Study On The Catalytic Hydrodehalogenation Process For The Resource Recycling Of Halogenated Organic Solid Waste

Halogenated organic matter is an extremely important substance widely used in medicine,dye,pesticide,perfume and other industries.Meanwhile,halogenated organic substance contains halogen atoms that are highly toxic and not easily degradable.At the same time,halogenated organic substance is highly toxic and not easily degradable due to halogen atoms.With the production and use of people,halogenated organic substance will also diffuse into the ecosystem,which will damage the environment and harm human health.Catalytic hydrodehalogenation is a green,economical and safe method that can transform toxic and harmful halogenated organic pollutants into low-toxic and non-toxic substances or higher-value products through hydrogenation reduction,one of the internationally recommended resource utilization methods of halogen-containing organic solid waste.This thesis includes three aspects of non-selective debromination,selective dechlorination and dechlorination coupling,focusing is on the utilization of halogen-containing organic solid wastes in the catalytic hydrodehalogenation process.The specific contents are as follows:Chapter 1:This part introduces the current status and common methods of resource utilization of halogen-containing organic solid waste,discusses the advantages of catalytic hydrodehalogenation to treat halogen-containing solid waste,and introduces the reaction mechanism of hydrodehalogenation.Given the critical issues of hydrodehalogenation,the critical factors of different halogen removal and selective dehalogenation are discussed.Finally,the basis for the topic selection and the main research contents of this thesis are described.Chapter 2:Using Pd/C as the catalyst,three different systems of halogen-containing solid waste(3-bromo-2-methyl)were studied from the perspectives of non-selective debromination,selective dechlorination and dechlorination coupling of halogencontaining organic solid waste.The effect of common solvent,amount of solvent and temperature on the catalytic hydrodehalogenation reaction are systematically investigated.Among them,the selectivity of 3-bromo-2-methylpyridine to methylpyridine by debromination is>99%;with cyclohexane as solvent the selectivity of hydrodechlorination of 3,4-dichloroaniline to prepare 3-chloroaniline can reach 95%;with CO as the reducing agent,4-chlorophthalic anhydride dechlorination coupling to prepare 3,3 ’,4,4’-biphenyltetracarboxylic acid yield can reach 98%.Chapter 3:The primary mechanism of catalyst deactivation is discussed and the main strategies to inhibit catalyst agglomeration is introduced.The method and production process of stabilizing the supported metal catalyst by using nitrogen-doped carbon as catalyst coating material is studied,which improves the stability of the catalyst,realizing the stable application of the catalyst.Chapter 4:On the basis of summarizing the research results of the thesis,some prospects for the resource utilization of catalytic hydrodechlorination of halogencontaining solid waste are prospected.