1. Context

1.1 Aqueous two-phase catalysis

Catalytic reactions fall into two broad categories, depending on whether the catalyst and reactants form a single phase (homogeneous catalysis) or several phases (heterogeneous catalysis). The advantages and disadvantages of both categories have been widely discussed. Homogeneous catalysts are known to be highly active and selective, as the electronic and steric properties of the catalysts can be modulated to suit the problems encountered. In contrast, this modulation is more difficult in heterogeneous catalysis. Indeed, mechanistic misunderstandings of certain heterogeneous catalysis reactions have led to it sometimes being referred to as "black art". However, the use of very expensive metals highlights one of the fundamental problems of homogeneous...