Synthesis and Properties of Alkyl <i>β</i>‐<scp>d</scp>‐Galactopyranoside

Abstract

Abstract A series of alkyl β ‐ d ‐galactopyranosides were prepared by the trichloroacetimidate method with d ‐galactose and alcohols with different chain lengths as raw materials. Their solubility, surface tension, emulsification, foaming, wettability, thermotropic liquid crystalline properties, and thermal stability were investigated. Alkyl β ‐ d ‐galactopyranosides are soluble in water and ethanol, and the solubility decreases with increasing alkyl chain length. Decyl β ‐ d ‐galactopyranoside was insoluble in water, but soluble in ethanol. Dissolution of alkyl β ‐ d ‐galactopyranoside in water is an endothermic process with dissolution enthalpies greater than zero. Nonyl β ‐ d ‐galactopyranoside had an excellent emulsifying property, better foaming ability and the best foam stability. The CMC values of alkyl β ‐ d ‐galactopyranosides decrease with increasing of alkyl chain length. Alkyl β ‐ d ‐galactopyranosides are thermally stable up to 270 °C. Alkyl β ‐ d ‐galactopyranosides show the distinctive optical texture of a thermotropic liquid crystal smectic A type phase. Decyl β ‐ d ‐galactopyranoside showed the strongest wettability.