The Synthesis Of High Performance Polycarboxylic Series Water-reducer And Study On The Oxidation Reaction Of The ?-bromoacetophenone Via Visible-light Photoredox

Polycarboxylic water-reducer has the unique comb-type structure which different from previous generations of water reducing agent and posses a series of characteristics such as high water reducing rate, low dosage, good initial fluidity, fluidity retention capacity, low slump and so on, which is an important component of concrete admixture and an important developing direction of the water reducing agent in the future. In addition, there is a great variety of high performance polycarboxylic series water-reducer, which can be synthesized to meet the need of different performances of concrete through the selection of different monomers, the design of molecular structure and controlling the molecular weight. As a consequence, the selection of a new kind of monomer to synthesize different type of high performance polycarboxylic series water-reducer is of important significance. In this paper, one monomer had been synthesized firstly, which is polyethylene glycol monomethyl methyl acrylate. Another large compound such as Cts, CMC-Na, ?-CD was selected, which could copolymerize with the first monomer to synthesize high performance polycarboxylic series water reducer. The optimum rection conditions were obtained, and the products were obtained by direct distillation or solvent extraction. However little research have done on the molecular weight and structure of the products and we haven't got the relevant properties about water-reducer temporarily.Recently the visible light photoredox catalysis grasps the attention of chemical researchers more and more, because of it is an economic efficient method in organic synthesis. Whereas ?-bromoacetophenone is more popular as it is the pioneer of free radical reaction. In this paper, the application of visible light photoredox in terms of dehalogenation is reviewed firstly, which introduces a variety of visible light catalysis dehalogenation reactions, such as functionalized and ring-close reactions of olefins, functionalities of aromatics, dehalogenation reduction and so on. Then, based on the reported dehalogenation reactions under visible light photoredox catalysis, the visible light photoredox catalytical reaction of ?-bromoacetophenone were also studied. It was found that benzoic acid derivatives were obtained, which could be further transformed to benzoyloxyphenylethanone.Then, the author not only optimized the reaction conditions, got the optimum reaction conditions and a satisfactory yield. But also expanded the reaction substrates, explored the reaction mechanism.