Synthesis and characterization of boron hydrotalcite-like compounds as catalyst for gas-phase transposition of cyclohexanone-oxime

Hydrotalcite-like compounds with boron anions in the interlayer were obtained using a coprecipitation method. The effect of different pH values during the preparation was investigated and the effect on crystallinity and phase distribution studied. The influence of different methods of acidity regulation was also analyzed. The efficiency of synthesis of boron-containing anionic clays was evaluated, and the good thermal stability of the materials was noted. Surface characteristics were determined by X-ray photoelectron spectroscopy and correlated to the bulk properties obtained by X-ray diffraction and Al-27 and B-11 MAS NMR. The samples tested in gas-phase Beckmann rearrangement showed caprolactam formation, and the results were related to the surface features.