Conversion of 2-Methylfuran to 2-Methylthiophene over Molecular Sieves

The use of MeI Y zeolites (MeI = Li, Na, K, Rb, Cs) for the title reaction has been studied at 623 K and atmospheric pressure, looking at the effect of the nature of monovalent alkali-metal ions on both physico-chemical and catalytic properties of the resulting catalyst. The catalyst is very active and selective and, after ageing, it can be regenerated quite easily by a proper redox treatment. Besides the desired product, small amounts to traces of ca. 30 byproducts were detected, the structure of which can be explained only by admitting two different parallel reactions, one based on an ionic-type and the other on a radical-type mechanism. Some hypotheses are proposed on the possible start-up of such mechanisms, based on different adsorption modes of H2S onto the catalyst surface.