AbstractTo determine the origin of the reaction rate acceleration in the synthesis of poly(butylene succinate) (PBS) upon microwave irradiation, we herein investigated the effect of the microwave-assisted activation of the reactants, viz. the monomers 1,4-butanediol (BD) and succinic acid (SA), and of the water produced as a by-product during the reaction. The rate of removal of the water by-product from the reaction solution was precisely measured under equivalent reaction conditions (i.e., time and temperature) using both microwave and conventional heating methods. Microwave heating selectively activated and removed the water from the reaction solution more rapidly and to a greater extent than oil bath heating. Measurement of the temperature-dependent dielectric properties of the reactants revealed that the dielectric loss factor (εʹʹ) of BD increased with increasing temperature, peaking at 80 °C. In contrast, the εʹʹ of the mixture of BD and SA was significantly lower than that of BD alone from 70–140 °C. These results indicate that the principal effect of microwave irradiation in the synthesis of PBS was the accelerated removal of the water by-product.The origin of the reaction rate acceleration in the microwave-assisted synthesis of poly(butylene succinate) (PBS) was investigated by measuring the rate of removal of the water by-product from the reaction solution under equivalent reaction conditions using both microwave and conventional heating methods. Microwave heating selectively activated and removed the water from the reaction solution more rapidly and to a greater extent than oil bath heating. These results indicate that the principal effect of microwave irradiation in the synthesis of PBS was the accelerated removal of the water by-product.

中文翻译：

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聚丁二酸丁二醇酯的微波辅助快速合成：微波辐射加速缩聚反应的主要作用

摘要 为了确定微波辐射下聚丁二酸丁二醇酯 (PBS) 合成中反应速率加速的起源，我们在此研究了反应物的微波辅助活化的影响，即。单体 1,4-丁二醇 (BD) 和琥珀酸 (SA)，以及反应过程中作为副产物产生的水。使用微波和常规加热方法在等效反应条件（即时间和温度）下精确测量从反应溶液中去除水副产物的速率。与油浴加热相比，微波加热选择性地活化并从反应溶液中除去水更迅速和更大程度。反应物随温度变化的介电特性的测量表明，BD 的介电损耗因子 (εʹʹ) 随温度升高而增加，在 80 °C 达到峰值。相反，在 70-140 °C 时，BD 和 SA 混合物的 εʹʹ 显着低于 BD 单独的。这些结果表明，微波辐射在 PBS 合成中的主要作用是加速去除水副产物。 研究了微波辅助合成聚丁二酸丁二醇酯 (PBS) 中反应速率加速的原因通过测量在等效反应条件下使用微波和常规加热方法从反应溶液中去除水副产物的速率。与油浴加热相比，微波加热选择性地活化并从反应溶液中除去水更迅速和更大程度。这些结果表明微波辐射在 PBS 合成中的主要作用是加速去除水副产物。