Research On Synthesize Of High Quality Bisphenol-A Liquid Epoxy Resin

There are some problems concerning with local Bisphenol-A (BPA)type liquid epoxy resin such as low epoxide value, dark color and bad transparency. So we have done some work regarding to this area. We have improved the normal equipment to synthesize the liquid epoxy resin, applying FTIR method to character the epoxide group amount instead of hydrochloric acid-acetone method. We researched the effect of one-step, two-step and mixed-step method on the epoxide value, on the basis of this we synthesized high quality liquid epoxy resin with high epoxide value, low viscosity and good transparency. The main work are as follows:1.We found out that using the normal size four-neck flask, there will be air blocking during the experiment which will impact the water content of the reacting system; using the normal filler to feed NaOH cannot assure a even feeding speed; using the fluorin stirring apparatus will result in air leaking in a short period and the air-proof is bad, as a result the experiment repetition cannot be assured. So we improved the experiment equipment, using wide diameter four-neck flask and water distilling equipment to avoid air blocking; using mechanical air-proof stirring machining to replace fluorin stirring apparatus; using mechanical NaOH feeding method to replace normal filler to feed NaOH, as a result, the experiment repetition is improved.2.The hydrochloric acid-acetone method is normally applied to character the epoxide value, this method is convenient but has errors. So we used FTIR method to character the epoxide group amount instead of hydrochloric acid-acetone method. FTIR method character the location and area of characteristic group to analyse the epoxide group content. Regarding to the certain epoxy resin we synthesized, the FTIR method is very accurate and has a good repetition.3.We researched the effect of one-step technique on the liquid epoxy resin during the etherification, ring-closing and refining process. The result indicate that when the etherification temperature raise from60-80℃, the BPA conversion ratio decrease from68%to56%; the NaOH feeding amount during ring-closing process is critical to the epoxide exponential, when NaOH amount is less than1.8molar ratio with BPA, the epoxide exponential increase with the increasing of NaOH feeding amount; when it is more than1.8molar ratio with BPA, the side-reaction will enhance, the side-product will also increase, and the epoxide exponential will not increase but decline instead. When the NaOH amount exceeds1.7molar ratio with BPA during the ring-closing reaction, refining process will not increase the epoxide exponential; when the NaOH amount is less than or equal to1.6molar ratio with BPA during the ring-closing reaction, refining process will increase the epoxide exponential. At last we choose the best reacting condition to synthesize epoxy resin and the epoxide exponential is0.54-0.56。4.With two-step synthesize method, we researched the effect of etherification time, reacting temperature, amount and category of phase-transfer catalyst on the epoxide exponential, applying the Tetramethyl ammonium bromide Methanaminium as the phase-transfer catalyst, when the etherification temperature is58-60℃, reacting time is40-120min, ring-closing temperature is60-62℃, ring-closing time is3hours, the product resin has a light color and epoxide exponential of0.570-0.593。Refining process is not needed so the reacting cycle is largely shortened and there is no waste water during the process. On the basis of this we deeply researched the effect of two-step etherification temperature, etherification time, amount and category of phase-transfer catalyst on the BPA conversion ratio, and then we choose the best reacting condition to synthesize epoxy resin that is etherification temperature80℃and etherification time3hours. The product resin is close to theory product with a epoxide exponential of0.610-0.629。5.On the basis of one-step and two-step method we developed a new synthesizing method——mixed method, we apply the NaOH and tetramethyl ammonium bromide methanaminium as the phase-transfer catalyst during the etherification process. First feeding some amount of tetramethyl ammonium bromide methanaminium into the system at58℃and reacting for60mins, then feeding NaOH reacting for120mins, and then the ring-closing reaction is proceeded. The refining process is not needed, the epoxide exponential is0.558.