Study On Hydrcyanation Of 3-pentenenitrile Catalyzed By Hydrogen-anthracene Bidentate Nickel Catalysts

Hydrocyanation of olefins is an important reaction for the synthesis of nitrile compounds,and the preparation of adiponitrile is the most important application of the hydrocyanation of olefins.Adiponitrile is used mainly as the raw material for the production of nylon 66.At present,the processes for adiponitrile are electrolytic dimerization of acrylonitrile and direct hydrocyanation of butadiene.Due to its advantages such as shorten process flow,low energy consumption,no pollution;direct hydrocyanation of butadiene has been concerned extensively.The key problem of hydrocyanation of olefins is development of catalyst.Therefore,it is very important to develop new catalyst for the preparation of adiponitrile by the hydrocyanation of 3-pentenenitrile.In this paper,the catalyst system for the hydrocyanation of 3-pentenenitrile were studied.A new type of hydrogen anthracene bidentate phosphite ligand was designed and a general synthetic method of these ligands was developed.The optimum reaction condition of synthesis of these ligands was obtained by investigating the solvents,reaction temperature,bases,and so on.The optimized reaction conditions: toluene as the solvent,triethylamine as the base,at-15?,m-methyl phenol was added dropwise into the mixture of trimethylamine and phosphorus trichloride,the yield is up to 65.1%.Four novel hydrogen anthracene bidentate phosphite ligands were synthesized and the catalytic performances were evaluated by catalyzing hydrocyanation of 3-pentenitrile with nickel in situ.The ligand L_2c showed the best catalytic performance in the four ligands.By using L_2c as ligand,3-pentenitrile and cyanohydrin as starting material;the process conditions of hydrocyanation of 3-pentenitrile were studied.The factors including the nickel compounds,the reducing agents,the co-catalysts,the solvents,reaction temperature,reaction time,the ratio of nickel chloride with acetone cyanohydrin,the ratio of ligand with nickel chloride were studied and the optimized reaction conditions were obtained: 3-pentenenitrile : acetone cyanohydrin=1:1,tetrahydrofuran as the solvent,nickel chloride as a zero-valent nickel source,zinc powder as a reducing agent,zinc chloride as a co-catalyst,nickel chloride : acetone cyanohydrin?molar ratio?= 0.1,ligand : nickel chloride?molar ratio?= 8:1,the reaction temperature : 100 ° C,reaction time: 4 hours,the yield of adiponitrile is up to 72.3%.In conclusion,a new bidentate phosphite ligand(L_2c)was obtained which shows good catalytic performance in hydrocyanation of 3-pentenenitrile in 72.3% yield.