Kinetic Study of the Hydrolysis of Ethyl-2-Bromoisobutyrate in Two-Phase Medium

在本研究中，主要探討溴化四丁基銨(TBAB)、氫氧化鈉、氫氧化鉀、碳酸氫鈉、酚和溫度這些因素對於在鹼性水溶液／有機溶劑之二相介質中2-溴異丁酸乙酯水解之影響。由實驗之結果，吾人在本研究中倡導2-溴異丁酸乙酯水解之反應機構。由實驗之觀察，獲得在2-溴異丁酸乙酯中所含之溴－烷基鍵和酯官能基水解成醇化合物和酸化合物之一些連續反應步驟，由這些連續反應步驟中建立動力學模式及速率方程式，從而獲得反應速率常數。而實際上，這些反應速率常數乃由2-溴異丁酸乙酯水解所獲得數據以參數估計法獲得，由結果獲知2-溴異丁酸乙酯水解之轉化率及反應速率很明顯地受到碳酸氫鈉及酚化合物之添加而遲滯，然而，其轉化率與反應速率卻隨著氫氧化鉀（或氫氧化鈉）及溴化四丁基銨之用量增加而增加。另外，2-溴異丁酸之水解同樣地也受到添加碳酸氫鈉之增加而遲滯。

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並列摘要

In this work, the effects of tetrabutylammonium bromide (TBAB), sodium hydroxide, potassium hydroxide, sodium carbonate, phenol and temperature on the hydrolysis of ethyl-2-bromoisobutyrate in an alkaline aqueous solution/organic solvent two-phase medium are investigated. The reaction mechanism of hydrolyzing ethyl-2-bromoisobutyrate is proposed and verified based on experimental evidence. On the basis of experimental observation, several sequential reaction steps of hydrolyzing the bromo-alkyl bond (Br-C bond) and ester functional groups (-COOR) of ethyl-2-bromoisobutyrate into alcohol and acid are proposed and discussed. The kinetic models of the sequential reaction steps are developed to derive the rate equations and to obtain the rate constants. In conjunction with the rate equation from the kinetic model, the intrinsic rate constants of the two main reactions are determined from the experimental data for hydrolyzing ethyl-2-bromoisobutyrate using parameter estimation. The results indicate that the conversion of hydrolyzing ethyl-2-bromoisobutyrate and its rate are significantly retarded by Na2CO3 and C6H5OH and increase with the increase in the concentration of KOH (or NaOH) and TBAB in the aqueous solution. The hydrolysis of 2-bromoisobutyric acid is also retarded by sodium carbonate.

並列關鍵字

Hydrolysis of ethyl-2-bromoisobutyrate ； Sodium carbonate ； Tetrabutylammonium bromide(TBAB) ； Alkaline compounds

國際替代計量

Kinetic Study of the Hydrolysis of Ethyl-2-Bromoisobutyrate in Two-Phase Medium

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