胶束介质中pH效应对含硫化合物催化降解β-乙二醇苯醚的影响  

pH Effect on Degradation of β-ethylene Glycol Phenyl Ether Catalyzed by Sulfur Compounds in Micelle Media

作　　者：李小红 张怡 陈鑫 吴德智 

机构地区：[1]贵州理工学院创新创业中心,贵州贵阳550003

出　　处：《现代食品科技》2017年第10期67-71,95,共6页Modern Food Science and Technology

基　　金：贵州省科学技术基金项目(黔科合LH字[2016]7094);创客空间(筑科合同[20151001]2-7号);贵州省大学生创新创业项目(201514440020)

摘　　要：本文以β-乙二醇苯醚为原料,研究了三种含硫亲核试剂在不同的pH下,5种不同的胶束中及巯基乙醇在两种溶剂中催化降解β-乙二醇苯醚(EGPE)的反应情况。结果发现巯基乙醇在1,4-二氧六环非质子性溶剂中反应速率远远大于在质子性溶剂乙醇。反应速率随着1,4-二氧六环和乙醇的体积的增大而增大,但是当1,4-二氧六环和乙醇的体积增大到14 m L(1,4-二氧六环和乙醇与水的比例为7:3)左右的时候,速率突然有一个突跃,达到最大值,然后随着它们体积的增大,速率减小。同时发现pH值的变化对五种胶束介质中亲核试剂的催化速率均有影响,且随着pH的增大催化EGPE降解的反应速率迅速增加,但是分别在超过它们的p Ka后又急速下降,由此可见,溶剂的极性、介电常数及环境的pH值对亲核试剂的催化活性均有影响。Three sulfur-containing nucleophiles with different pH, five different kinds of micelle media and mercaptoethanol in two solvents were used to catalyze the degradation of β-ethylene glycol（EGPE） in this study. The results showed that the reaction rate was much greater in 1, 4-dioxane than that in ethanol, reaction rate increased with the increase of volume of 1,4-dioxane and ethanol and then reached to the maximum when the volume of 1, 4-dioxane and ethanol increased to 14 m L（ratio of 1,4-dioxane with ethanol and water was 7：3）, and then decreased with the volume exceeded 14 m L. Meanwhile, the change of pH value had an effect on the degradation rate in five different kinds of micelle media, and the reaction rate increased rapidly with the increase of pH and then decreased when the pH value exceeded p Ka. In conclusion, polarity of solvent, dielectric constant and pH value had an effect on the catalytic activity of nucleophiles.

关 键 词：β-乙二醇苯醚 胶束介质 动力学 催化降解 

分 类 号：O621.251[理学—有机化学]