Coulometric titration of weak acids in tetrahydrofuran

Champion, Charles E.; Bush, D. G.

doi:10.1021/ac60326a023

Cited by 11 publications

(7 citation statements)

References 16 publications

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“…For example, the dielectric constant of (aprotic) 1-methylimidazole indicates it is a polar liquid, even if its value is frequency dependent (e.g., e = 21.5 at 5.8 GHz and 32.3 at 2.45 GHz). [123] Addition of HX (X = Cl À , Br À ) does not lead to sol- 14.5 [73] 25.9 [73] 1.99 [71] --17.2 [73] -CH 3 OH 1606.4 [c] 29.0 [1] À2.4 [74] 15.5 [1] -% 16.5 [30] --CH 3 [15] 12.3 [1] 23.51 [2] 4.75 [33] 10.3 [78] 9.52 [79] 13.5 [80] ClCH 2 CO 2 H 1408 [18] 9.00 [81] 18.8 [82] 2.81 [82] 8.3 [82] 7.8 [82] 10.1 [82] -C 6 H 5 CO 2 H 1400 [c] 11.0 [83] 20.7 [83] 4.2 [83] 10.25 [84] 9.4 [85] 12.3 [83] 4.20 [86] HCl 1396 [15] 1.8 [1] 8.9 [2] À8 [33] 2.08 [87] 1.23 [88] 3.55 [89] - -6.67 [91] 5.88 [91] 9.03 [91] -H 3 PO 4 1383 [33] --2.10…”

Section: Protic Molecules In Molecular Liquidsmentioning

confidence: 99%

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

2011

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Fundamental aspects of Brønsted acidity in ionic liquid systems, in relation to those of simple protic molecules in the gas phase, pure protic molecules in the condensed phase and solutions of protic molecules in molecular systems, are presented. The variety of acidities possible, beyond those observed in aqueous systems, is emphasised and discussed in terms of differences of solvent levelling, ionisation, dissociation, homo-/hetero-conjugate ion speciation and the stabilisation of proton-transfer products from solvent to solvent. It is argued that data regarding aqueous systems do not necessarily explain acid/base behaviour in other liquids satisfactorily. Methods of measuring acidity are reviewed, particularly by spectrophotometry and electrochemistry and recommendations proffered for estimating speciation and acidity of ionic liquids of various complexities.

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Section: Protic Molecules In Molecular Liquidsmentioning

confidence: 99%

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

2011

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“…39 Tetrabutylammonium bromide and tetrabutylammonium perchlorate as the supporting electrolyte were used to generate hydroxide ions by the reduction of water, which had been added to the solution in a concentration of up to 1% (m/v). 40 Few data in the literature report the application of organic compounds, which on reduction produce a strong base. Water can be used as a cathodic depolarizer (in concentrations of up to 0.5% (m/v)), although it has an adverse effect on the conditions of the titration.…”

Section: Coulometric-potentiometric Determinations Of Acids Using Pyrmentioning

confidence: 99%

Application of Pyrite and Chalcopyrite Electrodes for the Acid-Base Determinations in Nitriles

Simi¹,

Stani²,

Antonijevi³

2011

J. Braz. Chem. Soc.

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Os minerais naturais pirita e chalcopirita tem sido usados como sensores em eletrodos indicadores usando acetronitrila e propionitrila como solventes. Os resultados mostram vantagens excepcionais da pirita e chacopirita como sensores eletroquímicos e também a possibilidade de aplicação desses eletrodos para determinações em solventes não aquosos onde eletrodos de vidro mostram dificuldades. O comportamento dos eletrodos indicadores de pirita e chalcopirita em nitrila foi avaliado pela titulação de diversas bases e ácidos de forças diferentes usando prótons e íons liato gerados pela oxidação de alguns ésteres de ácido gálico e fenóis diidróxi, bem como m-cresol e 3-metóxifenol. Os resultados obtidos com esses eletrodos foram comparados com os de eletrodos de vidro nas mesmas condições, obtendo-se boa concordância, reprodutividade e precisão. Os desvios padrão na determinação dos ácidos e bases investigados foram menores do que 0,9%. Em titulações potenciométricas com pirita e chalcopirita como eletrodos indicadores, o potencial é instantaneamente estabelecido. Ambos os eletrodos podem ser usados sem qualquer limitação temporal ou divergências potenciais consideráveis.The natural minerals pyrite and chalcopyrite have been used as the indicator electrode sensors using acetonitrile and propionitrile as solvents. The results show the exceptional advantage of pyrite and chalcopyrite as electrochemical sensors and also the possibility of the application of these electrodes for the determination in nonaqueous solutions where glass electrode shows many defaults. The behaviour of the pyrite and chalcopyrite indicator electrodes in nitriles were checked by titrating several bases and acids of different strengths using protons and lyate ions generated by the oxidation of some gallic acid esters and dihydroxy phenols, as well as m-cresol and 3-metoxy phenol. The results obtained by using these electrodes were compared with those obtained by the application of a glass electrode under the same conditions, and good agreement, reproducibility and accuracy were obtained. The standard deviation of the determination of the investigated acids and bases was less than 0.9%. In the potentiometric titrations with pyrite and chalcopyrite indicator electrodes, the potential is instantaneously established throughout. Both electrodes can be used without any time limit or without considerable divergence in potentials.

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“…Johansson [17] titrated acids by generating OH − in isopropanol or a mixture of isopropanol and methylacetone, which contained a trace of water. Champion [18] determined organic acids by a coulometric generation of the base, at a platinum cathode, in tetrahydrofuran containing about 0.2% of water. Gonzaga [19] used lithium chloride as a supporting electrolyte to determine the acid content of the ethanol fuel.…”

Section: Introductionmentioning

confidence: 99%

Determination of Trace Amounts of Hydrofluoric Acid in Non-Aqueous Solutions by the Coulometric Titration Method

Huang

Shen

Liu

et al. 2018

Sensors

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For monitoring of trace amounts of hydrofluoric acid in the organic fluorine chemical industry, a facile method for determination of the hydrofluoric acid in an ethanol solution of lithium chloride, by coulometric titration, was proposed. Relying on homemade acid–base coulometric autotitrator, the electrolyte was 0.50 mol·L−1 LiCl ethanol solution and the constant current intensity was 0.2–2 mA. As for the working electrode pair, a platinum plate was used as a working electrode, and a platinum wire was used as an auxiliary electrode. The indicating electrode was the pH composite glass electrode and the titration endpoint was pH 5.50. The results showed that the relative standard deviation was below 2.0%, as the content of the hydrofluoric acid was between 2 μg to 100 μg. The recovery rate was 99.0–102.0%. This proposed route has the advantages of simplicity, convenience, quickness, accuracy, and automation, which can be applied to the accurate determination of trace amounts of hydrofluoric acid, in non-aqueous solutions.

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Coulometric titration of weak acids in tetrahydrofuran

Cited by 11 publications

References 16 publications

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

Application of Pyrite and Chalcopyrite Electrodes for the Acid-Base Determinations in Nitriles

Determination of Trace Amounts of Hydrofluoric Acid in Non-Aqueous Solutions by the Coulometric Titration Method

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