【作者】 王维娜；

【导师】 方云；

【作者基本信息】 江南大学 ， 应用化学， 2008， 硕士

【摘要】 聚乙二醇单醚甲基丙烯酸酯是合成新型功能材料的一类重要大分子单体,该单体参与共聚得到的两亲性梳状聚合物可用于药物载体、环保涂料、高效水泥减水剂等多种用途。含有该共聚组分的聚羧酸系减水剂具有其他减水剂不可比拟的优点。目前该类大分子单体的制备工艺是先以甲醇或乙醇为起始剂,在高温、高压、金属钠催化条件下与环氧乙烷加成制得聚乙二醇单醚,然后在有机溶剂中与甲基丙烯酸(或酯)反应。该传统工艺操作步骤繁杂,生产过程中需耗用等摩尔量的金属钠并释放出氢气,消耗大量酸用于中和并且需回收溶剂,这些工艺缺陷限制了该产品的推广应用。因此,研究开发一种聚乙二醇单醚甲基丙烯酸酯的新型合成技术具有十分重要的意义,这也正是本文的主要研究内容。本文先采用环氧乙烷嵌入乙酸乙酯的一步法嵌入反应合成了聚乙二醇(20)单乙醚乙酸酯(PEGMEA)中间体,再筛选金属、碱性催化剂催化其与甲基丙烯酸乙酯(EMA)进行酯交换反应,得到目标产物聚乙二醇(20)单乙醚甲基丙烯酸酯(PEGMEMA),并考察了反应条件对酯交换反应的影响。具体研究内容及结果如下:1、通过优化调整Al-Mg金属复合氧化物催化剂(AM系列),催化环氧乙烷嵌入乙酸乙酯的高加成数反应。利用FT-IR、ESI-MS、皂化价测定等方法对反应产物进行了分析,证实在AM系列催化剂作用下,乙酸乙酯与环氧乙烷发生了乙氧基化嵌入反应,生成了目标产物-聚乙二醇(20)单乙醚乙酸酯。AM系列催化剂组成不同对乙酸乙酯乙氧基化反应催化活性不同,其中较优的催化剂为AM4。2、筛选出合适的酯-酯交换催化剂和阻聚剂,实现了甲基丙烯酸酯和聚乙二醇单乙醚乙酸酯的酯交换反应,制备了合成梳状大分子的重要大分子单体-聚乙二醇单乙醚(甲基)丙烯酸酯,探讨了催化剂用量,反应时间,反应温度,反应物的物料比等因素对酯-酯交换反应的影响,优化了反应条件。通过FTIR、UV、GC方法对酯-酯交换产物的结构进行了分析,发现使用钛酸四正丁酯(TBOT)、钾或钠为催化剂;2,2,6,6-四甲基哌啶氧化物(TEMPO)为阻聚剂,EMA和PEGMEA能够发生酯-酯交换反应生成目标产物PEGMEMA。在一定范围内,反应温度越高,产率越高,但超过130℃后对反应反而不利;增加催化剂TBOT用量或提高原料EMA与PEGMEA的摩尔比对反应有利;反应时间对该反应的影响同温度,最终得到以TBOT为催化剂合成PEGMEMA的适宜反应条件为:反应温度130℃,反应时间3 h,催化剂w(TBOT)=7%,阻聚剂w(TEMPO)=0.1%,原料摩尔比n(PEGMEA):n(EMA)=1:3,PEGMEMA的产率为88.7%。更多还原

【Abstract】 Polyethylene glycol monoethyl ether methacrylate (PEGMEMA) is an important macromonomer for synthezing new functional materials. The comblike amphiphilic copolymers prepared from this macromonomer can be widely used such as, drug carrier, environmental friendly coatings, cement reducer. Polycarboxylic acid type water-reducer containing this copolymer component is characterized with many advantages. At present, the traditional process of preparing PEGMEMA includes two steps, firstly, Polyethylene glycol monoether is synthezised by adding ethylene oxide to methanol or ethanol with sodium as catalyst under the condition of high temperature and high pressure; then, Polyethylene glycol monoether reacts with methacrylic acid or methacrylate in organic solvent. The traditional techniches of preparing PEGMEMA is complicated and has some problems such as its equal molar ratio comsumption of sodium and hydrogen release,using a large amount of acid in neutralization as well as solvent recovery. Those defects limited the application of the macromonomer. Therefore, the research and development of a new PEGMEMA synthetic technology is of great significance, and this is precisely the main content of this article.A novel process to synthesize macromonomer polyethylene glycol monoethyl ether methacrylate (PEGMEMA) was investigated. PEGMEMA was obtained by transesterification of polyethylene glycol monoethyl ether acetate (PEGMEA) with ethyl methacrylate (EMA) in the presence of catalyst and polymerization inhibitor. The intermediate (PEGMEA) was prepared by directly inserting ethylene oxide into ethyl acetate. The main contents of this paper are as follows:1、A series of Al-Mg composite oxide catalysts(series of AM catalysts) were optimized for preparing polyethylene glycol monoethyl ether acetate(PEGMEA) by means of catalysizing one-step ethoxylation of ethyl acetate. The product was characterized by FT-IR and ESI-MS. The optimum catalyst for ethoxylation of ethyl acetate were screened out. It was found that the catalyst, AM4, has the highest catalytic activity for preparing PEGMEA.2、The screening of the catalyst and polymerization inhibitor, the influences of the dosage of catalyst, the molar ratio of reactants, reaction temperature and time on the transesterification were investigated. The product was analyzised by FT-IR, UV, together with GC. It was found that tetra-n-butyltitanate (TBOT) and 2,2,6,6-tetramethyl-1-Piperidinyloxy (TEMPO) possess the highest catalytic activity and the most effective polymerization inhibition respectively among the other tested catalysts and polymerization inhibitors. The optimal conditions were as following: TBOT as catalyst , TEMPO as polymerization inhibitor, n(PEGMEA):n(EMA)=1:3, w(TBOT)= 7%, w(TEMPO)=0.1% ,130℃and 3h, giving a yield of PEGMEMA of 88.7%.更多还原