Intermediates titanium silicalite

Cyclohexanone is thus converted to cyclohexanone oxime, an intermediate in the manufacture of Nylon-6. The catalyst is titanium silicalite-2. Commercialized by Enichem who built a 12,000 ton/year plant in Porta Marghera in 1994. 

In view of the current interest in environmental protection, we have studied the possibility of using transition substituted molecular sieves for catalyzing the heterogeneous oxidation of aniline and, more generally arylamines. We have recently reported that TS-l, the titanium-substituted silicalite-1, was an excellent catalyst for the selective oxidation of aniline into AZY [6], provided that the H202/aniline ratio was relatively low (< 1.6). We showed that the oxidation more likely proceeded via the formation of phenylhydroxylamine (PH) and nitrosobenzene (NSB) and that these intermediate compounds could react together to form AZY. Because of the small pore dimensions of the structure, the reaction could not be carried out with TBHP and was limited by diffusion of reagents and/or products in the channels. 

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