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作 者:李延升[1,2] 张保林[1] 张雪梅[2] 李红萍[1,3]
机构地区:[1]郑州大学化学工程学院,河南郑州450001 [2]许昌学院,河南许昌461000 [3]三门峡市环保局,河南三门峡472000
出 处:《信阳师范学院学报(自然科学版)》2009年第2期209-211,221,共4页Journal of Xinyang Normal University(Natural Science Edition)
基 金:国家“十一五”科技支撑计划课题子项目(2006BAD10B03-4)
摘 要:通过测量燃烧热的方法间接测量了丙交酯、低聚乳酸、高聚乳酸的生成焓,估算了这3种物质的标准熵,根据生成焓和标准熵的值计算了乳酸单体直接聚合、丙交酯的生成、丙交酯开环聚合为高聚乳酸3个反应的吉布斯自由能和平衡常数,得到的结论是,前2个反应为可逆反应,第3个反应为高度不可逆反应.结论与实验事实一致.The enthalpies of formation of lactide, lactic acid oligomer and lactic acid high polymer were measured indirectly by measuring combustion heat. The standard entropies of three compounds were estimated. Based on the data of enthalpies of formation and standard entropies, the Gibbs free energies and equilibrium constant of three reactions of the direct polymerization of lactic acid, the formation of lactide and the ring opening polymerization of lactic, were calculated. It was concluded that the first and the second reactions were reversible and the third reaction was highly irreversible.
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