Yang, W., Jung, S., Lee, J., Lee, S.W., Kim, Y.T. and Kwon, E.E. (2023) Selective Recovery of Caprolactam from the Thermo-Catalytic Conversion of Textile Waste over γ-Al₂O₃ Supported Metal Catalysts. Environmental Pollution, 329, Article ID: 121684.
https://doi.org/10.1016/j.envpol.2023.121684

has been cited by the following article:

• TITLE: Silica Gel Supported Trifluoromethanesulfonic Acid Catalyzed Beckmann Rearrangement of Cyclohexanone Oxime in Liquid Phase

  AUTHORS: Cheng Tian, Hanming Chen, Shihua Wu, Dong Xie, Mingqiao Zhu

  KEYWORDS: Beckmann Rearrangement, Silica Gel, Trifluoromethanesulfonic Acid, Cyclohexanone Oxime

  JOURNAL NAME: Advances in Chemical Engineering and Science, Vol.14 No.4, September 30, 2024

  ABSTRACT: The liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) using fuming sulfuric acid as a catalyst is a traditional method for preparing ε-caprolactam (CPL). This process has drawbacks, such as environmental pollution, corrosion of equipment, and low added value of by-product ammonium sulfate. This article designed and prepared a green silica gel-supported trifluoromethanesulfonic acid catalyst for the liquid-phase Beckmann rearrangement of CHO to prepare (CPL). The influencing factors of catalyst preparation and the optimal reaction conditions for Beckmann rearrangement were investigated. It was found that the optimal conditions for catalyst preparation were as follows: raw material silica gel:trifluoromethanesulfonic acid = 1:0.2 (mass ratio), room temperature, stirring time of 2.5 hours, and solvent of acetonitrile, silica gel mesh size is 100 - 200. The optimal reaction conditions for Beckmann rearrangement are CHO: catalyst = 1:2 (mass ratio), temperature of 130˚C, solvent of benzonitrile, volume of 30 mL/g CHO, and reaction time of 4 hours. Under the above conditions, the conversion of CHO is 90%, and the selectivity of CPL is 90%.