鹵化四級鹽類在油水兩相間之質傳

Mass Transfer of Halide Quaternary Salt between Organic and Aqueous phases

劉建邦(Jiahn-Bang Liu)

指導教授 ： 吳和生

元智大學/工程學院/化學工程與材料科學學系/碩士(1997年)

摘要

相間轉移觸媒催化技術（phase-transfer catalysis）是一種能夠幫助化學反應在溫和的條件下進行反應，且使反應速率變快。此種催化技術已經被廣泛的應用在各種類型的有機合成反應中，以往的學者對相間轉移觸媒合成技術研究很多，但是卻發現其催化機構十分複雜，牽涉相當廣泛。一般來說，相間轉移觸媒反應的反應速率決定於三步驟：（i）分別在油相及水相之反應速率，（ii）觸媒於兩相平衡時的分配比，（iii）觸媒於兩相的質傳。
本研究主要就相間轉移觸媒在油水兩相間的質傳做探討與分析，分別對一般相間轉移催化反應中較常使用的觸媒：溴化四丁基銨(C4H9)4NBr（TBAB），溴化四丁基鏻(C4H9)4PBr（TBPB），溴化苯甲基三丁基銨C6H5CH2N(C4H9)3Br（BTBAB），碘化四丁基銨(C4H9)4NI（TBAI）等做詳細的探討。實驗中分別改變反應溫度、攪拌速率、有機相中的觸媒濃度和有機相溶劑等變因，並求取各個操作條件下之總質傳係數、個別質傳係數、萃取速率、擴散係數以及活化能等動力學參數，希望藉由實驗數據來歸納並分析相間轉移觸媒在油水兩相中的質傳現象。因此，本研究分別採用垂直薄膜反應器與水平薄膜反應器來做探討，垂直式反應器主要以氯苯當作有機相溶劑，水平式反應器則是以二氯甲烷為主要研究，並比較兩種反應器在萃取反應效果的差異。
實驗結果顯示，不論垂直反應器或是水平反應器系統，提高溫度對質傳係數有正面的提昇，二氯甲烷當作有機相溶劑在觸媒的萃取方面有較高的反應性；在觸媒的萃取過程中薄膜對於質傳的阻力最大，在有薄膜的系統下，增加有機相的觸媒濃度其總質傳係數有降低的趨勢，此點可以從個別質傳係數看出Ko和km比較接近，ko則都遠大於Ko和km。

關鍵字

相間轉移觸媒 ； 質傳係數 ； 擴散係數 ； 薄膜

並列摘要

Two-phase reaction can proceed under mild reaction condition by phase-transfer catalysis. The phase-transfer catalysis has been used on various syntheses of organic reaction. There have been many studies in phase-transfer catalystic synthesis. These studies discovered that the mechanism of phase-transfer catalysis is very complicated. In general, the rate of phase-transfer catalysis reaction is determined by three steps：（i）rate in organic phase.（ii）equilibrium distribution of catalyst between the mixed phase.（iii）mass transfer of catalyst in two phase.
In this paper, we discuss and analize the mass transfer of phase- transfer catalyst between organic and aqueous phases. We selected the catalysts that are commonly used in phase-transfer catalystic reactions：tetra-n-butylammonium bromide, (C4H9)4NBr, TBAB，tetra-n-butylphosphonium, (C4H9)4PBr, TBPB，benzyltri-n-butylammonium bromide, C6H5CH2N(C4H9)3Br, BTBAB，tetra-n-butylammonium iodide (C4H9)4NI, TBAI. The factors we considered werw：temperature of reaction、agitation rate、kinds of catalysts、kinds of solvent of organic phase and amount of catalyst. We can obtain the kinetic parameters included overall mass transfer coefficient、extraction rate、diffusivity、activation energy and individual mass transfer coefficient. From an analysis of the experimental data, we hope to understand the phennomenon of mass transfer of the phase-transfer catalysts between organic and aqueous phases. In this study , we analyzed the difference between a vertical reactor using chlorobenzene as the organic phase and a horizontal reactor using dichloromethane as the organic phase.
From experimental result, no matter in horizontal or vertical reactors, mass transfer coefficient increase with increasing temperature and dichloromethane has the higher reactivity in extraction. In extraction, membrane is the max resistance of mass transfer. With membrane system, overall mass transfer coefficient decrease with increasing the concentration of catalysts of organic phase. From individual mass transfer coefficient, we can discovery that Ko is close to km and ko is more than Ko and km.

並列關鍵字

PTC ； mass transfer coefficient ； diffusivity ； membrane

參考文獻

1. Starks, C. M. , C. Liotta and M. Halpern, Phase Transfer Catalysis, Fundamentals, Application and Industrial Perspective, Chapman & Hall, London (1994).

3. Dehmlow, E. V. and S. S. Dehmlow, Phase Transfer Catalysis, Verlag Chemie, Weinheim (1993).

4. Weber, W. P. and G. W. Gokel, " Phase Transfer Catalysis in Organic Synthesis" , Springer-Verlag Berlin Heidelberg, New York (1977)

5. Freedman, H. H.,"Industrial Applications of Phase Transfer Catalysis (PTC) : Past, Present and Future", Pure & Appl. Chem., 58(6), 857-868(1986).

6. Starks, C. M.," Phase Transfer Catalysis", Am. Chem. Soc. Symp. Series 326(1985).