Cyclohexane nitrosation to ϵ-caprolactam with high selectivity over HY supported transition metals and phosphotungstic acid catalysts. (August 2014)

• Record Type: Journal Article
• Authors: Hao, F.; Liu, P.; You, K.; Luo, H.
• Is Part Of: Materials research innovations. Volume 18:Number 5(2014)
• Page Start: 321
• Page End: 326
• Publication Date: 2014-08
• Subjects: ϵ-Caprolactam, -- Cyclohexane, -- Nitrosation, -- Mechanism, -- Reaction medium; Materials -- Research -- Periodicals; Matériaux -- Recherche -- Périodiques; 620.1105
• DOI: 10.1179/1432891713Z.000000000255
• Languages: English
• ISSNs: 1432-8917

Abstract

Abstract : Transition metals and phosphotungstic acid were supported on HY by impregnation method. In addition, these prepared catalysts were used in the synthesis of ϵ-caprolactam from one-step nitrosation of cyclohexane in different reaction medium of oleum and concentrated sulphuric acid. Among these catalysts, the PW/HY gives better result of cyclohexane conversion of 9·9% and selectivity to ϵ-caprolactam of 75·9%. X-ray diffraction, Fourier transform infrared (FTIR), NH3 –temperature programmed desorption, pyridine FTIR, SEM, Brunauer–Emmett–Teller and N2 adsorption–desorption were used to characterise the HY and PW/HY. The characterisation results as well as the catalytic performance indicate that the increment of the Brønsted acid sites has positive effect on the cyclohexane nitrosation to ϵ-caprolactam. The catalysts play an important role in promoting nitrosyl sulphuric acid to form nitroso radical and further to obtain ϵ-caprolactam. In addition, a possible mechanism for liquid phase nitrosation of cyclohexane in different reaction medium was proposed.