Study on the properties of an inclusion complex of hydroxypropyl-β-cyclodextrin and benzyl isothiocyanates

In order to increase the solubility and improve the heat stability of benzyl isothiocyanates, an inclusion complex of hydroxypropyl-β-cyclodextrin and benzyl isothiocyanates was prepared using hydroxypropyl-β-cyclodextrin and benzyl isothiocyanates as the host and guest, respectively. The phase solubility curve for hydroxypropyl-β-cyclodextrin-benzyl isothiocyanates was investigated, and the properties of the inclusion complex were studied using infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The phase solubility curve, which was found to be of the AL type, indicated that hydroxypropyl-β-cyclodextrin could significantly increase the solubility of benzyl isothiocyanates. The inclusion complex of hydroxypropyl-β-cyclodextrin and benzyl isothiocyanates formed with a 1:1 ratio had an inclusion constant of 408.8 L/mol. In the IR spectrum, the intensity of the characteristic absorption peak of benzyl isothiocyanates decreased, indicating that the -N=C=S group of benzyl isothiocyanate entered into the hydroxypropyl-β-cyclodextrin cavity. TGA results showed that the heat stability of benzyl isothiocyanates improved to some extent. SEM observations revealed that the inclusion complex consisted of irregular crystals. The inclusion of benzyl isothiocyanate increased its solubility, and expand the scope of its application. In addition, the heat stability of benzyl isothiocyanate also improved, which reduced heat loss during the process. ©, 2014, South China University of Technology. All right reserved.