Characterization of some commercial soaps by x-ray diffraction

Abstract

Th e diffraction of X-r ays by 29 commercial soaps was investigated. The patterns ind icate that the oaps ar e crystalline, and t he data have been used to identify the various phases in the solid soaps. The s ingle long-spacing value obtained for the tOilet, medicated, glycerin, coco, and washing soaps is inclicatiye of the existence of a Single crystal type in t hese soaps. The exhibition of two or three sets of long-spacing values by t he 'having soa ps is indicative of t he presence in these soaps of two or three individual phases.'Ihe mo is ture conten t of these soaps indicates that the toilet and medicated soaps a r e either h emihydrates or monohydrates; the coco soaps, clibydr ates; and the sha ying soaps, monohydrates.

Some physical chemical properties of aqueous solutions of soaps and soapless detergents

“…The purpose of this paper is to present data for several physical-chemical properties of aqueous solutions of numerous commercial soaps and soapless detergent materials, and to correlate these with the structure and phase nature of the solid soaps as r evealed by investigations with X-ray diffraction [2] and electron microscopy [3], and to interpret the significance of the results in terms of fundamental colloid chemical hypotheses .…”

“…The commercial soaps were the same as those used in previous lllvestigations [2,3]. Of the soapless detergents, two (D 1 and D5) are reported by their manufacturers to be nonalkaline compounds, one (D6) as containing "a special ingredient that dissolves grease on contact," and one (D2) as a new kind of soap.…”

“…Structure of the Solid Soaps X-ray diffraction studies of commercial soaps have shown [2] that the toilet and "medicated" soaps consist essentially of beta sodium palmitate and small amounts of omega sodium oleate, the coco soaps consist primarily of omega sodium laurate and sodium myristate, the shaving soaps consist essentially of two or more distinct phases (alpha, and/or beta, omega, and del ta) of sodium palmitate, and the constituents of the glycerin and washing soaps are rather indefinite, the latter being probably in the omega phase. Electron microscopic investigations [3] also indicate that sodium palmitate may be in the washing soaps.…”