| Summary: | 碩士 === 國立中興大學 === 化學系 === 87 === 英文摘要
The phase-transfer Catalysis (PTC) technique greatly enhances the reaction rates of various organic reations under mild conditions in multiphase systems. The objectives of the present study are to apply solid-liquid phase-transfer catalytic technique in systhesizing diesters and ether-esters by conducting nucleophilic substitutions in the organic solution, and to study the reaction kinetics. The systheses of dibenzyl phthalate (DBP)and diallyl phthalate (DAP) were conducted from potassium phthalate with benzyl bromide and allyl bromide ,respectively. The ether-ester, 4-methoxyphenyl acetic acid butyl ester (4MPABE) was systhesized by reacting the sodium salt of 4-methoxyphenyl acetic acid with n-iodobutane or n-bromobutane. The above systems were all carried out effectively in solid-liquid PTC reactions .
The operating conditions for investigation include agitation speeds, reaction temperatures, catalyst amounts, type of solvents, molar ratios of reactants, type of additives, type of phase-transfer catalysts, etc. The apparent reaction rate constants were obtained from the experimental results.
The present study is divided into three parts and the conclusions of which are summarized as fallow.
(1) DBP:The pseudo-second-order kinetics was applied to correlate the experimental data successfully. Comparing the reactivity of various phase-transfer catalysts, the catalytic activity sequence was tested as TBAI≈TBAB＞TBPB＞BTEAB＞TBAHS. Moreover, the addition of potassium bromide and small amounts of water can enhance the overall phase-transfer catalytic reaction rates.
(2) DAP:The reaction systems include a solid-liquid and a liquid-liquid phases. The pseudo-second-order kinetic was also applied to describe the kinetic behaviors of phase-transfer catalysts. The catalytic activity sequence was tested as TBAB＞TBAI＞TBPB＞BTEAB. In addition, the introduction of small amounts of potassium iodide can increase the overall reaction rates. However, adding small quantites of potassium bromide inhibits the overall reaction rates.
(3) 4MPABE:The RI reactant and RBr reactant were used to evaluate the reactivity of phase-transfer catalysts, respectivity. The pseudo-first-order kinetics including catalyst decay was empolyed to correlate the experimental data of RI system successfully. Comparing the reactivity of various phase-transfer catalysts, the catalytic activity sequence was tested as TBPB≈TBAB＞TBAHS＞BTEAB＞PEG 1000＞TBAI for RI. While for RBr reactant, no catalyst decay was observed. A pseudo-first-order kinetic equation was enough to describe the system. The catalytic activity sequence was tested as TBAB≈TBPB≈TBAHS＞BTEAB＞PEG 1000.
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