一步乙氧基化合成甲基丙烯酸聚乙二醇单酯

Synthesis of Polyethylene Glycol Mono-Methacrylate Through One-Step Ethoxylation

通过甲基丙烯酸羟乙酯(HEMA)与环氧乙烷(EO)的一步乙氧基化开环聚合,制备了含末端双键和亲水性聚氧乙烯结构的甲基丙烯酸聚乙二醇单酯大分子单体(PEGMA)。研究了各种反应参数对反应的影响,最佳的工艺条件为:采用1%的四甲基哌啶氮氧化物(TEMPO)作为阻聚剂,采用1.25%的三氟化硼乙醚-四氯化锡(摩尔比为4∶1～6∶1)作为复合催化剂,反应温度为105～115℃,压力为0.3～0.4 MPa。红外光谱和核磁共振氢谱证实了大分子单体的结构与预期设计一致。水泥净浆流动度实验和混凝土实验显示采用该大分子单体合成的聚羧酸减水剂达到工业品的水平。

Polyethylene glycol mono-methacrylate (PEGMA) was synthesized by one-step ethoxylation of hydroxyethyl methacrylate (HEMA) and ethylene oxide (EO). Effects of various process parameters on the reaction were studied intensively. The optimal reaction conditions are as follow: 1% 2,2,6,6-tetramethylpiperidinooxy (TEMPO) used as inhibitor, 1.25% boron trifluoride etherate-tin tetrachloride (mole ratio of 4∶1~6∶1) used as composite catalyst, the reaction temperature is 105~115 ℃ and the pressure is 0.3~0.4 MPa. Fourier transform infrared spectrum (FT-IR) and 1H-nuclear magnetic resonance spectrum indicate that the structure of PEGMA is consistent with the designed. Dispersing performance and concrete performance incorporating polycarboxylate superplasticizers prepared by the commercial sample and the synthesized sample reveal that the synthesized PEGMA can meet the requirements of the industry.