乳酸合成丙交酯的催化剂回收的研究

Recycling Catalyst in the Synthesis of Lactide from Lactic Acid

丙交酯的合成是乳酸间接法合成聚乳酸的关键步骤,该过程产生的反应底物经水解后,残余物主要有催化剂、乳酸氧化产物和高温炭化物。采用了焚烧-沉淀的方法,回收其中催化剂并对废弃物进行有效处理。利用差热/热重分析仪(DTA/TG)和X射线衍射仪(XRD)分别对热分解过程、前驱物及产物进行了表征分析。试验结果表明,该方法催化剂的回收率为98%,其方法具有工艺简单、能耗小等优点。

The synthesis of lactide is the key process in the indirect preparation of polylacfic acid from lactic acid. The wastes from the key process include the catalyst ZnO, the oxidation products and by-products from high-temperature reaction. The heat-precipitation solution was used to recycle catalyst ZnO and dispose of wastes, and DTA/TG, XRD were used to analyse thermal decomposition process, and to characterize the precursor and catalyst. The flow diagram was designed according to the experimental conditions. The results show that, the recovery of catalyst can reach 98%, and the process is easily operated with low-energy consumption.