RAFT法制备负载型CBS催化剂及其在苯乙酮不对称还原中的应用

发布时间：2018-05-15 16:02

本文选题：可逆加成-断裂链转移聚合 + 窄分布　；参考：《高分子材料科学与工程》2017年12期

【摘要】：以苯乙烯(St)与自制的功能性苯乙烯(FSt)为单体,双硫代苯甲酸枯基酯(CDB)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,通过可逆加成-断裂链转移(RAFT)聚合法合成了相对分子质量可控、窄分布的负载型CBS催化剂,并应用于苯乙酮的不对称还原中。利用红外光谱、高温凝胶色谱进行了表征。研究了FSt含量对催化剂前驱体相对分子质量(Mn)及其分布(PDI)的影响,以及RAFT法与传统自由基聚合法制备的催化剂催化效果的差异,并考察了CBS催化单元与二硫酯活性端基的相互影响。结果表明,随着FSt含量的增加,聚合物的Mn降低,其PDI先变大后保持在1.25左右;二硫酯活性端基不影响催化剂的活性;随着催化剂中FSt含量的增加,苯乙醇的对映体过量值(ee值)先迅速增大后维持在94%,产率达97.2%。
[Abstract]:The relative molecular weight was controlled by reversible addition-break chain transfer polymerization with styrene-butyronitrile (AIBN) and styrene-butyronitrile (AIBN) as initiators, dithiobenzoate as chain transfer agent, dithiobenzoate (CDB) as chain transfer agent. Narrow distribution of supported CBS catalyst was applied to asymmetric reduction of acetophenone. It was characterized by IR and high temperature gel chromatography. The effects of FSt content on the relative molecular weight of catalyst precursors and their distribution were studied, and the difference of catalytic effect between the RAFT method and the traditional free radical polymerization method was also studied. The interaction between the catalytic unit of CBS and the active terminal group of dithioester was investigated. The results showed that with the increase of FSt content, the mn content of the polymer decreased, the PDI of the polymer increased first and then remained around 1.25, the active terminal group of dithioester did not affect the activity of the catalyst, and with the increase of the content of FSt in the catalyst, The enantiomeric excess value of phenylethanol increased rapidly at first, and then maintained at 940.The yield of phenylethanol was 97.2%.
【作者单位】：河北工业大学化工学院;
【分类号】：O621.251;O643.36

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