Solution Properties of Alkyl β‐D‐Maltosides

Abstract

Alkyl β‐D‐maltosides are an important class of sugar‐based nonionic surfactants and have been widely studied. Nevertheless, it is still necessary to investigate further their amphiphilic structure‐surface property relationships. In this article, we reported a series of properties of synthetic alkyl β‐D‐maltosides (6a–6i, n = 6–18) including their hydrophilic–lipophilic balance (HLB) number, water solubility, hygroscopicity, moisture‐retention capacity, foaming ability, surface tension, thermotropic phase behavior, and skin irritation. Their HLB number and water solubility decreased with increasing alkyl chain length. Hexyl β‐D‐maltoside exhibited the strongest hygroscopicity and moisture‐retention capacity. Decyl β‐D‐maltoside and dodecyl β‐D‐maltoside possessed excellent foaming power and foaming stability. Furthermore, the critical micelle concentration (CMC) of alkyl β‐D‐maltoside (6a–6g, n = 6–14) and their surface tension at CMC decreased with increasing alkyl chain length. At last, alkyl β‐D‐maltosides (6a–6g) should be considered as safe surfactants by the skin irritation assessment.

Water Solubility and Surface Activity of Alkoxyethyl β-d-Maltosides

“…The fan-shaped focal conic textures during the cooling process were considered to be a typical characteristic structure of the smectic liquid crystal. The structure was rather similar to previous research. ,, However, the texture of heptoxyethyl β- d -maltoside ( 4b ) had a somewhat fuzzy edge.…”

“…For hexoxyethyl 2,3,6,2′,3′,4′,6′-hepta- O -acetyl-β- d -maltoside ( 3a , n = 6), the chemical shift (δ) (coupling constant J 1,2 ) of its anomeric H-1 was 4.63 ppm ( J 1,2 = 7.9 Hz) in CDCl 3 while that (δ) (coupling constant J 1,2 ) of its anomeric H-1′ was 5.41 ppm ( J 1,2 = 4.0 Hz), and the newly formed glycosyl bond was 1,2-trans β-configuration . Meanwhile, for alkoxyethyl β- d -maltosides ( 4a – h , n = 6–16), the chemical shifts (δ) (coupling constants J 1,2 ) of their anomeric H-1s were 4.43–4.48 ppm ( J 1,2 = 7.8–8.0 Hz) ( 4a – d ) in D 2 O and 4.18–4.19 ppm ( J 1,2 = 7.8 Hz) ( 4e – h ) in DMSO-d6/D 2 O, as shown in Table , which were consistent with the literature data . All data demonstrated that the newly formed glycosyl bond was 1,2-trans β-configuration.…”

“…According to the literature, , some AGs and their reconstruction derivatives alkyl mono-/multioxyethyl glycosides should have the characteristic double melting transition temperatures ( T m and T c ) or even have sometimes an observed additional transition temperature (referred to as pretransition or solid–solid transition temperature), and the related data may depend on the molecular type, size, other complexities involved in the conditions of the experiment, thermal history, and way of preparation of the sample …”

“…The HLB numbers of β- d -maltosides ( 4a – h ) were calculated from eq by the Griffin method. , where M is the mass of the hydrophilic group (C 12 H 21 O 11 –CH 2 CH 2 O−) of β- d -maltoside ( 4a – h ) and T is the mass of the whole β- d -maltoside ( 4a – h ).…”

“…Indeed, the sharp rise and rapid development of mild sugar-based surfactants such as AGs and APGs have been highly accepted. − Nevertheless, APGs and/or AGs have weak hydrophilicity and poor water solubility , compared to other surfactants such as cationic surfactants, anionic surfactants, and other nonionic surfactants. Thus, their commercial application and scientific research are somewhat restricted.…”