Oxidation of Phenylethanol by Phase-Transfer Catalysis

• Main Authors: Hong Kan Wen, 溫鴻凱
• Other Authors: Ho-Shing Wu
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/15866208107628427849

碩士 === 元智大學 === 化學工程研究所 === 89 === The oxidation of 1-phenylethanol with TBHP (tert-butyl hydroperoxide) in to acetophenone different kinds of solvents was investigated by phase transfer catalysis. When only CuCl2 used as catalyst was added, the reaction rate was slowly. However if extra addition of phase transfer catalyst such as TBAB (tetrabutylammonium bromide) or triphase catalyst synthesized by our lab could enchance dramatically the reaction rate. Triphase catalyst was synthesized with styrene, vinyl chlorobenzyl and divinyl benzene(crosslinkage agent) using suspension polymerization. Then, tri-n-butylamine was immobilized on polymer particle . The characterization and reactivity of polyer-supported catalyst compared with that of commercial TBAB. Different reaction conditions would resulted in different the reaction rate of oxidation and the efficacy of oxidant to reagent. Four reaction systems were studied to achive the optimum reaction condition, including homogenous reaction, two phase reaction (liquid-liquid, solid-liquid) and triphase reaction. Meanwhile, the reactive roles of catalyst CuCl2, TBAB and triphase catalyst were observed for each reaction systems. According to the experimental result, the yield and the reaction rate in the presence of TBAB catalyst were better than these of the triphase catalyst in most condition, but some conditions the triphase catalyst better than TBAB e.g. high volume of solvent, high amount of catalyst obsered or high temperature. The yield and the reaction rate were oberved to descend tendency for both catalysts, but the tendency for the triphase catalyst was more gently decrease than that for TBAB. The reaction rate of homogenous and two-phase (solid-liquid) reaction were rapid than that of the other reaction system and the yield of acetophenone could be upto 60% after 5 hours. The yield of acetophenone for liquid-liquid and liquid-solid-liquid reaction were upto 60% after 15 hours or more time. The squence of the reactivity of the reaction system was homogenous＞two-phase (solid-liquid)＞two-phase (liquid-liquid) triphse reaction (liquid-solid-liquid). The degradation and reuse of the triphase catalyst were also conducted in this study. Because dissoluble catalyst can’t reuse easilywhich is a diffcult program in order to obtain. Triphase catalyst was used to overcome the separation problem and the properties of polymer resins were defermimed. It is found that reaction rate was slowly decreasingly with increasing reuse time of triphase catalyst and the yield was decrease less than 10% after five recycle times. In addition, the reactivity of triphase catalyst was more close to that the dissoluble catalyst if triphase catalyst was transnatured propenty, for example changing the hipophilic-hydrophilic balance.