Synthesis, characterization and surface properties of 1‐N‐l‐tryptophan‐glycerol‐ether surfactants

Abstract

A novel homologous series of 1-N-L-tryptophanglycerol-ether surfactants was synthesized and characterized. The precursor compounds, 3-alkyloxy-1-chloropropan-2-ols, were prepared from epichlorohydrin and aliphatic alcohols with alkyl chain lengths of 9-16 carbon atoms. Tryptophan was then attached to the monosubstituted glycerol backbone from its αamino group through an α-NH-C bond. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentrations of the new surfactants, as well as the negative logs of the surfactant concentrations required to reduce the surface tension of the solvent by 20 mN/m (pC 20 ) and the interfacial areas occupied by the surfactant molecules, were calculated from aqueous surface tension measurements using the Wilhelmy plate technique.

Langmuir monolayers of the zwitterionic surfactant hexadecyl 1-N-l-tryptophan glycerol ether

“…Monoalkyl glycerol ether surfactants with different alkyl chain lengths (R = C 9 to C 16 ) in the hydrophobic part and tryptophan as the polar group are a novel family of lipoaminoacid compounds synthesized by the Department of Surfactant Technology in Barcelona [6]. Due to the presence of the glycerol group, these surfactants can be used as emulsifiers; in addition, the tryptophan group reduces the surfactant toxicity and therefore constitutes an interesting alternative to conventional synthetic surfactants in pharmaceutical and cosmetic applications [7,8].…”

“…Due to the presence of the glycerol group, these surfactants can be used as emulsifiers; in addition, the tryptophan group reduces the surfactant toxicity and therefore constitutes an interesting alternative to conventional synthetic surfactants in pharmaceutical and cosmetic applications [7,8]. The main advantage of these ether-type surfactants over glycerol ester derivatives is their stability against temperature and extreme pH values [6].…”

Amino acid-based surfactants

“…Our group has a wide experience on the synthesis by means of chemical, enzymatic or, usually, by a combination of both methodologies, of amino acid-based surfactants obtained from the condensation of natural saturated fatty acids, alcohols, amines and acyl glyceride derivatives with different amino acid head groups through ester and amide linkages [18][19][20][21][22][23][24][25][26][27][28][29][30]. Thus, saturated single-chain, double-chain, gemini and amino acid glycerolipid conjugate surfactants derived from amino acids of different ionic character have resulted to be, in all cases, highly biodegradable, with low toxicity, ecotoxicity and irritation effects.…”

Straightforward Method for the Preparation of Lysine-Based Double-Chained Anionic Surfactants

“…Over the past decade, Infante and coworkers have been devoted to the synthesis of amino acidbased single-chain, double-chain, and gemini surfactants through employment of several chemical and chemoenzymatic methodologies and characterized their self-aggregation, biodegradability, and toxicity properties. [20][21][22][23][24][25][26][27][28][29][30] Among the different types of lipoamino acids created and studied by these authors, those derived from basic amino acids such as arginine presented interesting properties because of their low toxicity, high biodegradability, and antimicrobial activity. [26] The same research group has also explored some lysine-derived surfactants, including N a ,N e -dioctanoyl-lysine, which performed significantly better than classical anionic surfactants in terms of ocular and skin irritancy, haemolytic activity, antimicrobial properties, and aquatic toxicity.…”