Preparation of lactams from aliphatic .alpha.,.omega.-dinitriles

A process for the preparation of five-membered ring lactams or six-membered ring lactams form aliphatic .alpha.,.omega.-dinitriles, comprising:

• (a) contacting an aliphatic .alpha.,.omega.-dinitrile of either the formula:
• ##STR6## where R.sub.1 and R.sub.2 are both H, and;
• R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently selected from the group consisting of H, alkyl or substituted alkyl, or alkenyl or substituted alkenyl, or R3 and R4 taken together are alkylidene or substituted alkylidene, or independently R5 and R6 taken together are alkylidene or substituted alkylidene,
• in an aqueous reaction mixture with an enzyme catalyst selected from the group of consisting of:
• Acidovorax facilis 72W (ATCC 55746),
• Acidovorax facilis 72-PF-15 (ATCC 55747),
• Acidovorax facilis 72-PF-17 (ATCC 55745), and
• Comamonas testosteroni 5-MGAM-4D (ATCC 55744),
• whereby the .alpha.,.omega.-dinitrile is converted to an .omega.-nitrilecarboxylic acid ammonium salt;
• (b) contacting the aqueous product mixture resulting from step (a) with hydrogen and hydrogenation catalyst, whereby the .omega.-nitrilecarboxylic acid ammonium salt is converted directly to the corresponding lactam without isolation of the intermediate .omega.-nitrilecarboxylic acid, .omega.-nitrilecarboxylic acid ammonium salt, .omega.-nitrilecarboxylic acid or .omega.-nitrilecarboxylic acid ammonium salt;
• and
• (c) recovering the lactam from the aqueous product mixture resulting from step (b).

A process for the preparation of five-membered ring lactams or six-membered ring lactams from aliphatic +.alpha.,.omega.-dinitriles, comprising:

• (a) contacting an aliphatic .alpha.,.omega.-dinitrile of either formula ##STR7## where R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11 and R.sub.12 are each independently selected from the group consisting of H, alkyl or substituted alkyl, or alkenyl or substituted alkenyl, or R.sub.9 and R.sub.10 taken together are alkylidene or substituted alkylidene, or independently R.sub.11 and R.sub.12 taken together are alkylidene or substituted alkylidene, and where either or both R.sub.7 or R.sub.8 is not H;
• in an aqueous reaction mixture with Comamonas testosteroni 5-MGAM-4D (ATCC 55744), whereby the aliphatic .alpha.,.omega.-dinitrile is converted to an .omega.-nitrilecarboxylic acid ammonium salt;
• (b) contacting the aqueous product mixture resulting from step (a) with hydrogen and a hydrogenation catalyst, whereby the .omega.-nitrilecarboxylic acid ammonium salt is converted directly to the corresponding lactam without isolation of the intermediate .omega.-nitrilecarboxylic acid, .omega.-nitrilecarboxylic acid ammonium salt, .omega.-aminocarboxylic acid or .omega.-aminocarboxylic acid ammonium salt;
• and
• (c) recovering the lactam from the aqueous product mixture resulting from step (b).