Preparation Of Diethylene Glycol Vinyl Ethers In Liquid Phase Reaction By Tubular Reactor

Diethylene glycol vinyl ether is an important fine chemical intermediate and polymer monomer,which is widely used in coatings,electronic materials,medical materials,inks and other fields.The diethylene glycol vinyl ether was synthesized by diethylene glycol and acetylene in liquid phase reaction using tubular reactor,and the catalyst is potassium diethylene glycolate.The liquid homogeneous phase reaction could not only avoid the danger of acetylene explosion at high temperature and pressure,but also improve the heat and mass transfer efficiency.The process has the advantages of high yield,low side reaction,low cost,high safety and efficiency.In this paper,the solubility of acetylene in 12 alcohols and ketones are obtained at the temperature range from 278.15 to 318.15 K and pressure up to 0.25 MPa using isochoric saturation techniques respectively.It's shown that the experimental data of the solubility in some alcohols and ketones increase with the increasing pressure and decrease with the increasing temperature.The ketones we choose show a better performance in acetylene adsorption compare with alcohols at the same temperature and pressure.In additions,the solubility of acetylene would increase due to the existence of strong electronegative groups,and it would also be reduced by the intermolecular association effect.The Henry's law constants were calculated from the slope of linear isotherms of pressure versus the mole fraction of acetylene.In addition,other thermodynamic functions of solution,such as the standard dissolution Gibbs free energy,enthalpy and entropy changes,could also be obtained according to thermodynamic equations.The Henry's law constants and the standard dissolution enthalpy change were determined by the solubility data show that the dissolution of the acetylene is exothermic.Further study the dissolution characteristics of acetylene in diethylene glycol,and the influence of the potassium diethylene glycolate catalyst concentration.The results show that the solubility of acetylene decreases with the increasing concentration of potassium diethylene glycolate catalyst under the same conditions.The study of acetylene dissolution is of great significance to the preparation of diethylene glycol vinyl ether from acetylene in liquid phase reaction.In this paper,the effect of different reaction conditions on the conversion of acetylene per pass was studied,the results show that the suitable operating conditions are as following:the residence time is 175 s,the reaction temperature is 175 ?,the reaction pressure is 6 MPa and the amount of potassium diethylene glycolate is 4%of the diethylene glycol mass.Under this operating condition,the conversion rate of diethylene glycol reached 76.03%,the yield of diethylene glycol mono vinyl ether was 59.03%,the yield of diethylene glycol divinyl ether was 15.10%and the total yield of diethylene glycol vinyl ehter was up to 74.13%after 11 h of the circular reaction.Kinetic fitting of the reaction about diethylene glycol monovinyl ether synthesized from diethylene glycol and acetylene show that it is in good agreement with the first order reaction kinetics.The pre-exponential factor k0is 1.20x108 s-1 and the reaction activation energy E is 86.86 kJ·mol-1.