Authors:Dongshun Zhang, Rijie Wang, Xiaoxia Yang, and Wensheng Yao
A series of phosphorus modified Si-MCM-41 catalysts prepared via the impregnation method were used for the vapor-phase Beckmann
rearrangement of cyclohexanone oxime to caprolactam. The catalysts were characterized by XRD, N2 adsorption, FT-IR, and NH3-TPD. The results indicated that weak acid sites increased with P content, leading to enhanced catalytic activity. The catalyst
with Si/P mol ratio of 25 showed best performance at 633 K. The conversion of cyclohexanone oxime and the selectivity for
caprolactam were 92.7 and 64.2%, respectively. The P–OH groups are main active sites for the Beckmann rearrangement. Grafting
acid hydroxyl groups to cover the Si–OH groups may be a good way to improve the selectivity for this reaction.
Authors:Pingle Liu, Haike Zhang, Sihua Liu, Zhengjie Yao, Fang Hao, Kuiyi You, and He'an Luo
intermediates for the production of nylon-6 fibers, plastics and resins. The current commercial productions of cyclohexanoneoxime and ∊-caprolactam are mainly based on the traditional route that cyclohexane is oxidized to cyclohexanone through a very low
areas. They show better thermal stabilities than nitrate- or carbonate-LDHs [ 5 , 6 ] and can be used as effective catalysts in acid-catalysed reactions such as Beckmann rearrangement of cyclohexanoneoxime to caprolactam and aldol condensation
, Yokoyama , C , Sato , H , Yamashina , M . Preparation of ∊-caprolactam via Beckmann rearrangement of cyclohexanoneoxime: a mild and recyclable process . Chem Lett 2004 33 : 1350 – 1354 10.1246/cl.2004.1350 .
the reaction mixture was determined by its reaction with cyclohexanone to give cyclohexanoneoxime [ 21 ]. The actual procedure is as follows. When the amination reaction was stopped, the reaction mixture was cooled to 65 °C and 20 mmol cyclohexanone