Inorganic composite membrane containing molecular sieve crystals,
the membrane having a macroporous support to which molecular sieve
crystals and modifications thereof have been applied substantially
as monolayer, the crystals have been oriented to a substantial extent,
such that the pores of the sieve crystals form a significant included
angle with the support surface, the membrane has a gastight matrix
present between the crystals.
Large zeolite and zeolite-like molecular sieve crystals of from
3 to 500 .mu.m are fixed on moldings by a process in which an adhesion
promoter is used or the moldings are softened.
A method for preparing one or more specific dimethyltetralins from
either 5-(o-, m-, or p-tolyl)-pent-1- or -2-ene or 5-phenyl-hex-1-
or -2-ene, and optionally for preparing one or more specific dimethylnaphthalenes
from the aforesaid dimethyltetralins is disclosed wherein the orthotolylpentene
or phenylhexane is cyclized to the dimethyltetralin using an ultra-stable
crystalline aluminosilicate molecular sieve Y-zeolite.
Molecular sieve compositions are prepared by extracting aluminum
and substituting chromium and/or tin for extracted aluminum to give
molecular sieve products containing framework chromium and/or tin
atoms. The process of preparing the chromium and/or tin-containing
molecular sieves involves contacting a starting molecular sieve
with a solution or slurry of at least one of a fluoro salt of chromium
or a fluoro salt of tin under effective process conditions to provide
for aluminum extraction and substitution of chromium and/or tin.