Method For Making MAZ Framework Type Zeolites (Chevron)

CATEGORY: ZEOLITES 
Method For Making MAZ Framework Type Zeolites (Chevron)
United States Patent Application 20160137519
XIE; Dan    May 19, 2016
Assignee: Chevron U.S.A. Inc
Abstract

A method for preparing an MAZ framework type zeolite is disclosed using a trimethylphenylammonium cation as a structure directing agent. The MAZ framework type zeolite, in its as-synthesized form, contains in its intracrystalline pores the trimethylphenylammonium cation. The resultant MAZ framework type zeolite crystals have an average crystallite size of greater than 5 .mu.m.
TECHNICAL FIELD
[0001] This disclosure relates generally to MAZ framework type zeolites and methods for preparing the same using a trimethylphenylammonium cation as a structure directing agent. The resultant MAZ framework type zeolite crystals have an average crystallite size of greater than 5 .mu.m.
BACKGROUND
[0002] Molecular sieves 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," Sixth Revised Edition, Elsevier, 2007.
[0003] One known molecular sieve for which a structure has been established is the material designated as MAZ, which is a molecular sieve having a tubular 12-membered ring (12-MR) channel system having a diameter of 7.4 .ANG.. A secondary 8-membered ring (8-MR) channel system having dimensions of 3.4.times.5.6 .ANG. runs parallel to the 12-MR pore system. Examples of MAZ framework type materials include zeolite omega and ZSM-4. MAZ framework type materials are of interest for application in catalysis, particularly various hydrocarbon conversion reactions such as (hydro)cracking, reforming, isomerization, disproportionation, and alkylation and dealkylation processes.
[0004] U.S. Pat. No. 4,241,036 discloses zeolite omega and its synthesis using a tetramethylammonium cation as a structure directing agent.
[0005] Great Britain Patent No. 1,117,568 discloses zeolite ZSM-4 and its synthesis in the presence of a tetramethylammonium cation as a structure directing agent.
[0006] U.S. Pat. No. 4,021,447 discloses that pyrrolidine and choline salts can be used as structure directing agents in the synthesis of ZSM-4.
[0007] U.S. Pat. No. 4,331,643 discloses the synthesis of ZSM-4 using 1,4-diazobicyclo[2.2.2]octane as a structure directing agent.
[0008] U.S. Pat. No. 4,377,502 discloses the synthesis of ZSM-4 using various oxygen-containing and oxygen-nitrogen-containing organic compounds as a structure directing agent.
[0009] It has now been found that pure phase MAZ framework type zeolites can be prepared using a trimethylphenylammonium cation as a structure directing agent. The resultant MAZ framework type zeolite crystals have an average crystallite size of greater than 5 .mu.m.
SUMMARY
[0010] In accordance with the present disclosure, there is provided a method of preparing MAZ framework type zeolites by contacting under crystallization conditions (1) at least one source of silicon; (2) at least one source of aluminum; (3) at least one source of an element selected from Groups 1 and 2 of the Periodic Table; (4) hydroxide ions; and (5) a trimethylphenylammonium cation.
[0011] In another aspect, there is provided a process for preparing MAZ framework type zeolites by: (a) preparing a reaction mixture containing (1) at least one source of silicon; (2) at least one source of aluminum; (3) at least one source of an element selected from Groups 1 and 2 of the Periodic Table; (4) hydroxide ions; (5) a trimethylphenylammonium cation; and (6) water; and (b) subjecting the reaction mixture to crystallization conditions sufficient to form crystals of the MAZ framework type zeolite.
[0012] In yet another aspect, there is provided an MAZ framework type zeolite having a composition, as-synthesized and in its anhydrous state, in terms of mole ratios, as follows:
TABLE-US-00001 Broad Exemplary SiO.sub.2/Al.sub.2O.sub.3 5 to 10 5 to 10 Q/SiO.sub.2 0.015 to 0.15 0.04 to 0.10 M/SiO.sub.2 0.010 to 0.20 0.05 to 0.20
wherein Q is a trimethylphenylammonium cation; and M is selected from the group consisting of elements from Groups 1 and 2 of the Periodic Table.
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