Carta Daniela, Cao Giacomo, D'Angeli Claudio
Dipartimento di Ingegneria Chimica e Materiali, Unità di ricerca del Consorzio, Università di Cagliari, Piazza D'Armi, Cagliari, Italy.
Environ Sci Pollut Res Int. 2003;10(6):390-4. doi: 10.1065/espr2001.12.104.8.
In this paper we review an interesting method of PET recycling, i.e. chemical recycling; it is based on the concept of depolymerizing the condensation polymer through solvolytic chain cleavage into low molecular products which can be purified and reused as raw materials for the production of high-quality chemical products. In this work our attention is confined to the hydrolysis (neutral, acid and alkaline) and glycolysis processes of PET chemical recycling; operating conditions and mechanism of each method are reported and described. The neutral hydrolysis has an auto accelerating character; two kinetic models have been proposed: an half-order and a second order kinetic model. The acid hydrolysis could be explained by a modified shrinking core model under chemical reaction control and the alkaline hydrolysis by a first-order model with respect to hydroxide ion concentration. To describe glycolysis, two different kinetic models have been proposed where EG can act or not as internal catalyst. Further experimental and theoretical investigations are required to shed light on the promising processes of PET chemical recycling reviewed in this work.
在本文中，我们回顾了一种有趣的聚对苯二甲酸乙二酯（PET）回收方法，即化学回收；它基于通过溶剂解链断裂将缩聚物解聚为低分子产物的概念，这些低分子产物可被纯化并重新用作生产高质量化学产品的原料。在这项工作中，我们的注意力集中在PET化学回收的水解（中性、酸性和碱性）和醇解过程；报告并描述了每种方法的操作条件和机理。中性水解具有自动加速特性；已经提出了两种动力学模型：半级和二级动力学模型。酸性水解可以用化学反应控制下的修正缩核模型来解释，碱性水解可以用关于氢氧根离子浓度的一级模型来解释。为了描述醇解，已经提出了两种不同的动力学模型，其中乙二醇（EG）可以作为或不作为内部催化剂。需要进一步的实验和理论研究来阐明本文中综述的PET化学回收的有前景的过程。
