Thermally-induced transition in aqueous solution of cationic surfactant containing aromatic ring

Citation
K. Endoh et al., Thermally-induced transition in aqueous solution of cationic surfactant containing aromatic ring, J THERM ANA, 57(3), 1999, pp. 669-678
Citations number
10
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
ISSN journal
13886150 → ACNP
Volume
57
Issue
3
Year of publication
1999
Pages
669 - 678
Database
ISI
SICI code
1388-6150(199909)57:3<669:TTIASO>2.0.ZU;2-J
Abstract
Heat capacities of aqueous solutions of cetyltrimethylammonium (CTA) salicy late, of CTA m-hydroxybenzoate and of CTA p-hydroxybenzoate were measured u sing a scanning microcalorimeter. Only the salicylate solution exhibited he at-capacity anomaly around 330 K, depending on the heating rate. The transi tion enthalpy was 3.5+/-0.2 kJmol(-1), which was similar to that observed i n solution of 1:1 intermolecular compound between CTA bromide (CTAB) and o- iodophenol (OIPh). The enthalpy of formation Delta H-f of the 1:1 intermole cular compound from CTAB and OIPh was determined by measuring the enthalpie s ofsolution of the relevant crystals into ethanol. Positive value Delta(f) H=3.0+/-0.3 kJmol(-1) was explained from a large difference between the he at capacities of the 1:1 compound and 1:1 mixture of the component crystals .