Synthesis Of Methyl Propionate Based On CO₂ As C₁ In Ioninc Liquid

As a greenhouse gas,CO₂ has the advantages of low cost,non-toxicity,and easy transportation.Converting CO₂ into valuable chemicals has a great significance for alleviating energy pressure and the long-term development of human society.The carbonylation reaction has the characteristics of environmental friendliness,high selectivity for the reaction and atom economy.It has been a bridge between petrochemical industry and C₁ chemical industry.In this article,carbon dioxide was used as C₁ to synthesize methyl propionate.The main research contents are as following.1.SBA-15 molecular sieve was used as carrier,imidazole ionic liquid[TesPmim]Cl was loaded by chemical method and Ru₃?CO?₁₂ by impregnation.The content of rhenium was determined by UV standard curve.After that,the catalyst was characterized by FT-IR,elemental analysis,XRD,etc.Then,methyl propionate was prepared by heterogeneous catalysis with methanol,carbon dioxide and ethylene as raw materials,and its yield was measured by gas-phase internal standard method.2.The yields of methyl propionate synthesized in ionic liquids[Bmim]Cl and[Bmim]OH was compared to determine the effect of anions.By searching the synthesis of methyl propionate in ionic liquid[TesPmim]Cl under different experimental conditions,we determine the optimal reaction conditions.In addition,we add the inorganic salts LiCl,MgCl₂ and test its cycle performance.Then we analyze the thermal stability of[TesPmim]Cl and the effect of vacuum time on the synthesis of methyl propionate.The synthesis of methyl propionate from the hydrolysis product of[TesPmim]Cl demonstrates the Si-O-CH₂-CH₃ group was hydrolyzed with the product water during the reaction,which could effectively increase the yield.3.Ionic liquid[TmsPmim]Cl was prepared by the 3-chloropropyltrimethoxysilane and N-methylimidazole.,the methanol produced by the hydrolysis of the Si-O-CH₃ group can be reused as a raw material in the reaction.Methyl propionate was prepared by methanol,CO₂ and ethylene as raw materials.The reaction conditions such as reaction temperature,reaction time and reaction pressure were explored.The effects of different inorganic salts and the amount of inorganic salts on the yield of methyl propionate in the reaction system were also investigated.Furthermore,the effect of inorganic salts added to the catalytic system on the active species of Ru-N-heterocyclic carbene was investigated and the reaction mechanism was preliminarily explored.