四級胺鹽相間轉移觸媒催化合成醚酯類之界面特性與反應動力學

interfacial characteristics and reaction kinetics on the synthesis of ether-ester compounds by phase-transfer catalysis with quaternary ammonium salts

劉興潮(Shing-Chaur Liu)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(1996年)

摘要

本論文探討相間轉移觸媒催化合成醚酯類化合物本質上的反應機構和確
立反應區域。本研究測定相間轉移觸媒(PTCs)，水相反應物（對甲氧基苯
基乙酸，RH）及不同鹼(NaOH)濃度水溶液存在於不同溶劑（正己烷(n-
Hexane)和甲苯(Toluene)）的界面張力。經由界面張力及反應物在水相中
解離常數(Ke)等，獲得的數據，配合Gibb's及Langmuir單層吸附方程式之
處理，獲得界面性質包括分子的界面積(Molecular area)大小和吸附常
數(Adsorptionconstant)...等等。由界面吸附特性所導出的界面吸附模
式，可預估實際反應系統的界面張力與反應物濃度的趨勢。在反應動力學
部份，利用反應傳送槽來探討傳送動力學，估算系統中個物質的質傳速率
，扣除擴散造成的阻力，可算出真正的界面反應濃度，以求出真正的(
Intrinsic)速率表示式，在界面張力與反應速率部份，反應速率會隨著界
面上所吸附物質的活性改變，界面活性越大相對的界面張力越小，反應速
率越快，因此改善兩相間互不相容的反應系統，可以降低界面張力增加反
應速率。

關鍵字

界面張力 ； 界面活性 ； 相間轉移觸媒 ； 反應動力學

並列摘要

In this paper, interfacial tension of water/n-hexane and
water/toluene systems were measured in the presence of PTCs
(quaternary ammonium salts), an aqueous-phase reactant
(4-methoxyphenylacetic acid, RH), and an alkali (NaOH). These
data were treated by using Gibbs isotherm coupled with Langmuir
monolayer adsorption equation. Thus, interfacial properties of
the surface-active species like surface excess and molecular
area could be determined. It was shown that the Langmuir
constant was a measure of the activity of PTCs. In order to
studythe kinetics of interfacial mass transfer, a Lewis type
stirred cell was used.The rate for the synthesis reaction was
determined first and the mass transfercoefficient of each
reactive component was then estimated. By subtraction ofthe
resistance from diffusion, the real interfacial concentration
and the intrinsic reaction rates were obtained consequently. Our
results suggested the reaction rate increased with decreasing
interfacial tension. A possible reactionmechanism was also
discussed.

並列關鍵字

Interfacial tension ； Interface-active ； Quaternary ammonium salts ； Reaction kinetics