Oxidative Desulfurization Of Sulfur Compounds Over The Metal Modified Ti-MWW

Concerning the increasing seriously environmental problems,many countries have constituted a more and more stringent level for sulfur content in liquid fuels.The traditional hydrodesulfurization process(HDS)becomes economically insufficient with the decreasing lower sulfur in fuels.It has now attracted more research groups in finding a more economical and efficient process to obtain low sulfur fuels.In recent years,oxidative desulfurization combined with extraction/adsorption has been paid more and more attention due to its mild reaction conditions and high sulfur removal.As high active oxidation catalysts,Ti-containing molecular sieves were used to catalyze the oxidation of sulfur compounds at mild conditions.Therefore,in the ODS process we do basic study solving the problems which still exist higher temperature,the usage of oxidant and so on.The major content of this paper is composed of two parts.1.Oxidative desulfurization of sulfur compounds over the metal ions modified Ti-MWWDibenzothiophene(DBT)in octane was investigated using metal modified Ti-MWW as catalyst and hydrogen peroxide as the oxidant.The catalytic activity of noble metal(Ag,Pd,and Au)modified Ti-MWW showed much higher activity than that of non-noble metal modified Ti-MWW,the gold modified Ti-MWW has the highest catalytic activity.Proper loading content of the gold was important,the optimal loading of the gold is 0.05%,the optimal temperature is 40℃,and the optimal reaction ratio(H₂O₂/S)is 3.In comparison,the oxidation activity of 0.05%Au/ Ti-MWW gave higher activity for TH,BT,DBT and DMDBT than that of Ti-MWW. The conversion of TH BT,DBT and DMDBT increased by 16,22,24,26% respectively.At the same reaction conditions,the oxidative conversion of DBT was decreasing in the presence of olefins.The oxidation of organic of sulfur compounds in commercial diesel oil was also investigated;the organic sulfur could be reduced from initial 1015μg/g to 251μg/g over Au/Ti-MWW at optimal conditions.The desulfurization yield was 75%. 2.Kinetics of dibenzothiophene and benzothiophene oxidation over Au/Ti-MWW using H₂O₂ under mild conditions.The kinetics of benzothiophene and dibenzothiophene was studied over Ti-MWW, Au/Ti-MWW respectively.The obvious reaction order was obtained both for substrate and the catalyst.The following results were obtained:●The reaction order of BT is 1;the reaction order of Ti-MWW is 0.61. And the obvious reaction constantκ=2.76×10⁴ exp(-41.43/RT)●The reaction order of DBT is 1;the reaction order of Ti-MWW is 0.87. And the obvious reaction constantκ=3.224×10³ exp(-46.64/RT)●The reaction order of BT is 1;the reaction order of Au/Ti-MWW is 0.40. And the obvious reaction constantκ= 2.59×10² exp(-27.15/RT)●The reaction order of DBT is 1;the reaction order of Au/Ti-MWW is 0.55. And the obvious reaction constantκ=2.84×10² exp(-31.7/RT)...