Reductive Alkylation

Reductive alkylation is an effective method to synthesize primary and higher amines from aldehydes and ketones and hence is commercially used for the synthesis of a variety of fine and specialty chemicals. The amine (or ammonia) is condensed with a carbonyl group to yield the intermediate imine (a Schiff’s base) which can then be catalytically hydrogenated to the desired amine. The main challenge in these types of reaction is the selectivity to the desired amine while minimizing the reduction of the carbonyl group. Platinum group metals are capable of facilitating reductive alkylation of alkyl and aryl amines with ketones or aldehydes.

Example: Manufacture of 6-PPD via reductive alkylation over sulfided-Pt/C

Dedicated Catalysts for Reductive Alkylation

E 105 N/W 5% Pd
E 105 NN/W 5% Pd
E 101 NE/W 20% Pd
F 1082 QHA/W 3% Pt

Evonik has developed several carbon supported Pd and Pt-based catalysts that can effect high conversion and selectivity. Platinum is more effective than palladium in alkylating amines and carbonyls of higher molecular weight. Typical operating conditions for reductive alkylation include pressure of 5-35 bars and temperature of 50-150°C. Evonik can work with catalyst users to optimize the process and the amount of precious metal required to achieve high productivity.