Alkylation desulfurization of FCC gasoline over organic-inorganic heteropoly acid catalyst

Abstract

The alkylation reaction of thiophenic sulfides with olefin in model fluid catalytic cracking (FCC) gasoline has been carried out over many kinds of organic-inorganic heteropoly acids, H3PW12O40, and AlPW12O40. The results have showed that organic-inorganic heteropoly acid [Bmim]H2PW12O40 exhibits the best catalytic activity for the alkylation of thiophene (T), 2-methyl thiophene (2-MT) and 3-methyl thiophene (3-MT). Many effect factors for the alkylation of thiophenic sulfides catalyzed by [Bmim]H2PW12O40 have been fully investigated. Under the optimal reaction conditions (the catalyst dosage 1wt%, reaction temperature 120°C, reaction time 40min and the stirring rate 500rpm), the conversions of T, 2-MT and 3-MT all can nearly reach up to 100%. [Bmim]H2PW12O40 has also exhibited good stability and recyclability. The conversions of thiophenic sulfides nearly remain unchanged during 11 recycles of [Bmim]H2PW12O40. Apparent reaction kinetics for the alkylation of thiophenic sulfides is studied. The alkylations of T, 2-MT and 3-MT all show the pseudo-first-order kinetic characteristics. The order of the reaction rate constants of three thiophenic sulfides is 2-MT>3-MT>T. However, the calculated apparent activation energies of T, 2-MT and 3-MT are 62, 45.54 and 71.33kJ/mol, respectively. So, the order of apparent activation energies is 3-MT>T>2-MT.