Thermodynamics of the dissociation of morpholinium ion in seawater from 5 to 40�C

Czermiński, Jurand; Dickson, Andrew G.; Bates, Roger G.

doi:10.1007/bf01036376

Cited by 27 publications

(12 citation statements)

References 12 publications

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“…Moreover, Figure 3 shows the almost linear dependence of log Q on the reciprocal temperature in Kelvin to 300 °C, that further supports the use of the isocoulombic approach. Note that in neither the fit of Hetzer et al 7 nor Czerminiski et al 8 shown in Figure 3, were the high-temperature data of Mesmer and Hitch 5 used. The fits of Hetzer et al 7 and Czerminiski et al 8 have clearly been extrapolated well beyond the experimental range of the two studies, yet they remain in agreement with the present data to high temperatures.…”

Section: Discussionmentioning

confidence: 99%

“…Note that in neither the fit of Hetzer et al 7 nor Czerminiski et al 8 shown in Figure 3, were the high-temperature data of Mesmer and Hitch 5 used. The fits of Hetzer et al 7 and Czerminiski et al 8 have clearly been extrapolated well beyond the experimental range of the two studies, yet they remain in agreement with the present data to high temperatures. However, it is important to note that the ionic strength dependence of log Q determined by Czerminiski et al 8 based on a synthetic seawater mixture of electrolytes, was excluded from the fit of the present study because it was significantly larger than found in other studies.…”

Section: Discussionmentioning

confidence: 99%

“…1 In this context, the behavior of morpholine at elevated temperatures has been of significant interest. 1,[4][5][6] Three major independent potentiometric studies have been performed in the past by Hetzer et al, 7 Mesmer and Hitch, 5 and Czerminiski et al 8 The first study utilized platinum/hydrogen and silver/silver chloride electrodes in cells without liquid junctions (i.e, so-called Harned cells) and extended from (0 to 50) °C at 5 K intervals in very dilute solutions. The investigation by Mesmer and Hitch 5 involved measurements from (50 to 294) °C in 0.081 m KCl using a flow-through hydrogen-electrode concentration cell.…”

Section: Introductionmentioning

confidence: 99%

“…The investigation by Mesmer and Hitch 5 involved measurements from (50 to 294) °C in 0.081 m KCl using a flow-through hydrogen-electrode concentration cell. Czerminiski et al 8 also employed Harned cells in the range (5 to 40) °C in synthetic seawater containing NaCl, MgCl 2 , Na 2 SO 4 , CaCl 2 , and KCl in amounts corresponding to ca. 10, 20, 30, 35, and 40 parts per 1000 (equivalent to 0.2 to 0.8 m ionic strength).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2000

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2000

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“…There are a numerous studies for the ionization equilibria of morpholine in aqueous solutions near ambient temperature. , Mesmer and Hitch determined values for the ionization constant of morpholine over the temperature range 50−295 °C in dilute KCl media as a function of pressure using a potentiometric technique that employed platinum/hydrogen electrodes in a novel concentration cell with a flowing liquid junction. A critical review of the high-temperature ionization constant and volatility data for a number of industrially important amines has been done by Wetton …”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Properties of Aqueous Morpholine and Morpholinium Chloride at Temperatures from 10 to 300 °C: Apparent Molar Volumes, Heat Capacities, and Temperature Dependence of Ionization

1997

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Apparent molar heat capacities C p,φ of aqueous morpholine and morpholinium chloride were determined with a Picker flow microcalorimeter at temperatures from 10 to 55 °C. The apparent molar volumes V φ have been determined with platinum vibrating tube densitometers at temperatures from 10 to 300 °C and pressures in excess of steam saturation. Values of V φ for morpholine approach large positive values at elevated temperatures, consistent with a lowering of the critical temperature in the solutions relative to water. The effect in aqueous morpholinium chloride is reversed, confirming the profound effect of ionic charge on the high-temperature thermodynamic properties of aqueous solutes, even for large organic molecules. Standard partial molar heat capacity functions were estimated from the high-temperature V φ data and low-temperature values of C p,φ using an empirical model based on the appropriate solvent density derivatives and the revised Helgeson-Kirkham-Flowers model. The results from both models are consistent with literature values for the heat capacity of ionization determined from high-temperature potentiometric measurements to within the combined experimental uncertainties. The results show that the effects of solvent expansion by the neutral species is significant at elevated temperatures. The effective Born radius of ions containing organic groups could be significantly larger than the radius calculated from the formula for simple cations because of this effect.

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The Nitroprusside Ion as a Nitrosating Reagent. Kinetic Studies on the Nitrosation of Morpholine

Casado

López‐Quintela

Mosquera

et al. 1983

Ber Bunsenges Phys Chem

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This article reports a kinetic study of the nitrosation of morpholine (MOR) by the nitroprusside ion. [Fe(CN)5NO]2-, to form N-nitrosomorpholine, a substance of proven carcinogenicity. The reaction is of order one with respect to the nitroprusside ion and order two with respect to morpholine. The influence of the pH and the ionic strength of the medium on the rate of reaction has been studied in detail. A reaction mechanism is proposed whose first step is a fast reaction between the amine and the coordinated nitrosyl group to form a complex which reaches equilibrium with the reagents and then reacts with another molecule of amine to produce the corresponding nitrosamine and the complex (Fe(CN)5MOR]3 -.The nitrosation of methylurea has been studied under catalysis by acetate and mono-, di-and trichloroacetate buffers. The following general equation for the rate of reaction as a function of the total concentrations of the reagents has been deduced: v = [MU] [nit] [H+Iz K , [nit] + E K , + [H'] K , + [H']Ki + [H+l where K , is the acidity constant of nitrous acid and K2 that of carboxylic acid. The catalysis observed has been found to be due to the organic anions, and Brpnsted relation is obeyed with / 3 = Oi24. -The experimental results have been interpreted in terms of a reaction mechanism which features the rapid formation of a intermediate, MeNH(NO)CONH,, when the methylurea is nitrosated. The rate controlling step is the transfer of a proton from this intermediate to the solvent or to a basic catalyst (the nitrite ion or the organic anion). That it is this step that controls the overall rate of reaction is supported by the isotopic effect ( k , / k , = 3.5) observed on carrying out kinetic measurements in D,O.

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Thermodynamics of the dissociation of morpholinium ion in seawater from 5 to 40�C

Cited by 27 publications

References 12 publications

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

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

Thermodynamic Properties of Aqueous Morpholine and Morpholinium Chloride at Temperatures from 10 to 300 °C: Apparent Molar Volumes, Heat Capacities, and Temperature Dependence of Ionization

The Nitroprusside Ion as a Nitrosating Reagent. Kinetic Studies on the Nitrosation of Morpholine

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