A hydrogen-nitrogen gas coulometer

Page, John A.; Lingane, James J.

doi:10.1016/s0003-2670(00)89908-0

Cited by 37 publications

(15 citation statements)

References 2 publications

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“…Reduction was continued until the current fell to a low value and the quantity of electricity passed ( 1.8-1.9 Faraday mol-') was measured with a hydrazine coulometer. 22 The catholyte was then evaporated to a small volume under vacuum, water (100 nil) was added, and the product was extracted with ether. The extract was washed with water, dried Reduction o j 2-iodo-4'-methoxy-N-methy2benzanilzde ( la ; X = I).…”

Section: -Iodo-n2'6'-trinzethylbenzaniladementioning

confidence: 99%

Electrochemical reactions. Part 19. Intermolecular radical substitution during the reduction of 2-halogeno-N-methylbenzanilides

Grimshaw¹,

Haslett²,

Trocha-Grimshaw³

1977

J. Chem. Soc., Perkin Trans. 1

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The reduction of 2-halogeno-N-methylbenzanilides gives N-methyl-N-phenylcarbamoylphenyl radicals, which (i) react by substitution to yield phenanthridones and biphenyl-2-carboxamides or (ii) are reduced further to the Nmethyibenzanilide. Occurrence of the substitution process confirms the presence of phenyl radical intermediates. The maximum yield of intramolecular substitution products is limited by the proportion of syn-amide rotamer present a t equilibrium. When the halogen is chlorine, intramolecular trapping of the resulting phenyl radical is an efficient process and only the anti-amide rotamer forms the N-methylbenzanilide. When the halogen is bromine or iodine a significant proportion of the phenyl radical derived from the syn-amide rotamer is also converted by further reduction and protonation into the N-methylbenzanilide. Intramolecular radical substitution leads to both phenanthridones and biphenyl-2-carboxamides when the aniline component of the N-methylbenzanilide does not carry an ortho-substituent. Only the biphenyl-2-carboxamide is formed when an ortho-substituent is present on the aniline component. These results are compared with the results from related radical reactions. THE overall reaction observed during electrochemicalreduction of aryl halides is replacement of the halogenosubstituent by a hydrogen atom. For some halogenated derivatives of n i t r ~b e n z e n e , ~. ~ ben~ophenone,~ fluore n ~n e , * . ~ and benzonitrile it has been possible to dernonstrate the stages in this reduction in aprotic solvents: (i) formation of a x-radical-anion which is in redox equilibrium with the substrate, (ii) decomposition of this radical-anion in a reaction with measurable first-order kinetics to generate a a-radical and a halide ion, and (iii) either abstraction of a hydrogen atom from the solvent by the o-radical, or reduction of this 0-radical to a carbanion which is protonated by traces of water remaining in the solvent. It is not, however, possible to demonstrate the individual steps in the reduction of the vast majority of aryl halides by purely electrochemical methods. It occurred to us that if the aradical is intermediate in the reduction of most aryl halides, as is presumed, then by choosing a substrate with a suitably placed phenyl substituent the a-radical intermediate will be made to undergo an intramolecular cyclisation reaction in competition with other processes which may occur. A preliminary communication of our first experiments on the reductive cyclisation of 2-halogeno-N-methylbenzanilides has appeared. We

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Section: -Iodo-n2'6'-trinzethylbenzaniladementioning

confidence: 99%

Electrochemical reactions. Part 19. Intermolecular radical substitution during the reduction of 2-halogeno-N-methylbenzanilides

Grimshaw¹,

Haslett²,

Trocha-Grimshaw³

1977

J. Chem. Soc., Perkin Trans. 1

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“…A 5-ml capacity hydrogen-nitrogen coulometer similar to that described by Page and Lingane (13) was used in most of the present experiments. Figure 3.…”

Section: Coulometric Analysis Of 22-dinitroproponementioning

confidence: 99%

“…Fill the micro gas coulometer with 0.1M hydrazine sulfate and saturate the solution with gas by a preliminary electrolysis (13). Fill the micro gas coulometer with 0.1M hydrazine sulfate and saturate the solution with gas by a preliminary electrolysis (13).…”

Section: Assemble the Cell As Shown Inmentioning

confidence: 99%

A simple low-current potentiostat coulometric analysis

Stock¹

1968

J. Chem. Educ.

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“…By choosing a proper size buret for monitoring the volume of gases, the instrument was readily adapted to measuring diverse quantities of electricity down to about 10 coulombs [ 5 ]. Enhanced current efficiency was noted for the hydrogen–nitrogen coulometer [ 21 ] in which hydrazine sulfate was used as an electrolyte responsible for producing nitrogen gas instead of oxygen gas at the platinum anode. An electrolysis cell was used to measure the volume of O 2 (g) and monitor an acid-base titration [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of Using an Electrolysis Cell for Quantification of the Electrolytic Products of Water from Gravimetric Measurement

Melaku

Gebeyehu

Dabke

2018

Journal of Analytical Methods in Chemistry

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A gravimetric method for the quantitative assessment of the products of electrolysis of water is presented. In this approach, the electrolysis cell was directly powered by 9 V batteries. Prior to electrolysis, a known amount of potassium hydrogen phthalate (KHP) was added to the cathode compartment, and an excess amount of KHCO3 was added to the anode compartment electrolyte. During electrolysis, cathode and anode compartments produced OH−(aq) and H+(aq) ions, respectively. Electrolytically produced OH−(aq) neutralized the KHP, and the completion of this neutralization was detected by a visual indicator color change. Electrolytically produced H+(aq) reacted with HCO3 −(aq) liberating CO2(g) from the anode compartment. Concurrent liberation of H2(g) and O2(g) at the cathode and anode, respectively, resulted in a decrease in the mass of the cell. Mass of the electrolysis cell was monitored. Liberation of CO2(g) resulted in a pronounced effect of a decrease in mass. Experimentally determined decrease in mass (53.7 g/Faraday) agreed with that predicted from Faraday's laws of electrolysis (53.0 g/Faraday). The efficacy of the cell was tested to quantify the acid content in household vinegar samples. Accurate results were obtained for vinegar analysis with a precision better than 5% in most cases. The cell offers the advantages of coulometric method and additionally simplifies the circuitry by eliminating the use of a constant current power source or a coulometer.

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A hydrogen-nitrogen gas coulometer

Cited by 37 publications

References 2 publications

Electrochemical reactions. Part 19. Intermolecular radical substitution during the reduction of 2-halogeno-N-methylbenzanilides

Electrochemical reactions. Part 19. Intermolecular radical substitution during the reduction of 2-halogeno-N-methylbenzanilides

A simple low-current potentiostat coulometric analysis

Feasibility of Using an Electrolysis Cell for Quantification of the Electrolytic Products of Water from Gravimetric Measurement

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