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首页> 外文期刊>Journal of Applied Polymer Science >The polycondensation of lithium 11-bromoundecanoate in aqueous media
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The polycondensation of lithium 11-bromoundecanoate in aqueous media

机译：11-溴癸酸锂在水性介质中的缩聚反应

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To obtain a biodegradable plastic, polycondensation, the substitution of bromine by carboxylate was carried out on lithium 11-bromoundecanoate. Using water as a solvent, the formation of a double bond was detected between 70 and 100degreesC, yielding a good quantity of polymer. Water is recommended as the best solvent for the reaction. Thermodynamic investigations were carried out by using ethylene glycol and water. The reaction is believed to proceed according to the S(N)2 mechanism. The DeltaH and DeltaG values for condensation in ethylene glycol were slightly higher than for those in water, but the reaction rate in water at 70degreesC was 7 times greater than that in ethylene glycol. The enhancement of dissociation accounts for the advantageous condensation in aqueous media. Furthermore, DeltaS shows negative values and DeltaG shows positive values, meaning that the reaction should proceed exothermically and not spontaneously. Experiments to condense 11-bromoundecanoate in aqueous media were carried out for ten days in a water bath, kept at 70degreesC, using 25 mL of 0.05M 11-bromoundecanoate. The degree of polymerization for the resulting polymer was found to be 23 by the end group assay for both bromine and carboxylate. Neither a melting point nor glass transition point for the product were observed. The polymer formed decomposes at 300degreesC and instantly disperses. (C) 2003 Wiley Periodicals, Inc. [References: 6]
机译：为了获得可生物降解的塑料，进行缩聚反应，在11-溴代癸酸锂上进行溴化，以羧酸盐取代溴。使用水作为溶剂，在70至100℃之间检测到双键的形成，产生了大量的聚合物。建议将水作为反应的最佳溶剂。通过使用乙二醇和水进行热力学研究。据信该反应根据S（N）2机理进行。乙二醇中缩合的DeltaH和DeltaG值略高于水中，但在70℃的水中的反应速率是乙二醇的7倍。离解的增强解释了在水性介质中的有利冷凝。此外，DeltaS显示负值，而DeltaG显示正值，这意味着反应应放热而不是自发进行。在保持于70℃的水浴中，使用25mL的0.05M 11-溴癸酸酯，将11-溴癸酸酯在水介质中缩合的实验进行了十天。通过溴和羧酸酯的端基分析，发现所得聚合物的聚合度为23。既没有观察到产物的熔点也没有观察到玻璃化转变点。形成的聚合物在300℃分解并立即分散。 （C）2003 Wiley Periodicals，Inc. [参考：6]

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