Preparation Of Thiazole Salt-graphene Grafting Catalyst And Its Catalytic Synthesis Of Dioioin

Dioioin compound is a kind of organic compound with ortho-hydroxy ketone structure,which is the general term for a series of compounds.Common dioioin compounds include benzoin（benzophenone）,acetoin（3-hydroxy-2-butanone）,propionoin（4-hydroxy-3-hexanone）,3-hydroxy-2-Pentanoneand2-hydroxy-3-pentanone,etc.As an important chemical product,dioioin compounds have a wide range of uses,mainly as food flavors,pharmaceutical intermediates and photosensitizer materials.The traditional synthetic methods of acyloin compounds have problems such as low yield,complex synthetic processes,serious environmental pollution and large operational risk factors.Therefore,the research and development of green,safe and efficient synthetic processes has important application value.In the thesis,the benzene ring was grafted onto the graphene by diazotization reaction,and then the benzene ring modified graphene（G-Ph）was obtained.The chloromethyl group is then introduced into the product of chloromethylation（followed by G-PhCH₂Cl）by a benzene ring modified graphene（or the edge of the carrier）via a Blanc chloromethylation;Finally,G-PhCH₂Cl reacts with5-（2-hydroxyethyl）-4-methylthiazole to form a catalyst for the covalent grafting of Graphene（expressed as G-PhCH₂-Th,where Th stands for5-（2-hydroxyethyl）-4-methylthiazole）.The structures of G-Ph,G-PhCH₂Cl and G-PhCH₂-Th were analyzed by FTIR,XPS and Raman.By optimizing the preparation conditions of G-PhCH₂-Th,the maximum supported active component content of G-PhCH₂-Th catalyst can reach 17%.The synthesis of Benzoin from Benzaldehyde catalyzed by G-PhCH₂-Th showed that the yield of benzoin was 25.27%when the mass ratio of catalyst to Benzaldehyde was 8:200,the reaction temperature was 120°C and the reaction p H was 10 for 10 h.After the reaction is completed,the mixed liquid is filtered,and the solid is recovered by washing and drying to obtain the catalyst G-PhCH₂-Th.The yield of Benzaldehyde Benzoin condensation is stable at 15%.After five cycles of reaction,the catalyst still retains better catalytic activity,it shows good cycle performance.