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为提高L-丙交酯的纯度和产率,对L-丙交酯的制备技术进行改进。根据聚乳酸合成、裂解、环化反应和重结晶过程的特点和规律,优化了L-乳酸的脱水、聚合温度、裂解温度、L-丙交酯蒸出速度和粗产品的重结晶等工艺条件,改进了冷凝装置及接收装置。在制备过程中注意控制裂解温度不超过230℃,使用自行设计的接收装置控制L-丙交酯蒸出速度,采用重结晶和水洗交替进行的纯化方法,使粗品产率超过80%,纯品产率达到40%。
In order to improve the purity and yield of L-lactide, the preparation technology of L-lactide is improved. According to the characteristics and rules of polylactic acid synthesis, pyrolysis, cyclization reaction and recrystallization process, the optimal conditions of dehydration, polymerization temperature, pyrolysis temperature, L-lactide distilling rate and recrystallization of crude product were optimized , Improved condensing device and receiving device. In the preparation process, pay attention to the control of the cracking temperature does not exceed 230 ℃, the use of self-designed receiving device control L-lactide speed, the use of recrystallization and washing alternately purification method, the crude product yield over 80%, pure The yield reached 40%.