相转移催化反应的研究IV．聚乙二醇催化机理

Studies on Phase Transfer Catalysis IV. Catalytic Mechanism of Polyethylene Glycol

摘要: 选用相对分子质量为８００的聚二醇（ＰＥＧ－８００）作为相转移催化剂，使其与硫氰酸钠（ＮａＳＣＮ）水溶液作用而产生络合，然后提取出络合物。对该络合物进行有关的分析鉴定，确定其组成为：ＰＥＧ：ＮａＳＣＮ＝１：１，即络合物为（ＰＥＧ·Ｎａ￣＋）ＳＣＮ￣－。用该络合物与三种反应底物（氯化苄、仲丁基溴和２，４－二硝基氯苯）作用，合成相应的三种硫氰酸酯衍生物，证明该络合物中含有硫氰酸根（ＳＣＮ￣－），且具有反应活性，从而揭示了聚乙二醇作为相转移催化剂的催化机理。

Abstract: The polyethylene glycol with molecular weight of 800(PEG-800)was used asphase transfer catalyst.A kind of complex was separated from reactlon product of PEG withaqueous solution of sodium thiocyante.The appraisal shows that the complex consists of onemolecular PEG and one molecular sodium thiocyante by several kinds of analytical methods.That three thiocyanic esters were synthesised from the complex shows that the complex con-tains thiocyanate radical and is reactive.The phase transfer catalytic mechanism of PEG wasdiscussed.