Ammonia synthesis from dinitrogen and dihydrogen over the catalysts based on supported mononuclear potassium carbonyl ruthenate. Promoting effect of alkyllithium compounds

Abstract

New catalysts for the ammonia synthesis from dinitrogen and dihydrogen based on supported mononuclear potassium carbonyl ruthenate K2Ru[(CO)4] as a precursor of catalytically active particles have been developed. Magnesium oxide and graphite-like active carbon Sibunit were used as supports, while aliphatic organolithium compounds (BunLi and ButLi) were employed as electron promoters in these catalysts. The systems with MgO as a support are the most efficient. The introduction of RLi into these systems allows one to considerably increase the ammonia synthesis rate. When using carbon Sibunit, the promoting effect of organolithium compounds is much weaker but the activity of such catalysts can be essentially increased by the introduction of an additional electron promoter, viz., metallic potassium, into the system. All the catalysts tested are active in the ammonia synthesis at atmospheric pressure and temperatures ≥250 °C.