Synthesis of “Ternary Embedded System” Loaded-heteropoly Acid Catalysts and Their Research on DBT Removal in Oxidative Desulfurization Process

Author:Li Si Wen

Supervisor:zhao jian she


Degree Year:2019





In recent years,along with the world economy development rapidly,the plenty of car ownership shows a trend of linear rise,followed by a series of serious air pollution problems,and the widespread occurrence of haze phenomenon is the best proof.The main components are sulfur dioxide,nitrogen oxides and particulate matter,which are closely related to automobile exhaust emissions.The source of its problem is the quality of oil products.Therefore,upgrading the quality of oil products to reduce the pollution caused by vehicle exhaust emissions,alleviating air pollution,has become a top priority to the environmental protection.Oxidative desulfurization technology has attracted much attention due to its mild reaction conditions,low cost and high removal effect on thiophene and its derivatives,and aimed to remove the dibenzothiophene(DBT)in fuel oil in this present paper.Oxygen is easy to get,low cost and no pollution,which has a broad prospect of research and application.Heteropoly acid,as a new,green catalyst,has been widely applied in various fields,and have achieved good results,but its low surface area and its aggregation,which leading to difficult to be recycled and limit its development.Therefore,finding a new type of heteropoly acid catalyst,to suitable overcome problems,has become the focus of research in this field.The main content of the paper is as follows:1.8 kinds of P-Mo-W Keggin-type heteropoly acids(H3PMo12-xWxO40)were synthesized by solution method,and then the MOF-199 and MCM-41 molecular sieve were used as the carrier.POM template self-construction of MOF-199 in the pore of MCM-41,called“ternary embedded system”loaded-heteropoly acid catalyst,was used in the DBT removal process.The results showed that the desulfurization rate of K6-PMM catalyst could reach 98.5%under the optimal reaction conditions.2.Substitution method was used to synthesize 8 kinds of transition metal-modified heteropoly acid salts M-POM(M=Cr,Mn,Fe,Co,Ni,Cu,Zn and Cd),and then the corresponding"ternary embedded system"supported heteropoly acid catalysts were synthesized.Under the same conditions,the performance of 8 catalysts in the removal of DBT from simulated fuel was compared,and it was found that the Co-PMM showed the best desulfurization effect,99.1%within 180min,and it could be reused for 10 times..3.Selecting the bi-quaternary ammonium Gemini surfactant–SRL,owing the high surface activity,to modify the heteropoly acid,and then the"ternary embedded system"phrase-transfer supported heteropoly acid catalyst was obtained.The introduction of phase transfer catalyst can not only promote the progress of catalytic reactions,but also further accelerate the combination of catalyst and extraction agent after the reaction,improving the recovery rate and increasing the number of repeated use.The results showed that SRL-3-PMM had a 100%desulfurization efficiency and could be reused for more than 13times.4.Using the lower price and stronger acidic caprolactam as raw materials,and grafting on heteropoly acid effectively,the new catalytic-extraction kind of heteropoly acid ionic liquid catalyst was synthesized,no later extraction process to simple the reaction operation.It was found CIL-3-PMM gained the completed desulfurization effect in 90 min and could be reused15 times.5.The DBT removal effect of different heteropolyacid active components was compared by using the macroporous molecular sieve LZSM-5 as the carrier.For the more active components introduced and their agglomeration decreased,a theoretical and practical basis could be provided,for which the application of macroporous materials as the carrier in oxidative desulfurization.