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首页> 外文期刊>Journal of Chemical Technology & Biotechnology >Kinetics for penoylsis of ethyl 2-bromoisobutyrate via phase-transfer catalysis in a soldi-liquid system
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Kinetics for penoylsis of ethyl 2-bromoisobutyrate via phase-transfer catalysis in a soldi-liquid system

机译：液相-液相体系中相转移催化2-溴异丁酸乙酯的戊酰基化反应动力学

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The kinetics of phase-transfer catalyzed etherification of sodium phenoxide with ethyl 2-bromoisobutyrate to produce ethyl 2-phenoxyisobutyrate in a solid-liquid system has been investigated. Being catalyzed by the quaternary ‘onium salts, the reaction was carried out in a stirred batch reactor to explore the effects of various operating variables. At a temperature of 80 0C and a molar ratio of tetra-n-butylammonium bromide to sodium phenoxide equal to 0.372, 94% conversion was obtained after 4h, and no other side products were observed. A kinetic model of pseudo-first-order reaction accompanied by catalyst deactivation was proposed to describe the overall reaction. A deactivation function was employed to evaluate the kinetic parameters. The decay of catalytic activity was mainly caused by the deposition of the salts produced on the surface of solid particles. The results show that the initial reaction rate was not influenced by the agitation rate when exceeding 350rpm, but the deactivation rate increased with Increasing stirring speed and the amount of catalyst used. The intrinsic organic reaction was conducted by the phase-transfer catalytic intermediate. The order of reactivity for different phase-transfer catalysts was determined as tetra-n-butylphosphoniuifl bromide> tetra-n-butylantmoniunl bromide> tetra-n-butylamnionium iodide~tefra-n-butyl-ammonium hydrogen sulfate Aliquat 336. The apparent activation energy for tetra-n-butylammo-nium bromide was estimated as 51.4kJ mol~(-1). This work provides an improved method for synthesizing phenolic substances in solid-liquid phases and preventing unfavorable side reactions.
机译：研究了固液体系中苯氧基钠与2-溴异丁酸乙酯的相转移催化醚化反应生成2-苯氧基异丁酸乙酯的动力学。在季铵盐的催化下，该反应在搅拌式间歇反应器中进行，以探索各种操作变量的影响。在80 0℃的温度下，四正丁基溴化铵与苯酚钠的摩尔比等于0.372，在4h后获得94％的转化率，并且未观察到其他副产物。提出了伴随催化剂失活的拟一级反应动力学模型来描述整个反应。使用失活函数来评估动力学参数。催化活性的下降主要是由于固体颗粒表面上产生的盐的沉积所致。结果表明，当超过350rpm时，初始反应速率不受搅拌速率的影响，但随着搅拌速度和催化剂用量的增加，失活速率增加。通过相转移催化中间体进行本征有机反应。确定不同相转移催化剂的反应顺序为：四正丁基膦腈溴化物>四正丁基溴化铵溴化物>四正丁基碘化铵〜四正丁基硫酸氢铵Aliquat 336。对四正丁基溴化铵的估计值为51.4kJ mol〜（-1）。这项工作提供了一种在固液相中合成酚类物质并防止不利的副反应的改进方法。

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