Highly efficient and selective N-alkylation of amines with alcohols catalyzed by in-situ rehydrated titanium hydroxide

Catalytic N-alkylation of amines by alcohols to produce desired amines is an important catalytic reaction in industry. Various noble metal-based homogeneous and heterogeneous catalysts have been reported for this process. Development of cheap non-noble metal heterogeneous catalysts for N-alkylation reaction would be highly desirable. Hereby, we propose the N-alkylation of amines by alcohols over a cheap and efficient heterogeneous catalyst - titanium hydroxide. The catalyst provides the selectivity higher than 90% to secondary amines for functionalized aromatic, aliphatic alcohols and amines at high catalytic activity and stability. Mild Bronsted acidity formed by continuous rehydration of Lewis acidity excludes side reactions and deactivation by adsorbed species. The mechanism of the reaction involves dehydration of alcohols to ethers with subsequent C-O bond cleavage by amine with formation of secondary amine and recovery of alcohol.