Patent ID: 7488700

Claim:
A hydrothermally stable porous molecular sieve catalyst, which consists of a product obtained by the evaporation of water from a raw material mixture comprising 100 parts by weight of a molecular sieve having a framework of —Si—OH—Al—, 0.0 1-5.0 parts by weight of a water-insoluble metal salt, and 0.05-17.0 parts by weight of a phosphate compound selected from a group consisting of phosphoric acid (H 3 PO 4 ), ammoniunm phosphate and alkyl phosphate; in which surface pores of the molecular sieve are modified with one of compounds represented by following formulas 1 to 3: [Formula 1] M x (H 2 PO 4 ) y , wherein M is a metal, x is 1, and y is an integer from 2 to 6; [Formula 2] M x (HPO 4 ) y , wherein M is a metal, x is 2, and y is an integer from 2 to 6; and [Formula 3] Mx(PO 4 ) y , wherein M is a metal, x is 3, and y is an integer from 2 to 6.