Homogeneous catalysis of the water gas shift reaction using a platinum chloride-tin chloride system

Abstract

An efficient homogeneous catalyst consisting of K/sub 2/PtCl/sub 4/, SnCl/sub 4/, H/sub 2/O, and HCl dissolved in glacial acetic acid was developed for the water gas shift reaction, H/sub 2/O + CO reversible H/sub 2/ + CO/sub 2/. Requirements and features of the catalyst are: (1) no reaction takes place in the absence of the platinum chloride salt; (2) the omission of tin chlorides greatly diminishes catalytic activity, leading to decomposition and formation of a brown precipitate; (3) large excesses of the tin chlorides inhibit catalysis- e.g., at a tin/ platinum ratio of 300/1, no reaction occurs; (4) if acetic acid is replaced by water, only a trace of carbon dioxide is produced and a dark brown precipitate is obtained; (5) no catalysis occurs in the absence of either a strong protic acid or a chloride source. A mechanism involving the tin(II)/tin(IV) couple and a platinum species is proposed.