Patent ID: 7754934
Filing Date: 2010-07-13
Classification: C07C,Y02P

Abstract:
1. A method of producing ethylene and propylene which comprises contacting a hydrocarbon starting material containing 20% by mass or more of at least one olefin of 4-12 carbon atoms with a catalyst containing a medium pore diameter zeolite, the zeolite containing silver and substantially no protons, having a molar ratio SiO 2 /Al 2 O 3 of 200-5000 and selected from the group consisting of ZSM-5 type zeolites, in a reaction vessel under conditions of a reaction temperature of 400-600° C., a partial pressure of the hydrocarbon starting material of 0.01-0.5 MPa and a weight hourly space velocity of 1-100 hr −1 to carry out a catalytic conversion reaction of said at least one olefin of 4-12 carbon atoms, thereby obtaining a reaction mixture containing ethylene and propylene, separating the reaction mixture into a fraction A containing mainly hydrogen and hydrocarbons of 1-3 carbon atoms and a fraction B containing mainly at least one hydrocarbon of 4 or more carbon atoms, and separating ethylene and propylene from the fraction A, said method meeting the following requirements (i) and (ii): (i) to satisfy ΔAROMA/P≦13 (ii) to recycle 10-95% by mass of the fraction B to the reaction vessel without removing heavy materials and use it as the hydrocarbon starting material.