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Beckmann rearrangement of cyclohexanone oxime over Silicalite-1: an FT-IR spectroscopic study

2003; Elsevier BV; Volume: 60; Issue: 1-3 Linguagem: Inglês

10.1016/s1387-1811(03)00385-8

1873-3093

C. Flego, L. Dalloro,

Chemical Synthesis and Reactions

The study of cyclohexanone oxime (CEOX) adsorption and reaction into ε-caprolactam (CPL) by FT-IR spectroscopy was performed with Silicalite-1 (S-1) as a catalyst. Information of both active sites and reaction mechanism of the Beckmann rearrangement was obtained. At low temperature the physical sorption of CEOX on/in S-1 is the most relevant phenomenon. The accessibility of the internal OH's to the reactant increases at higher temperatures due to an easier diffusion. At 200 °C CEOX molecules present inside the zeolite are in proximity of the most acidic OH groups of S-1, the OH nests. The co-operation of more than one OH site transforms CEOX into ε-CPL, allowing the right reactant-active site configuration and favouring the stabilisation of the intermediate.