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Acylation of unprotected lactose with 1,18‐octadec‐9‐enedioyl chloride for the synthesis of monocatenary and bolaform agro‐based surfactants
Author(s) -
Chorfa Nasima,
Belkacemi Khaled,
Arul Joseph,
Hamoudi Safia
Publication year - 2018
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23248
Subject(s) - chemistry , acylation , lactose , pulmonary surfactant , organic chemistry , yield (engineering) , chloride , catalysis , biochemistry , materials science , metallurgy
Agro‐based surfactants have one of two hydrophilic or hydrophobic parts of vegetable origin. They can be produced from renewable and readily available resources. Carbohydrate fatty acid esters are non‐toxic, non‐ionic, and biodegradable agro‐based surfactants with applications in the pharmaceutical, cosmetic, and food industries. In this work, the chemical synthesis of agro‐based surfactants through lactose acylation with 1,18‐octadec‐9‐enedioyl chloride (Acyl‐Cl) was investigated at room temperature. The acylation reaction proved to be regioselective to the primary hydroxyl group of the glucose‐moiety in the lactose molecule and was promoted by an excess of lactose to produce higher substituted derivatives. Acyl‐Cl conversion was ∼98 % after 1 h of reaction. The production of monocatenary agro‐based surfactant, mono‐lactose 1,18‐octadec‐9‐enoate, was favoured with a molar ratio lactose/Acyl‐Cl of 1 achieving a yield of 48 % after 20 min. Moreover, production of bolaform agro‐based surfactant, di‐lactose 1,18‐octadec‐9‐enedioate, was favoured with a molar ratio of 3 lactose/Acyl‐Cl with a yield of 33 % after 1 h of reaction. A one‐pot synthesis of agro‐based bolaform surfactant was successfully achieved for the first time in the open literature. Monocatenary and bolaform agro‐based surfactants were isolated by preparative liquid chromatography with high purity according to their chemical structure identification by liquid chromatography coupled to mass spectrometry and 1 H nuclear magnetic resonance. Their critical micellar concentration (12–9 μM) determined by fluorescence spectroscopy with pyrene used as a probe, and hydrophilic:lipophilic balance values (10.7–14.2) indicated that monocatenary and bolaform agro‐based surfactants can act as oils in water emulsion.