The Application Of Palladium And Platinum Based Precious Metal Catalysts In Green Chemical Production

As one of the important fields of chemical industry,fine chemical industry belongs to highly integrated technology-intensive industry.Fine chemicals have many varieties and are updated quickly.The production process involves many organic synthesis unit reactions.There are many problems such as production decentralization and environmental pollution based on the development of traditional industries.For this reason,we urgently need to develop green,sustainable chemical technologies to replace some of the traditional high-pollution process technologies.Therefore,it is necessary to study the technical transformation of some traditional production methods for organic synthesis reactions in fine chemicals.Main research findings have been summarized as following:Chapter 1:Firstly,the hydrogenation of aromatic nitro compounds and N-alkylation reaction were introduced as important unit reactions in chemical production.The synthetic process of aromatic amines and the strategy of selective hydrogenation synthesis were also summarized.Finally,the topic basis and content of this thesis were listed.Chapter 2:The Pt/C catalyst is used in the hydrogenation synthesis reaction of 1,5/1,8-diaminonaphthalene.Through the direct hydrogenation of 1,5/1,8-diaminonaphthalene mixed nitro compounds,the complicated separation process after the nitration process can be omitted and the requirements of the green chemical production can be met.In view of the deactivation of the catalyst after reaction,the pretreatment process of the nitro compound and the increase in the catalyst loading have been used to ensure the stability of the catalyst.After the subsequent separation and purification process,product purity of 96%-98%can be achieved.Chapter 3:Replacing ethanol system with chlorobenzene system significantly improved the hydrogenation process of 1,5/1,8-dinitronaphthalene mixed nitro compounds.At the same time,the experiment analyzes the impurities produced by the reaction and makes a corresponding discussion on the mechanism of action of the additive.Chapter 4:N-ethyl carbazole was synthesized by a two-step process.N-vinyl carbazole was first prepared from carbazole and then hydrogenated to give N-ethyl carbazole,which was greener and more environmentally friendly than conventional N-alkylation methods.However,due to the strong electron transfer ability of the carbazole group,the hydrogenation reduction of N-vinyl carbazole is difficult.Therefore,highly active Pd2 catalyst was applied to the hydrogenation reaction of N-vinylcarbazole.By optimizing the hydrogenation reaction conditions and the carrier types,the two factors of the catalyst's anti-toxicity and cycle stability were investigated.Chapter 5:The research work of this thesis is summarized,and the prospect of hydrogenation reduction in actual production and application is given.