Synthesize And Characterization1,3-glycerol Diacrylate

1,3-glycerol diacrylate is a new special acrylate. Because there are two high reactivity bond of C=C, a-H and a hydrophilic group of-OH in its molecular structure. It not only can be used as grafting agent to improve the impact resistance, durability, toughness and flexibility of PVC, but also can be used as modification agent for rubber and coating to make them having good resistance, impact strength, low shrinkage and other excellent performance.1,3-glycerol diacrylate has a double propylene acyl making itself together and also contains a hydroxyl making mutual crosslinking with other molecules.So1,3-glycerol diacrylate is hard to synthesize with high yield because of vice polymerization reaction between it and reactant, byproducts. Therefore, it’s significant to study the synthesis conditions for1,3-glycerol diacrylate.Three synthesis pathways were decided via comparing and analyzing the basic method of industrial synthetic esters and laboratorial synthetic ester. They are direct esterification method using acrylic acid and glycerol as raw materials, ester-exchange method using acrylic acid methyl ester and glycerol as raw material and semi-synthesis method using glycidyl ester of acrylic acid and acrylic acid as raw material. The optimal synthetic conditions for each synthesis method were investigated and the results are shown as follows.(1) The optimal conditions for direct synthesizing1,3-glycerol diacrylate are acrylic acid with57.6g, glycerol with30.2g, cyclohexane as water-carried agent with70ml, p-toluenesulfonic acid as catalyst with1.5g, p-methoxy phenol and phenothiazine as compounded inhibitor withl.5g, the alcohol acid ratio with1:2.4, the reaction time with10h. A high yield of88.1%was found.(2) The optimal conditions for ester-exchange method to synthesize1,3-glycerol diacrylate are methacrylate with108.0g, glycerol with30.2g, p-toluenesulfonic acid as catalyst with4.0g, p-methoxy phenol and phenothiazine as compounded inhibitor with3.0g, the reaction time with14h. A high yield of72.8%was gained.(3) The optimal conditions for semi-synthesis method to synthesize1,3-glycerol diacrylate are hexamethylenetetramine as catalyst with3.0g, metoxyphenol and methylene blue as compounded inhitoer with1.5g. An esterification rate of87.5%was obtained.(4) According to the ester-exchange reaction mechanism, kinetics model has been founded, and the results show that the interesterification between glycerol and methacrylate obeys the second order reaction kinetics and the apparent rate constant K at constant temperature was4.85×102.The conclusions of this study can be gotten as follows. The suitable synthetic route for laboratorial preparation of1,3-glycerol diacrylate is semi-synthesis method with glycidyl acrylate and acrylic acid. This method obtained a high yield and high purity of. While the ester-exchange method for synthesizing1,3-glycerol diacrylate shall be the most promising way. It is significant to get much research on this method.