Oxidation of amines over alumina based catalysts

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• 作者：Karol Rakottyay ; Alex ; er Kaszonyi ; Stanislav Vají ; č ; ek
• 关键词：Alumina ; Cycloalkylamine ; Primary aliphatic amine ; Isoalkylamine ; Oxidation ; Acidic sites determination ; NH₃-TPD ; FT-IR ; Catalyst titration ; Caprolactam ; Oximes ; Nitriles ; Schiff bases ; Carbonyl compounds ; Condensation reactions ; Reaction pathw
• 刊名：Applied Catalysis A: General
• 出版年：2010
• 出版时间：15 April 2010
• 年：2010
• 卷：378
• 期：1
• 页码：33-41
• 全文大小：675 K

文摘

Amines were oxidized by molecular oxygen in the vapor phase at atmospheric pressure over alumina and silicotungstic acid/alumina catalysts. The study is focused on the influence of structure of amine and catalyst properties on the composition of the main reaction products and byproducts. Coating of γ-Al₂O₃ with silicotungstic acid or its semisalt can significantly enhance its catalytic activity in amine oxidation. The adsorption of amine on weak acidic sites of catalyst is essential for its oxidation to main reaction products. Cycloalkylamines are oxidized mainly to cyclic oximes (selectivity up to 64 % ) and Schiff bases of appropriate cycloalkanone and cycloalkylamine (selectivity up to 38 % ). Mainly nitriles (selectivity up to 55 % ) and appropriate Schiff bases (selectivity up to 54 % ) were observed in the oxidation products of primary alkylamines. Their molar ratio depends on the catalyst acidity and reaction conditions. 1,6-Hexanediamine is oxidized mainly to caprolactam (yield 48 % ) and other cyclic lactames and Schiff bases as well as to dinitrile (yield 13 % ).