Technology Research On Synthesis And Purification Of Glyceryl Monolaurate

Glyceryl monolaurate is an excellent food emulsifiers and preservatives. At first it was screened as a kind of new safe and efficient antibacterial agent by Kabara, and then approved to be GRAS food additive by the US FDA in 1977. Used in food it can not only improve the quality of products, but also extend the shelf life. Taking glycerol and lauric acid as the raw material, this paper purified crude glycerol monolaurate by molecular distillation equipment to make the GML with a purity of more than 90% in the absence of solvent catalytic synthesis of glycerol monolaurate.Taking the purity of glyceryl monolaurate as the measurement, four kinds of catalysts which were Phosphoric acid, respectively, p-toluenesulfonic acid, potassium hydroxide, β-zeolites were separately used to find out its effect on glyceryl monolaurate that synthesized by lauric acid and glycerol. The results showed that the p-toluenesulfonic can catalytic and synthesized the best GML with the highest purity, and the glyceryl monolaurate content is 46.1%.Using the single factor experiment and response surface analysis this paper obtained the optimal synthesis method of preparing glycerol monolaurate by glycerol and lauric acid: the reaction temperature was 189.16, the reaction time was 2.61 h, and glycerol and lauric acid molar ratio of 2.09, a catalyst p-toluenesulfonic acid content was 0.37, glyceryl monolaurate yield of 46.92%. Under these conditions, glyceryl monolaurate can reach the content of 46.78%. Compare the advantages and disadvantages of the two methods of periodic acid and meteorological chromatography, this paper found that meteorological chromatography is high in accuracy and good in efficiency.In order to obtain the glyceryl monolaurate with a purity of more than 90%, this paper used the molecular distillation method to purify the crude glyceryl monolaurate. During this process each of distillation temperature, feed liquid flow rate, the condensing temperature, operating pressure was seen as the single factor to determine optimal parameters of distilling glyceryl monolaurate, and the optimal condition are as follows: the purity of DML is 83.2%, with the feed liquid flow rate of 200 ml / h, distillation temperature of 120 ℃, the condensing temperature of 80 ℃, operating pressure of 0.1Pa. Then the distillation temperature was adjusted to 100 ℃, and the condensing temperature to 50 ℃, with the operating pressure of 1Pa. Three levels of distillation were made to compare the purity and yield of the GML. The second level of distillation with a purity of 91.3% of glyceryl monolaurate got the highest rate.The purity of 91.2% was obtained by referring to the toluene sulfonic acid catalyzed and synthesized conditions and molecular distillation process conditions in the trial of the product. The effect is ideal.