Study On The Production Process Of Glyceryl Tributyrate

With the research and development of the application field of glyceryl tributyrate,its market demand is increasing year by year,and the production process of glyceryl tributyrate has attracted the attention of many researchers in recent years.However,the traditional production process of glyceryl tributyrate has the disadvantages of significant environmental pollution by wastewater,corrosion of equipment,low product yield and high energy consumption,which restricts its industrial application.To overcome these problems,this research has optimized the synthesis process of glyceryl tributyrate by selecting efficient catalysts and designed a production process of glyceryl tributyrate with an annual capacity of 10,000 tons and a purity of more than 95%.In this paper,the catalysts and water-carrying agents in the esterification reaction of butyric acid glycerol were firstly selected to determine the basic conditions of the reaction,and then the effects of catalyst dosage,reaction temperature and material proportioning on the product yield in the esterification reaction were investigated.The optimal process conditions were optimized by single-factor experiments as n(butyric acid):n(glycerol)=5:1,the amount of catalyst p-toluenesulfonic acid was 5 w%glycerol,and the reaction temperature was 130°C.Under this condition,the yield of glyceryl tributyrate was 92.15%;Furthermore,based on the single-factor experiments,an experimental model based on the response surface optimization method was constructed to analyze the effects of the interactions between the above three factors on the product yields.The optimized theoretical optimum process conditions were n(n-butyric acid):n(glycerol)=5.39:1,the reaction temperature was 133.3°C,and the catalyst dosage was 5.32 w%glycerol,the predicted value of glyceryl tributyrate yield under this condition was 93.61%,and the average product yield under this condition was93.48%after experimental verification,with an absolute error of 0.13%from the predicted value,which proved that the model could better optimize the reaction conditions and predict the yield of product.The optimized process conditions effectively solve the problems of equipment corrosion and environmental pollution caused by the traditional process,as well as provide theoretical support for the new technology of glyceryl tributyrate production.The reaction kinetics was investigated by using the optimized optimal process conditions.The kinetic curve of glycerol concentration variation versus time variation at a certain temperature was measured through experiments.The experimental data was fitted using Origin software,and the relevant kinetic equations and parameters were obtained.The reaction process of the esterification reaction was analyzed by gas chromatography-mass spectrometry(GC-MS)and infrared spectroscopy(IR).The analysis of the esterification reaction mechanism shows that the p-toluenesulfonic acid proton H~+goes to attack the carbonyl site in the butyric acid molecule to protonate the butyric acid,and the carbonyl carbon atom has higher electrophilicity and is more likely to undergo nucleophilic substitution with the alcohol hydroxyl group to form a new C-O single bond,accompanied by the generation of a molecule of water.Due to the unique spatial structure of glycerol,the secondary hydroxyl group of glycerol is less active than the primary hydroxyl group,so the primary hydroxyl group of glycerol preferentially attacks the carbonyl carbon atom of butyric acid to generate tributyrin,following the same reaction mechanism to eventually generate glyceryl tributyrate.Aspen Plus software was used to design and simulate the distillation process of glyceryl tributyrate with an annual capacity of 10,000 tons and a purity of more than95%.The sensitivity analysis was performed on the reflux ratio,theoretical column plate number,feed position of raw material butyric acid and glycerol in the reaction distillation column in order to optimize the product purity of the column kettle and the reboiler load,the optimized operating parameters were:theoretical column plate number was 25,the reflux ratio was 4,the butyric acid feed position was the 15th plate,and the glycerol feed position was the 14th plate.Under the optimal operating parameters,the purity of the glyceryl tributyrate in the tower kettle was 97.07%,and the annual output of the product was 10149.53 tons,which achieved the expected simulation results.