Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3315
標題: chih ch''ing li
應用固定化相間轉移觸媒催化酚鈉鹽之離子交換及醚化反應動力學研究
作者: 李志清
關鍵字: Phase-transfer catalyst;相間轉移觸媒;Kinetics;Allylation;Immobilized catalyst;Ion-exchange;動力學;醚化作用;固定化觸媒;離子交換反應
出版社: 化學工程學系
摘要: 
The objective of the study is to apply triphase catalytic technique to catalyze allylation of sodium phenoxide with allyl bromide for synthesizing ally phenyl ether by conducting nucleophilic substitutions in the organic solution in solid-liquid-liquid system. The product allyl phenyl ether is used in the production of insecticides, herbicides, delation agent of coronary artery, dropping agent of blood pressure, tranquilizer and thermoplastic resins. Macroporous and microporous polymer supports were prepared for the immobilization of different active functional groups. The triphase reaction was carried out in a stirred batch reactor under mild operating conditions. A kinetic model was also proposed to describe allylation in the solid-liquid-liquid triphase system and the experimental data were well described by the pseudo-first-order kinetics. For the experimental data shown, when the agitaton speed exceeds 350 rpm, the external mass transfer resistance can be ignored. The overall reaction rates decrease with increasing the mean particle size. This demonstrates that the allylation of sodium phenoxide is controlled by the combination of intraparticle diffusion and intrinsic reaction under triphase conditions. Moreover, the characteristics and structure of the catalyst support also affect the catalytic efficiency. With the same degree of crosslinking, macroporous catalysts have higher activities than microporous catalysts do. The reactivity of the recovered catalyst only loses less than 5% of that of fresh catalyst after 5 times of recovery. This result indicates that the stability of the catalyst prepared in the present study is good to be used in the allylation of sodium phenoxide. Other factors influencing the performance of the supported catalyst were also studied.
The ion-exchange reaction is one of the fundamental processes of S-L-L triphase reactions. In this work, we also proceed the ion-exchange reaction by triphase catalysts for sodium phenoxide solution. The kinetics for the ion-exchange reaction between triphase catalysts and imbibed organic solvent/water solution have been studied to understand triphase reaction mechanism in more detail. The kinetics model proposed can be applied to describe the experimental data of the ion-exchange process successfully. Under the intraparticle diffusion-controlled kinetics, three variables including concentration of the solution , reaction temperature and types of organic solvents have been identified important to affect the ion-exchange rate.

本研究主要探討以三相觸媒催化酚鈉鹽之丙烯化反應去合成丙烯基苯基醚。產物丙烯基苯基醚是一種用途非常廣泛的中間原料,由此化合物可合成殺蟲劑、除草劑等農藥化學品;冠狀動脈擴張劑、血壓下降劑、中樞神經鎮靜劑等醫藥化學品,以及高經濟價值的熱固性高分子樹脂等。而後,製備巨孔與微孔高分子擔體,進行不同活性官能基之觸媒固定化實驗,三相反應以一溫和操作條件在批式攪拌反應器中進行。提出一反應機構來描述固-液-液三相系統之醚化反應,且利用產率之虛擬一階方程式可以完整、清楚地解釋實驗結果。實驗結果:當攪拌速率超過350 rpm 時,其外部質傳阻力可忽略不計。總反應速率隨平均粒徑的增加而降低,這顯示在三相反應系統下,酚鈉鹽之醚化反應同時受粒內擴散與本質反應之影響。然而,觸媒的特性與結構也影響著觸媒反應活性,相同交聯度下,巨孔隙觸媒活性較微孔隙觸媒活性佳。由觸媒回收反應性來看,結果顯示反應性依回收的次數依次緩慢降低,但差距並不是很大,約在5%左右,為頗佳之觸媒穩定性。而其他影響固定化觸媒性能之因素也有詳細的探討。
由於,離子交換反應是重要的三相反應過程之一,故使用三相觸媒對酚鈉鹽進行離子交換反應,探討三相觸媒在水-油溶液中進行離子交換反應之動力學,來充分瞭解三相反應之機制。經由實驗數據可導出一動力式來描述此離子交換之過程。在粒內控制下,下列三種變因即溶液起始濃度、反應溫度與有機溶劑效應等,對離子交換速率均有重要之影響。
URI: http://hdl.handle.net/11455/3315
Appears in Collections:化學工程學系所

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.