Study On Hydrocyanation Of 3-pentenenitrile Catalyzed By Spiro-Bidentate Phosphite Nickel Catalysts

Adiponitrile was used mainly as a start material for the production of polyamide66,and also widely used in electronic appliances,light industry,rganic synthesis industries and so on.The direct hydrocyanation process of butadiene to produce adiponitrile is one of the major processes for producing adiponitrile in the world.And the production method has many advantages,such as short process flow,low pollution low energy consumption and high productivity.The development of catalysts in the hydrocyanation of 3-pentenenitrile is the key to the development of adiponitrile.In the paper,the catalyst system for the hydrocyanation of 3-pentenenitrile were studied.First,SPINOL was synthesized,using 3-methoxybenzaldehyde as a raw material.The synthetic route included aldol condensation,reduction hydro-genation,oxidationreaction,bromination reaction,dehydration formation,debromination reaction,and demethylation reaction.After,a new type of spiro-bidentate phosphite ligand was synthesized using SPINOL as a raw material and the optimum reaction condition of synthesis of these ligands was obtained by investigating the solvents,reaction temperature,bases,and so on.The final yield of eight-step reaction could reach 17.3%.Later,four novel spiro-bidentate phosphite ligands were synthesized and the catalytic performances were studied by catalyzing hydrocyanation of 3-pentenenitrile with nickel in situ.The ligand L_2a showed the best catalytic-performance in the four ligands.Last,the L_2a ligand was used to investigate the reaction conditions for the hydrocyanation of3-pentenenitrile.The factors including the nickel compounds,the co-catalysts,the ratio of nickel chloride with acetone cyanohydrin,the ratio of ligand with nickel chloride,the solvents,the temperature and the time,were studied and the optimized reaction conditions were obtained:tetrahydrofuran as the solvent,nickel chloride as a zero-valent nickel source,zinc powder as a reducing agent,zinc chloride as a co-catalyst,n?NiCl₂?:n?ZnCl₂?:n(L_2a):n?acetone cyanohydrin?=1:3:8:12.5,the reaction temperature was one hundred degrees centigrade,reaction time was 2.5 hours.The conversion rate of 3-pentenenitrile was 27.5%,the selectivity of adiponitrile was 84.4%.In word,the hydrocyanation of 3-pentenenitrile was catalyzed by a new type of nickel catalyzed system with a new type of spiro-bidentate phosphite ligand.The conversion rate of 3-pentenenitrile could reach 27.6%,and the selectivity of adiponitrile could reach 86.3%.The research results have reference value and theoretical significance to further explore the new bidentate phosphite nickel catalyst for the catalytic hydrogenation of 3-pentenenitrile.