Ichiro Anazawa

Polyoxyethylene oligomer distribution of nonionic surfactants

Thin layer chromatography with a flame ionization detection (TLC-FID) technique was applied to the separation and determination of nonionic surfactants containing oxyethylene (OE) chains. The OE adducts with an average number of 4.2, 6.0 and 8.0 oxyethylene units were separated on Chromarod S-II (Silica gel-coated rods) with double development using benzene:ethyl acetate (6:4) and ethyl acetate:acetic acid:water (8:1:1). OE adducts of nonionic surfactants were well separated by the TLC-FID method using simple and standard techniques that eliminate the need for any chemical modification.

Micellar structure and micellar inner polarity of octaethylene glycol n-alkyl ethers

The effects of the alkyl chain length of non-ionic surfactants on micellar structure and micellar inner polarity have been investigated. The aggregation number increases while the degree of hydration decreases with increased alkyl chain length. Also, a decrease in micellar inner polarity is found to occur as the alkyl chain length increases. An interpretation of these results is given.

Effects of molecular weight distribution of nonionic surfactants on stability of O/W emulsions

From the relationship between the distribution width of oxyethylene (OE) or alkyl chains and O/W emulsions stability, it became evident that even with the same average OE or alkyl chain lengths, the phase-inversion temperature (PIT) and O/W emulsion stability depend on width. However, emulsification at the PIT invariably results in a very stable O/W emulsion. Emulsifiers with a large distribution width of OE or alkyl chains were also found to improve O/W emulsion stability.

Correlation between distribution of oxyethylene chains of nonionic surfactants and stability of cyclohexane droplets

Abstract The correlation between the distribution of the oxyethylene (OE) chains of nonionic surfactants and the stability of cyclohexane droplets at the oil/water interface has been studied by applying the “multiple-drop” method. It was concluded that stable oil droplets are obtained by using broadly distributed surfactants. Interpretation of this result is discussed in view of the interfacial tension and mechanical strength in the adsorbed layer at the oil/water interface.

Changes in physico-chemical properties during decomposition of nonionic surfactant solutions

The decomposition and accompanying changes in surface chemical properties of nonionic surfactants were investigated. The decomposition of nonionic surfactants occurs in the polyoxyethylene and ester chains. Ester chains were susceptible to decomposition with an increase in the polyoxyethylene chain length, but polyoxyethylene chains were not. Surface chemical properties such as solubilizing power, surface tension, effective specific volume, and intrinsic viscosity also deteriorated during decomposition of the surfactants.

Effects of photo-irradiation on coals

Abstract The influences of Xe-lamp irradiation on coals liquefaction were studied in the presence of tetralin solvent. Irradiation increased the yield of the benzene-soluble fraction from a low rank Joban coal to 23.6%. The average molecular weights of the benzene-soluble fractions obtained from the irradiated coals were smaller than those of the non-irradiated coals. These results suggest that coal depolymerization is favourably affected by Xe-lamp irradiation.