Polarographic reduction of α-(4-ethylbenzoyl)-α,β-dibromopropionic acid on mercury dropping electrode

1979 ◽  
Vol 44 (4) ◽  
pp. 1318-1323
Author(s):  
Miloslava Počtová
Keyword(s):  
Electrochemical Reduction ◽  
Carbonyl Group ◽  
Polarographic Reduction ◽  
Polarographic Wave ◽  
Intermediate Products ◽  
Active Intermediate

A mechanism of the electrochemical reduction of β-(4-ethylbenzoyl)-α,β-dibromopropionic acid is suggested based on the results of classical polarography and polarography with Kalousek's switch and on the identification of the polarographically active intermediate products. The substance converts to β-4-ethylbenzoylacrylic acid on the electrochemical elimination of the bromine atoms, and the latter acid is reduced further to β-4-ethylbenzoylpropionic acid. The most negative polarographic wave corresponds to the reduction of the carbonyl group in the benzoyl part of the last acid.

Electrochemical Reduction of Aromatic Ketones in N,N-Dimethylformamide Containing Benzoic Acid. Effect of the Basicity of the Carbonyl Group

1988 ◽  
Vol 41 (12) ◽  
pp. 1963 ◽  
Author(s):  
B Kwiatek ◽  
MK Kalinowski
Keyword(s):  
Benzoic Acid ◽  
Electrochemical Reduction ◽  
Carbonyl Group ◽  
Carbonyl Compound ◽  
Double Layer ◽  
Linear Correlation ◽  
Acidity Constant ◽  
Polarographic Reduction ◽  
Aromatic Ketones ◽  
Acid Effect

The effect of benzoic acid on the polarographic reduction of a series of aromatic ketones in N,N- dimethylformamide has been investigated. In the presence of this acid a new cathodic wave (pre-wave) appears at more positive potentials than the original (orig.) wave of the reactant. A linear correlation has been found between ΔE½ and the pKBH+ values, where ΔE½ = E½ pre.wave -E½orig.wave and pKBH+ stands for the negative logarithm of the acidity constant of the protonated ketone . It is concluded that the pre-wave is associated with the cathodic reduction of a hydrogen-bonded adduct of 1 : 1 type formed between the carbonyl compound and the acid in the double layer. The effect of the double layer on the basicity of the ketones is discussed.

The Polarographic Reduction of Diazoacetone

1974 ◽  
Vol 29 (7-8) ◽  
pp. 489-491 ◽  
Author(s):  
Giulio Paliani ◽  
Salvatore Sorriso ◽  
Sandro Maria Murgia
Keyword(s):  
Acid Solution ◽  
Electrochemical Reduction ◽  
Ethanol Solution ◽  
Alkaline Media ◽  
Polarographic Reduction

The electrochemical reduction of diazoacetone in 10 % water: ethanol solution, between pH = 3 and pH = 9, has been studied. Two waves have been observed in acid solution: the first is attributed to the reduction of diazoacetone to aminoacetone and the second one to the reduction of 2,5-dimethyldihydropyrazine (formed by dimerization of the aminoacetone) to 2,5-dimethylpiperazine. In neutral and alkaline media the first wave splits into two waves corresponding to a reduction of diazoacetone to hydrazone and aminoacetone.

Intermediate products of electrochemical reduction of nitrofurans in aprotic media

1983 ◽  
Vol 28 (4) ◽  
pp. 495-500 ◽  
Author(s):  
J. Stradins ◽  
R. Gavars ◽  
L. Baumane
Keyword(s):  
Electrochemical Reduction ◽  
Intermediate Products

Polarographic reduction of 3-O-methylpyridoxal 5'-phosphate

1980 ◽  
Vol 45 (6) ◽  
pp. 1662-1668 ◽  
Author(s):  
Enrique López-Cantarero ◽  
Juan Llor ◽  
Manuel Cortijo
Keyword(s):  
Carbonyl Group ◽  
Aldehyde Group ◽  
The Other ◽  
Polarographic Reduction ◽  
Acid Base ◽  
Proton Transfers

The polarographic reduction of 3-O-methyl-pyroxidal 5'-phosphate has been studied as a function of pH. The reduction of the aldehyde group by a two electrons process occurs in all conditions studied. The rate of interconversion between the free and hydrate forms of the carbonyl group has been computed. This reaction is acid-base catalyzed. The other reactions (proton transfers) that precede the electrodic reaction are very much faster. The results are compared with those previously obtained for pyridoxal 5'-phosphate.

Salzbildung der Diazoaminobenzole (Triazene) im Zuge der Elektrolyse in aprotischem Lösungsmittel / Salt Formation during Electrolysis of Diazoaminobenzenes (Triazenes) in Aprotic Solvent

1972 ◽  
Vol 27 (10) ◽  
pp. 1166-1169 ◽  
Author(s):  
Ludwig Holleck ◽  
Gholamali Kazemifard
Keyword(s):  
Aprotic Solvent ◽  
Supporting Electrolyte ◽  
Limiting Current ◽  
Polarographic Reduction ◽  
Salt Formation ◽  
Polarographic Wave ◽  
Mercury Compounds ◽  
Current Region ◽  
Electron Reduction ◽  
Second Wave

In contrast to aqueous and methanolic solutions the polarographic reduction of diazoaminobenzenes (DAAB) in the aprotic solvent dimethylformamid occurs in two waves with the combined hight corresponding to a four electron reduction.The first wave results from the four electron reduction of the fraction (1/5) of the DAAB molecules which obtain the necessary protons from the remaining (4/5) DAAB molecules. The resulting DAAB anions are only reduced at the considerably more negative potentials of the second wave. Then the reduction occurs also in a four electron step and leads to the cleavage of the molecule. Potentiostatic electrolysis at the limiting current region of the first polarographic wave results in coloured solutions. The colour depends on the nature of the substituent. Salt formation was monitored spectrophotometrically and inferences pertaining to structure are drawn. The experimental results show that mercury compounds which might possibly be formed as intermediary species react immediately with the cations of the supporting electrolyte to form the corresponding DAAB salts.

scholarly journals The Electrochemical Mechanism of Preparing Mn from LiMn2O4 in Waste Batteries in Molten Salt

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1066
Author(s):  
Jinglong Liang ◽  
Rui Zhang ◽  
Hui Li ◽  
Le Wang ◽  
Zongying Cai ◽  
...  
Keyword(s):  
Molten Salt ◽  
Electrochemical Reduction ◽  
Deionized Water ◽  
Reduction Mechanism ◽  
Constant Voltage ◽  
Intermediate Products ◽  
Electrochemical Mechanism

The electrochemical reduction mechanism of Mn in LiMn2O4 in molten salt was studied. The results show that in the NaCl-CaCl2 molten salt, the process of reducing from Mn (IV) to manganese is: Mn (IV)→Mn (III)→Mn (II)→Mn. LiMn2O4 reacts with molten salt to form CaMn2O4 after being placed in molten salt for 1 h. The reaction of reducing CaMn2O4 to Mn is divided into two steps: Mn (III)→Mn (II)→Mn. The results of constant voltage deoxidation experiments under different conditions show that the intermediate products of LiMn2O4 reduction to Mn are CaMn2O4, MnO, and (MnO)x(CaO)(1−x). As the reaction progresses, x gradually decreases, and finally the Mn element is completely reduced under the conditions of 3 V for 9 h. The CaO in the product can be removed by washing the sample with deionized water at 0 °C.

Preparation, chemical and electrochemical reduction of pyrido[2,3-b]quinoxalines and pyrido[3,4-b]quinoxalines

1988 ◽  
Vol 66 (6) ◽  
pp. 1500-1505 ◽  
Author(s):  
Joseph Armand ◽  
Line Boulares ◽  
Christian Bellec ◽  
Jean Pinson
Keyword(s):  
Electrochemical Reduction ◽  
Catalytic Hydrogenation ◽  
Polarographic Wave ◽  
Dihydro Derivative

The reaction of 2,3-diaminopyridine with the dimeric 4,5-dimethylcyclohexa-3,5-dien-1,2-dione gives 7,8-dimethylpyrido[2,3-b]quinoxaline, 1, in good yields; in the same way 3,4-diaminopyridine gives the 7,8-dimethylpyrido[3,4-b]quinoxaline 2. The electrochemical reduction of 1 and 2 in hydroorganic medium gives the 5,10-dihydro compounds 6 and 7; 1 and 2 present a single 2e− polarographic wave, in contrast to phenazine which shows two monoelectronic waves. The catalytic hydrogenation of 1 and 2 gives 6 and 7 and does not involve the pyridinic ring as in the case of pyridopyrazines. AlLiH4 does not react with 2 but 1 is reduced into the 1,2-dihydro derivative 8. The behavior of 1 and 2 is thus different from that of pyridopyrazines (which give the 1,2,3,4-tetrahydro compounds) and from that of phenazine (which gives the 5,10-dihydro derivative). NaBH4 reacts with pyridopyrazines to give, according to the substituents, 1,2- or 5,6-dihydro or 1,2,3,4-tetrahydro derivatives. Methylmagnesium chloride reacts with 1 to give a mixture of 2-methyl-1,2-dihydro, 2,6,7-trimethyl, and 4,6,7-trimethylpyrido[2,3-b]quinoxaline. In the case of 2, 4,6,7-trimethylpyrido[3,4-b]quinoxaline is obtained.

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