Abstract:

Phthalic anhydride is an important raw material for synthesizing high-value fine chemicals, such as plasticizers and coatings. In the recent decades, the production of phthalic anhydride from o-xylene is the main industrial process with minor from naphthalene. Vanadium-based catalysts are primarily employed in industry and have been widely studied due to their high selectivity for phthalic anhydride. In order to increase the yield of phthalic anhydride and reduce the bed temperature, strategies of multi-stage catalyst beds and high load have been gradually developed. This article focuses on the o-xylene synthesis process with a brief introduction of the development history of catalysts. Especially, the synthetic routes and catalytic mechanisms are discussed in detail. The application of industrial catalysts often faces deactivation problems, such as carbon compound deposition, loss of active components and TiO₂ anatase-rutile transformation. Thus, the deactivation mechanism of catalysts is also discussed in detail. Finally, prospects for the development of synthetic technologies of phthalic anhydride are proposed. Towards the industrial problems of high energy consumption, CO _x generation, and short catalyst life, efforts should be made to develop new efficient catalysts and green reaction processes for the phthalic anhydride synthesis, so as to promote the sustainable development of this technology in the future.

Key words: phthalic anhydride, vanadium-based catalysts, reaction network, reaction mechanism, deactivation mechanism, catalyst characterizations

摘要：

邻苯二甲酸酐（简称苯酐）是合成增塑剂、涂料等高价值精细化学品的重要原料，在工业生产中以邻法苯酐合成工艺为主，萘法合成工艺为辅，其中钒系催化剂因具有高苯酐选择性而备受关注。为了提高苯酐收率、降低床层温度，催化剂在工业应用中已逐步进入多床层、高进料负荷的发展阶段。本文以邻法苯酐为主要研究对象，简要讨论了催化剂的发展历程，重点关注合成工艺路线及催化机制研究进展。工业催化剂易因生成积炭、活性组分流失、TiO₂晶相转变等导致其失活，因此也重点探讨了催化剂的失活机制。最后对苯酐工艺的发展提出了展望，为解决当前生产工艺存在的高耗能、高碳排放、催化剂寿命短等挑战，未来苯酐合成应致力于开发新型高效催化剂和绿色反应新工艺，以推动该技术的可持续发展。

关键词: 苯酐, 钒系催化剂, 反应网络, 反应机制, 失活机制, 催化剂表征