Wasaburo Kimura

Studies on the Analysis of Surface Active Agent. XXXIII

A rapid method for the determination of micromoisture in surfactants by near-infrared spectroscopy was established.Using carbontetrachloride-DMSO (3 : 1, vol/vol) as the solvent, water has strong absorption at 1.94 u in the near-infrared region. The linear relationship is obtained between the absorbance value at 1.94μ and water content. Further, various surfactants is dissolved readily by DSMO.Based on these facts, in this method, surfactant sample (containing 520 mg of the water) was weighed into 50 ml volumemetric flask, and was dissolved with 12.5 ml of DMSO, and carbontetrachloride was added until marked line. The spectrum of the solution was measured from 1.7 to 2.1 μ in 10 cm quartz cell. And the absorbance value was obtained from peak-height of the band at 1.94μ by the baseline method. The moisture content was obtained from the absorbance value and the calibration curve.The results show that the micromoisture of various surfactants can be determined rapidly and with accuracy (deviation 2.1%) by this method. The concentration of detection limit was 1 mg in 50 ml sample soln.

Studies on the Analysis of Surface Active Agents. XXXII

A rapid method for the determination of moisture in liquid and granulated detergents by nearinfrared spectroscopy was established.Using DMF as the solvent, water has strong absorption at 1.93μ in the near-infrared region. The linear relationship is obtained between the absorbance value at 1.93μ and water content. Further, water in detergent is dissolved or extracted readily by DMF.Based on these facts, in this method, detergent sample (containing 0.20.3g of the water) was weighed into 50ml volumemetric flask, DMF was added until marked line, and the flask was shaken. The spectrum of the solution was mesured from 1.7μ to 2.2μ in 1cm silica cell. And the absorbance value was obtained from peak-height of the band at 1.93μ by the baseline method. The moisture content was obtained from the absorbance value and the calibration curve.By this method, the moisture content in liquid and granulated detergent can be determination with a standard diviation of 0.94% as contrasted to Karl Fischer method.

Studies on the Analysis of Surface Active Agents. XXXI.

A rapid method for the determination of ethylene oxide contents in POE type nonionic surfactants by near-infrared (NIR) spectroscopy was established.POE type nonionic surfactants have strong absorption at 1.42μ and 1.74μ in near-infrared region. The band at 1.42μ is the O-H stretching vibration, and the band at 1.74μ is the first overtone of the C-H stretching vibration. The linear relationship is obtained between the absorbance ratio a1.74/a1.42 and EO contents of POE type nonionics. The absorbance ratio is not affected by concentration (0.21.2g/50ml) and by temperature (8°38°C) of the sample solution.Based on these facts, in this method, a 0.7 to 1.0g of nonionics sample was dissolved into 50ml of carbon tetrachloride solution. The solution was mesured by NIR from 1.2 to 2.0μ in 10cm silica cell. The absorbances were obtained from peak-height of the band at 1.42 and 1.74μ. The EO contents was calculated from the absorbance ratio and the calibration curve.This method allows determination of the EO contents in POE type nonionics within relative accuracy of 3.5% until about 30 moles.

Analysis of Amphoteric Surface Active Agents by Phosphotungstic Acid

A new analytical method for the determination of amphoteric surfactants was established with the use of phosphotungstic acid.The cationic form of amphoterics is precipitated by the addition of phosphotungstic acid to form a complex in dilute aquous acid. On the other hand, Benzopupurine 4 B, an anionic dye, combines with amphoterics and does not shove their acid color even in acid solution but the acid color appears at the end point when titrated with phosphotungstic acid. Based on these facts, 10 ml of sample solution are adjusted at pH 3-2 with hydrochloric acid after adding 1-2 drops Benzopupurine 4 B solution as the ind icater and titrated with phosphotungstic acid standard solution until the acid color appears. The precipitates are filtered and washed with pure water, and then dried in vacuum and weighed.The content of the active component of amphoterics in the sample and its molecular weight are calculated from the titration value and the weight of precipitates.The results of this method show that various amphoterics betain type, ethoxylated betain type, sulfonated betain type, imidazoline type, sulfated imidazoline type, alanine type etc. nca be analysed with satisfactory accuracy.

Studies on the Synthesis and the Applications of Polyalkylene Glycol Derivatives. XI

The sodium polyoxybutylated ethyl and octyl sulfates, which had 1, 2, 3, 5, 7, and 10 units of butylene oxides, were prepared by adding 1, 2-butylene oxide to the corresponding alcohols, and the relation of their surface activities, such as surface tension, foaming properties, wetting power, dispersing power and emulsifying powers, and the length of oxy-butylene chain was studied. The following conclusions were obtained. 1) Sodium polyoxybutylated ethyl sulfates having less than 3 moles of butylene oxide had little surface activities, but the products having more than 5 moles of butylene oxide had good surface activities. The surface tensions of the products having over 5 moles of butylene oxide were low, and their c.m.c. values were more than 0.25% approx. The foaming properties, except 10 mole adduct, and dispersing powers of all products were inferior. The wetting powers of 5, 7 and 10 mole adducts and emulsifying power of 10 mole adduct were superior. 2) As compared with sodium octyl sulfate, the surface tensions of sodium polyoxybutylated octyl sulfates were lower in the low concentration, and their c.m.c. values were also lower. The foaming properties and emulsifying powers of the products having over 5 moles of butylene oxide were excellent. The products having 5 and 7 moles of butylene oxide had good wetting power. All products had poor dispersing power.