scholarly journals Kinetics of the Oxidation of Hydrogen Sulfide by Atmospheric Oxygen in an Aqueous Medium

2021 ◽  
Vol 4 (3) ◽  
Author(s):  
Deepak Singh Rathore ◽  
Vimlesh Kumar Meena ◽  
Chandra Pal Singh Chandel ◽  
Krishna Swarup Gupta
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Rate ◽  
Dissociation Constants ◽  
Atmospheric Oxygen ◽  
Total Concentration ◽  
Order Rate Constant ◽  
Order Conditions ◽  
Rate Law ◽  
Oxidation Of Hydrogen ◽  
Kinetics Of

Hydrogen sulfide is an important acid rain precursor and this led us to investigate the kinetics of its oxidation in aqueous phase by atmospheric oxygen. The kinetics was followed by measuring the depletion of oxygen in a reactor. The reaction was studied under pseudo order conditions with [H2S] in excess. The kinetics followed the rate law: -d[O2]/dt = k[S][O2]t (A) Where [S] represents the total concentration of hydrogen sulfide, [O2]t is the concentration of oxygen at time t and k is the second order rate constant. The equilibria (B - C) govern the dissolution of H2S; the sulfide ion in water forms different species: H2S K1 HS- + H+ (B) HS- K2 S2- + H+ (C) Where K1 and K2 are first and second dissociation constants of H2S. Although, H2S is present as undissociated H2S, HS- and S2- ions, nature of [H+ ] dependence of reaction rate required only HS- to be reactive and dominant. The rate law (A) on including [H+ ] dependence became Equation (D). -d[O2]/dt = k1K1[H+ ][S][O2]t / ([H+ ] 2 + K1[H+ ] + K1K2) (D) Our results indicate anthropogenic VOCs such as acetanilide, benzene, ethanol, aniline, toluene, benzamide, o-xylene, m-xylene, p-xylene and anisole to have no significant effect on the reaction rate and any observed small effect is within the uncertainty of the rate measurements.

Kinetics of the self-fouling oxidation of hydrogen sulfide on activated carbon

AIChE Journal ◽  
1984 ◽  
Vol 30 (6) ◽  
pp. 1021-1025 ◽  
Author(s):  
Pan Zhenglu ◽  
Hung-Shan Weng ◽  
Feng Han-Yu ◽  
J. M. Smith
Keyword(s):  
Hydrogen Sulfide ◽  
Activated Carbon ◽  
The Self ◽  
Oxidation Of Hydrogen ◽  
Kinetics Of

Kinetics and mechanism of dehydrochlorination of N-aryl-C-ethoxycarbonylformohydrazidoyl chlorides

1986 ◽  
Vol 64 (5) ◽  
pp. 871-875 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Hassan A. Albar
Keyword(s):  
Rate Constants ◽  
Water Solution ◽  
Chloride Ion ◽  
Order Conditions ◽  
Rate Law ◽  
First Order ◽  
Rate Determining Step ◽  
Pseudo First Order ◽  
Reaction Constants ◽  
Kinetics Of

The kinetics of triethylamine (TEA) catalyzed deydrochlorination of a series of N-aryl-C-ethoxycarbonylformohydrazidoyl chlorides 1a–m have been studied under pseudo-first-order conditions in 4:1 (v/v) dioxane–water solution at 30 °C. For all compounds studied, the kinetics followed the rate law: kobs = k2 (TEA). The values of the overall second-order rate constants for the studied compounds were correlated by the equation: log k2 = 0.533σ−-0.218. The results are compatible with a mechanism involving a fast reversible deprotonation step leading to the anion of 1, followed by rate-determining step involving the loss of the chloride ion from the anion. The reaction constants of these two steps were estimated to be 0.845 and −0.312, respectively.

Kinetics and mechanism of the oxidation of proline by periodate

1989 ◽  
Vol 67 (4) ◽  
pp. 634-638 ◽  
Author(s):  
Rosa Pascual ◽  
Miguel A. Herraez ◽  
Emilio Calle.
Keyword(s):  
Amino Acid ◽  
Rate Constants ◽  
Reaction Rate ◽  
Ph Dependence ◽  
Kinetics And Mechanism ◽  
Appreciable Amount ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of proline by periodate has been studied at pH 1.40–8.83 and 30.0 °C. The reaction rate is first order in both periodate and amino acid, and the overall reaction follows second-order kinetics. There was no evidence for the formation of an appreciable amount of intermediate. The reaction rate is highest at pH 4–7 and the oxidation is catalysed by [Formula: see text] ions. The pH dependence of the reaction rate can be explained in terms of reaction of periodate monoanion and the protonated and dipolar forms of the amino acid. The mechanism proposed and the derived rate law are consistent with the observed kinetics. The rate constants obtained from the derived rate law are in agreement with the observed rate constants, thus justifying the rate law and the proposed mechanistic scheme. Keywords: oxidation of proline, oxidation by periodate.

scholarly journals The kinetics and mechanism of the ligand substitution reaction of aquapentacyanoruthenate(II) with d-penicillamine in aqueous medium

2020 ◽  
pp. 174751982096101
Author(s):  
Rupal Yadav ◽  
Radhey Mohan Naik
Keyword(s):  
Aqueous Medium ◽  
Reaction Rate ◽  
Electronic Effect ◽  
Ligand Substitution ◽  
Order Conditions ◽  
Reaction Parameters ◽  
First Order ◽  
Coloured Complex ◽  
Kinetics Of ◽  
Ligand Substitution Reaction

The kinetics of the formation of the light orange–coloured complex [Ru(CN)5D-PA]3− are studied spectrophotometrically through substitution of a coordinated H2O molecule in aquapentacyanoruthenate(II) [Ru(CN)5OH2]3− by interaction with D-penicillamine [D-PA] in aqueous medium at 490 nm (λmax of [Ru(CN)5D-PA]3−). The reaction is monitored under pseudo-first-order conditions, taking [D-PA] in excess over [Ru(CN)5OH23−]. The effects of various reaction parameters on the rate of the reaction are investigated. Experimental observations reveal that the variation in [D-PA] obeyed the first-order rate law while it is found to be invariant with [Ru(CN)5OH23−] in the whole experimental range. With ionic strength variation, as the reaction advances a decrease in the reaction rate is noticed. The product stoichiometry is assigned as 1:1. The ease of substitution at an H2O molecule in [Ru(CN)5OH23−] is considered on the basis of the electronic effect generated through interactions of the M–OH2 bond. A provisional mechanism based on the calculated results is proposed based on the slowest step of the reaction.

Direct oxidation of hydrogen sulfide over vanadium catalysts: I. Kinetics of the reaction

2015 ◽  
Vol 56 (1) ◽  
pp. 106-114 ◽  
Author(s):  
P. N. Kalinkin ◽  
O. N. Kovalenko ◽  
V. M. Khanaev ◽  
E. S. Borisova
Keyword(s):  
Hydrogen Sulfide ◽  
Direct Oxidation ◽  
Vanadium Catalysts ◽  
Oxidation Of Hydrogen ◽  
Kinetics Of

The mechanism of the oxidative deamination and decarboxylation of serine and threonine by periodate in acid medium

1985 ◽  
Vol 63 (9) ◽  
pp. 2349-2353 ◽  
Author(s):  
Rosa Pascual ◽  
Miguel A. Herráez
Keyword(s):  
Amino Acid ◽  
Acid Medium ◽  
Rate Constants ◽  
Reaction Rate ◽  
Oxidative Deamination ◽  
Experimental Conditions ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of serine and threonine by periodate have been investigated in acid medium at 10 °C. The reaction rate is first order in both periodate and amino acid, and the overall reaction follows second-order kinetics. The rates decrease with increase in [H+]. A catalytic effect of the buffers was not observed in the oxidation process. An analysis of the dependence of the rate on [H+] reveals that the reactive species under the experimental conditions are periodate monoanion and dianion and the dipolar form of the amino acid. The mechanism proposed and the derived rate law are consistent with the observed kinetics. The rate constants predicted using the derived rate law are in agreement with the observed rate constants, thus justifying this rate law and hence the proposed mechanistic scheme.

scholarly journals Soluble fibrin preparations inhibit the reaction of plasmin with α2-macroglobulin. Comparison with α2-antiplasmin and leupeptin

1991 ◽  
Vol 275 (1) ◽  
pp. 53-59 ◽  
Author(s):  
P K Anonick ◽  
S L Gonias
Keyword(s):  
Mixed Type ◽  
Dissociation Constants ◽  
Proteinase Inhibitors ◽  
Covalent Binding ◽  
Order Rate Constant ◽  
Chromogenic Substrate ◽  
Maximum Change ◽  
Α2 Macroglobulin ◽  
Small Change ◽  
Kinetics Of

The kinetics of plasmin inhibition by alpha 2-antiplasmin (alpha 2AP), alpha 2-macroglobulin (alpha 2M) and leupeptin were studied in the presence of fibrin monomer (Fn) and CNBr fragments of fibrinogen (Fg-CNBr). Active plasmin was detected in continuous and discontinuous assays using the chromogenic substrate D-Val-L-Leu-L-Lys p-nitroanilide hydrochloride (S-2251). The two ‘fibrin-like’ preparations functioned as hyperbolic mixed-type inhibitors of S-2251 hydrolysis. The dissociation constants (KF) for the binding of plasmin to Fn and Fg-CNBr were 22 nM and 17 nM respectively. Fn and Fg-CNBr inhibited the reaction of plasmin with alpha 2AP: the extent of inhibition depended on the fibrin concentration. In the presence of 800 nM-Fn or 800 nM-Fg-CNBr, the experimental second-order rate constant (K″app.) was decreased from 2.4 x 10(7) M-1.s-1 to 1.2 x 10(6) and 5.3 x 10(5) M-1.s-1 respectively. The effect of Fn and Fg-CNBr on the rate of plasmin inhibition by alpha 2M was even greater. The k″app. value was decreased from 4.0 x 10(5) M-1.s-1 to 8.0 x 10(2) and 1.3 x 10(3) M-1.s-1 in the presence of 800 nM-Fn and -Fg-CNBr respectively. By contrast, the fibrin preparations caused only a small change in the rate of plasmin inhibition by leupeptin. The maximum change in k″app. was 3-fold. All plasmin inhibition curves were linear, suggesting that free and fibrin-bound forms of plasmin remained in equilibrium during the course of reaction with proteinase inhibitors. Fn and Fg-CNBr had no effect on the reaction of miniplasmin with S-2251, alpha 2AP or alpha 2M. When 125I-plasmin was incubated with Fg-CNBr and then allowed to react with a premixed solution of alpha 2AP and alpha 2M, the Fg-CNBr did not significantly change the percentage of plasmin bound to alpha 2AP. These experiments demonstrate that the reaction of plasmin with alpha 2M is inhibited by the non-covalent binding of plasmin to fibrin. We propose that plasmin bound to the surface of a clot is protected from inhibition by alpha 2M as well as by alpha 2AP.

STUDYING THE KINETIC CHARACTERISTICS OF THE EXTRACTION OF ANTHOCYANINS FROM THE SQUEEZE OF KRASNOSTOP ZOLOTOVSKY

2020 ◽  
Author(s):  
M.A. Egyan ◽  
Keyword(s):  
Reaction Rate ◽  
Sugar Content ◽  
Extraction Process ◽  
Efficiency Coefficient ◽  
Kinetic Characteristics ◽  
Reaction Rate Constants ◽  
Solids Content ◽  
Kinetics Of ◽  
Process Speed

The article shows studies characterizing the quality of the squeeze: the mechanical composition of the squeeze is determined, the structural moisture of each component is determined, the sugar content in the formed process of sedimentation of the juice and its acidity are determined refractometrically. The kinetics of anthocyanins extraction was determined in two ways, the solids content in the extract was calculated, and the reaction rate constants of the extraction process and the efficiency coefficient of ultrasonic amplification of the extraction process speed were calculated.

Sign in / Sign up

Export Citation Format

Share Document