Hexadecyltrimethylammonium chloride and bromide in aqueous solutions containing urea and several alkylureas: a differential scanning calorimetric study

Autor:	Barbara Briggs, Jbfn Engberts, PM Cullis, Butt, L Gorse, Michael J. Blandamer
Rok vydání:	1992
Předmět:	Aqueous solution Chemistry Enthalpy Inorganic chemistry Penetration (firestop) Chloride Micelle chemistry.chemical_compound Adsorption Bromide medicine Urea Physical and Theoretical Chemistry medicine.drug
Zdroj:	Journal of the Chemical Society, Faraday Transactions. 88:2871
ISSN:	1364-5455 0956-5000
DOI:	10.1039/ft9928802871
Popis:	With increase to the concentration of urea over the range 0 ⩽[urea]/mol dm–3⩽ 3.0, the extremum in the differential heat capacity, δCp, of hexadecyltrimethylammonium bromide (CTAB; aq; 0.02 mol dm–3; reference, water) moves from 45 °C to lower temperatures and the associated enthalpy change characterising cluster reorganisation decreases. Addition of ethylurea to this CTAB solution produces a more dramatic shift in the extremum; the effect is even more striking when 1, 3-diethylurea is added. Addition of other alkylureas including, 1,1-diethylurea both shifts the extremum in δCp and reduces its magnitude. A similar pattern emerges for aqueous solutions containing hexadecyltrimethylammonium chloride (CTAC). The effect of these ureas on CTAB(aq) is attributed to adsorption and penetration of the alkylureas into the CTAB micelles and clusters.
Databáze:	OpenAIRE
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