Improved Process for Hydrogenation of Benzenepolycarboxylic Acids and Derivatives Thereof

A process for ring hydrogenation of a benzenepolycarboxylic acid or derivative thereof, said process comprises the steps of:

• a) a first hydrogenation step in which a feed stream comprising said benzenepolycarboxylic acid or derivative thereof is contacted with a first hydrogen-containing gas in the presence of a first catalyst in a first hydrogenation reactor under hydrogenation conditions to produce an at least partially hydrogenated intermediate product, wherein said first catalyst comprises a support material, and wherein said first catalyst comprises ruthenium and rhodium;
• b) an intermediate product separation step, in which said at least partially hydrogenated intermediate product is separated into a first intermediate product fraction and a second intermediate product fraction;
• c) a second hydrogenation step, in which said second intermediate product fraction is contacted with a second hydrogen-containing gas in the presence of a second catalyst in a second hydrogenation reactor under hydrogenation conditions to produce a hydrogenated product, wherein said second catalyst comprises a support material, and wherein said second catalyst comprises ruthenium and rhodium;
• wherein said first intermediate product fraction is recycled to said first hydrogenation reactor.