]. Soc. Cosmetic Chemists, 21, 107-118 (Feb. 4, 1970) A New Approach to the Analysis of Fatty Alkanolamides JOSEPH J. HEJNA, M.S., and DIANE DALY, B.S.* Presented be[ore the Midwest Chapter, October, 1968 Synopsis--COLUMn CHROMATOGRAPHY in conjunction with INFRARED SPECTROSCOPY can be used to elucidate the composition of the SUPERAMIDE and the KRITCItEVSKY AMIDE. The method is quantitative and yields information pertaining to the secondary products along with reverting and realTanging of the various components. INTRODUCTION The synthesis and properties o[ the alkanolamides have been known for some time and there has been a great deal o[ speculation about the course of reaction and possible interactions concerning the molecular rearrangement to give the secondary products. The complexity of the reaction is due to the bifunctional activity o[ the diethanolamine, a secondary amine with two hydroxyl groups, which accounts for the various by-products. There have been a number of chemical and instrumental methods suggested for the analysis of the alkanolamide condensates. The chemical method proposed by Kroll and Lennon (1) is designed for the analysis of the Kritchevsky type of amide. The analytical scheme employs the standard wet methods. A similar method has been proposed by Livengood and Johnson (2). The wet methods have certain shortcomings in that the results are based on speculative assumptions. The methods do not distinguish between the mono- and diesters of the amines, if present, or between the mono- and diesters of the amide. There is also no distinction between the • Helene Curtis Industries, 4401 West North Avenue, Chicago, Ill. 107

108 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS amine and amide esters. No procedure has been proposed for the de- termination of 1,4-diethanoi piperazine, which may be present in the Kritchevsky type of amide. In the work described here, the amides have been separated chromatographically and then analyzed by infrared spectroscopy. The chromatographic method of separation of fatty alkanolamides was developed using an extension of Rosen's method (3) for separating surface active agents and has proven to be a valuable analytical tool. EXPERIMENTAL A chromatographic column, 20 in. long and 1 in. in diameter, was packed with 75 g of silica gel (Davison No. 992, 100 to 200 mesh) by pour- ing a chloroform slurry into the column. It is essential that no air is entrapped in the column. A 1.25- to 2.0-g sample was dissolved in 20 ml of chloroform and was added to the column. All the chemicals were of reagent grade and they were not treated in any way prior to their use. The column was eluted by solvent series increasing in polarity as fol- 70 ml of chloroform, 100 ml of a mixture of 1 ml of ethyl ether and 99 ml of chloroform, 70 ml of a mixture of 35 ml of ethyl ether and 35 ml of chloroform, 80 ml of a mixture of 40 ml of acetone and 40 ml of chloroform, 100 ml of a mixture of 5 ml of methyl alcohol and 95 ml of chloro- form, (6) 70 ml of a mixture of 7 ml of methyl alcohol and 63 ml of chloro- form, (7) 75 ml of a mixture of 25 ml of methyl alcohol and 50 ml of chloro- form, (8) 100 ml of methyl alcohol. The above eluents were not polar enough to remove free amines however, amines can be eluted from the column by using a 2% solution of hydrochloric acid in water. The amines are eluted as the hydro- chloride salt. The eluted material was collected in 10-ml fractions into 50-ml beak- ers at a flow rate of 1 ml every 1.5 min. The solvents were evaporated on a steam bath under a stream of air. In general, 60-75 such fractions were collected. After the solvent was removed, the beaker was wiped to re- move any moisture on the outside, cooled, and weighed. Samples of the various fractions were then examined by infrared spectroscopy. lows: (1) (2) (5)