The Purification And Electronic Grade Preparation Process Of Propylene Glycol Methyl Ether

Propylene glycol methyl ether（1-methoxy-2-propanol）as a kind of harmfulless environmental solvent is widely used in the field of coatings,printed circuit board and electronic manufacturing.With the rapid development of microelectronics industry in recent years,the demand for high quality electronic grade propylene glycol methyl ether is increasing.Propylene glycol methyl ether is produced in China mainly through the epoxidation of propane to produce propylene oxide,which reacts with methanol.The process would generate a large amount of water and a few 2-methoxy-1-propanol.Ordinary distillation for the removal of metal ions require a lot of energy consumption and the effect is unsatisfied.In order to optimize the production process,this article through the following basic research which divided into three aspects,and provide scientific basis for production.（1）The modified Rose-Williams still type apparatus was used to measure the vapor-liquid equilibria data for three binary systems of water+1-methoxy-2-propanol,water+2-methoxy-1-propanol and 1-methoxy-2-propanol+2-methoxy-1-propanol at30.0kPa and 101.3kPa respectively.On the basis of Herington area test and Van Ness point test,the thermodynamic consistency of the experiment data was verified.Meanwhile,the VLE data that we obtained were correlated with NRTL and Margules activity coefficient models.The results demonstrated that the calculated values were in good conformity with the experimental data in this study.In addition,azeotropic behavior was observed in two binary systems of water+1-methoxy-2-propanol,water+2-methoxy-1-propanol.（2）On the basis of the phase equilibrium data,the separation process of mixture of water,1-methoxy-2-propanol and 2-methoxy-1-propanol was drawn.Through the pre dehydration process by a screened azeotropic agent,the 1-methoxy-2-propanol and 2-methoxy-1-propanol were separated by distillation.Using the NRTL thermodynamic equation as the physical method,the material composition,feeding position,temperature,operating pressure and reflux ratio of each tower were calculated.The simulation results shown that the water removal rate of mixture was as high as 99.9%and the purity of propylene glycol methyl ether was more than 99.0%.（3）The industrial grade propylene glycol methyl ether was purified by ion exchange resin method.By measuring the physicochemical properties of different resins and using static ion exchange experiment to study the adsorption kinetics and thermodynamics of different resins for Na⁺,K⁺,Ca²⁺and Fe³⁺respectively,the suitable macroporous resin Amberlyst?15 and chelate resins Amberlite IRC747 were selected.Dynamic ion exchange experiment was used to study the effect of different operating conditions on ion exchange.Finally,the feed flow rate was 10BV/h and the ratio of height to diameter was 10.Propylene glycol methyl ether with each metal ion concentration less than 5ppb was obtained through the continuous adsorption experiment at 20℃.