Research Of The Synthesis Of Complicated Glycerol Ethers From Glycerin

The rapid development of the biodiesel industry has brought a large surplus of the byproduct glycero.How to consume the excess glycerol or converse it into a more commercially valuable chemical products become a major global generally concerned hotspots. Among them,the use of biomass for glycerol production alkyl glyceryl ether fuel additives is such a high-value-added glycerol conversion route.Ethyl glyceryl ether,generated by the etherification of biodiesel-based glycerol with bioethano, is a valuable new oxygenated fuel additives.It can be incorporated into the diesel fuel to reduce the viscosity of diesel fuel, improve the low-temperature fluidity, and increase the combustion internal combustion engine performance to promote complete combustion and reduce polluting emissions, but also replace methyl tert-butyl ether(MTBE) to improve the octane number of diesel fuel.Thermodynamic calculation and analysis for synthesis of complicated glycerol ethers from glycerin and ethanol was done in the paper. In order to forecast the product distribution and determine the optimal experimental conditions for the complex reactions of the body,and provide theoretical guidance for the experiment and offer basic data for the reference value of industrial production.The standard molar enthalpy of formation,entropy,molar heat capacity and molar latent heat of vaporization of reactants and products were calculated in the papper by some estimation methods, such as Benson group contribution, Joback group contribution and Rozicka-Domalski,et.al. The relationships of the molar enthalpy changes, molar Gibbs free energy changes and equilibrium constants of the reactions in the liquid phase reaction system and gas phase reaction system were established according to the chemical thermodynamics principle in order to systematically research on the direction and limits of the reaction.The influences of phase state, temperature and molar ratio of glycerin to ethanol on the equilibrium conversion, equilibrium yield and equilibrium composition of the system were investigated under the conditions of 298.15~653K,0.1MPa.The main conclusions of this paper are as follows:(1)The reaction of glycerol with ethanol to synthesis glycerol ethers can occur spontaneously in the range of 298K~650K.(2)Glycerol and ethanol composite glycerol ether reaction is three step tandem reaction,synergistic effect between the three responses to the transformation system of ethanol rate has been increased.(3)Within the studied range, the best conditions to maximize glycerol conversion and yield towards ethyl glyceryl ethers are:298.15~653K,glycerol /ethanol molar ratio =1/4.Under these conditions, 100% glycerol equilibrium conversionthe and approximately 100%equilibrium yield to TEGE clould achieve.(4)In thermodynamics, the vast majority of glycerol were transformed into TEGE after reaction I, II and III continuous reaction with ethanol, which is not consistent with the results of TEGE in the experiment.The reason is: 60% of the water in the system inhibited the reaction to generate DEGE and TEGE.(5)How to remove moisture on line in order to solve the problem of water inhibition is the key problem to be solved in the process of industrialization of the reaction system.