Method of making a molecular sieve of MFS framework type with controllable average size

摘要

A method of making a crystalline molecular sieve of MFS framework type, preferably ZSM-57, from a synthesis mixture comprising at least one source of tetravalent element (Y), at least one source of trivalent element (X), at least one source of alkali metal hydroxide (MOH), at least one structure-directing-agent (R) and water, said alkali metal (M) comprising potassium, and having the following mole composition (expressed in terms of oxide):
YO2:(p)X2O3:(q)OH−:(r)R:(s)H2O,
wherein (p) is in the range from 0.005 to 0.05, (q) is in the range from 0.01 to 3, (r) is in the range from 0.03 to 2 and (s) is in the range from 10 to 75 (based on total weight of said synthesis mixture); wherein the crystals of molecular sieve formed having an average diameter (D) of less than or equal to 1.5 micron and an average thickness (T) of less than or equal to 300 nanometers.

主权项

1. A method of making a crystalline molecular sieve of MFS framework type, said method comprising the steps of:
(a) providing a synthesis mixture comprising at least one source of tetravalent element (Y), at least one source of trivalent element (X), at least one source of alkali metal hydroxide (MOH), at least one structure-directing-agent (R) and water, said alkali metal (M) being a mixture of sodium and potassium, said synthesis mixture having the following molar composition (expressed in terms of oxide):
YO2:(p) X2O3:(q) MOH:(r)R:(s)H2Owherein (p) is in the range from 0.005 to 0.05,(q) is in the range from 0.01 to 3, (r) is in the range from 0.03 to 2, (s) is in the range from 10 to 75 and the molar ratio of sodium (q1) divided by the molar ratio of potassium (q2,) is less than or equal to 2.0; and
(b) treating said synthesis mixture under crystallization conditions to form crystals of molecular sieve of MFS framework type, said crystals having an average diameter (D) of less than or equal to 1.5 micron and an average thickness (T) of less than or equal to 300 nanometers.