5048-19-1Relevant articles and documents
Hierarchical silicalite-1 octahedra comprising highly-branched orthogonally-stacked nanoplates as efficient catalysts for vapor-phase Beckmann rearrangement
Chang, Albert,Hsiao, Hsu-Ming,Chen, Tsai-Hsiu,Chu, Ming-Wen,Yang, Chia-Min
supporting information, p. 11939 - 11942 (2016/10/09)
A triblock structure-directing agent was designed to synthesize hierarchical silicalite-1 octahedra comprising highly-branched, orthogonally-stacked and self-pillared nanoplates that exhibited excellent and stable activity for the vapor-phase Beckmann rearrangement of cyclic oximes and high lactam selectivity.
Catalytic properties of WOx/SBA-15 for vapor-phase Beckmann rearrangement of cyclohexanone oxime
Bordoloi, Ankur,Halligudi
experimental part, p. 141 - 147 (2010/09/05)
WOx/SBA-15 nanocomposite materials with different WOx loadings were prepared by one step hydrothermal synthesis and used in the vapor-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. The catalysts were thoroughly characterized by X-ray diffraction (XRD), sorption analysis, energy dispersive X-ray analysis (EDAX) and Raman spectroscopy. The acidities of the catalysts were estimated by ammonia temperature programmed desorption (NH3-TPD) and Fourier transform infrared studies of adsorbed pyridine (pyridine-FTIR). The optimum temperature for the Beckmann rearrangement was 350 °C. Using WOx/SBA-15(20) under the vapor-phase reaction conditions [temperature = 350 °C, WHSV = 0.6 h-1, oxime concentration = 2.5% (w/w) in MeOH] gave 79% cyclohexanone oxime conversion with 93%, ε-caprolactam selectivity. The ε-caprolactam selectivity was found to be dependent on temperature and space velocity. A correlation has been made between the rearrangement activity and acidity and the structural properties of the catalysts.
Synthesis of ε-caprolactam from cyclohexanone oxime using zeolites Hβ, HZSM-5, and alumina pillared montmorillonite
Ouyang, Kuang-Hao,Chen, Chih-Wei,Ko, An-Nan
, p. 137 - 144 (2007/10/03)
The Beckmann rearrangement of cyclohexanone oxime (CHO) to ε-caprolactam (ε-C) was studied in a plug flow reactor at 300-400°C under atmospheric pressure by using Hβ, ZSM-5, and alumina pillared montmorillonite. With Hβ(X)Y zeolites, raising the SiO2/Al2O3 molar ratio (X) results in the enhancement of catalyst acid strength with concomitant decrease of the total acid amount. Increasing the calcination temperature (Y) causes remarkable diminution of catalyst surface area, acid strength, and acid amount. A similar trend was found for AIPMY catalysts. In the reaction of CHO, the initial catalytic activity correlates well with the total acid amount of various catalysts except for Hβ(10)Y (Y > 600°C). The reaction proceeds on both Broensted and Lewis acid sites and the catalyst deactivation most likely occurs at the strong Broensted acid sites. The effect of solvents in the feed on the catalytic results was also investigated; it was found that polar solvents such as ethanol or n-butanol give high ε-C yield and longer catalyst lifetime. In the reaction of CHO/C2H5OH over Hβ(10)800 at 400°C and W/F 74.6 g·h/mol, the CHO conversion and ε-C yield remain 100% and 92%, respectively, for at least 20 h time-on-stream. The reaction paths and the mechanism for ε-C formation are proposed.
