Unlocking high selectivity and stability of a cobalt-based catalyst in the n-butanol amination reaction†

Abstract

Primary amines, exemplified by n-butylamine, serve as critical intermediates in the synthesis of pharmaceuticals and agrochemicals. Amination of n-butanol with ammonia over supported cobalt catalysts represents a promising synthetic route. To enhance the catalytic performance of cobalt-based amination catalysts, we reported an acid-treated strategy that allows for precise regulation of cobalt speciation. Among the evaluated supports, silicalite-1 demonstrated superior amination performance, attributed to its unique ability to enhance cobalt dispersion and suppress acid-induced side reactions. Through acid treatment, oversized Co₃O₄ nanoparticles are selectively removed, thereby preserving highly dispersed cobalt species. Under rigorous reaction conditions (WHSV = 2.5 h⁻¹), the acid-treated catalyst achieved 90% selectivity toward n-butylamine, accompanied by improved stability compared to untreated counterparts. Mechanistic investigations revealed that well-dispersed metallic Co⁰ nanoparticles promoted selective C–N bond formation via efficient coupling, whereas larger cobalt domains facilitated dehydrogenation-driven carbon deposition pathways. This work establishes a clear structure–performance relationship for cobalt-based amination catalysts, offering a blueprint for sustainable amine production.