Study On The Synthesis Of Asymmetric Bisacylhydrazid

Dihydrazides have special structure and rich in nitrogen,so they have certain biological activity and are widely used in many fields.They can be used as important intermediates of pesticide products such as insect growth agents and herbicides.They can be used as synthetic enzyme inhibitors,anti-tumor,anticonvulsant,anti-inflammatory,anti malaria and other drugs.They can also be used in industrial products such as electroluminescent systems,liquid crystals and biomedical equipment,It is one of the important precursors in heterocyclic synthesis.Among them,N-isooctyl-N’-cyanoacetic hydrazine is the key intermediate of many dyes.Optimizing its synthesis conditions has important industrial value.At present,the main synthesis method of asymmetric dihydrazide is to use monosubstituted hydrazide and acyl chloride as raw materials,add organic solvents,and react in the presence of acid binding agent,and the reaction time is long.Expensive and toxic organic solvents have certain health risks and pollution problems in the process of production and use,and also increase the process cost.Therefore,the development of a green synthesis process of dihydrazide without organic solvent has certain economic value and environmental protection significance.On the basis of references,this paper designed a route to synthesize N-isooctyl-N’-cyanoacetic hydrazine with isooctanoic acid and ethyl cyanoacetate as raw materials and isooctyl chloride and cyanoacetic hydrazine as intermediates.Phase transfer catalysis technology was introduced into the synthesis of the final product,and a green synthesis route with water as reaction solvent was constructed.The specific contents of the experiment are as follows:1.In the synthesis of intermediate product isooctyl chloride,isooctanoic acid was acyl chlorinated with thionyl chloride.The reaction time,reactant ratio and reactant dropping time were investigated.Orthogonal experiments and single factor condition experiments were designed and completed.The optimum process conditions for the reaction were as follows: the ratio of reaction raw material n(isooctanoic acid):n(thionyl chloride)was(1:1.3),the dropping time of isooctanoic acid was 60 min,and the reaction was 2H at reflux temperature,The yield of the reaction can reach 97.17%,and the yield can be further increased to more than 99.5%.2.In the synthesis of intermediate product cyanoacetic hydrazine: hydrazinolysis reaction takes place with ethyl cyanoacetate and hydrazine hydrate as raw materials.The four non interactive factors of raw material ratio,reaction temperature,dropping temperature and dropping time were investigated by single factor experiment.The optimum reaction conditions were as follows: the ratio of n(ethyl cyanoacetate):n(80%hydrazine hydrate)was(1:1.1),the reaction temperature was 10-15℃,the dropping temperature was 0-5℃,the dropping time was 30 minutes,and the reaction yield was93.04%.3.In the synthesis of the final product N-isooctyl-N’-cyanoacetic hydrazine: two synthetic routes of solvent method and aqueous phase method were investigated,and the phase transfer catalyst was screened.After the comparison of test results and consideration of economy and environmental protection,tetrabutyl ammonium bromide was selected as the best catalyst for the reaction,and orthogonal experiment and single factor experiment were completed.The optimum process conditions of the reaction were obtained as follows:taking water as solvent,The ratio of n(cyanoacetyl hydrazine):n(2-ethylhexyl chloride)is(1:1.1),the phase transfer catalyst is tetrabutyl ammonium bromide,the addition amount of phase transfer catalyst is 3%,and the emulsifier is OP-10.The reaction yield can reach84.24% at 0-5℃.After the mother liquor is applied,the yield can be further increased to more than 87%.