Novel ethoxylated inositol derivatives--hybrid carbohydrate/oligoethylene oxide surfactants.

Carbohydrate- and oligoethylene oxide-based surfactants behave quite differently despite the fact that they are both classes of nonionic surfactants. Intensive studies of a mixture at fixed molar ratio (1:1) of two very common sugar- and oligoethylene oxide-based surfactants, namely n-dodecyl-ß-D-maltoside (ß-C(12)G(2)) and n-dodecyl hexaethylene oxide (C(12)E(6)), revealed that most properties of the mixture are similar to those of the oligoethylene oxide-based surfactant. In the present work, this mixture is compared to respective "hybrid surfactants". Such hybrid surfactants are surfactants whose head group contains chemically linked carbohydrate and oligoethylene oxide units. In order to study the behaviour of this sort of compounds, we synthesised a new class of surfactants whose head group consists of one carbohydrate-like unit (myo-inositol) and three ethylene oxide units. New regiochemically defined ethoxylated inositol derivatives (referred to as C(12)I(1)E(3) and C(12)E(3)I(1) in the following) were synthesised and studied for their thermotropic and lyotropic liquid crystalline properties as well as for their surface activities. The results are compared with those of the reference systems ß-C(12)G(2) and C(12)E(6), and their 1:1 mixture, respectively, and are discussed in terms of structure-property relations.

New ethoxylated inositol surfactant.

Carbohydrates are an attractive class of starting materials for organic syntheses because they are of natural origin, environmentally friendly, and highly functionalized, in this way promoting a sustainable chemistry. A somewhat exotic but nevertheless readily available family of carbohydrates allowing a fascinating chemistry are inositols (cyclohexane-1,2,3,4,5,6-hexols), which we currently use for the synthesis of new surfactants. In our previous work, we reported on the synthesis of a number of new regiochemically defined myo-inositol ethers and esters and studied their surface activity in aqueous solution as well as their ability to form thermotropic liquid crystals. It turned out that the hydrophilicity of the myo-inositol head group alone does not ensure sufficient water solubility of these surfactants. To improve the water solubility, we increased the inositol head group by the introduction of a tri(ethylene oxide) unit. The resulting surfactant is the first representative of a new class of inositol-based surfactants (CiEjIk) that combine the properties of classical sugar surfactants (CnGm) and oligo(ethylene oxide) alkyl ether surfactants (CiEj).