Processes and catalysts for the selective hydrogenation of compounds having carbonyl carbon atoms

Abstract

Selective hydrogenation processes are disclosed that can upgrade impure feeds, such as those obtained from biomass and containing a number of small (e.g., 2-6 carbon atom) molecules having aldehyde and/or ketone carbon atoms. For example, whereas glycolaldehyde and its methylated derivative, hydroxyacetone (acetol) are both high value intermediates for certain downstream processing reactions, they are normally recovered in a condensate from pyrolysis of carbohydrates (e.g., aldose-containing sugars) together with glyoxal and its methylated derivative, pyruvaldehyde. The selective hydrogenation of these compounds bearing two carbonyl carbon atoms, without over-hydrogenation to ethylene glycol and propylene glycol, can increase the concentration of the desired intermediates. These beneficial effects of selective hydrogenation may be achieved through the use of a hydrogenation catalyst comprising noble metals such as Ru and Pt.