Abstract Among anionic surfactants used in detergent products, the sodium salt of linear alkylbenzene sulfonate (NaLAS) is the only surfactant belonging to the aromatic class; the others are aliphatic, e.g., the sodium salt of secondary alkyl sulfonate (NaSAS). We observed earlier that certain conformational changes taking place in aromatic anionic surfactants (NaLAS) upon micellization can be brought about in aliphatic anionic surfactants (NaSAS) by addition of phenol. In this paper we examined how conformational changes at the molecular level translated into macroscopic properties such as foam and detergency. We performed foam and detergency measurements on NaLAS, NaSAS, and NaSAS/phenol systems. Foam behavior of these systems is shown to be dependent only upon calcium ion sensitivities of the surfactants whereas the detergency results have a dependence on conformational changes at the molecular level.
Abstract Precipitation of anionic surfactants, linear alkylbenzene sulfonate (LAS) and alpha olefin sulfonate (AOS), by calcium ions was studied in the presence of sodium oleate. Lather stability was determined by the Ross‐Miles method, precipitation was followed by measuring the optical density (OD), and equilibrium surface tension (EST) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the nature of the precipitate formed. For the 5 mM LAS‐0.7 mM oleate system, lather was unstable, and the OD was high in the 2–5°FH region of calcium hardness, while at higher calcium hardness levels, lather was stable and the turbidity of solutions decreased. On the other hand, in the 5 mM AOS‐0.7 mM oleate system, lather was unstable throughout the calcium hardness region studied (0–20°FH). Also, the turbidity build‐up was much higher in the AOS system than in the LAS system. Analysis of the precipitates formed in these systems by FTIR spectroscopy indicated that the precipitate from the AOS system had an additional band at 1190 cm −1 , corresponding to the sulfonate group. These results, together with the EST data, confirm that the precipitate formed in the LAS system between 2–5°FH calcium is calcium oleate, and that formed in the AOS system is likely to be calcium (AOS) oleate. It is tempting to hypothesize that the similarity of AOS and oleate in chainlength could be responsible for the coprecipitation of AOS and oleate with calcium, whereas LAS, which has a larger headgroup with a benzene ring and two smaller chains (average length is C8) is unlikely to precipitate with the oleate.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical shift changes on micellization of linear alkyl benzenesulfonate and oleateS. Das, R. G. Bhirud, N. Nayyar, K. S. Narayan, and V. V. KumarCite this: J. Phys. Chem. 1992, 96, 18, 7454–7457Publication Date (Print):September 1, 1992Publication History Published online1 May 2002Published inissue 1 September 1992https://doi.org/10.1021/j100197a059Request reuse permissionsArticle Views175Altmetric-Citations31LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (430 KB) Get e-Alerts
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