Thermodynamic properties of the ionization of morpholine as a function of temperature and ionic strength

Moira K. Ridley; Caibin Xiao; Donald A. Palmer; David J. Wesolowski

doi:10.1021/je9903146

Thermodynamic properties of the ionization of morpholine as a function of temperature and ionic strength

Moira K. Ridley, Caibin Xiao, Donald A. Palmer, David J. Wesolowski

Geosciences

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14 Scopus citations

Abstract

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; ΔC_p = (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.

Original language	English
Pages (from-to)	502-507
Number of pages	6
Journal	Journal of Chemical and Engineering Data
Volume	45
Issue number	3
DOIs	https://doi.org/10.1021/je9903146
State	Published - May 2000

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@article{2d4cee38102f46d9a16cfa1342462af1,

title = "Thermodynamic properties of the ionization of morpholine as a function of temperature and ionic strength",

abstract = "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.",

author = "Ridley, {Moira K.} and Caibin Xiao and Palmer, {Donald A.} and Wesolowski, {David J.}",

year = "2000",

month = may,

doi = "10.1021/je9903146",

language = "English",

volume = "45",

pages = "502--507",

journal = "Journal of Chemical and Engineering Data",

issn = "0021-9568",

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TY - JOUR

T1 - Thermodynamic properties of the ionization of morpholine as a function of temperature and ionic strength

AU - Ridley, Moira K.

AU - Xiao, Caibin

AU - Palmer, Donald A.

AU - Wesolowski, David J.

PY - 2000/5

Y1 - 2000/5

N2 - 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.

AB - 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.

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U2 - 10.1021/je9903146

DO - 10.1021/je9903146

M3 - Article

AN - SCOPUS:0034188618

SN - 0021-9568

VL - 45

SP - 502

EP - 507

JO - Journal of Chemical and Engineering Data

JF - Journal of Chemical and Engineering Data

IS - 3

ER -

Thermodynamic properties of the ionization of morpholine as a function of temperature and ionic strength

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