摘要
通过对多种金属氧化物及其盐类催化解聚乙醇酸低聚物(PGA)的对比研究发现,乙酰丙酮锌作催化剂可以明显降低反应体系的解聚温度,减轻乙交酯制备过程中的结焦现象,提高乙交酯的收率。进一步将其应用于PGA的溶剂共沸解聚工艺中,可以防止共沸溶剂在较高温度下发生热劣化现象。对乙酰丙酮锌与传统金属氧化物在催化机理上进行了探讨,并且利用热重分析对PGA低聚物的降解过程进行了动力学分析。结果表明,乙酰丙酮锌作为催化剂反应体系的解聚温度仅为200℃,加入量为低聚物质量的0.4%,乙交酯收率最高可达95%,且PGA低聚物在其催化作用下与传统催化剂三氧化二锑相比所需的活化能更低,裂解更容易进行。
Several metal oxides and their salts are used as catalysts to study the depolymerization of polyglyolic acid （PGA） oligomers. It is found that the temperature of depolymerization reaction decreases obviously under the catalysis of Zn（acac）2. At the same time, the coking is reduced in the process of preparing glycolide with the improved yield of glycolide. Zn（acac） 2 is also applied in the solution depolymerization of PGA, and thermal degradation of the azeotropic solvent is prevented at high temperature. It proves that Zn（acac） 2 can enhance the efficiency of depolymerization and the higher catalytic activity is thought to correlate to the coordination-insertion mechanism. The experimental results show that PGA oligomer is depolymerized at lower temperature （200℃） under Zn（acac） 2 catalyst with a mass fraction of O. 4%. The yield of glycolide reaches 95%. The activation energy value in process of oligomer depolymerization is lower in the presence of Zn （acac） 2 than the other catalysts, enhancing the efficiency of depolymerization.
出处
《现代化工》
CAS
CSCD
北大核心
2015年第5期117-120,共4页
Modern Chemical Industry
基金
江苏省高校自然科学研究重大项目(11KJA430007)
关键词
乙醇酸
乙交酯
溶剂共沸解聚
乙酰丙酮锌
glycolic acid
glycolide
solution depolymerization
Zinc （ Ⅱ ） acetylacetonate
