Enthalpimetric analysis

Jordan, Joseph; Grime, J. Keith; Waugh, Dan H.; Miller, Cynthia; Cullis, Herbert M.; Lohr, D.

doi:10.1021/ac60368a036

Cited by 8 publications

(7 citation statements)

References 13 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The reaction of the iodine titrant with hydrazines and hydrazides is an oxidation process.36 Gasometric studies of the reactions between iodine and benzoylhydrazine and iodine and isonicotinoylhydrazine, under the conditions used in the nonaqueous titrations but with the ethyl vinyl ether omitted, confirm that nitrogen is evolved, and in amount approximating to that required by the following reaction: FtCONHNH2 + 2I2 -RCOI + 3HI + N2t (16) As in the other iodometric titrations, the measured reaction stoichiometries are dependent on the structure of the analyte, and in most instances are not integral values.…”

Section: B Precipitation Reactions (Table Vi)mentioning

confidence: 99%

“…Figure16. Effect of water on the catalytic thermometric titration of morpholine (10 mg in 1 mL of toluene plus 10 mL of 2-methylpropyl vinyl ether indicator) with 0.1 M boron trifluoride in dioxan: (a) no water added;(b) +10 mg of water; (c) +22 mg of water, (d) +95 mg of water; (e) +120 mg of water; (f) +104 mg of water +0.5 g of molecular sieve 4A; and (g) +73 mg of water (only 2 mL of 2-methylpropyl vinyl ether).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Catalytic thermometric titrimetry

Greenhow¹

1977

Chem. Rev.

View full text Add to dashboard Cite

Section: B Precipitation Reactions (Table Vi)mentioning

confidence: 99%

mentioning

confidence: 99%

Catalytic thermometric titrimetry

Greenhow¹

1977

Chem. Rev.

View full text Add to dashboard Cite

“…[1][2][3][4][5][6][7][8][9][10][11][12][13]) sind Konzentrationsbestimmungen in Ein-oder Vielkomponentensystemen und die Bestimmung yon Stoffdaten. Sie umfassen die kalorimetrischen Verfahren mit kontinuierlicher oder diskonlinuierlicher Reagenzzugabe zu einer im Titrations-gef~13 vorgelegten L6sung bezw.…”

Section: Einfiihrungunclassified

“…Carr [68] hat auf der Grundlage dieses Gleichungssystems mittels kritischer Datenanalyse eine maximale Genauigkeit der Methode yon 0.1 ~ ermittelt und damit die Zuverl~ssigkeit der anisothermen Verfahren festgestellt. Zur Endpunktbestimmung aus den ersten und h6heren Abteilungen des Thermogramms AT = f(t) und deren Aussagen s. [10]. Zur Endpunktbestimmung aus den ersten und h6heren Abteilungen des Thermogramms AT = f(t) und deren Aussagen s. [10].…”

Section: C(t~)(r-tp)= Ws(t -Tp) -C(tp)lc(t -Tp)(tr -6))unclassified

Thermometrische und Enthalpimetrische Titrationsmethoden

Barthel

1981

Journal of Thermal Analysis

View full text Add to dashboard Cite

Starting from the most general form of the balance equation of thermal performance for thermometric and enthalpimetric methods of titration, the possibilities of these methods in analytical chemistry and in the field of determining data on materials are demonstrated and critically appreciated. The demand for reliable data on materials opens new fields of application of thermometric and enthalpimetric titration methods in the sphere of the thermal chemistry of solutions.

show abstract

“…Taking into account the likewise synchronous titrant delivery (and the concentration of the titrant), the abscissa was calibrated in terms of moles of titrant added. Detailed procedures and instrumentation have been described previously (14).…”

mentioning

confidence: 99%

Redox thermodynamics and electron transfer reactivity of heme by enthalpimetry and voltammetry

Bury¹,

Jordan²

1977

Anal. Chem.

View full text Add to dashboard Cite

The first extensive Investigation of the redox thermochemistry of protoheme Is described. A wealth of thermodynamic Information was obtained by judiciously combining results of potentiometrlc and thermometric titrations. Heats, Gibbs free energies, and entropies of the reduction of ferriheme to femoheme have been determined In (Hmethytformamide (DMF), In dimethylacetamide (DMA), and In mixtures of DMF or DMA and water. The reducing agent was chromous acetate. In order to segregate solvent effects attributable to the ferroferrlheme half-reaction, the AH, AG, and AS assignments have been referred to the ferrocene/ferrlcinlum couple whose energetics are known to be virtually Independent of solvent. The thermodynamic parameters of the ferroheme-ferrlheme redox process exhibited remarkable nonmonotonic trends as function of solvent composition. The results were generally consistent with concomitantly observed effects of solventsolute Interactions on electrode kinetics. Relevant electrochemical rate constants were evaluated by polarography and cyclic voltammetry.Oxidation-reduction properties of octahedral complexes of iron with the equatorial ligand protoporphyrin IX are of evident biological interest because the prosthetic groups of hemoproteins ("heme") are moieties of this type. They are implicated in crucial physiological functions (1) including oxygen transport (by hemoglobin), oxygen storage (by myoglobin), and cellular respiration (via cytochrome c). Extensive information is available in classical monographs (2, 3) on the standard and formal potentials of metalloporphyrin redox couples. Because heme tends to dimerize and polymerize in aqueous solutions (1, 4-7) many recent electrochemical studies have been carried out in the presence of nonaqueous solvents (I, 4, [8][9][10][11] where the situation is not complicated by aggregation.Surprisingly, data on the thermochemistry of oxidationreduction reactions of heme are conspicuous by their absence.In fact, only one study on the redox thermochemistry of any iron porphyrin (viz., of hematoporphyrin) has been reported in the literature (12). In the present paper, calorimetric results are presented and discussed involving the heat of reduction of ferriheme to ferroheme with chromous acetate in the aprotic solvents , -dimethylformamide (DMF) and IV^V-dimethyl acetamide (DMA), and in mixtures of these with water. Concomitantly, Gibbs free energies were estimated by electrochemical methods and corresponding entropies were computed. These thermodynamic findings were complemented by evaluation of electrode kinetics via cyclic voltammetry yielding illuminating insights on mechanistically significant solvent effects. EXPERIMENTAL General Conditions. Very dilute solutions of ferriheme, ferroheme, and chromous acetate (in a range between 0.0001 M and 0.001 M) were prepared in purified solvents (DMF, DMA, 1 Postdoctoral Scholar (1974-75) on leave from Université Pierre

show abstract

Enthalpimetric analysis

Cited by 8 publications

References 13 publications

Catalytic thermometric titrimetry

Catalytic thermometric titrimetry

Thermometrische und Enthalpimetrische Titrationsmethoden

Redox thermodynamics and electron transfer reactivity of heme by enthalpimetry and voltammetry

Contact Info

Product

Resources

About