Abstract

Apparent molar heat capacities and volumes of amylamine (PentNH2) 0.02m, capronitrile (PentCN) 0.02m and nitropentane (PentNO2) 0.009m in decyltrimethylammonium bromide (DeTAB) micellar solutions, in water and in octane were measured at 25°C. By assuming that their concentration approaches the standard infinite dilution state, heat capacities and volumes were rationalized by means of previously reported equations following which the distribution constant between the aqueous and the micellar phase and heat capacity and volume of the additives in both phases are simultaneously derived. The present results are compared to those we have previously obtained for pentanol (PentOH). The thermodynamic properties of PentNH2 in water and in micellar phase are substantially identical to those of PentOH but different from those of PentCN and PentNO2 whereas the opposite behavior was observed in their pure liquid state and in octane. The nature of the solvent medium seems to affect the thermodynamic behavior of PentNH2. Also, the study of the apparent molar heat capacities of the amyl compounds investigated here in micellar solutions as a function of surfactant concentration shows evidence of a maximum at about 0.4m DeTAB, which can be attributed to a micellar structural transition. Accordingly, the solubilities of PentCN and PentNO2 as a function of the DeTAB concentration drop in the neighborhood of the concentration where heat capacities display the maximum.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.