A Novel Synthesis Technology of Ethyl-β-Cyclodextrin

A novel green synthesis process of methyl-β-cyclodextrin was investigated through the reaction betweenβ-cyclodextrin and dimethyl carbonate in DMF (dimethyl formamide) with anhydrous potassium carbonate as catalyst. The influences of factors including reaction time and temperature, molar ratio of β-cyclodextrin to dimethyl carbonate and dosage of anhydrous potassium carbonate on the average degree of substitution of methyl-β-cyclodextrin were studied via orthogonal experiments. The results show that the average degree of methyl-β-cyclodextrin depends on the reaction temperature and the molar ratio of raw material primarily. The optimal maximum average degree of substitution of methyl-β-cyclodextrin can reach 14.2 when the molar ratio of β-cyclodextrin to dimethyl carbonate, reaction temperature, reaction time and molar ratio of β-cyclodextrin to catalyst are 1:28, 85℃, 24 h and 1:14, respectively. The structures of the synthesized methyl-β-cyclodextrin were characterized by TLC, IR, MS, 1H-NMR and 13C-NMR, respectively. All the results are concordant with those of methyl-β-cyclodextrin synthesized by dimethyl sulfate or methyl iodide. It should be pointed out that the methyl-β-cyclodextrin synthesis technology proposed is a simple and green one.