화학공학소재연구정보센터
Journal of Colloid and Interface Science, Vol.286, No.1, 245-252, 2005
Distribution of amines in water/AOT/n-hexane reverse micelles: influence of the amine chemical structure
The distribution of different aliphatic and aromatic amines: n-butylamine (n-BA), isobutylamine (i-BA), tert-butylamine (i-BA), piperidine (PIP), N,N-dimethylaniline (DMA) and N-methylanifine (MA) in water/sodium 1,4-bis(2-ethylhexyl)sulfosuceinate(AOT)/n-hexane reverse micelles was investigated by steady-state fluorescence measurements. The partition constants were measured by an indirect method based on the effect that amme partitioning exert on the bimolecular rate of the reaction between a microphase incorporated fluorophore (Ru(bpy)(2+)(3)) and the quencher, (Fe(CN)(3-)(6)).For MA, that can act as a quencher of the fluorophore a direct method was used. The results show that primary arnines have larger partition constants than the secondary ones. For tertiary amines the distribution constants were practically negligible. Laser flash photolysis experiments confirmed that tertiary amines, both aliphatic and aromatic, are not incorporated to the micellar pseudophase. The effect of the amine structure on the partition constant was analyzed through linear solvation free energy relationships (LSER) using solute parameters and compared with those obtained for alcohols. Hydrogen bond interactions with the AOT polar heads appear to be the main driving force for the distribution of amines between the organic and miceller pseudophases, whereas the size of the alkyl or aromatic group tends to hinder it. © 2005 Elsevier Inc. All rights reserved.