Study On Synthesis And Kinetics Of One-step Ethoxylation Of Methyl Methacrylate

Methyl methacrylate (MMA)- polyethenoxy ether is a new type of non-ion surface active agent, with double bond, ester bond and polyether key concurrently. It can be used as water-reducing agent in building, soft or hard foam stabilizer in polyurethane, synergistic agent in agricultural organic silicon, washing chemicals with low foam, lubricating oil and textile, and many other areas. This paper describes the current application prospects and research progress of (methyl) acryl ate polyoxyethylene ester. For the problems of two-step complex process that the glycol monomethyl ether was prepared first and then was esterified, with complex process, low conversion, more by-products, polymerization in the esterification process, poor quality of product, one-step progress (the method of ethoxylation) is proposed.The synthesis of methyl methacrylate polyethenoxy ether(MMEA)taking MMA and ethylene oxide (EO) as raw material was established on the base of main catalyst B, sub-catalysts magnesium-aluminum compounds, polymerization inhibitor D. The detection methods of methyl MMEA were completed, and the reaction conditions were optimized by real single factor and orthogonal experiments. The optimal reaction conditions are: the molar ratio of MMA to EO 1:10, the initial system pressure 0.20MPa, the reaction temperature 75℃, the inhibitor D dosage 0.30wt%, the amount of catalyst 0.50wt%, EO feed rate 2.0g/min, and holding time 1.Oh.By the methods LC-MS, NMR, FT-IR and others, it is testified that the expected product with narrow distribution of the molecular weight is got, the double bond of methacrylate is intact, and the epoxy ethane is embedded at the proper place. In the optimized process conditions, polymerization degree of MMEA is up to 27.2. The number-average molecular weight of product is 784.61, while the weight average molecular weight is 813.52, and the product yield is 90.2%.Under the elimination of external diffusion resistance, the same material ratio, and different reaction temperatures, the pressure changes of autoclave were measured during the holding time. Through analysis of the data, the kinetic parameters were determined using the software origin, with the process of ethoxylation following the first order reaction kinetics model. Between the temperature range of 303 to 343 K, the activation energy of each step addition reaction is 16.16 kJ/mol, and exponential factor of the equation is 0.4902 min-1.