Reactions of thiyl radicals with phenothiazines and other antioxidants in aqueous solutions. A pulse radiolysis study

1990 ◽  
Vol 68 (8) ◽  
pp. 1376-1382 ◽  
Author(s):  
Manohar Lal ◽  
H. S. Mahal
Keyword(s):  
Molecular Weight ◽  
Ascorbic Acid ◽  
Aqueous Solutions ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Reaction Rate ◽  
Mercaptopropionic Acid ◽  
Molecular Weights ◽  
Reaction Rate Constants ◽  
Thiyl Radicals

Reaction rate constants of thiyl radicals with phenothiazines, promethazine (PMZ), chlorpromazine (CPZ), prochlorperazine (PPZ), trimeperazine tarterate (TPZ), and other antioxidants, e.g., ascorbic acid and 2,2-azinobis(3-ethyl benzthiazoline-6 sulphonate) (ABTS) have been estimated using pulse radiolysis technique. In general they are quite high (108–109 M−1 s−1). The k values for cysteine, cysteamine, mercaptoethanol, and mercaptopropionic acid with similar structures and molecular weights are more or less similar for PMZ, CPZ, and PPZ.Rate constants are lower in value for [Formula: see text] radicals of phenothiazines showing that they are dependent upon the structure and the molecular weight of the compound.Rate constants are the same whether the thiyl radicals are generated from thiols or their corresponding disulphides. The k values for chlorine-containing phenothiazines, chlorpromazine, and prochlorperazine are higher than those of promothazine Keywords: pulse radiolysis, thiyl radicals, phenothiazines, ABTS, ascorbic acid.

Isotope effects in solution: contrasts between muonium and hydrogen in reactions with acetone

1990 ◽  
Vol 68 (10) ◽  
pp. 1719-1724 ◽  
Author(s):  
David C. Walker
Keyword(s):  
Free Radicals ◽  
Physical Properties ◽  
Rate Constants ◽  
Nuclear Physics ◽  
Reaction Rate ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Reaction Rate Constants ◽  
Thiyl Radicals ◽  
Kinetic Isotope

Munonium atoms are hydrogen isotopes with positive muons rather than protons, deuterons, or tritons as nuclei. Thus, they have one ninth the mass of 1H, and microsecond lifetimes. By using nuclear physics counting techniques, muonium can be studied in a wide variety of media and its chemical and physical properties used to appraise hydrogen. Results are described for the interaction of muonium with acetone, showing two types of kinetic isotope effects, formation of free radicals, evidence for intermolecular "muonium bonding", and micelle-induced enhancements of reaction rate constants. Keywords: isotope effects, muonium atoms, muonium bonding, thiyl radicals, micelles.

scholarly journals Kinetic Study on Acrylic Acid Polymerisations in Isopropanol

2021 ◽  
Vol 11 (20) ◽  
pp. 9719
Author(s):  
Kai C. Betz ◽  
Anna Westhues ◽  
Werner Pauer
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Acrylic Acid ◽  
Rate Constants ◽  
Reaction Rate ◽  
Monomer Concentration ◽  
Similar Reaction ◽  
Reaction Conditions ◽  
Reaction Rate Constants ◽  
Linear Correlations

The radical polymerisation of acrylic acid is largely concentration dependent and affected by the type of the surrounding solvent. This work investigates reaction rate constants, the activation energy, heat flux and the molecular weight in the industrially relevant synthesis of low molecular mass acrylic acid polymers in 2‑propanol. The polymerisations were carried out isothermally in an RC1e calorimeter with inline Raman spectroscopy for monomer concentration monitoring. For a non-neutralised acrylic acid in isopropanol (150 g/L), a monomer reaction order of 1.73 ± 0.15, an activation energy of 58.6 ± 0.8 kJ/mol (0.5 mol% AIBN) and 88.5 ± 1.5 kJ/mol (1.0 mol% AIBN), and a reaction enthalpy of 66.4 ± 4.8 kJ/mol could be shown. This data is in accordance with the literature values for acrylic acid polymerisation in water. In addition, linear correlations between the respective reaction parameters and the molecular weight for customised polymer synthesis in the range from 1.2 to 1.7 × 104 g/mol could be established. In comparison with aqueous acrylic acid polymerisation, it was found that the reaction rate constants in isopropanol were slower by a factor of approximately 10 under similar reaction conditions.

scholarly journals Aquation reaction of iminodiacetate complex of oxidovanadium(IV) with 2,2’-bipyridine induced by Fe(III) ions: Kinetic studies

2019 ◽  
Vol 44 (4) ◽  
pp. 300-306
Author(s):  
Joanna Drzeżdżon ◽  
Agnieszka Piotrowska-Kirschling ◽  
Lech Chmurzyński ◽  
Dagmara Jacewicz
Keyword(s):  
Aqueous Solutions ◽  
Computer Program ◽  
Rate Constants ◽  
Reaction Rate ◽  
Kinetic Studies ◽  
Reaction Rate Constants ◽  
Different Temperatures ◽  
Kinetics Of

The kinetics of the aquation reaction of the [VO(ida)(bipy)]·2H2O (VO(ida)(bipy)) complex (where ida = iminodiacetate anion and bipy = 2,2’-bipyridine) promoted by [Fe(H2O)6]3+ ions were investigated in aqueous solutions. Spectrophotometric studies were carried out at different temperatures in the range of 293.15–313.15 K. The concentration of the [Fe(H2O)6]3+ (Fe3+) ions was kept within the range of 2 × 10–4 to 8 × 10–4 mol L–1, and the concentration of VO(ida)(bipy) was 1 × 10–3 mol L–1. The values of the observable reaction rate constants were calculated based on the Glint computer program. Furthermore, the mechanism for the aquation of VO(ida)(bipy), induced by Fe(III) ions, has been proposed.

scholarly journals Studies on the Thiophene Analogues of Malachite Green. I. Protolytic Equilibria and Reaction Rate Constants of Thiophene Green in Aqueous Solutions.

1962 ◽  
Vol 16 ◽  
pp. 1837-1848 ◽  
Author(s):  
Rune Cigén ◽  
Gösta Bengtsson ◽  
Svend Erik Rasmussen ◽  
A. Block-Bolten ◽  
J. M. Toguri ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Malachite Green ◽  
Rate Constants ◽  
Reaction Rate ◽  
Protolytic Equilibria ◽  
Reaction Rate Constants
Sign in / Sign up

Export Citation Format

Share Document