Synthesis of two β-cyclodextrin derivatives containing a vinyl group.

β-CD maleate (CDM) and β-CD itaconate (CDI) were prepared by esterification of β-cyclodextrin (β-CD) with maleic acid and itaconic acid using phosphate as a catalyst in a semi-dry process. The esterification of β-CD was carried out using [Itaconic acid ] or [Maleic acid ] 4 mol/mol of CD; M/L ratio 1:0.6; temperature 110 °C; [4-methoxyphenol] 2.5% amount of acid; reaction time 3.5h. The esterification rates of CDM and CDI are 70.38% and 21.02%, respectively. We found that CDM and CDI were both monoesters. Here, we also established a new evaluation method for the rate of esterification.