“…Various bases (pyridine, DMAP and t-BuOK) were tested: while pyridine's basicity was not sufficient and DMAP yielded only low degrees of substitution (2.1-6.6%), best results (up to 75% degree of substitution) were obtained with t-BuOK at 48 h reaction time and 4 times molar excess of oxirane. Attempts to employ Zn(BF 4 ) 2 as a catalyst in acidic aqueous media (pH 1, as reported in the literature for similar reactions) [29,30] only resulted in products with a low degree of substitution (<1.8%). Following product purification by extraction and dialysis, the modification of dextran with alkyl glyceryl chains was confirmed by FT-IR and 1 H/ 13 C NMR spectroscopy.…”