Study On Green Synthesis Of Glycidol And Its Methacrylate

Glycidyl methacrylate is an important functional fine chemical product and organic synthesis intermediate.Theoretically,glycidyl methacrylate can be obtained either by the direct esterification reaction of glycidol and methacrylate or by the transesterification reaction of glycidol and methyl methacrylate.Because glycidol is very difficult to synthesize,it is expensive.At the same time,the glycidol molecule contains epoxy groups,which is prone to ring-opening polymerization reaction when placed,which is not easy to transport and store for a long time.So far,no valuable report on the synthesis of glycidyl methacrylate from the esterification reaction of glycidol with methacrylic acid or the transesterification of glycidyl alcohol with methyl methacrylate has been reported so far.In industry,methacrylic acid and epichlorohydrin are mainly used as raw materials,and a two-step method was used to synthesize glycidyl methacrylate.During the reaction,hydrogen chloride or sodium chloride was produced,which pollutes the environment and is not a green production process.As natural fatty acids,natural fatty alcohols and biodiesel are produced and applied on a large scale in industry,bioglycerol,a by-product,is increasingly generated,from which an excess phenomenon has resulted.Glycerol is a renewable,inexpensive,non-toxic,and harmless polyol that can undergo esterification,etherification,oxidation and other reactions.It is a green chemical and a basic chemical raw material.Therefore,the use of bioglycerol to produce high value-added fine chemical products,and the research on its new methods and processes have become one of hot research topics in the chemical industry.In this study,the green glycerol was first reacted with dimethyl carbonate to produce glycidol which was then reacted with methacrylic acid and methyl methacrylate respectively to make glycidyl methacrylate by esterification or transesterification.The synthetic route was an industrial chain with application value.The Benson group sum method was used for the thermodynamic analysis of the synthesis of glycidol and glycidyl methacrylate,and the enthalpy change,entropy change,Gibbs free energy,and equilibrium rate constant of the reaction were calculated.It was concluded after calculation that it is thermodynamically feasible to produce glycidol by the reaction of glycerol with dimethyl carbonate and glycidyl methacrylate from glycidol by esterification and transesterification.The synthesis of glycidol from glycerol and dimethyl carbonate was studied,with sodium metaaluminate as the catalyst.Good reaction conditions: the molar ratio of the reactants was 1:3,the amount of catalyst was 4 %,reaction temperature was 72 ?,reaction time was 2.5 h,The yield of glycidol was 82.00 %.When glycerol was reacted with dimethyl carbonate and methanol to synthesize glycidol,organic J alkali was used as the catalyst.Ideal reaction conditions: the molar ratio of the reactants was 1:3,the amount of catalyst was 3 %,reaction temperature was 65 ?,reaction time was 1.5 h.The yield of glycidol was 88.20%.P-toluenesulfonic acid was used as the catalyst and cyclohexane as the water-carrying agent for the synthesis of glycidyl methacrylate from glycidol and methacrylic acid by esterification.Appropriate reaction conditions: the amount of catalyst was 2 %,the amount of compound polymerization inhibitor was 0.5 %,the molar ratio of reactants was 1:2,reaction temperature was 75 ?,reaction time was 4 h,the stirring speed was 300 rpm.The reaction conversion rate was 66.07 %.If J alkali was used as the catalyst,the catalyst was completely compatible with the reaction system,and there was a high catalytic activity and a high yield of glycidyl methacrylate.The ideal reaction conditions for the transesterification of glycidol with methyl methacrylate to synthesize glycidyl methacrylate: the amount of catalyst was 1 %,the amount of polymerization inhibitor was 0.15 %,the molar ratio of the reactants was 1:3,reaction temperature was 95 ?,reaction time was 2.5 h,The yield of glycidyl methacrylate was 98.84 %.Experiments show that when glycerol was used to synthesize glycidol with dimethyl carbonate and methanol,the reaction temperature was low,the reaction time was short,and the yield of glycidol was high.When transesterification of methyl methacrylate and glycidol was used to synthesize glycidyl methacrylate,the operation was easy,the reaction was stable,the yield of glycidyl methacrylate was high,and the by-product,methanol,could be utilized separately.