A process for reducing the aldehyde concentration in a target stream of a carbonylation process is disclosed. More specifically, a process for reducing the aldehyde concentration in an internal process stream or feed stream of a carbonylation process is disclosed. In particular, a process in which a target stream comprising a carbonylatable reactant and a first aldehyde concentration is subjected to a reaction comprising a supported catalyst that comprises at least one Group 8 to Group 11 metal at conditions sufficient to reduce the first aldehyde concentration to a second aldehyde concentration is disclosed.