Premium
C‐21 dicarboxylic acids in soap and detergent applications
Author(s) -
Robinson Philip L.
Publication year - 1992
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02635877
Subject(s) - aqueous solution , chemistry , dicarboxylic acid , solubility , surface tension , organic chemistry , oleic acid , fatty acid , cyclohexene , catalysis , biochemistry , physics , quantum mechanics
A unique polycarboxylic acid, 5(6)‐carboxy‐4‐hexyl‐2‐cyclohexene‐1‐octanoic acid, has been available commercially for over 15 years. A new high‐purity (>97%), light‐color version of the C‐21 dicarboxylic acid has been developed recently. Soaps of the C‐21 dicarboxylic acid can be used as hydrotropes to increase the solubility of nonionic surfactants in aqueous solutions containing builders and/or anionic surfactants. Since these soaps are anionic fatty acid derivatives, they reduce the surface tensions of formulations, thus improving detergency. The nontoxic and biodegradable nature of this dicarboxylic acid makes it an attractive formulation component. This paper outlines application evaluations of the soaps prepared from the C‐21 dicarboxylic acids. These evaluations demonstrate how the soaps interact with nonionic surfactants or pine oil to provide clear formulations, how they wet cotton skeins in neutral to highly alkaline solutions, and how they inhibit gel formation when preparing high‐solids fatty acid soap solutions. Furthermore, the preparation and characterization of the soaps of the C‐21 dicarboxylic acid products are discussed. Mass‐balance equations describe the preparation of aqueous soap solutions at any given concentration. Characterization of the resulting soap solutions includes acid number, pH, color, color stability, foam stability, surface tension as a function of concentration, and hard‐water compatibility.