenite has a size greater than 30m²A/g, preferably greater than 40m²G, in some cases greater than 45m²Mesopore surface area in g, determined by BET.

The mesoporous mordenite preferably has a height of greater than 500m²A/g, more preferably more than 550m²G, in some cases greater than600m²Total surface area in g. The total surface area includes the surface area of the internal pores (zeolite surface area) and the surface area outside the crystals (external surface area). The total surface area is determined by BET.

Preferably, the ratio of said mesoporous surface area to the total surface area of the mesoporous mordenite is greater than 0.05.

The mesoporous mordenite preferably has a mesopore volume of greater than 0.1mL/g, more preferably greater than 0.12mL/g, and in some cases greater than 0.15 mL/g.

The Si: al (Al)₂(or SiO)₂/Al₂O₃) The molar ratio is preferably greater than 10 and may be, for example, in the range from 10 to 60, preferably in the range from 15 to 40. Si of post-treated mordenite: al (Al)₂The ratio is preferably in the range of 40 to 300, more preferably in the range of 60 to 150.

The mesoporous mordenite may be prepared by a process comprising the steps of:

a) providing a synthesis mixture comprising a source of silicon, a source of aluminum, an alkali metal (M) hydroxide, a source of Structure Directing Agent (SDA) selected from the group consisting of tetraethylammonium cation (TEA), methyltriethylammonium cation (MTEA), and mixtures thereof, optionally seed crystals, and water, the synthesis mixture having a composition comprising the following molar ratios:

SiO₂：Al₂O₃ 15-40

OH^-：SiO₂≤0.32

M⁺：SiO₂≤0.32

SDA：SiO₂≤0.10

H₂O：SiO₂≤20

b) subjecting the synthesis mixture to crystallization conditions to form crystals of mordenite zeolite comprising Structure Directing Agent (SDA) within its pores. The components of the synthesis mixture are combined and maintained under crystallization conditions.

Suitable sources of silicon (Si) include silica, colloidal suspensions of silica, precipitated silica, alkali metal silicates such as potassium and sodium silicates, tetraalkyl orthosilicates, and fumed silicas such as Aerosil and Cabosil. Preferably, the Si source is a precipitated silica, such as Ultrasil (available from Evonik Degussa) or HiSil (available from PPG Industries).

Suitable aluminum (Al) sources include aluminum sulfate, aluminum nitrate, aluminum hydroxide, hydrated aluminas such as boehmite, gibbsite and/or pseudoboehmite, sodium aluminate, and mixtures thereof. Other sources of aluminum include, but are not limited to, other water soluble aluminum salts or aluminum alkoxides, such as aluminum isopropoxide, or aluminum metal, such as aluminum in chip form. Preferably, the aluminium source is sodium aluminate, for example an aqueous sodium aluminate solution at a concentration of 40-45%, or aluminium sulphate, for example an aluminium sulphate solution at a concentration of 45-50%.

Alternatively or in addition to the Si and Al sources mentioned before, aluminosilicates may also be used as sources of both Si and Al. Preferably, SiO in the synthesis mixture₂：Al₂O₃The molar ratio is in the range of 15 to 40, more preferably in the range of 20 to 30.

The synthesis mixture also contains a source of alkali metal cations, M +. The alkali metal cation M + is preferably selected from sodium, potassium and mixtures of sodium and potassium cations. Sodium cations are preferred. Suitable sodium sources may be, for example, sodium salts such as NaCl, NaBr or NaNO₃Sodium hydroxide or sodium aluminate, preferably sodium hydroxide or sodium aluminate. Suitable potassium sources may be, for example, potassium hydroxide or potassium halides such as KCl or KBr or potassium nitrate. Preferably, the molar ratio M in the synthesis mixture⁺Si is in the range of 0.15 to 0.32, more preferably in the range of 0.20 to 0.32. Optionally, the molar ratio M⁺Si is less than 0.30.

The synthesis mixture also contains a source of hydroxide ions, for example an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. Hydroxide may also be present as a counter ion to the structure directing agent or by using aluminum hydroxide as an aluminum source. Preferably, OH^-: the Si range is greater than 0.13, and may be, for example, in the range of 0.15 to 0.32, preferably in the range of 0.20 to 0.32. Optionally, the OH^-: the Si ratio is less than 0.30. The synthesis mixture optionally comprises seeds. The seeds may be of any suitable boiling pointStone seed crystals, such as ZSM-5 or mordenite seed crystals. Preferably, the seeds are mesoporous mordenite crystals. The seed may be present, for example, in an amount of 0 wt% to 10 wt%, preferably 0.01 wt% to 10 wt%, for example 0.1 wt% to 5.0 wt% of the synthesis mixture. In a preferred embodiment, the synthesis mixture comprises seeds.

The structure directing agent (also referred to as SDA) is TEA and/or MTEA, preferably TEA, and may be present in any suitable form, for example in the form of a halide, but is preferably present in the form of its hydroxide. Suitable sources of structure directing agents include TEABr, TEAOH, MTEACl, MTEABr and MTEAOH. A preferred source of structure directing agent is TEABr. Preferably, the molar ratio SDA: Si is in the range of 0.005 to 0.10, more preferably in the range of 0.02 to 0.10, especially in the range of 0.02 to 0.05.

Having a relatively high solids content in the synthesis mixture facilitates the synthesis of small crystal mordenite. Preferably, H₂The O to Si ratio is not more than 20, for example, in the range of 5 to 20, preferably in the range of 5 to 17, especially in the range of 10 to 17. The synthesis mixture may, for example, have the composition shown in table 1 below in molar ratios.

The crystallization can be carried out under static or stirred conditions in a suitable reactor vessel such as a polypropylene tank orLined autoclaves or stainless steel autoclaves. Suitable crystallization conditions include temperatures of from 100 ℃ to 200 ℃, for example from 135 ℃ to 160 ℃. Preferably, the temperature is below 145 ℃. The synthesis mixture may be maintained at the elevated temperature for a time sufficient for crystallization to occur at the temperature used, for example, 1 day to 100 days, optionally 1 day to 50 days, for example, 2 days to 40 days. In some cases, the synthesis mixture may be held at a first temperature for a first time period of 1 hour to 10 days, then raised to a second, higher temperature for a time period of 1 hour to 40 days. After the crystallization step, the synthesized crystals are separated from the liquid and recovered.

TABLE 1 Synthesis of mesoporous mordenite mixtures

Molar ratio of	It is preferable that	More preferred	Particularly preferred
				SiO2：Al2O3	15-40	20-35	20-30
OH-：SiO2	0.15-0.32	0.20-0.32	0.20 to<0.30
				M+：SiO2	0.15-0.32	0.20-0.32	0.20 to<0.30
SDA：SiO2	0.005-0.10	0.02-0.10	0.02-0.05
				H2O：SiO2	5-20	5-17	10-17

In its as-synthesized form, the second zeolite typically has a chemical composition having the molar relationship shown in formula (F-1):

mQ：nSiO₂：Al₂O₃ (F-1)

in the formula (1), the relationship of m and n satisfies 0.001. ltoreq. m/n.ltoreq.0.1, for example, 0.001. ltoreq. m/n.ltoreq.0.05. In formula (1), n is at least 10, such as 10 to 60, preferably 15 to 40, and Q is a structure directing agent.

Since the as-synthesized mesoporous mordenite contains a structure directing agent in its pore structure, the product is typically activated prior to use in such a way that the organic portion of the structure directing agent, i.e., TEA and/or MTEA, is at least partially removed from the zeolite.

Calcined mesoporous mordenite is optionally prepared by calcining mordenite to remove the structure directing agent. The mesoporous mordenite may also be subjected to an ion exchange step to replace the alkali metal or alkaline earth metal ions present in the as-synthesized product with other cations. Preferred replacing cations include metal ions, hydrogen precursors such as ammonium ions, and mixtures thereof, more preferably hydrogen ions or hydrogen precursors. For example, the mesoporous mordenite can be subjected to an ion exchange step to replace the alkali or alkaline earth metal ions with ammonium cations and then calcined to convert the ammonium form of the mesoporous mordenite to the hydrogen form of the mesoporous mordenite. In one embodiment, the mesoporous mordenite is first subjected to a calcination step (sometimes referred to as "precalcination") to remove the structure directing agent from the pores of the mesoporous mordenite, then subjected to an ion exchange treatment, and then subjected to a further calcination step. However, it has been found that a pre-calcination step is not always required for the mesoporous mordenite of the present invention. In an alternative embodiment, the mesoporous mordenite is thus subjected to an ion exchange treatment without being subjected to a prior calcination step (or pre-calcination) and is calcined after said ion exchange treatment to remove the structure directing agent from the pores, thereby providing a calcined mesoporous mordenite for use in the second zeolite of the present invention.

The ion exchange step may comprise, for example, contacting the mesoporous mordenite with an aqueous ion exchange solution. Such contacting may occur, for example, 1 to 5 times. The contacting with the ion exchange solution is optionally performed at ambient temperature, or may be performed at elevated temperature. For example, mesoporous mordenite can be ion-exchanged by contacting with an aqueous ammonium nitrate solution at room temperature, followed by drying and calcination.

Suitable calcination conditions include heating at a temperature of at least 300 ℃, preferably at least 370 ℃ for at least 1 minute and generally not longer than 20 hours, for example a time of 1 to 12 hours. Although the heat treatment may be performed using a pressure lower than atmospheric pressure, atmospheric pressure is desirable for convenience. The heat treatment may be carried out at a temperature of up to 925 ℃. For example, the heat treatment may be carried out at a temperature of 400 ℃ to 600 ℃, for example 500 ℃ to 550 ℃, in the presence of an oxygen-containing gas.

The calcined mesoporous mordenite typically has a Si: al (Al)₂And (4) the ratio.

The catalyst composition of the invention comprises a first zeolite corresponding to a MEL framework type zeolite having a constraint index of from 3 to 12, for example ZSM-11; a second zeolite comprising a mesoporous mordenite zeolite; at least one first metal of group 10 of the IUPAC periodic table, such as Pt; and at least one second metal of groups 11 to 15 of the IUPAC periodic Table, such as Sn. In some embodiments, the weight ratio of the first zeolite to the second zeolite in the catalyst can be any convenient ratio, for example, having from 1 wt% to 99 wt% or from 10 wt% to 80 wt% of the first zeolite and/or from 1 wt% to 99 wt% or from 10 wt% to 80 wt% of the second zeolite. In some embodiments, the weight ratio of the first zeolite to the second zeolite may be in the range of 0.3 to 1.2, or in the range of 0.3 to 1.1, or in the range of 0.3 to 1.0. The first and second zeolites may be present in a mixture formed in any convenient manner. For example, the zeolites may be co-extruded into particles, or the zeolites may be separately extruded into particles and then mixed in the catalyst bed.

In addition to the first zeolite and the second zeolite, the catalyst comprises at least one first metal of group 10 of the IUPAC periodic Table and at least one second metal of groups 11-15 of the IUPAC periodic Table. The first metal of the group 10 metal includes, but is not limited to, one or more of nickel (Ni), palladium (Pd), platinum (Pt), and compounds containing its natural metal or ion, preferably platinum. The second metal of groups 11-15 includes, but is not limited to, one or more of copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), gallium (Ga), indium (In), tin (Sn), bismuth (Bi), and compounds containing their natural metals or ions, preferably tin.

In some embodiments, the catalyst composition may include 0.001 wt% to 5.0 wt%, or 0.01 wt% to 1.0 wt%, or 0.05 wt% to 0.6 wt% Pt. For example, the catalyst composition can include 0.005 wt% or more Pt, or 0.01 wt% or more, or 0.05 wt% or more, or 0.10 wt% or more, such as up to 2.0 wt%, or up to 5.0 wt%, based on the weight of the catalyst composition. Additionally or alternatively, in such embodiments, the catalyst composition may include 0.005 wt% to 5.0 wt% Sn, or 0.05 wt% to 2.0 wt%. For example, the catalyst composition can include 0.005 wt% or more Sn, or 0.01 wt% or more, or 0.05 wt% or more, or 0.10 wt% or more, such as up to 2.0 wt%, or up to 5.0 wt%, based on the weight of the catalyst composition. Optionally but preferably, the catalyst composition may comprise a Sn to Pt molar ratio of 0.5 to 10, alternatively 1.0 to 10, alternatively 0.5 to 7.0, alternatively 1.0 to 7.0.

The metal component, such as the first metal and/or the second metal, may be provided on the catalyst composition in any manner, such as impregnation or ion exchange of the first zeolite and/or the second zeolite by conventional methods, such as with a solution of a compound of the relevant metal, either before or after formation of the catalyst particles.

It may be desirable to incorporate into the first zeolite and the second zeolite in the catalyst composition another material that is resistant to the temperatures and other conditions employed in the transalkylation process of the invention. Such materials include active and inactive materials and synthetic or naturally occurring zeolites as well as inorganic materials such as clays, silica and/or metal oxides such as alumina. The inorganic material may be naturally occurring or may be in the form of a gelatinous precipitate or gel, including mixtures of silica and metal oxides.

The catalyst may further comprise at least one binder. Non-limiting examples of binders that can be used in the catalyst compositions of the present disclosure are: alumina, silica, clay, titania, zirconia, kaolin, clay, mixtures of two or more thereof, and the like. The use of a material that is itself catalytically active in combination with (i.e., in combination with or present during the synthesis of) the first and second zeolites can alter the conversion and/or selectivity of the catalyst composition. Inert materials are suitably used as diluents to control the amount of conversion so that the transalkylation product can be obtained in an economical and orderly manner without employing other means for controlling the rate of reaction. These catalytically active or inactive materials may be incorporated into, for example, naturally occurring clays such as bentonite and kaolin to improve the crush strength of the catalyst composition under commercial operating conditions. It is desirable to provide a catalyst composition having good crush strength because it is desirable in commercial applications to prevent the catalyst composition from breaking down into a powdery material.

Naturally occurring clays which can be composited with the first and second zeolites as the binder for the catalyst composition include the montmorillonite and kaolin families which include the subbentonites and the kaolins commonly known as Dixie, McNamee, Ga. and Florida clays or other clays in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the original state as originally mined or initially subjected to calcination, acid treatment or chemical modification.

In addition to the above materials, the first and second zeolites may be composited with a porous matrix binder material, such as an inorganic oxide selected from the group consisting of: silica, alumina, zirconia, titania, thoria, beryllia, magnesia, and combinations thereof 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. It may also be advantageous to provide at least a portion of the aforementioned porous matrix binder material in colloidal form to aid in the extrusion of the catalyst composition.

Each zeolite is typically mixed with the binder or matrix material such that the final catalyst composition contains the binder or matrix material in an amount of from 5 to 90 wt%, typically from 10 to 60 wt%, based on the weight of the catalyst. For example, the binder may correspond to 5 wt% to 50 wt%, or 5 wt% to 30 wt%, or 10 wt% to 30 wt% of the catalyst composition.

Prior to use, the catalyst composition may be steamed to minimize the aromatic hydrogenation activity of the catalyst composition. In the steaming process, the catalyst composition is typically mixed with 5% to 100% steam at a temperature of at least 260 ℃ to 650 ℃, at a pressure of 100-^-1To 20hr^-1At a WHSV of (a) for at least 1 hour, in particular from 1 to 20 hours.

Additionally, the hydrogenation component may be sulfided prior to contacting the catalyst composition with the hydrocarbon feed. This is conveniently achieved by contacting the catalyst with a source of sulphur, such as hydrogen sulphide, at a temperature in the range 320 ℃ to 480 ℃. The sulfur source may be contacted with the catalyst by a carrier gas such as hydrogen or nitrogen.

After the catalyst composition is contacted with the hydrocarbon feed, the catalyst may deactivate due to coking or metal agglomeration. The deactivated catalyst may be obtained by coke combustion with a stream containing oxygen or oxygen-containing compounds such as ozone, oxygen chloride (oxochlorine), carbon dioxide, etc., redispersion of the metal using oxidation-reduction cycles, oxygen chloride treatment, etc., washing with liquid hydrocarbons or aqueous solutions of inorganic and/or organic compounds such as water, ethanol, acetone, etc., or reversion with a stream containing hydrogenIs regenerated easily. Regeneration or rejuvenation may be at a temperature in the range of ambient temperature to 600 deg.C, a pressure in the range of 100kPa-a to 5000kPa-a, and 0.2hr^-1To 100hr^-1At WHSV of (1).

Raw materials

The feedstock used in the process of the present invention comprises one or more aromatic hydrocarbons containing at least 8 carbon atoms, such as C₈An aromatic hydrocarbon. Specific examples of C₈Aromatic hydrocarbons include ethylbenzene and the dimethylbenzene isomers. Typically, such C₈₊The aromatic hydrocarbons comprise aromatic hydrocarbons having boiling points in the range of 135-230 ℃ at atmospheric pressure.

In some embodiments, the feedstock may include an aromatic hydrocarbon having 9 or more carbon atoms, such as C₉₊An aromatic hydrocarbon. Specific C found in typical feeds₉₊The aromatic hydrocarbon may include mesitylene (1,3, 5-trimethylbenzene), durene (1,2,4, 5-tetramethylbenzene), hemimellitene (1,2, 4-trimethylbenzene), pseudocumene (1,2, 4-trimethylbenzene), ethyltoluene, ethylxylene, 1, 2-methylethylbenzene, 1, 3-methylethylbenzene, 1, 4-methylethylbenzene, propyl-substituted benzene, butyl-substituted benzene, dimethylethylbenzene, methylpropylbenzene, methylbutylbenzene, and mixtures of two or more thereof.

C₉₊Suitable sources of aromatics are any C rich in aromatics from any refinery process₉₊And (6) cutting. In some embodiments, the aromatic fraction may include a substantial proportion of C₉+ arenes, e.g. at least 80 wt% of C₉+ aromatic hydrocarbons, preferably at least 80 wt%, more preferably more than 90 wt% of the hydrocarbons will be at C₉-C₁₂Within the range of (1). Typical refinery fractions that may be useful include catalytic reformate, Fluid Catalytic Cracked (FCC) naphtha or zemof-type fluid bed catalytic cracked (TCC) naphtha.

The feedstock may also comprise benzene or toluene or a mixture of benzene and toluene. Thus, in a practical embodiment, the feed to the transalkylation reactor of the transalkylation process may comprise ethylbenzene, C₉+ aromatics and toluene. The feedstock may also include recycled/unreacted/produced benzene, toluene,Ethylbenzene and C₉+ aromatic hydrocarbons, obtained by distillation of the transalkylation effluent product itself. Typically, toluene comprises 5 wt% to 90 wt% of the feedstock and C₉+ is from 10 to 95% by weight of the said starting material. In a typical light feedstock, toluene comprises from 40 wt% to 90 wt%, e.g., from 50 wt% to 70 wt%, and C of the total feed to the transalkylation reaction zone₉The + aromatic components comprise from 10 to 60 wt%, for example from 30 to 50 wt%, of the total feed to the transalkylation reaction zone. In a typical heavy feed, toluene comprises from 15 wt% to 50 wt%, e.g., from 25 to 40 wt%, and C of the total feed to the transalkylation reaction zone₉The + aromatic components comprise from 50 to 85 wt%, for example from 60 to 75 wt%, of the total feed to the transalkylation reaction zone.

Hydrocarbon conversion process

For containing C₈₊A process for converting a feedstock of aromatic hydrocarbons to a conversion product mixture comprises the step of contacting the feedstock and optionally hydrogen in the presence of any one of the catalyst compositions of the present invention under suitable conversion conditions to produce a conversion product mixture comprising, for example, benzene, toluene, and xylenes.

The process may be carried out in any suitable reactor, including a radial flow, fixed bed, continuous flow, or fluidized bed reactor. In one alternative, the reactor used to contact the feedstock under suitable conversion conditions comprises at least one single fixed catalyst bed of the catalyst. In another alternative, the reactor for contacting the feedstock under suitable conversion conditions comprises at least one moving catalyst bed of the catalyst.

The conversion conditions typically include a temperature in the range of 340 ℃ to 515 ℃, e.g., 400 ℃ to 454 ℃; a pressure in the range of 380kPa-a to 4240kPa-a, such as 1480kPa-a to 3550 kPa-a; a hydrogen to hydrocarbon molar ratio of 1 to 5, e.g., 1 to 3; and 0.2hr^-1To 100hr^-1E.g. 1hr^-1To 100hr^-1WHSV of (1). The transalkylation reaction conditions being sufficient to convert a feed containing heavy aromatics to a feed containing a substantial amount of C₆-C₈Aromatic hydrocarbons such as benzene, toluene and xylenes, especially the products of benzene and xylenes. The above-mentionedThe transalkylation reaction conditions are also sufficient to convert ethylbenzene in the feed to benzene and ethane.

In a preferred embodiment, the contacting of the feedstock with the catalyst composition is carried out in the presence of hydrogen fed to the reactor. The presence of hydrogen is particularly advantageous when dealkylation of certain alkylbenzenes occurs to produce olefins in the conversion process. Desirably, such olefins are saturated with the hydrogen present in the reaction in the hydrogenation reaction catalyzed by the catalyst composition of the present disclosure.

In a particularly advantageous embodiment of the conversion process of the present disclosure, C in the feed₉₊The hydrocarbons are reacted with benzene and/or toluene in the feed in the presence of the catalyst composition to produce a xylene-rich conversion product mixture, which can be separated to produce valuable products, such as para-xylene and/or ortho-xylene.

In this disclosure, "feed" or "feedstock" is used to mean the aggregate of all materials fed into a reactor or vessel. It is to be understood as meaning that one or more material streams having the same or different composition are fed into a reactor or vessel.

Examples

The determination of the average primary particle size and the primary particle size distribution was carried out as follows. Several TEM pictures of the zeolite sample were taken; primary particles are identified and measured. For each primary particle having an aspect ratio greater than 1, the longest dimension is determined by drawing a line between the two points that are furthest apart at the edge of the particle. The length of the primary particles along a diagonal of 45 ° to the longest dimension and passing through the midpoint of the longest dimension is then measured as the particle size. Each measurement was grouped by being assigned to one of 10 particle size ranges covering the size range found in the sample. For example, size ranges centered around 187.5, 250, 312.5, 375, 437.5, 500, 562.5, and 625 angstroms may be used. The percent (%) crystal values on the y-axis were calculated as follows: the number of particles in each group/total number of particles measured multiplied by 100. Based on the grouping results, the average particle size was calculated as an arithmetic average.

The total BET and t-Plot micropore surface areas were measured by nitrogen adsorption/desorption using a Micromeritics Tristar II 3020 instrument after degassing the calcined zeolite powder at 350 ℃ for 4 hours. The mesopore surface area is obtained by subtracting the t-plot micropores from the total BET surface area. Mesopore volumes were from the same dataset. More information about the method can be found in, for example, "Characterisation of ports Solids and Powders: surface Area, Pore Size and Density ", s.lowell et al, Springer, 2004.

X-ray diffraction data (powder XRD or XRD) using a probe withThe Bruker D4 endevator diffraction system of the multichannel detector uses copper K-alpha radiation collection. The diffraction data was recorded by a 0.018 degree 2 theta scan pattern, where theta is the bragg angle and an effective count time of 30 seconds was used for each step.

The crystal sizes at the a, b and c crystal vectors were calculated based on the three (200), (020) and (002) peaks in the X-ray diffraction pattern using the Scherrer equation (p.scherrer, n.g.w.gottingen, Math-pys., 2, p.96-100 (1918)). The process and its use in zeolites are also described in a.w. burton, k.ong, t.rea, i.y.chan, microporus and mesoporus Materials,117, p.75-90 (2009). For the measurements described herein, calculations were performed using X-ray diffraction analysis software, Jade version 9.5.1, of Materials Data, inc.

Alpha value is a measure of the cracking activity of the catalyst and is described in U.S. Pat. No. 3,354,078 and Journal of Catalysis, Vol.4, p.527 (1965); vol.6, p.278(1966) and Vol.61, p.395(1980), each of which is incorporated herein by reference. The experimental conditions used herein for the tests included a constant temperature of 538 ℃ and variable flow rates as described in detail in Journal of Catalysis, Vol.61, p.395 (1980).

EXAMPLE 1 preparation of mesoporous mordenite crystals

A mixture was prepared using water, TEABr (50% solution), Ultrasil silica, sodium aluminate solution (45%), and 50% sodium hydroxide solution. Mordenite seeds were then added to the mixture. The mixture had the following molar composition:

the mixture was allowed to react for 72 hours at 290 ℃ F. (145 ℃) with 350RPM stirring. The product was filtered, washed with Deionized (DI) water and dried at 250 ° F (120 ℃). The XRD pattern of the as-synthesized material shows a typical mordenite pure phase topology. SEM of the as-synthesized material shows the morphology of irregularly shaped aggregates consisting of small crystals. The as-synthesized crystals were pre-calcined at 540 ℃ under nitrogen, then converted to the hydrogen form by three ion exchanges with ammonium nitrate solution at room temperature and then dried at 250 ° F (120 ℃) and calcined at 1000 ° F (540 ℃) for 6 hours. The resulting mordenite crystals had an SiO of about 21₂/Al₂O₃Mole ratio, 637 m/g surface area, 56 m/g mesopore surface area, 53.3 mg/g hexane adsorption, and 1200 a value.

Examples 2 to 4: synthesis of ZSM-11 crystals

Consists of water, TBABr (50% solution), Ultrasil^TMA mixture was prepared of silica, aluminum sulfate solution (47%), 50% sodium hydroxide solution and ZSM-11 seeds. The composition of the three synthesis mixtures is shown in table 2. Table 2 also shows the initial mixing and stirring conditions.

TABLE 2 ZSM-11 Synthesis of mixtures

The product was then filtered, washed with Deionized (DI) water and dried at 250 deg.F (120 deg.C). The XRD pattern of each of the resulting crystals (i.e., as-synthesized material) showed a typical ZSM-11 pure phase topology. SEM of the as-synthesized material shows the morphology of agglomerates consisting of small crystals with a size of less than 0.05 microns. The as-synthesized crystals were ion exchanged three times with ammonium nitrate solution at room temperature and then dried at 250 ° F (120 ℃)And calcined at 1000F (540 c) for 6 hours to convert to the hydrogen form. The crystal from example 2 had 481m²Total Surface Area (SA) per gram (i.e., microporous SA + mesoporous SA) and 96.9mg/g hexane adsorption. The crystal from example 4 had 484m²Total Surface Area (SA) per gram (i.e., microporous SA + mesoporous SA) and 98.2mg/g hexane adsorption.

EXAMPLE 5 (COMPARATIVE) -ZSM-5 Crystal Synthesis

Comprises water, TPABr (35% solution), HiSil^TMA mixture was prepared of silica, 45% sodium aluminate solution, 50% sodium hydroxide solution and ZSM-5 seeds. The mixture had the following molar composition:

the mixture is reacted with stirring at a temperature in the range of 100 ℃ to 150 ℃. The product was filtered, washed with Deionized (DI) water and dried at 250 ° F (120 ℃). The XRD pattern of the as-synthesized material shows a typical ZSM-5 pure phase topology. The SEM of the as-synthesized material shows the morphology of aggregates consisting of small crystals with a size of less than 0.1 micron. The as-synthesized crystals were pre-calcined at 540 ℃ under nitrogen, then converted to the hydrogen form by three ion exchanges with ammonium nitrate solution at room temperature and then dried at 250 ° F (120 ℃) and calcined at 1000 ° F (540 ℃) for 6 hours. The resulting ZSM-5 crystals have a SiO of about 50₂/Al₂O₃Molar ratio, 480 square meters per gram total Surface Area (SA), and about 100mg/g hexane adsorption.

Example 6 (comparative) -0.30 wt% Pt/3xGa Supported on 50 wt% mesoporous mordenite/20 wt% ZSM-5/30 wt% alumina

50 parts of the medium pore mordenite crystals from example #1 were mixed with 20 parts of ZSM-5 crystals from example 5 and 30 parts of alumina (Versal 300) in a mill. A solution of platinum tetraammine chloride and gallium (III) nitrate in water was added to the mill, and then a target loading of 0.03 wt% Pt and 0.032 wt% Ga was formed on the final extrudate. Sufficient water is added to produce a paste extrudable on an extruder with a total solids content of 49-53%. The mixture was extruded into 1/16 inch cylinders and then dried in a convection oven on a conveyor belt at 121 ℃ for several hours. The dried extrudates were pre-calcined at 538 ℃ under nitrogen to decompose and remove the organic templating agent. The pre-calcined extrudates were then humidified at ambient conditions with saturated air at a flow rate of 2cc/g/min for 1 hour. After humidification, the extrudate was exchanged with 1N ammonium nitrate to remove sodium. The extrudate was then washed with deionized water to remove residual nitrate ions, then dried at 121 ℃ for at least 4 hours, followed by calcination in air at 538 ℃.

Examples 7 to 31: preparation of mesoporous mordenite/ZSM-11/Binder

A series of catalysts comprising mesoporous mordenite, ZSM-11, alumina binder, Pt and Sn were prepared using the following procedure. The amounts of the components in the resulting catalyst are shown in table 3 below. The relative molar amounts of Sn and Pt are also shown.

The medium pore mordenite crystals from example 1 were mixed with ZSM-11 crystals and alumina (as a binder) in a mill. Most of the mixtures included ZSM-11 crystals from example 2. The exceptions are examples 22 and 23 (ZSM-11 of example 3, indicated by x) and examples 24 and 25 (ZSM-11 of example 4, indicated by x). The binder was alumina (Versal 300) unless it was noted that silica was used as the binder (examples 23, 25, and 30). An aqueous solution of platinum tetraammine chloride and tin (II) chloride dehydrate was added to the mill to achieve the desired target loading before the final extrudates of Pt and Sn were formed. Sufficient water was added to produce a paste extrudable on a1 inch extruder with a total solids content of 49-53%. The mixture of medium pore mordenite (example 1), ZSM-11, alumina and water was extruded into 1/16 inch cylinders and then dried overnight in a heated oven (hot pack oven) at 121 ℃. The dried extrudates were pre-calcined at 538 ℃ under nitrogen to decompose and remove the organic templating agent. The pre-calcined extrudates were then humidified at ambient conditions with saturated air at a flow rate of 2cc/g/min for 1 hour. After humidification, the extrudate was exchanged with 1N ammonium nitrate to remove sodium. The extrudate was then washed with deionized water to remove residual nitrate ions, then dried at 121 ℃ for at least 4 hours, and then calcined in air at 538 ℃.

TABLE 3 compositions of examples 7-31

TABLE 3-compositions of examples 7-31 (continuation Table)

Example 32 aromatic conversion results

The catalysts of examples 7-31 were used in a fixed bed unit on a laboratory scale corresponding to 60 wt% C₉The feed of + raffinate and 40 wt% toluene was tested. For each example, the extrudate was 14-18 mesh (1000-. The catalyst was activated by heating to 400 ℃ in hydrogen and holding at this temperature for 2 hours. The catalyst was then cooled to 350 ℃ before the feed blend was introduced.

The catalyst was brought to a temperature of 350 deg.C with the feed at a pressure of 390psig (about 2.7MPa-g) and 3.0hr^-1To produce a result. Temperature excursions of up to 400 ℃ were periodically used in the presence of the feed to simulate catalyst aging.

Table 4 below shows the results for the various catalysts indicated by the example numbers.

The results in Table 4 include aromatics selectivity, C, in the conversion effluent₉+ conversion and xylene yieldAnd (4) rate. And also provides C₉+ conversion and xylene yield. With respect to the results in table 4, the results are reported as an index or normalized value compared to the results obtained in comparative example 6. Thus, the aromatic Selectivity, C, of comparative example 6₉The + conversion, xylene yield and aging rate were normalized to 1.0 or 0 (aging rate). It should be noted that for the aging rate, negative values indicate less aging of the catalyst, so negative values mean that the catalyst retains more of the indicated activity over time.

TABLE 4 aromatics Selectivity, C₉₊Conversion and xylene yield

Table 4 shows the various results. First, in addition to example 28, various combinations of mesoporous mordenite and ZSM-11 with various Pt and Sn ratios appear to provide significant catalyst life advantages while providing similar or better aromatics selectivity, C₉+ conversion and xylene yield. Example 28 is notable for an increased Sn to Pt ratio (12 molar). Therefore, a Sn to Pt molar ratio of 1.0 to 10 is preferable for providing improved aging resistance while also providing desired activity.

Another result, demonstrated in table 4, is that reducing the metal content of the catalyst appears to provide improved aromatics selectivity, as shown in examples 13 and 15.

Another result in table 4 can be observed in examples 7, 11, 19 and 25. These examples represent the greatest reduction in the rate of catalyst aging relative to the baseline catalyst from example 6. It is noted that examples 7, 11 and 19 correspond to catalysts having a 4:1 weight ratio of mesoporous mordenite to ZSM-11. However, example 25 corresponds to a medium pore mordenite to ZSM-11 weight ratio of only 2.5: 1. Practice ofExample 25 also corresponds to a catalyst comprising a silica binder instead of an alumina binder. Thus, the use of a silica binder provides an unexpected improvement in catalyst life for catalysts corresponding to mixtures of mesoporous mordenite and ZSM-11. Note that example 24 has the same zeolite and metal content, but with an alumina binder. Selectivity, C of examples 24 and 25₉The + conversion and xylene yield were similar, but example 25 provided an unexpectedly superior aging rate.

Although table 4 shows that increased intermediate pore mordenite to ZSM-11 ratio results in reduced catalyst aging, it has been unexpectedly found that reducing the weight ratio of intermediate pore mordenite to ZSM-11 can provide an increase in selectivity to aromatics over the amount of ethyl substituted aromatics converted. FIG. 2 shows the aromatics selectivity versus ethyl-substituted aromatics conversion for the various catalysts in Table 4. In fig. 2, the trend line in the upper right hand corner of the graph corresponds to the trend line for a catalyst with a favorable combination of aromatics selectivity and ethyl-substituted aromatics conversion. As shown in fig. 2, examples 7 and 15 provide the most advantageous combination of aromatics selectivity and ethyl-containing aromatics conversion, which corresponds to a mesoporous mordenite to ZSM-11 ratio of about 1:1 (46: 34 and 42:38, respectively). It appears that the lower metal content in example 15 provides a further benefit. In contrast, example 13 provides the worst performance of aromatics selectivity versus ethyl aromatics-containing conversion, which corresponds to a 64:16 ratio of mesoporous mordenite to ZSM-11. More generally, a weight ratio of mesoporous mordenite to ZSM-11 of 3.0 or less or 2.5 or less may provide unexpected improvements in the ratio of selectivity to conversion of the aromatic hydrocarbon to the ethyl-substituted aromatic hydrocarbon.

It has been noted that one of the conventional difficulties with medium pore mordenite and Pt/Sn supported on ZSM-11 is that the conversion of ethyl substituted aromatics may be relatively low compared to the conversion temperature. The results shown in fig. 2 indicate that while the activity for converting ethyl substituted aromatics may be low relative to the conversion temperature, the resulting combination of aromatics saturation and ethyl substituted aromatics conversion is surprisingly beneficial.

In addition to the above, it is noted that all catalysts corresponding to the supported Pt/Sn mesoporous mordenite/ZSM-11 have an excellent combination of aromatics selectivity and ethyl substituted aromatics conversion relative to comparative example 6 (supported Pt/Ga mesoporous mordenite/ZSM-5).

Example 33 additional Activity trends

Other trends can be determined from various embodiments by comparing embodiments in which one of the features varies while the other remains constant. The data are shown in table 5. With respect to the data in Table 5, the initial values and the aromatics selectivity, C, after two weeks of catalyst aging are shown₉+ conversion and xylene yield.

TABLE 5 Activity trends

Table 5 includes two different comparisons wherein the weight ratio of the intermediate pore mordenite to ZSM-11 is different, but the remaining variables are held constant. Example 11 corresponds to a 64:16 mesoporous mordenite to ZSM-11 weight ratio, whereas example 12 corresponds to a 26:26 weight ratio. Examples 11 and 12 are otherwise similar, both including 0.03 wt% Pt and a 1:1 Sn to Pt molar ratio. As shown in Table 5, the higher intermediate pore mordenite to ZSM-11 ratio provided higher selectivity, C₉+ conversion and xylene yield. Examples 13 and 14 are related in a similar manner and again the higher intermediate pore mordenite to ZSM-11 ratio in example 13 provides higher selectivity, C₉+ conversion and xylene yield.

As another comparison, Table 6 shows the modification of Si to Al in ZSM-11₂Comparison of the effect of the ratio on the catalyst activity. With respect to the examples in Table 6, example 24 corresponds to Si and Al of about 27₂In contrast, example 8 corresponds to about 50 Si to Al₂In contrast, example 22 corresponds to Si and Al of about 100₂And (4) the ratio.

TABLE 6 Si/Al in ZSM-11₂Variation of ratio

As shown in Table 6, Si and Al were increased₂The ratio of (a) results in a decrease in the selectivity to aromatics. For C₉+ conversion and xylene yield, intermediate amounts of Si and Al₂The ratio results in the highest value.

Examples 34 to 47: alternative supported metals

A series of catalysts comprising mesoporous mordenite, ZSM-11, an alumina binder, Pt and a second metal selected from Mg, Re, Ag, Cu and Ga were prepared using the following procedure. The amounts of the components in the resulting catalyst are shown in table 3 below. The relative molar amounts of the second metal and Pt are also shown.

The mesoporous mordenite crystals from example 1 were mixed with zeolite crystals and alumina (as binder) in a mill. Most of the mixtures included ZSM-11 crystals from example 2. The exception is example 30, which contains ZSM-5 from example 6. The binder was alumina (Versal 300). An aqueous solution of platinum tetraammine chloride and a second salt providing a second metal was added to the mill prior to shaping to the desired target loading of Pt and second metal on the final extrudate. The second salt used was the nitrate of the second metal, except for Re, for which an ammonium salt was used. Sufficient water was added to produce a paste extrudable on a1 inch extruder with a total solids content of 49-53%. The mixture of EMM-34, ZSM-11, alumina and water was extruded into 1/16 inch cylinders and then dried in a heated oven at 121 ℃ overnight. The dried extrudates were pre-calcined at 538 ℃ under nitrogen to decompose and remove the organic templating agent. The pre-calcined extrudates were then humidified at ambient conditions with saturated air at a flow rate of 2cc/g/min for 1 hour. After humidification, the extrudate was exchanged with 1N ammonium nitrate to remove sodium. The extrudate was then washed with deionized water to remove residual nitrate ions, then dried at 121 ℃ for at least 4 hours, and then calcined in air at 538 ℃.

TABLE 7 compositions of examples 34-47

Some of the catalysts in table 7 were tested under aromatic conversion conditions in example 2. The results are shown in table 8, indicated by example no. The results in Table 8 include aromatics selectivity, C, in the conversion effluent₉+ conversion and xylene yield. And also provides C₉₊Conversion and xylene yield. With respect to the results in table 8, the results are reported as an index or normalized value compared to the results obtained in comparative example 6. Thus, the aromatic Selectivity, C, of comparative example 6₉The + conversion, xylene yield and aging rate were normalized to 1.0 or 0 (for aging rate). It should be noted that for the aging rate, negative values indicate less aging of the catalyst, so negative values mean that the catalyst retains more of the indicated activity over time.

TABLE 8 aromatic Selectivity, C₉₊Conversion and xylene yield

As shown in Table 8, example 39(Pt + Re) is at relative C₉₊The conversion, the relative xylene yield and the relative aging have advantageous values. However, overall aromatics selectivity is not as good. Other catalysts in table 8 generally have poor aging rates.

All numbers expressing "about" or "approximately" used in the specification and claims are to be understood as being modified in all instances by the term "about" and by consideration of experimental error and variations that are expected by those of ordinary skill in the art.

While the invention has been described and illustrated in connection with certain embodiments, it is to be understood that the invention is not limited to the details disclosed, and extends to all equivalents within the scope of the claims. All percentages, parts, ratios, etc., are by weight unless otherwise indicated. Unless otherwise indicated, reference to a compound or component includes the compound or component by itself as well as in combination with other elements, compounds, or components, e.g., mixtures of compounds. Further, when an amount, concentration, or other value or parameter is given as a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of an upper preferred value and a lower preferred value, regardless of whether ranges are separately disclosed. All patents, test procedures, and other documents cited herein, including priority documents, are fully incorporated by reference to the extent such disclosure is not inconsistent with this invention and for all jurisdictions in which such incorporation is permitted.