Study On Synthesis Of New Type Of Azo Initiator

Azo compounds are important chemical compounds which are used as initiator, vesicant, and make good use of in our daily lives and modern technology. Recently, azo compounds are major be used as polymers or radical initiators, including the development of aqueous or oil azo-initiator, azocarboxylic esters and so on. This degree put on the emphasis research of improving the methods to synthesize several different new azo initiators.In the synthesis of 4,4'-Azobis(4-cyanovaleric acid), we chose levulinic acid, sodium cyanide and hydrazine as starting material in two steps to prepare 4,4'-hydro- azobis(4-cyanovaleric acid), then was oxidized by NaClO3 or H2O2. The optimum process conditions of synthesizing hydroazo: n(levulinic acid): n(sodium cyanide): n(hydrazine) =1.0:1.05:0.5; reaction temperature 0～5℃, reaction time 3h. In the oxidation process, sodium chlorate as oxidant, get the optimum process conditions: n(hydrazinenitrile): n(sodium chlorate): n(HBr) =1.0:0.33:0.1, reaction temperature 20～25℃, PH<1, reaction time 4h, yield 86.0%; H2O2 as oxidant, take HBr for example, get the optimum process conditions: n(hydrazinenitrile): n(H2O2): n(HBr) = 1.0:1.3:0.1, reaction temperature 20～25℃, PH<1, reaction time 4h, yield 87.5%. The structures were assigned by elementary analysis and IR, 1HNMR .In the synthesis of 1,1'-azobis(cyclohexanecarbonitrile), we explored the synthesis of hydrogenate azo-compound by using"one-pot"method, then was oxidized by H2O2. The optimum process conditions of"one-pot"method: n(cyclohexanone): n(sodium cyanide): n(hydrazine) =1.0:1.3:0.5; at 30℃for 1.5h; then we make the best method during option of reaction tempreture, oxidation and catalyst, and get the optimum process conditions: n(hydrazinenitrile): n(H2O2): n(HBr) : n(H2SO4) = 1.0:1.3:0.1:0.7, reaction temperature 20～25℃, yield 92.6%. The product was assignd by elementary analysis, IR and 1HNMR.In the synthesis of 2,2'-azobis (2,4-dimethyl- 4-methoxypent anenitrile), the ketone material was prepared by mesity oxide, methanol as strating material, then the hydrogenate azo-compound was prepared by using"one-pot"method, oxidated by H2O2 with the presence of HBr, Br2 and NaBr/KBr as catalyst to get V-70. We explored the optimum process conditions: n(methanol): n(mesity oxide): n(catalyst) = 2.5:1.0:0.1, at 25℃for 6h, yield 75.5%. In the oxidizing process, take HBr for example, we fixed the optimal technological conditions: n(ketone): n(sodium cyanide): n(hydrazine):n(H2O2):n(HBr):n(H2SO4)=1.0:1.3:0.5:0.65:0.05:0.35;cyaniding reaction tempreture 0～5℃, oxidating reaction tempreture 20～25℃, yield 95.6%.The method this thesis explored was a common use for preparing azonitrile, which made the reaction condition moderate, the amount of material easily controlled, reduced the pollution to the environment and greatly enhanced the purification and yield of the production.