US Patent 8129549 Method for preparing dianhydrohexitol diester compositions

A method for preparing a dianhydrohexitol diester composition, characterized in that it comprises a step which consists in esterifying a dianhydrohexitol composition with a carboxylic acid in the presence of an acid catalyst and hypophosphorous acid. Preferably, the hypophosphorous acid is introduced in an amount ranging between 0.05 and 2 wt. % of dianhydrohexitol, and in a hypophosphorous acid/acid catalyst weight ratio less than 1/1. The method enables novel dianhydrohexitol diester compositions, for example isosorbide diesters, isomannide and/or isoidide richer in diester(s) and/or less colored, useful in numerous industrial applications, in particular in plastic compositions, to be obtained.