Thermodynamic Properties of the Ionization of Morpholine as a Function of Temperature and Ionic Strength

Autor:	Moira K. Ridley, Donald A. Palmer, David J. Wesolowski, Caibin Xiao
Rok vydání:	2000
Předmět:	chemistry.chemical_compound Molar volume chemistry Ionic strength General Chemical Engineering Morpholine Physical chemistry General Chemistry Heat capacity Concentration cell Acid dissociation constant Ion Dilution
Zdroj:	Journal of Chemical & Engineering Data. 45:502-507
ISSN:	1520-5134 0021-9568
Popis:	A hydrogen−electrode concentration cell was used to monitor pH in a study of morpholine ionization in aqueous solutions to temperatures of 290 °C and to ionic strengths of 1 m, maintained with either sodium trifluoromethanesulfonate or sodium chloride. The resulting hydrolysis quotients were combined with values from two previous potentiometric investigations of this reaction, as well as existing heat capacity and apparent molar volume data, to provide a global fitting equation. The computed thermodynamic parameters for the acid dissociation of the morpholinium ion at 25 °C and infinite dilution are log K = (−8.491 ± 0.003); ΔH = (39 ± 1) kJ·mol-1; ΔS = (−31 ± 1) J·K-1·mol-1; ΔCp = (40 ± 7) J·K-1·mol-1; and ΔV = (3 ± 1) cm3·mol-1. At low ionic strengths, including values at infinite dilution, the log Q data were found to be near linear with respect to the reciprocal temperature in Kelvin over the measured temperature range of 0 °C to 300 °C.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::6dfe95b70bc1453eb68c2ce34f52ecf7 https://doi.org/10.1021/je9903146 Zobrazit plný text záznamu