Synthesis, characterization and applications of azo-containing photodestructible surfactants

Photodestructible surfactants, sodium 4-(2-cyano-2-undecylazo)benzoate and a series of sodium 4-alkylphenylazosulfonates, have been synthesized and were shown to be surface active in solution, each exhibiting a distinct critical micelle concentration (CMC). UV irradiation of aqueous solutions of the...

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Bibliographic Details
Published inJournal of the Chemical Society, Perkin Transactions 2 no. 9; pp. 1837 - 1842
Main Authors Dunkin, IR, Gittinger, A, Sherrington, DC, Whittaker, P
Format Journal Article
LanguageEnglish
Published CAMBRIDGE Royal Soc Chemistry 1996
Subjects
Chemistry
Chemistry, Organic
Chemistry, Physical
Physical Sciences
Science & Technology
CATIONIC SURFACTANTS
ACTIVE PROPERTIES
MOIETY
DETERGENTS
MODELS
RING
DECOMPOSITION
MEMBRANES
MICELLES
MONOLAYERS
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Summary:Photodestructible surfactants, sodium 4-(2-cyano-2-undecylazo)benzoate and a series of sodium 4-alkylphenylazosulfonates, have been synthesized and were shown to be surface active in solution, each exhibiting a distinct critical micelle concentration (CMC). UV irradiation of aqueous solutions of the alkylazobenzoate led to a distinct increase in surface tension, but even after complete photolysis significant surface activity remained, indicating a substantial amount of cage recombination after nitrogen evolution. UV irradiation of sodium 4-dodecylazosulfonate caused a photoscission reaction, completely destroying its surface active properties. In the case of azosulfonates with shorter alkyl chains, however, some residual surface activity remained after complete removal of the azo linkage, indicating that secondary surfactants were formed by the photolysis. The 4-alkylphenylazosulfonates were able to solubilize an oil-soluble dye in water to produce isotropic coloured solutions. Photoirradiation of these solutions led to complete-loss of colour, presumably as a result of microprecipitation of the dye. The azosulfonate surfactants also-readily emulsified vinyl monomers, such as styrene, in water. Attempts to achieve emulsion polymerization led to only low conversion of monomer, most likely owing to side reactions between initiating radicals and the azo linkage of the surfactant, leading in turn to disruption of the micelle.
ISSN:0300-9580
1364-5471
DOI:10.1039/p29960001837