Catalytic dehydration of sorbitol to isosorbide in the presence of metal tosylate salts and metallized sulfonic resins

Abstract

Homogeneous catalytic dehydration of sorbitol to isosorbide has been performed with a series of metal tosylates as catalysts. Conversions up to 100 % and selectivities into isosorbide up to 67% were obtained with Bi(OTs)3. The metals were exchanged with acidic sites of sulfonic resins and the resulting materials were evaluated as heterogeneous catalysts. On the contrary to their homogeneous counter parts, the heterogenized metal sites are non-active. The catalytic activity of the modified resins was systematically diminished in comparison to the native resins. The inhibition is greatly dependent on the nature of the metal and, on a larger extent, of the used resin for the cation exchange.