SYNTHESIS AND PROPERTIES OF PIPERAZINE DERIVATIVES AND THEIR QUATERNARY AMMONIUM AMPHIPHILIC SALTS

Citation
Lh. Gan et al., SYNTHESIS AND PROPERTIES OF PIPERAZINE DERIVATIVES AND THEIR QUATERNARY AMMONIUM AMPHIPHILIC SALTS, Journal of colloid and interface science, 183(2), 1996, pp. 329-338
Citations number
27
Categorie Soggetti
Chemistry Physical
ISSN journal
00219797
Volume
183
Issue
2
Year of publication
1996
Pages
329 - 338
Database
ISI
SICI code
0021-9797(1996)183:2<329:SAPOPD>2.0.ZU;2-L
Abstract
A series of long-chain piperazine derivatives, N-alkyl-N'-methyl piper azine and their amphiphilic salts, N-alkyl-N'-ethyl-N'-methyl piperazi nium bromide, and the related N-alkyl-N,N'-dimethyl piperazinium bromi de were synthesized and characterized by H-1 and C-13 NMR and FTIR spe ctroscopy. Under the experimental conditions used, the NMR data showed unequivocally that quaternarization of N-alkyl-N'-methyl piperazine b y the reaction with ethyl bromide occurred exclusively at the nitrogen atom bearing the methyl group due to the steric hindrance of the long -chain alkyl group attached to the other nitrogen atom. Critical micel le concentration (cmc) and surface-active properties of the amphiphile s were investigated. Plots of surface tension, gamma, against log conc entration were presented. At cmc, the number of molecules adsorbed at the air-water interface was found to decrease with increasing chain le ngth. This was attributed to the increase in electrostatic repulsion w ithin the adsorption layer as suggested by Lunkenheimer et al. (Colloi ds Surf. A 101, 197 (1995)). (C) 1996 Academic Press, Inc.