Preparation of Cyclodextrin Precipitates with Volatile Hydrocarbons in Aqueous Media, and Determination of Hydrocarbon/Cyclodextrin Molar Ratios in the Precipitates

A technique is proposed to prepare cyclodextrin (CyD) precipitates with volatile hydrocarbons. On introducing the vapor of a liquid or solid hydrocarbon into α-, β-, or γ-CyD in an aqueous solution and circulating it in a closed system, CyD can be easily precipitated. The CyD precipitates isolated from aqueous solutions were analyzed for the hydrocarbon/CyD molar ratio. The concentration of CyD in the supernatant aqueous solution was also measured. The technique has been applied at 25 °C to such hydrocarbons as n-alkanes (C5 to C10), cyclohexane, halobenzenes(fluoro-, chloro-, bromo-, and iodo-benzene), p-difluorobenzene, benzene, naphthalene, biphenyl, and diphenylmethane. Precipitates were also prepared in β-CyD solutions with the vapor of C5—C9 mixtures at various mixing ratios.