Homogeneous catalysis

Homogeneous catalysis is a catalytic process in which the catalyst and the reactants are in the same phase (all gaseous or all in one solution), forming a single homogeneous mixture.

Examples:

• 2SO₂(g) + O₂(g) → 2SO₃(g), catalyst NO(g) (lead chamber process; all gaseous)
• CH₃COOCH₃(l) + H₂O(l) → CH₃COOH + CH₃OH, catalyst H⁺ (acid hydrolysis of ester, all in solution)
• C₁₂H₂₂O₁₁ + H₂O → C₆H₁₂O₆ + C₆H₁₂O₆, catalyst H⁺ (inversion of cane sugar)

Such catalysis is best explained by the intermediate compound formation theory: the catalyst forms an unstable intermediate with a reactant, which then reacts to give the product and regenerates the catalyst. It is easy to control and gives good selectivity, but separating the catalyst from the products is difficult.