Synthesis And Characterization Of Dialkyl Carbonate By Transesterification

Dialkyl carbonate?DAC?is a kind of widely used organic compound.Short-chain dialkyl carbonate,such as dimethyl carbonate?DMC?,is an important organic synthesis raw material intermediate to replace phosgene,dimethyl sulfate,methyl chloride and other traditional toxic chemical raw materials due to its high activity reaction group carbonyl,methyl and methoxide,etc.Long-chain dialkyl carbonate has advantage of low pour point and good lubricity which can be used as lubricating base.In recent years,transesterification catalyzed by solid base catalyst with easy separation and mild reaction conditions becomes a feasible and efficient approach for the synthesis of DOC.In this study,Na doped ZnO?ZnO?Na??and CeO₂ exhibited great catalytic activity for the transesterification with DMC and octanol alcohol?OctOH?among mental oxides.Different kinds K species?KOH?KNO₃ and K₂CO₃?showed high catalytic activity in this transesterification.K₂CO₃/ZnO?Na?and K₂CO₃/CeO₂ was produced by loading K₂CO₃ on ZnO?Na?and CeO₂.These catalysts were applied to the transesterification between DMC and OctOH to synthesis DOC.Base on the results obtained,K₂CO₃/ZnO?Na?has higher initial catalytic activity,and the yield and the selection of dioctyl carbonate are 76%and 94%,respectively.Moreover,K₂CO₃/CeO₂ shows more stable catalytic activity,the yield and the selection of dioctyl carbonate are 72%and 90%,respectively.Supported catalyst K₂CO₃/ZnO?Na?shows higher catalytic activity,but the stability of the catalyst decreased after repeated use.The properties of the catalyst were studied in depth by means of X-ray diffraction?XRD?,high resolution transmission electron microscopy?HRTEM?,scanning electron microscopy?SEM?and Raman spectroscopy?Raman?.The result shows that doped sodium existed in the catalyst cattier ZnO.K₂CO₃/ZnO?Na?with higher synthesis efficiency was applied in the transesterification reaction between dimethyl carbonate and long-chain alkyl alcohol to prepare dialkyl carbonate.In this work,diheptyl carbonate,dinonyl carbonate,didecyl carbonate and dilauryl carbonate were synthesized and characterized.