Influence of the alkyl chain length on the physicochemical properties and microbial biocompatibility of phosphonium based fatty acid ionic liquids.

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From: Canadian Journal of Chemistry(Vol. 100, Issue 1)
Publisher: NRC Research Press
Document Type: Report
Length: 7,381 words
Lexile Measure: 1650L

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Abstract :

Ionic liquids (ILs) have remarkable properties and applications in many areas of science. Phosphonium ILs have become important because of their unique chemical and thermal stabilities. The present work is focused on the synthesis, characterisation, physicochemical properties, and microbial toxicity assessment of phosphonium ILs bearing seven different fatty acid anions. The structures of the synthesised ILs were confirmed by [.sup.1]H and [.sup.13]C nuclear magnetic resonance (NMR) and FTIR spectroscopy. Physicochemical properties such as density and viscosity of pure ILs were measured at temperatures ranging from 298.15 to 313.15 K. The experimental density decreased, whereas the viscosity increased with an increasing number of carbon atoms in the anion. The derived properties were also found to be anion dependent. The thermal decomposition temperature was investigated by TGA. Subsequently, the toxicity profile of the ILs was determined for selected Gram positive and Gram negative bacteria and some species of fungi in terms of minimum inhibitory concentrations (MIC). The results show that the antimicrobial activities of the ILs are strongly related to the structures of the ILs, where an increase in toxicity was observed with increasing alkyl group chain length of the fatty acid anion. Key words: ionic liquids, fatty acid anion, tetrabutylphosphonium cation, molecular volume, biological activities. Les liquides ioniques (LI) sont remarquables de par leurs proprietes et leurs applications dans de nombreux domaines scientifiques. Les LI a base de phosphonium sont devenus importants en raison de leur stabilite chimique et thermique particuliere. Les presents travaux portent sur la synthese, la caracterisation, les proprietes physicochimiques et l'evaluation de la toxicite microbienne de LI a base de phosphonium comportant sept differents anions acides gras. Nous avons confirme la structure des LI synthetises par spectroscopie de resonance magnetique nucleaire (RMN) [.sup.1]H et [.sup.13]C et spectroscopie infrarouge a transformee de Fourier (FTIR). Nous avons mesure les proprietes physicochimiques telles que la densite et la viscosite de LI purs a des temperatures allant de 298,15 K a 313,15 K. La densite experimentale diminue, tandis que la viscosite augmente, avec le nombre croissant d'atomes de carbone qui constituent l'anion. Les proprietes derivees sont egalement dependantes de l'anion. Nous avons etudie la temperature de decomposition thermique par analyse thermogravimetrique. Par la suite, nous avons evalue le profil de toxicite des LI a l'egard de certaines bacteries a Gram positif et a Gram negatif et de certaines especes de champignons en determinant les concentrations inhibitrices minimales. Les resultats montrent que l'activite antimicrobienne des LI est fortement liee a leur structure, ou l'on observe une augmentation de la toxicite avec l'augmentation de la longueur de la chaine alkyle qui caracterise l'anion acide gras. [Traduit par la Redaction] Mots-cles : liquides ioniques, anion acide gras, cation tetrabutylphosphonium, volume moleculaire, activite biologique.

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Gale Document Number: GALE|A689991240