Catalytic Synthesis Of Hydroxyethyl Phosphate Monomethacrylate

Ethylene glycol methacrylate phosphate(EGMP)is a kind of acidic phosphate esters which contains double bond.It is widely used in metal coatings,medical adhesive,flame retardants,etc.Currently,ethylene glycol methacrylate phosphate is generated by the reaction of phosphorus oxychloride(POCl3)with hydroxyethyl methacrylate(HEMA),but POCl3 is very expensive,and the reaction will produce hydrogen chloride gas which can corrode equipment and pollutes the environment.In addition,the reactions of phosphorus oxychloride with Compounds containing OH-group are quite fierce and need cooling equipment,which consequentially increasing the investment.Since then,we used the cheaper and milder phosphorus pentoxide(P2O5)as the phosphorus source.In order to get higher yields of ethylene glycol methacrylate phosphate,we applied polyoxometalates([TEAH]3 PW12O40 and H3PW12O40)that of high catalytic properties as catalysts of the reaction above.Small specific surface,solubility in polar solvents and the difficulty of recycle are the problems existing in the practical application of POMs.We can solve the challenges by loading them with carriers which with high surface area.This paper compared the catalytic performance of 12 kinds of POMs as catalysts just in the reaction of hydroxyethyl methacrylate with P2O5 and selected the best catalysts with highest esterification yield and monoalkyl dihydrogen phosphate yield—[TEAH]3PW12O40 and H3PW12O40.We used phosphotungstic acid as catalyst of the reaction of hydroxyethyl methacrylate and P2O5 and discussed the effects of reaction conditions(volume of water,esterification temperature,hydrolysis temperature,esterification time,hydrolysis time,mole ratio of reactants and catalyst amount).At last,we got the best condition of the reaction.we loaded POMs on SB A-15 molecular sieve and activated carbon by dip-molding method and acquired supported catalysts,then,we used them as catalysts of the reaction of hydroxyethyl methacrylate and P2O5.The supported catalysts were characterized by infrared spectroscopy(FTIR),X-ray diffraction(XRD),Low-temperature Nitrogen Adsorption Method and NH3-TPD,and their catalytic activity were measured by esterification of hydroxyethyl methacrylate and P2O5.The product was characterized by infrared spectroscopy(FTIR).Influence of load quantity and amount of catalysts to the yield and selectivity of ethylene glycol methacrylate phosphate was investigated and then the best composition and quantity of catalyst were selected.We studied the reusability of supported catalysts and found that TEAPW/AC which was used for six times also showed high catalytic activity just as that of the first used.The IR spectrum of the supported catalysts which used for 3 times and 6 times were basically remain unchanged,indicated that the supported catalysts were of good repeatability.