A temperature above which an ionic surfactant dissolves well is called Krafft point and below which, surfactant solubility in solution is very small. Hence, the Krafft point of a given surfactant should be lower than each temperature for practical usage. Based on the physical meaning of Krafft point, various ionic surfactants whose Krafft point are low were synthesized. Depending on the practical purposes, respective ionic surfactant suitable for the applications may be used, such as detergent in hard water, surfactants for tertially oil recovery and so on.
A method was developed for determining of steryl glycosides (SG) in commercially available concentrated phospholipids. ASG (acylated SG) and NASG (non-acylated SG) were separated by TLC and determined by HPLC equipped with an evaporative light scattering detector (ELSD). Two separation modes [gel permeation (GP) and reversed phase (RP)] were examined in this study. A good linear correlation was obtained between the logarithm of concentration and peak intensity in ELSD. Individual calibration curves were essential for the determining of NAGS and ASG due to the dependency of ELSD on molecular weight. To simplify the method, ASG was determined following hydrolysis with 0.25 N KOH in methanol. Data for steryl and acyl group in ASG were obtained from acetylated ASG using the RP mode for separation. The limit of detection was 0.05 % for commercial concentrated phospholipids.
An examination was made of the solution properties of sodium dodecyl sulfate (SDS) -alkyl glucoside (AG : octyl-, decyl-glucoside) mixed surfactant solutions by comparison with those of SDS-alkyl poly (oxyethylene) ether (CmPOEn : m=10, 12; n=7, 9, 12, 20). The SDS-AG mixed system showed no molecular interaction in mixed micelles, while the SDS-CmPOEnmixed system did so. In the solubilization of the oil soluble dye, SDS-AG mixed systems exhibited no synergism, in contrast to SDS-CmPOEn mixed systems. Increase in the ionic dissociation of mixed micelles by the addition of AG to SDS was less than that by the addition of CmPOEn to SDS. Interaction of SDS and AG would thus appear to occur to leseer extent than that of SDS and CmPOEn. Differences in the hydrophilic group AG and CmPOEn are considered the reasen for this.
Using the s-alcohols having a carbon range C12C14 prepared from available technical paraffins (C12C14), a technically effective synthetic method for obtaining highly purified s-alkyltri (oxyethylene) ethers using a BF3 catalyst was developed. To prepare s-alkyl tri (oxyethylene) ethers, about 1.5 mol of EO were added to the alcohol and as a result, unreacted alcohols were recovered by distillation. The recovered alcohols were recycled after purification by a newly developed ketone elimination method, in which esterification for the first portion of recovered alcohols with boric acid was carried out followed by separation of carbonyl compounds present in the alcohols by distillation. s-Alkyl tri (oxyethylene) ethers were continuously obtained with consistently excellent quality, containing no unreacted alcohols. The bad odor of s-ethylene oxide adducts of s-alkohol was thus shown to be due to the accumulation of carbonyl compounds such as ketone or diketone. In this study, a mechanism for the formation of by-product of PEG is also discussed.
To clarify changes in and detergency of oxidized oily soils, oxidized linoleic acid was analyzed by reverse phase high performance liquid chromatography (HPLC) using a UV detector. The oxidized products were separated and their molecular weights determined using liquid chromatography-mass spectrometry (LC-MS). Finally, their molecular structures were estimated. During HPLC, compounds from oxidized linoleic acid having a polarity higher than pure linoleic acid were finely separated using an eluent of acetonitorile and water (8 : 2). Compounds with lower polarity than the pure acid were separated using an eluent of acetonitrile, tetrahydrofuran, and water (6 : 3 : 1). Based on the results of LC-MS, the main products obtained by oxidation were hydroperoxide, hydroxy compounds, a dienone compound, and dimers formed by secondary reactions. By HPLC analysis, retention times of the dimers were shown to be longer, and their polarities, less than that of pure linoleic acid.
Clays bearing quinine derivatives were synthesized by three types of intercalations (1) ion exchange, (2) layer surface immobilization and (3) interlayer adsorption. The modified clyas were applied to the Michael addition of thiophenol to 2-cyclohexen-1-one to give the corresponding asymmetric adduct. Type (1) clays preferentially gave the S-form product, while type (2) and (3) preferentially gave the R-form product. The optical purity of the products varied on changing the amount of catalyst.