CRYSTALLINE MOLECULAR SIEVE LAYERS AND PROCESSES FOR THEIR MANUFACTURE.

摘要

A process is described for the manufacture of crystalline molecular sieve layers with good para-xylene over meta-xylene selectivity's good para-xylene permeances and selectivities. The process requires impregnation of the support prior to hydrothermal synthesis using the seeded method and may be undertaken with pre-impregnation masking. The crystalline molecular sieve layer has a selectivity (alphax) for para-xylene over meta-xylene of 2 or greater and a permeance (Qx) for para-xylene of 3.27 x 10-8 mole(px)/m2.s.Pa(px) or greater measured at a temperature of = 250 degree C and an aromatic hydrocarbon partial pressure of = 10 x 103 Pa.