Crystalline aluminosilicates and their use in the conversion of methanol to low molecular weight hydrocarbons

A method for the conversion of methanol comprising:

• contacting methanol in the presence of a hydrogen cofeed with a catalytically effective amount of a crystalline aluminosilicate composition under conversion conditions effective to provide C.sub.2 -C.sub.4 hydrocarbons at a selectivity of at least 50%, said conversion conditions comprising a temperature of 325.degree.-500.degree. C. and a pressure of 50-1000 psig and said crystalline aluminosilicate composition being prepared by a method which comprises:
• (a) contacting a crystalline aluminosilicate with a Group VIII metal salt solution to incorporate about 0.2 to about 5% by weight of said metal onto said crystalline aluminosilicate, said Group VIII metal being platinum, palladium or ruthenium and said crystalline aluminosilicate being ZSM-5, zeolite Y, or mordenite;
• (b) calcining the Group VIII metal crystalline aluminosilicate in air at a temperature of about 300.degree. C. to about 600.degree. C. for at least 4 hours;
• (c) heating the calcined Group VIII metal crystalline aluminosilicate in the presence of hydrogen from ambient temperature to an elevated temperature of about 300.degree. C. to about 500.degree. C. at a rate of temperature increase of about 0.5.degree. to about 2.0.degree. C. per minute;
• (d) maintaining said crystalline aluminosilicate at said temperature for about 0.75 to about 1.25 hour;
• and
• (e) cooling said crystalline aluminosilicate to ambient temperature in the presence of hydrogen.