Synthesis of zeolite ZSM-5
AssigneeMobil Oil Corporation
InventorBruce Patrick Pelrine
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Abstract
As synthesized by conventional technique, zeolite ZSM-5 crystals are cubic with some twinning and measure in size over the range of from about 3 .times. 3 microns to about 8 .times. 8 microns. By synthesizing crystalline aluminosilicate zeolite ZSM-5 according to the present method, i.e. in the presence of a tetraureacobalt (II) complex and with a specifically defined reaction mixture composition, the crystalline product will consist of highly twinned rectangular prismatic crystals exhibiting extreme uniformity in size of from about 5 .times. 10 microns to about 10 .times. 20 microns, depending on the ratio of said tetraureacobalt (II) complex to silica in the zeolite synthesis reaction mixture. Synthesis of ZSM-5 in accordance hereto will provide a zeolite with enhanced catalytic activity for certain chemical reactions.
Claims10
A method for synthesizing crystalline aluminosilicate zeolite ZSM-5 in a highly twinned, rectangular prismatic crystal form of uniform size which comprises the steps of
- preparing a reaction mixture containing sources of sodium oxide, tetraalkylammonium oxide, an oxide of aluminum, an oxide of silicon, water and a tetraureacobalt (II) complex and having a composition, in terms of mole ratios of oxides, falling within the following ranges:
- ______________________________________ SiO.sub.2 /Al.sub.2 O.sub.3 = 5-100 H.sub.2 O/SiO.sub.2 = 0.7-3000 OH.sup.- /SiO.sub.2 = 0.07-10.0 X/SiO.sub.2 = 0.0047-0.047 M/SiO.sub.2 = 0.3-3.0 R/SiO.sub.2 = 0.01-2.0 ______________________________________
- wherein M is an alkali metal ion and R is a tetraalkylammonium cation, the alkyl groups of which contain 2-5 carbon atoms and X is a tetraureacobalt (II) complex,
- and maintaining said mixture at a temperature of from about 100.degree. F to about 400.degree. F until crystals of said zeolite are formed.
Dependencies are inferred from the claim text.