Thermodynamic quantities for the protonation of amino acid amino groups from 323.15 to 398.15 K

Gillespie, Sue E.; Oscarson, John L.; Izatt, Reed M.; Wang, P.; Renuncio, J.A.R.; Pando, Concepción

doi:10.1007/bf00972830

Cited by 28 publications

(49 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For glycine log K a,NH4ϩ values compiled by Smith et al (1997) and measured values from Gillespie et al (1995) are included in the plot. Our results are ϳ3% higher than those of Gillespie et al (1995) at 75°C and 125°C, which were obtained by titration calorimetry. Both sets of data show a trend towards increasing ionization with increasing temperature with a maximum at some temperature above the range of our measurements.…”

Section: Ammonium Ionization Constantsmentioning

confidence: 99%

“…Values for K a,NH4ϩ (298.15K) and ⌬ r H a o , NH4ϩ (298.15K) were fixed to those of Martell and Smith (1974). Both our data and the high-temperature data from Gillespie et al(1995) were used in the least squares regression. The fitted mean standard partial molar heat capacity of reaction, ⌬ r C p o , NH4ϩ ϭ Ϫ173 Ϯ 42 J.K Ϫ1 mol Ϫ1 , is more negative than the value ⌬ r C p o , NH4ϩ ϭ Ϫ77 Ϯ 10 J K Ϫ1 mol Ϫ1 , obtained by Gillespie et al (1995).…”

Section: Ammonium Ionization Constantsmentioning

confidence: 99%

“…Both our data and the high-temperature data from Gillespie et al(1995) were used in the least squares regression. The fitted mean standard partial molar heat capacity of reaction, ⌬ r C p o , NH4ϩ ϭ Ϫ173 Ϯ 42 J.K Ϫ1 mol Ϫ1 , is more negative than the value ⌬ r C p o , NH4ϩ ϭ Ϫ77 Ϯ 10 J K Ϫ1 mol Ϫ1 , obtained by Gillespie et al (1995). Further measurements will be conducted on both glycine, ␣-alanine, and proline to extend these results to elevated temperatures.…”

Section: Ammonium Ionization Constantsmentioning

confidence: 99%

“…Heat-of-mixing flow calorimetry has been used to determine ionization constants and enthalpies of reaction for the protonation of the amino and carboxylate groups of several amino acids at temperatures of up to 125°C (Izatt et al, 1992;Gillespie et al, 1995;Wang et al, 1996). Vibrating-tube densimeters and a Picker-type flow microcalorimeter have recently been used to determine experimental values for the standard partial molar volumes and heat capacities of glycine, ␣-alanine, ␤-alanine, proline, and the dipeptide glycyl-gylcine, at temperatures as high as 275°C (Hakin et al, 1995(Hakin et al, , 1998Clarke and Tremaine, 1999;.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ionization constants of aqueous amino acids at temperatures up to 250°C using hydrothermal pH indicators and UV-visible spectroscopy: Glycine, α-alanine, and proline

Clarke

Collins

Roberts

et al. 2005

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Abstract-Ionization constants for several simple amino acids have been measured for the first time under hydrothermal conditions, using visible spectroscopy with a high-temperature, high-pressure flow cell and thermally stable colorimetric pH indicators. This method minimizes amino acid decomposition at high temperatures because the data can be collected rapidly with short equilibration times. The first ionization constant for proline and ␣-alanine, K a,COOH , and the first and second ionization constants for glycine, K a,COOH and K a,NH4ϩ , have been determined at temperatures as high as 250°C. Values for the standard partial molar heat capacity of ionization, ⌬ r C p o , COOH and ⌬ r C p o , NH4ϩ , have been determined from the temperature dependence of ln (K a,COOH ) and ln (K a,NH4ϩ ). The methodology has been validated by measuring the ionization constant of acetic acid up to 250°C, with results that agree with literature values obtained by potentiometric measurements to within the combined experimental uncertainty.We dedicate this paper to the memory of Dr. Donald Irish (1932-2002 of the University of Waterloofriend and former supervisor of two of the authors (R.J.B. and P.R.T.).

show abstract

Section: Ammonium Ionization Constantsmentioning

confidence: 99%

Section: Ammonium Ionization Constantsmentioning

confidence: 99%

Section: Ammonium Ionization Constantsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ionization constants of aqueous amino acids at temperatures up to 250°C using hydrothermal pH indicators and UV-visible spectroscopy: Glycine, α-alanine, and proline

Clarke

Collins

Roberts

et al. 2005

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…The same equipment has also been used to determine heats of reaction of electrolytes and amino acids. For instance, the heat of reaction of phosphate anions with hydrochloric acid as a function of temperature and pressure was used to determine the protonation constants of phosphate at high temperature [23], and the heat of reaction of amino acids with basic solutions as a function of temperature, pressure and concentration was used to determine, for the first time, the acid disociation constant as a function of temperature [24,25]. …”

mentioning

confidence: 99%

Calorimetry in the near-critical and supercritical regions. Nitrous oxide + hydrocarbon mixtures

Renuncio¹,

Cabañas²,

Pando³

1999

Pure and App Chemis

View full text Add to dashboard Cite

Abstract:The high pressure calorimeters developed in the last 20 years are briefly reviewed. Most of them have been used to obtain excess enthalpy data (H E m ) in the critical and supercritical regions. Data are available for many mixtures formed by carbon dioxide and for a few involving other supercritical fluids such as ethane, methane, nitrous oxide, etc. Data for several N 2 O þ hydrocarbon mixtures were recently measured from 308.15 to 323.15 K and from 7.64 to 15.00 MPa. Excess enthalpies for N 2 O þ hydrocarbon mixtures were calculated using several cubic equations of state (EOS). Two noncubic EOS which combine the Carnahan-Starling hard-sphere term with the van der Waals and Redlich-Kwong attractive terms, were also used. The classical van der Waals mixing rules and those proposed by Wong and Sandler were used. The ability of the cubic EOS to correlate the excess enthalpies of the N 2 O þ hydrocarbon mixtures seems to be related to the proximity of conditions of temperature and pressure to the N 2 O critical point. CALORIMETRY IN THE CRITICAL REGIONThe increasing interest in supercritical fluids runs parallel with the increasing use of calorimetry in the near-critical and supercritical regions. The aim is to study the energetic interactions of molecules under these particular conditions. During the last two decades, high pressure calorimetry has shifted almost completely to supercritical fluid applications. The first experimental device to measure the endothermic excess enthalpies of simple mixtures such as CH 4 þ N 2 , CH 4 þ H 2 or CH 4 þ Ar was developed by Wormald et al. [1,2] in 1976. A new version is able to reach up to 700 K and 20 MPa, and to measure exothermic processes as well [3]. Simultaneously, Christensen et al. [4,5] were setting up a new highpressure flow calorimeter able to detect both exothermic and endothermic processes which was quickly applied to determine the excess enthalpies of CO 2 þ hydrocarbon mixtures in the critical region. From 1983 to his early dead, James J. Christensen published data of mixtures such as CO 2 þ ethane [6], þ pentane [7,8], þ hexane [9,10], þ cyclohexane [11][12][13][14], þ decane [15,16], þ toluene [17][18][19][20] and þ pyridine [21,22]. Figure 1 shows the experimental P,T conditions at which data are available for three of these systems. It may be seen that several types of mixtures-subcritical, supercritical, liquid-were studied. The data showed striking features: highly exothermic or endothermic enthalpies, large temperature and pressure effects, and two-phase linear sections in the H E m vs. composition diagrams. The same equipment has also been used to determine heats of reaction of electrolytes and amino acids. For instance, the heat of reaction of phosphate anions with hydrochloric acid as a function of temperature and pressure was used to determine the protonation constants of phosphate at high temperature [23], and the heat of reaction of amino acids with basic solutions as a function of temperature, pressure and concentration was used to determ...

show abstract

Acid–Base Properties

Sharma¹

2012

Oxidation of Amino Acids, Peptides, and Proteins

View full text Add to dashboard Cite

Thermodynamic quantities for the protonation of amino acid amino groups from 323.15 to 398.15 K

Cited by 28 publications

References 29 publications

Ionization constants of aqueous amino acids at temperatures up to 250°C using hydrothermal pH indicators and UV-visible spectroscopy: Glycine, α-alanine, and proline

Ionization constants of aqueous amino acids at temperatures up to 250°C using hydrothermal pH indicators and UV-visible spectroscopy: Glycine, α-alanine, and proline

Calorimetry in the near-critical and supercritical regions. Nitrous oxide + hydrocarbon mixtures

Acid–Base Properties

Contact Info

Product

Resources

About