Microcalorimetric investigation on the kinetics of the oxidation of ascorbic acid with hydrogen peroxide

Catalytic oxidation of salicylic acid by molecular oxygen, induced by the oxidation of ascorbic acid, leads to the formation of a mixture of isomers of dihydroxybenzoic acid. The reaction is catalyzed by a series of metal chelates, especially Fe(II) and Co(II), the most marked catalytic effect having been found in the case of tetrasulphophthalocyanine of cobalt (CoTSP). The kinetics of the oxidation of ascorbic acid in the presence of salicylic acid was followed, and the formation of hydrogen peroxide as reaction intermediate was proved.

Download Full-text

Kinetics of the Complex Reaction of Ascorbic Acid with Hydrogen Peroxide Catalyzed by CTAB

Acta Physico-Chimica Sinica ◽

10.3866/pku.whxb20050311 ◽

2005 ◽

Vol 21 (03) ◽

pp. 283-286

Author(s):

MENG Xiang-Guang ◽

◽

LI Jian-Mei ◽

PANG Qin-Hui ◽

ZHU Jie ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Ascorbic Acid ◽

Complex Reaction ◽

Kinetics Of

Download Full-text

The kinetics of photosensitized decomposition of ascorbic acid and the determination of hydrogen peroxide as a reaction product

Food Chemistry ◽

10.1016/s0308-8146(96)00167-7 ◽

1997 ◽

Vol 59 (1) ◽

pp. 81-86 ◽

Cited By ~ 10

Author(s):

Ülfet Şansal ◽

Güler Somer

Keyword(s):

Hydrogen Peroxide ◽

Ascorbic Acid ◽

Kinetics Of

Download Full-text

Kinetics of oxidation of hydrogen peroxide and ascorbic acid by a tribridged manganese(IV,IV) dimer in feebly acidic media

Canadian Journal of Chemistry ◽

10.1139/v99-062 ◽

1999 ◽

Vol 77 (4) ◽

pp. 451-458 ◽

Cited By ~ 3

Author(s):

Anup Kumar Bhattacharya ◽

Anath Bondhu Mondal ◽

Anadi C Dash ◽

G S Brahma ◽

Rupendranath Banerjee

Keyword(s):

Hydrogen Peroxide ◽

Ascorbic Acid ◽

Dehydroascorbic Acid ◽

Kinetics Of Oxidation ◽

First Order ◽

Kinetic Activity ◽

First Order Kinetics ◽

Oxidation Of Hydrogen ◽

Kinetics Of ◽

Complex Ion

In weakly acidic, aqueous buffer (MeCO2-+ bipy), the complex ion [Mn2IV(μ-O)2(μ-MeCO2)(bipy)2(H2O)2]3+, 1 (bipy = 2,2prime-bipyridine), coexists in rapid equilibrium with its hydrolytic derivatives, [Mn2IV(μ-O)2(bipy)2(H2O)4]4+, 2, and [Mn2IV(μ-O)2(μ-MeCO2)(bipy)(H2O)4]3+, 3. The solution quantitatively oxidizes hydrogen peroxide to oxygen and ascorbic acid to dehydroascorbic acid, itself being reduced to MnII. In the presence of excess reductant, the reactions follow simple first-order kinetics with no evidence for the accumulation of a significant amount of any intermediate manganese complex. The ascorbate anion shows overwhelming kinetic dominance over ascorbic acid, but no evidence is available for deprotonation of hydrogen peroxide. The preferred intimate mechanism for hydrogen peroxide is inner sphere but that for ascorbic acid is uncertain. For both reductants, increased extent of aquation leads to increased kinetic activity in the order: 1 < 2 < 3.Key words: kinetics, manganese, ascorbic acid, hydrogen peroxide, 2,2prime-bipyridine.

Download Full-text

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

Communications in Physics ◽

10.15625/0868-3166/29/3/13763 ◽

2019 ◽

Vol 29 (3) ◽

Author(s):

Mai Ngọc Tuan Anh

Keyword(s):

Hydrogen Peroxide ◽

Silver Nanoparticles ◽

Ascorbic Acid ◽

Silver Nitrate ◽

Sodium Borohydride ◽

Trisodium Citrate ◽

Synthesis And Characterization ◽

Silver Nanoplates ◽

Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

Download Full-text

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19910923 ◽

1991 ◽

Vol 56 (4) ◽

pp. 923-932

Author(s):

Jana Stejskalová ◽

Pavel Stopka ◽

Zdeněk Pavlíček

Keyword(s):

Hydrogen Peroxide ◽

Ascorbic Acid ◽

Amino Acid ◽

Peroxidase Activity ◽

Amino Acid Analysis ◽

Superoxide Radical ◽

Esr Spectra ◽

The Other ◽

Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

Download Full-text