The Conductance, Dissociation Constant and Heat of Dissociation of Triethylamine in Water<sup>1</sup>

Ablard, J. E.; McKinney, D. S.; Warner, John C.

doi:10.1021/ja01865a075

Cited by 10 publications

(9 citation statements)

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“…Hamborg and Versteeg and Kamps et al used electromotive force (emf) measurements, Oscarson et al used a flow calorimeter, and Kim et al, Littel et al, and Schwabe et al used potentiometric titrations to measure the dissociation constants. The values obtained in this work are in better agreement with values reported by Littel et al ln K a values of TREA measured in this work deviated from Hamborg and Versteeg, Cox et al, Fyfe et al, Ablard et al, and Bergstrom and Olofsson by 0.6 %, 0.61 %, 0.54 %, 0.39 %, and 0.77 %, respectively. The deviations are within acceptable experimental deviations for TREA and are plotted in Figure .…”

Section: Resultssupporting

confidence: 92%

Dissociation Constants (pK_a) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

et al. 2014

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The dissociation constants of the conjugate acids of 14 amines (diethylethanolamine, monoethanolamine, n-butyldiethanolamine, t-butyldiethanolamine, n,n-dimethylpropanolamine, methyl-diethanolamine, ethyldiethanolamine, monoethylethanolamine, n,n-dimethylisopropanolamine, triethanolamine, 4-methylpiperazine-1-amine, 3-morpholino propylamine, 4,2-hydroxylethylmorpholine, and triethylamine) were measured over a temperature range between 293.15 and 333.15 K using the potentiometric titration method. The change in standard state thermodynamic properties was derived from the van’t Hoff equation. The influence of the steric hindrance, number of −OH groups, and length of alkyl chain on the dissociation constants was identified. Of the studied amines, few sterically hindered derivatives of piperazine, a secondary amine monoethylethanolamine, and a tertiary amine n,n-dimethylpropanolamine have high pK a values but lower standard enthalpy than those of the benchmark amine, monoethanolamine (MEA), and thus were deemed promising for CO2 capture technology. Monoethylethanolamine (MEEA) was found to have the highest basicity (pK a) with the lowest standard state enthalpy (ΔH°/kJ·mol–1).

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Section: Resultssupporting

confidence: 92%

Dissociation Constants (pK_a) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

et al. 2014

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“…The global effect of these three terms in equation 1 is an increase in the current when NH 3 is added to water, which accounts for the high current recorded here. We postulate that similar physicochemical properties are obtained for water droplets seeded with other amines (e.g., triethylamine and piperidine), though solubility and conductivity are available only for triethylamine [49][50][51]. The spraying current is a key parameter for electrochemical processes occurring in electrospray and plays a central role in the pH changes observed at the exit of the emitter tip, before the generation of the spray plume [36,[41][42][43].…”

Section: Effect Of Basic Vapors On the Spraying Current And Electrochmentioning

confidence: 84%

Basic Vapor Exposure for Tuning the Charge State Distribution of Proteins in Negative Electrospray Ionization: Elucidation of Mechanisms by Fluorescence Spectroscopy

Girod

Antoine

Dugourd

et al. 2012

J. Am. Soc. Mass Spectrom.

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Manipulation for simplifying or increasing the observed charge state distributions of proteins can be highly desirable in mass spectrometry experiments. In the present work, we implemented a vapor introduction technique to an Agilent Jet Stream ESI (Agilent Technologies, Santa Clara, CA, USA) source. An apparatus was designed to allow for the enrichment of the nitrogen sheath gas with basic vapors. An optical setup, using laser-induced fluorescence and a pH-chromic dye, permits the pH profiling of the droplets as they evaporate in the electrospray plume. Mechanisms of pH droplet modification and its effect on the protein charging phenomenon are elucidated. An important finding is that the enrichment with basic vapors of the nitrogen sheath gas, which surrounds the nebulizer spray, leads to an increase in the spray current. This is attributed to an increase in the electrical conductivity of water-amine enriched solvent at the tip exit. Here, the increased current results in a generation of additional electrolytically produced OH -ions and a corresponding increase in the pH at the tip exit. Along the electrospray plume, the pH of the droplets increases due to both droplet evaporation and exposure to basic vapors from the seeded sheath gas. The pH evolution in the ESI plume obtained using pure and basic seeded sheath gas was correlated with the evolution of the charge state distribution observed in mass spectra of proteins, in the negative ion mode. Taking advantage of the Agilent Jet Stream source geometry, similar protein charge state distributions and ion intensities obtained with basic initial solutions, can be obtained using native solution conditions by seeding the heated sheath gas with basic vapors.

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“…In Table 1 to Table 10, correlated experimental results and the values of the standard state thermodynamic properties are given and compared to available temperature-dependent literature values. Literature dissociation constants based on the molarity scale [9][10][11][12][13][14][15] were converted to the molality scale by 20 Bates & Schwarzenbach 21 Kim et al 17 Antelo 22 Campbell & Lam 12 Ablard et al 13 Fyfe 14 Bergström & Olofsson 23 …”

Section: Resultsmentioning

confidence: 99%

“…During measurements of the first dissociation constants, the amino groups of PZ have to be partly first-step and second-step protonated. The solution thus contains a mixture of 1:1 and 1:2 salts, and accurate estimates for the activity coefficients C KCl parameter kg · mol -1 kg · mol -1 kg 2 · mol -2 u 1 -2.10289 · 10 -2 2.20813 · 10 -1 0.0 u 2 6.03967 · 10 -1 -4.61849 7.64891 · 10 -4 u 3 3.67768 · 10 -3 -4.10116 · 10 -2 0.0 u 4 -7.05537 · 10 -6 1.10445 · 10 -4 -1.12131 · 10 -8 u 5 1.97968 · 10 -9 -4.73196 · 10 -8 1.72256 · 10 -11 u 6 -2.47588 · 10 -3 -2.74120 · 10 -2 0.0 u 7 1.44160 · 10 -1 3.32883 · 10 -1 -5.71188 · 10 -3 f L (T r , 1 bar) 6.77136 · 10 -4 9.67854 · 10 -4 -4.12364 · 10 -5 f L (T r , P r ) 6.56838 · 10 -4 9.67854 · 10 -4 -4.12364 · 10 -5 f G (T r , 1 bar) 4.8080 · 10 -2 2.18752 · 10 -1 -3.94 · 10 -4 f G (T r , P r ) 5.0038 · 10 -2 2.18752 · 10 -1 -3.94 · 10 B KCl V parameter kg · mol -1 · bar -1 q 1 0.0 q 2 0.0 q 3 9.45015 · 10 -8 q 4 -2.90741 · 10 -10 q 5 3.26205 · 10 -3 q 6 8.39662 · 10 -7 q 7 0.0 q 8 -4.41638 · 10 -9 q 9 6.71235 · 10 -12 q 10 -4.42327 · 10 -5 q 11 -7.97437 · 10 -10 q 12 0.0 q 13 4.12771 · 10 -12 q 14 -6.24996 · 10 -15 q 15 4.16221 · 10 -8 are important for an accurate result. 26 The larger deviations have likely followed from this.…”

Section: Resultsmentioning

confidence: 99%

Dissociation Constants and Thermodynamic Properties of Amines and Alkanolamines from (293 to 353) K

Hamborg¹,

Versteeg

2009

J. Chem. Eng. Data

135

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The dissociation constants of protonated 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, diethylmonoethanolamine, diisopropanolamine, dimethylmonoethanolamine, monoethanolamine, 1-amino-2-propanol, methylmonoethanolamine, triethanolamine, and the first and the second dissociation constants of piperazine and hydroxyethylpiperazine have been determined by electromotive force measurements from (293 to 353) K. The dissociation constants of protonated triethylamine have been determined with the same technique from (293 to 333) K. The experimental results and derived values of the standard state thermodynamic properties are reported and compared to available literature values. IntroductionAqueous solutions of (alkanol)amines are frequently used for the removal of acid gases, such as CO 2 and H 2 S, from a variety of gas streams. The dissociation constant is one of the important factors in the selection of an (alkanol)amine solution for acid gas removal or in the interpretation of the kinetic mechanism of the absorption of the acid gas in the (alkanol)amine solution. 1 Dissociation constants can provide the following information:(1) a measure of the basic strength of the (alkanol)amine at a specific temperature and (2) a conventional acid gas removal plant is operated with an absorption/desorption cooling/heating cycle. In the absorber, the acid gas is (chemically) absorbed by the basic absorbent. At an elevated temperature in the desorber, the basic strength of the absorbent is reduced and the acid gas released. The basic strength is reduced as a result of less dissociation of the unprotonated absorbent at higher temperatures. Temperature-dependent dissociation constants provide the change in the reaction enthalpy which indicates the change of the basic strength of the absorbent within a given temperature range.The dissociation constants of protonated 2-amino-2-ethyl-1,3-propanediol (AEPD), 2-amino-2-methyl-1-propanol (AMP), diethylmonoethanolamine (DEMEA), diisopropanolamine (DIPA), dimethylmonoethanolamine (DMMEA), monoethanolamine (MEA), 1-amino-2-propanol (MIPA), methylmonoethanolamine (MMEA), triethanolamine (TEA), and the first and the second dissociation constants of piperazine (PZ) and hydroxyethylpiperazine (HEPZ) have been determined in this work by electromotive force measurements from (293 to 353) K. The dissociation constants of protonated triethylamine (TREA) have been determined with the same technique from (293 to 333) K. The results from the current work extend the temperature range of available literature values for the compounds investigated. For some of the compounds, no literature values were found, and the current work provides these values. Theory and Experimental ProcedureThe theory and experimental procedure behind the measurements of dissociation constants of an (alkanol)amine have been given in detail elsewhere. 2 Measurements of the first and second dissociation constant of diamines are carried out in a similar manner. A protonated diamine dissociates according toThe equilibriu...

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The Conductance, Dissociation Constant and Heat of Dissociation of Triethylamine in Water¹

Cited by 10 publications

References 0 publications

Dissociation Constants (pK_a) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

Dissociation Constants (pK_a) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

Basic Vapor Exposure for Tuning the Charge State Distribution of Proteins in Negative Electrospray Ionization: Elucidation of Mechanisms by Fluorescence Spectroscopy

Dissociation Constants and Thermodynamic Properties of Amines and Alkanolamines from (293 to 353) K

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The Conductance, Dissociation Constant and Heat of Dissociation of Triethylamine in Water1

Cited by 10 publications

References 0 publications

Dissociation Constants (pKa) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

Dissociation Constants (pKa) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

Basic Vapor Exposure for Tuning the Charge State Distribution of Proteins in Negative Electrospray Ionization: Elucidation of Mechanisms by Fluorescence Spectroscopy

Dissociation Constants and Thermodynamic Properties of Amines and Alkanolamines from (293 to 353) K

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The Conductance, Dissociation Constant and Heat of Dissociation of Triethylamine in Water¹

Dissociation Constants (pK_a) of Tertiary and Cyclic Amines: Structural and Temperature Dependences

Dissociation Constants (pK_a) of Tertiary and Cyclic Amines: Structural and Temperature Dependences