Method for the hydrogenation of nitriles to primary amines

In a process of the type wherein an aliphatic nitrile is hydrogenated with hydrogen in the presence of a cobalt catalyst to an aliphatic primary amine, the improvement which comprises using as said catalyst a Raney cobalt catalyst which contains from about 2 to 35% by weight on a 100 weight percent total catalyst weight basis of aluminum, said catalyst having been prepared by contacting an aqueous medium containing dissolved therein alkali metal hydroxide with a group of cobalt-aluminum alloy particles, the aqueous dissolved alkali metal hydroxide being added incrementally to the medium during the contacting over a time interval;

• A. Said aqueous alkali metal hydroxide solution containing from 0.5 to 50 weight percent dissolved alkali;
• B. Said group having an average particle diameter in the range of from about 0.002 to 0.5 inch;
• C. Said cobalt-aluminum alloy having an initial cobalt to aluminum weight ratio of from about 30:70 to 70:30;
• D. Said contacting being accomplished over a total interval of 2-30 hours;
• E. The addition rate of alkali metal hydroxide solution being so added to said medium during said contacting being from about 0.01 to 7 moles alkali metal hydroxide per mole of aluminum initially in said alloy particles per hour;
• F. The total quantity of alkali metal hydroxide so added being in the range of from about 0.5 to 20 moles of alkali metal hydroxide per mole of aluminum initially present in said alloy;
• and
• G. The resulting aqueous medium produced during said contacting being maintained at a temperature at or below about 50.degree. C.

In an improved process for selectively, catalytically hydrogenating aliphatic nitriles to their corresponding primary amine the improvement which comprises contacting said aliphatic nitrile with hydrogen in the presence of a Raney cobalt catalyst, said catalyst having been prepared by contacting a prechosen group of cobalt-aluminum alloy particles confined to a reaction zone with a liquid aqueous medium containing dissolved therein alkali metal hydroxide while maintaining a reaction rate between said particles and of said hydroxide such that not more than about 0.02 moles of hydrogen per mole of said aluminum initially present in said alloy on a 100 weight percent total initial alloy basis is evolved per minute, said contacting being contacted while keeping a bulk temperature in said medium in the region of said group ranging from about 0.degree. to 50.degree. C., said contacting being continued until at least about 35 weight percent of said aluminum initially present in said alloy on a 100 weight percent total initial alloy basis is removed, said alloy particles initially having a ratio of cobalt to aluminum in the range from about 30:70 to 70:30, said alloy particles further initially having average particle diameters in the range of from about 0.002 to 0.5 inch the total molar quantity of alkali metal hydroxide charged to said medium during the total time of said contacting being at least about 0.5 times the number of moles of aluminum initially present in said alloy particles, the total weight of water initially present in said medium at the beginning of said contacting plus water added to said medium during contacting ranges from about 1.5 to 100 times the total weight quantity of dissolved alkali metal hydroxide contacted with such particles.