Tri-Liquid-Phase Phase Transfer Catalysis --- Effects of Sodium Hydroxide and Salts on the Formation of Third Liquid Phase and the Reaction between N-Butyl Bromide and Sodium Phenolate

• Main Authors: Der-Her Wang, 王德和
• Other Authors: Professor Hung-Shan Weng
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/14794816049512632804

博士 === 國立成功大學 === 化學工程研究所 === 83 === In a preliminary study on the reaction between benzyl chloride (BzCl) and sodium bromide with tetrabutylammonium bromide (Bu4 NBr) as a phase transfer catalyst, we found that a third liquid phase with rich catalyst appeared and the reaction rate constant increased sharply when the amount of Bu4NBr or NaBr exceeded a critical value. The catalyst in such a tri-liquid- phase catalysis (TLPC) system can be recovered and recycled from the reaction system as easily as the immobilized solid ctalyst in solid-liquid-liquid triphase catalysis system. The advantages are incentives for further investigations regarding the formation of the third liquid phase and its effects on reaction mechanism and rate. Except the BzCl/NaBr reaction system, in this dissert- ation we mainly investigate another system of TLPC, the reaction of n-butyl bromide/sodium phenolate (BuBr/NaOPh) with Bu4NBr as a catalyst. The influencing factors explored include the kinds of organic solvents and quaternary onium salts as well as the amounts of salts and NaOH added. In many cases, a third liquid phase was formed and some peculiar phenomena were observed. The formation of third liquid phase and the occurrences of these phenomena are elucidated based on the distribution of catalyst between two or among three liquid phases and the concentration of bases in the organic phase. The effects of these factors on the reaction mechanism and reaction rate are also explained. Several reaction mechanisms and rate expressions for TLPC reaction system are proposed. The pseudo-first-order kinetic models can be employed most cases. (omit)