Homogeneous catalysis

Homogeneous catalysis is a chemistry term which describes catalysis where the catalyst is in the same phase (ie. solid, liquid and gas) as the reactants. It is the opposite to heterogeneous catalysis.

Notice that two liquids can be different phases. Therefore, for example, the petrochemical alkylation process features heterogeneous catalysis, although both the catalyst (acid) and reactants (hydrocarbons) are liquids.

The hydrolysis of esters by acid catalysis is an example of this - all reactants and catalyst are dissolved in water:

CH₃CO₂CH₃(aq) + H₂O(l) ↔ CH₃CO₂H(aq) + CH₃OH(aq) - with H⁺ catalyst.

Contemporary examples of homogeneous catalysis utilizing metal complexes include hydroformylation, Ziegler-Natta polymerization, hydrogen transfer catalysis, hydrogenation, and C-H activation.