Abstract
The hydrophilic moiety of nonionic surfactants is composed primarily of oxyethylene grou ps. From standpoint of biodegradability, safety and renewability of resources, it is preferable to use nonionic surfactants whose hydrophilic portion is derived from pentose, hexose or glycerol.
The characteristic properties of nonionic surfactants with hydroxyl groups as the hydrophilic moiety including alkyl glyceryl ethers and alkyl glucosides were studied and compared with those with oxyethylene groups. The major properties of the hydrophilic moiety are lipophobicity and hydrophilicity. Lipophobicity is a particularly important feature of oil soluble surfactants, but high lipophobic solutes are watersoluble in the case of alkyl poly (oxyethylene) ethers.
The lipophobicity of the secondary hydroxyl group, >CH (OH), was shown to be about 4.5 times higher than that of the oxyethylene group, CH2CH2O. Although the lipophobicities of dodecyl hexa (oxyethylene) ether and of 3-dodecyloxy -1, 2-propanediol (monoglyceryl-1-dodecyl ether) are essentially the same, the former is water insoluble whereas the latter, oil soluble. Nonionic surfactants with hydroxyl groups thus posses strong hydrophilicity and lipophobicity. The effects of temperature on the solution properties of alkyl glyceryl compounds are much less pronounced than on those of alkyl oligo (oxyethylene) ethers. It is imortant to use them properly according to purposes.
In practical applications such as solubilizers, emulsifiers and a detergents, polyol-type surfactants show characteristic properties. The application of these polyol-type surfactants should be broadened.
