Study On High Selective Synthesis Of Glycerol Dimethyl Ether And Its Vapor-liquid Equilibrium

As a kind of high quality clean fuel, biodiesel can replace petrochemical diesel. In theproduction process of biodiesel, a great quantity of glycerin byproducts were produced.Therefore, highly utilization of excessive glycerol has become an urgent problem and hasimportant research significance. Alkyl glycerin ether synthesized by etherification fromglycerol can be used as green renewable fuel additives and to develop the industry chain ofbiodiesel. A novel reaction route to synthesis glycerol dimethyl ether(2,3-dimethoxy-1-propanol) from glycerol and methanol was proposed. Particularly, thereaction performance of catalytic synthesis of glycerol dimethyl ether with ionic liquid andthe vapor-liquid equilibrium basis data for the separation process were studied.The effect of reaction performance of2,3-dimethoxy-1-propanol synthesis fromepichlorohydrin and methanol was studied in the high-pressure reaction still. The ionicliquid ([HSO3-b-N(CH3)3]HSO4) catalyst is the most productive in this reaction. Under thereaction conditions of mole ration of methanol/epichlorohydrin/catalyst=5/1/0.01, reactionpressure of0.1MPa, temperature of393K, reaction time of10h, the selectivity of2,3-dimethoxy-1-propanol was99%and the conversion of epichlorohydrin was100%.After the reaction, the catalyst can be recovered by vacuum distillation and be used for thenext reaction directly. The catalytic effect decreased, and after five reused cycles, the yieldof2,3-dimethoxy-1-propanol maintain80%.The data of saturated vapor pressure for2,3-dimethoxy-1-propanol were measured bystatic method, then the parameters of Antoine equation were obtained. The VLE data forthe binary of methanol-epichlorohydrin, methanol-glycerol dimethyl ether was obtained bya modified Ellis-type VLE equilibrium still and were correlated by the NRTL andUNIQUAC models, and the corresponding model parameters were obtained. The resultsshowed that NRTL model was better than UNIQUAC model. The average deviation oftemperature and vapor phase molar fraction between calculated value and experimentaldata for binary system of methanol-epichlorohydrin,methanol-2,3-dimethoxy-1-propanolwere0.1071%,0.0115,0.8639%and0.0145. The VLE data for the ternary system ofmethanol-epichlorohydrin-2,3-dimethoxy-1-propanol have been predicted using the binaryinteraction parameters obtained from the regression and simulation process of vapor liquid equilibrium by Flash model in Aspen Plus, which provided important theoretical basis forthe industrial design and operation control of separation and purification for the product2,3-dimethoxy-1-propanol.