In the hydrocyanation reaction of butadiene proceeding through pentenenitriles to adiponitrile, catalysis by complexes of zerovalent nickel with bidentate phosphorus-based ligands of the NiL.sub.2A type wherein L.sub.2 is a bidentate ligand and A is an unsaturated compound, can be rate-limited by the solubility of the catalytic complex. The present invention concerns solvent compositions for the nickel-ligand complex comprising mixtures of unsaturated nitriles that provide for increased metal solubility, particularly in the absence of a Lewis acid promoter, resulting in higher hydrocyanation reaction rates in an industrial-scale process for production of important nylon manufacturing intermediates. The mixed nitrile solvent compositions can include mixtures of pentenenitriles and/or methylbutenenitriles. The mixtures of mixed unsaturated nitriles can be, at least in part, from recycle streams from the hydrocyanation reaction for which the nickel-bidentate ligand complexes are used as catalysts.

In the hydrocyanation reaction of butadiene proceeding through pentenenitriles to adiponitrile, catalysis by complexes of zerovalent nickel with bidentate phosphorus-based ligands of the NiL.sub.2A type wherein L.sub.2 is a bidentate ligand and A is an unsaturated compound, can be rate-limited by the solubility of the catalytic complex. The present invention concerns solvent compositions for the nickel-ligand complex comprising mixtures of unsaturated nitriles that provide for increased metal solubility, particularly in the absence of a Lewis acid promoter, resulting in higher hydrocyanation reaction rates in an industrial-scale process for production of important nylon manufacturing intermediates. The mixed nitrile solvent compositions can include mixtures of pentenenitriles and/or methylbutenenitriles. The mixtures of mixed unsaturated nitriles can be, at least in part, from recycle streams from the hydrocyanation reaction for which the nickel-bidentate ligand complexes are used as catalysts.

The present invention relates to the fine purification of isophoronenitrile (IPN) by melt crystallization.

The present invention relates to the fine purification of isophoronenitrile (IPN) by melt crystallization.

Phosphorus-containing ligands are recovered from mixtures comprising 3-pentenenitrile (3PN) and adiponitrile (ADN), using liquid-liquid extraction. ADN is produced by hydrocyanation of 3PN. The ADN is hydrogenated to produce a hexa-methyiene diamine (HMD) and at least one byproduct including bis-hexamethylene triamine (BHMT) or 1,2-diaminocyclohexane. At least a portion of the HMD product or byproduct is used to enhance the liquid-liquid extraction to recover phosphorus-containing ligand.

Phosphorus-containing ligands are recovered from mixtures comprising 3-pentenenitrile (3PN) and adiponitrile (ADN), using liquid-liquid extraction. ADN is produced by hydrocyanation of 3PN. The ADN is hydrogenated to produce a hexa-methyiene diamine (HMD) and at least one byproduct including bis-hexamethylene triamine (BHMT) or 1,2-diaminocyclohexane. At least a portion of the HMD product or byproduct is used to enhance the liquid-liquid extraction to recover phosphorus-containing ligand.

Phosphorus-containing ligands are recovered from mixtures comprising 3-pentenenitrile (3PN) and adiponitrile (ADN), using liquid-liquid extraction. ADN is produced by hydrocyanation of 3PN. The ADN is hydrogenated to produce a hexa-methyiene diamine (HMD) and at least one byproduct including bis-hexamethylene triamine (BHMT) or 1,2-diaminocyclohexane. At least a portion of the HMD product or byproduct is used to enhance the liquid-liquid extraction to recover phosphorus-containing ligand.

A multidentate phosphite ligand is used in the catalytic synthesis of adiponitrile. The ligand is represented by the following general formula (I). The method of catalytic synthesis of adiponitrile comprises primary hydrocyanation, isomerization, and secondary hydrocyanation reactions, wherein the catalyst adopted each comprises a phosphite ligand-nickel complex composed of a nickel precursor and a multidentate phosphite ligand. The ligand molecule has a higher electron cloud density, and the phosphorus content capable of participating in coordination in the ligand molecule per unit mass is higher, so that the catalytic activity of the catalyst is improved, and the amount of the catalyst is reduced. ##STR00001##

A multidentate phosphite ligand is used in the catalytic synthesis of adiponitrile. The ligand is represented by the following general formula (I). The method of catalytic synthesis of adiponitrile comprises primary hydrocyanation, isomerization, and secondary hydrocyanation reactions, wherein the catalyst adopted each comprises a phosphite ligand-nickel complex composed of a nickel precursor and a multidentate phosphite ligand. The ligand molecule has a higher electron cloud density, and the phosphorus content capable of participating in coordination in the ligand molecule per unit mass is higher, so that the catalytic activity of the catalyst is improved, and the amount of the catalyst is reduced. ##STR00001##

A multidentate phosphite ligand comprising a backbone which comprises a substituted or unsubstituted spirobiindane compound and at least two organophosphite groups chemically bonded to the backbone, wherein the organophosphite groups are alkyl phosphite groups or wherein the organophosphite groups are aryl phosphite groups, wherein the aryl moieties on the aryl phosphite groups are phenyl rings substituted with one or more C.sub.1-C.sub.4 alkyl groups; or which comprises a substituted or unsubstituted spirodifluorene compound and at least two organophosphite groups chemically bonded to the backbone.