Study On Synthesis Of Glycidol From Glycerol

In this study, there are two methods of the preparation of Glycidol from Glycerol: Glycerol/Urea method and Glycerol/3-Chloro-1, 2-propanediol method. The standard heat of formation, free energy and heat capacity of raw materials and products were calculated by the methods of Joback's group contribution, Benson's group contribution and Rozicka-Domalski's group contribution. A thermodynamic analysis of synthesis process of Glycidol from Glycerol was carried out with the emphasis on calculations of equilibrium constants of different temperature. Temperature rising is beneficial to the synthesis process of Glycidol by Glycerol/Urea method, on the contrary, temperature rising is unfavorable to the preparation of Glycidol by Glycerol/3-Chloro-1, 2-propanediol method. The study can provide the thermodynamic basis for the research of synthesis process of Glycidol.Glycerol Carbonate was firstly prepared through the reaction of Glycerol and Urea with ZnSO4 as catalyst on the synthesis process of Glycidol by Glycerol/Urea method. The appropriate reaction conditions were obtained from single factor experiment: reaction time 2.5 h, reaction temperature 145℃, reaction pressure 5 KPa, dosage of catalyst 5 %(w/w). And the regression equation was obtained through uniform experiment design: Y=-184.092+5.7X1+1.6704X2+1.649X3. Then, Glycidol was synthesized through the carbon dioxide removed reaction of Glycerol Carbonate, and the influencing factors of the reaction, such as the time, temperature, pressure, species and dosage of catalyst, were studied in detail. The appropriate reaction conditions were obtained from response surface methodology: reaction time 4 h, reaction temperature 215℃, reaction pressure 2 KPa, dosage of catalyst 2.5 %(w/w). Glycerol Carbonate and Glycidol was analyzed with IR, HNMR and GC, the yield of glycidol was above 80%.To prepare Glycidol by Glycerol/3-Chloro-1, 2-propanediol method, 3-Chloro-1, 2-propanediol was firstly prepared through the reaction of Glycerol and HCl gas with acetic anhydride as catalyst. The appropriate reaction conditions were obtained from single factor experiment: reaction time 4 h,reaction temperature 90℃,dosage of catalyst 6 %(w/w) , HCl gas flow capacity 20 L/h. The yield of 3-Chloro-1, 2-propanediol was above 80%. And the regression equation was obtained through uniform experiment design: Y=62.028+0.0216X1+1.149X2+2.175X3+0.134X4. Then, Glycidol was synthesized through the reaction of 3-Chloro-1,2-propanediol and D201, and the appropriate reaction conditions were obtained from single factor experiment: reaction time 2 h, reaction temperature 0℃, volume of dichloromethane 75 mL, dosage of D201 25 g(dosage of 3-Chloro-1, 2-propanediol 10g). On this condition, the yield of glycidol was above 80%. The reaction conditions were farther optimized by four factors and four levels orthogonal experiments, and the conclusion accorded with the fact.