Desilicated ZSM-5 catalysts for xylene isomerization

A method of making a xylene isomerization catalyst comprising:

• (i) contacting a ZSM-5 zeolite starting material having a silica to alumina molar ratio of about 20 to about 50, in the form of a powder having a mesopore surface area in the range of about 50 m2/gram to about 200 m2/gram in a reactor with a base at a temperature of about 20° C. to about 100° C. for a caustic base treatment period of about 1 minute to about 10 hours to provide an intermediate zeolite material,
• wherein the ZSM-5 zeolite is present in the base in an amount of about 1 weight % to about 20 weight %, and
• wherein the base is added to the reactor incrementally or continuously during the caustic base treatment period;
• (ii) recovering the intermediate ZSM-5 zeolite material of step (i);
• (iii) contacting the intermediate zeolite material with an acid at a temperature of about 20° C. to about 100° C. for an acid treatment period of about 1 minute to about 10 hours to provide to provide an acid treated ZSM-5 zeolite product;
• and
• (iv) recovering the acid treated ZSM-5 zeolite material;
• (v) mixing the acid treated ZSM-5 zeolite material with a support selected from the group consisting of an alumina support, a silica support, a silica-alumina support, a titanic support, a zirconia support, and any combination thereof, and
• (vi) calcining the acid treated ZSM-5 zeolite material at a temperature in the range of about 300° C. to about 700° C. for a period of time in the range of about 0.2 hours to about 6 hours to provide a supported xylene isomerization catalyst comprising a desilicated ZSM-5 zeolite product supported on a support, the desilicated ZSM-5 zeolite product having a silica to alumina molar ratio of about 20 to about 150 and having a mesopore surface area in the range of about 100 m2/gram to about 400 m2/gram.