Thiophene(C4H4S) is a typical sulfur-containing compound in fluid catalytic cracking(FCC) gasoline.Oxidative desulfurization of C4H4S in n-heptane solution was conducted with hydrogen peroxide (H2O2) and formic acid over a catalyst of 5A molecular sieve loaded with ceria.The effects of oxidative agent, solvent,reaction temperature as well as the addition of phase transfer catalyst were investigated in detail.The reaction course of oxidative desulfurization of C4H4S was preliminarily studied.The oxidation of C4H4S was achieved under mild reaction conditions and it was easy to raise the reaction temperature or increase the reaction time to achieve high oxidation conversions.The results showed that the conversion of C4H4S in n-heptane solution was 78.2% under the condition of reaction temperature of 50℃,nH2O2∶nS=10∶1,VH2O2∶VHCOOH=1∶1.The conversion of C4H4S was 94.5% when an emulsifier OP was added to this system.However, with the addition of tetrabutylammonium bromide (TBAB), a bromine substitution product appeared in the oxidation of C4H4S.
Desulfurization from cracking of gasoline via selective oxidation catalyzed by phase tranfer catalyst is investigated.Using cetyltrimethyl ammonium bromide(CTAB) as the phase transfer catalyst,hydrogen peroxide as the oxidant,acetic anhydride as the assistant oxidant,the effects of different conditions,such as reaction time,reaction temperature,the content of phase transfer catalyst,on the desulfurization rate are investigated.When the volume ratio of gasoline and oxidative system is 0.2,the volume ratio of hydrogen peroxide and acetic anhydride is 5,the content of phase transfer catalysis is 0.06 g,reaction time is 0.5 h,the desulfurization rate of the FCC gasoline is 80.13%.After analyzed by GC-FPD,there is no oxidized sulfur-containing compounds remained in the gasoline.
