Synthesis and surface properties of alkyl β‑D‑thioglucopyranoside

Abstract

Alkyl thioglycosides are a class of nonionic sugar-based sulfur-containing surfactants and bioreagents. The surfactants 1,2‑trans alkyl β‑D‑thioglucopyranosides with different alkyl chain length (n = 6–12) were stereoselectively prepared by the Helferich method. Their properties including HLB number, logP value, water solubility, foam property, emulsifying property, surface property and thermotropic liquid crystal property were mainly investigated. The results showed that their HLB numbers and water-solubility decreased as the related logP values increased with increasing the alkyl chain length. Alkyl β‑D‑thioglucosides were already insoluble in water with n ≥ 10. Both β‑D‑thioglucopyranosides (n = 8, 9) reduced the surface tension of the related aqueous solution to nearly 29 mN·m−1 at the critical micelle concentration (CMC), they also had excellent foaming ability and foam stability. Nonyl β‑D‑thioglucopyranoside had good emulsifying properties for both n‑octane/water system and toluene/water system. Alkyl β‑D‑thioglucopyranosides (n = 6–12) were observed to have the thermotropic liquid crystal properties.