Síntese e propriedades de soluções de tensoativos catiônicos derivados de (3-dimetilaminopropil)amidas de ácidos carboxílicos / Synthesis and solution properties of cationic surfactants derivated from fat acids of (3-dimethylaminopropyl)amides.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

The following surfactants have been synthesized: benzyl-(3-acyl-aminopropyl)dimethylammonium chloride, RCONH(CH ind.2 ) ind.3 N pot.+ (CH ind.3 ) ind.2 CH ind.2 C ind.6 H ind.5 Cl pot.- and (3-acylaminopropyl) trimethylammonium chloride, RCONH(CH ind.2 ) ind.3 N pot.+ (CH ind.3 ) ind.3 Cl ind.- , where RCO = C ind.10 to C ind.16 . The two series have been synthesized from the precursor RCONH(CH2)3N(CH3)2, by quaternization with benzyl chloride, and/or methyl iodide (followed by ion exchange), respectively. Adsorption at solution/air interface and micellization in aqueous solution has been studied, and the results compared with those of other cationic surfactants. Some properties, e.g., critical micelle concentrations, degrees of micelle dissociation, and aggregation numbers are similar to those of other cationic surfactants of equivalent hydrophobic chain length. The Gibbs free energies of adsorption at solution/air interface, and of micellization are, however, more favorable. The group [-CO-NH-CH ind.2 -CH ind.2 -CH ind.2 -] is a part of the interface, and lead to favorable micellization. The microscopic polarity of interfacial water has been measured by appropriate solvatochromic probes, and is less than that of bulk water.

ASSUNTO(S)

3-dimetilaminopropilamidas organic physical-chemistry surfactants amido-amines detergentes síntese orgânica tensoativos catiônicos properties synthesis micelas amido-aminas 3-dimethylaminopropylamides cationic micelles

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