Kinetics of copper(II)‐catalyzed oxidation of S(IV) by atmospheric oxygen in ammonia buffered solutions

Sharma, Anil Kumar; Singh, Anirudh; Mehta, R. K.; Sharma, Sudhanshu; Bansal, Seema; Gupta, K. C.

doi:10.1002/kin.20550

Cited by 15 publications

(14 citation statements)

References 64 publications

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“…S(IV), were studied by following the decrease in the concentration of S(IV). This procedure was the same as that described by Brodizinsky et al [42] and subsequently used by us [43][44][45][46]. The reactions were conducted in 0.15 L Erlenmeyer flasks open to air, to allow the passage of atmospheric oxygen.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of Atmospheric Aqueous Phase Autoxidation of Sulphur Dioxide by Volatile Organic Compounds: Mono-, di- and Tri-Substituted Benzenes and Benzoic Acids

Meena

Dhayal

Rathore

et al. 2017

Progress in Reaction Kinetics and Mechanism

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Like many other volatile organic compounds (VOCs), the methoxy derivatives of benzene and benzoic acid are found in the atmosphere and, therefore, looking to their possible intervention in aqueous phase atmospheric oxidation of the major acid rain precursor, SO2, by oxygen, the kinetics of SO2 [hereafter referred to as S(IV)] autoxidation have been studied in the presence of methoxybenzene (anisole) and disubstituted 1,2-dimethoxybenzene, 1,3-dimethoxybenzene and 1,4-dimethoxybenzene. The effects of benzoic acid and its 2,6-dimethoxy, 3,4-dimethoxy, 2,3,4-trimethoxy and 2,4,5-trimethoxy derivatives have also been examined, as have the influences of 4-hydroxybenzoic acid, benzanilide and o-sulfobenzimide. As the methoxy group is known to influence the reaction SO4–· + organics [Formula: see text] SO42– + non-chain products, to understand the degree of influence of the methoxy group on the inhibition of this reaction, this series of methoxy compounds was selected. The kinetics were first-order in S(IV). Most of the VOCs inhibited S(IV) autoxidation, except benzanilide and o-sulfobenzimide, in accordance with kobs = k0/(1 + B [Inh]), where kobs and k0 are the first-order rate constants in the presence and absence of VOCs respectively and B is the inhibition parameter. The most interesting feature of this work is that, despite the high kinh values, the B values are unexpectedly quite low and benzanilide and o-sulfobenzimide showed no effect. The B values appear to be independent of kinh, which is opposite to that found in the case of a series of hydroxyl compounds. It appears probable that additional steps involving peroxy intermediates are involved.

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Section: Methodsmentioning

confidence: 99%

Inhibition of Atmospheric Aqueous Phase Autoxidation of Sulphur Dioxide by Volatile Organic Compounds: Mono-, di- and Tri-Substituted Benzenes and Benzoic Acids

Meena

Dhayal

Rathore

et al. 2017

Progress in Reaction Kinetics and Mechanism

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“…As reported by Sharma 36 and Mudgal 37 a radical mechanism operates in those reactions in which the inhibition parameter lies the range 10 3 -10 4 . In this study the value of inhibitor parameter is found to be 2.46×10 3 , which lies in the same range.…”

Section: Effect Of Temperaturementioning

confidence: 73%

Co2O3 Catalyzed Oxidation of SO2 in Aqueous Solution Differing Effect of Benzamide in Alkaline Medium

2018

Chem Sci Trans

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We report that benzamide is a good inhibitor for SO 2 oxidation in the pH range 7.8-9.4 in the presence of Co 2 O 3. Based on the observed results the following rate law is given and a free radical mechanism has been proposed.-d[S(lV)]/dt = (k 1 +k 2 [Co 2 O 3 ]) [S(lV)]/1+B [benzamide]. Experiments were carried out at 30 ≤ T °C ≤ 40, 7.8 ≤ pH ≤ 9.4, 1×10-3 mol/dm 3 ≤ [S(lV)] ≤ 6 × 10-3 mol/dm 3 , 0.1 g/L ≤ [Co 2 O 3 ] ≤ 0.4g/L, 1×10-3 mol/dm 3 ≤ [benzamide] ≤ 5×10-3 mol/dm 3. Rate constants and the order of reaction were calculated and the reaction was found to be pseudo-first order in all cases. The effect of pH and temperature are also discussed. The value of apparent activation (E a) energy was determined to be 8.7 kJ mol-1. The activation of energy was calculated by Arrhenius equation. (k = A e-Ea/RT).

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“…The experimental procedure was same as described previously by Brodzinsky et al and subsequently used by us , and is briefly given here. The reactions were conducted in 0.15 L Erlenmeyer flasks, open to air, to allow the passage of atmospheric oxygen.…”

Section: Methodsmentioning

confidence: 99%

“…The kinetics was followed by withdrawing the aliquot samples periodically and titrating the unreacted sulfur(IV) iodometrically in slightly acidic medium using sodium thiosulfate as a titrant and starch as an indicator as described earlier . The reproducibility of the replicate measurements was generally ∼10%.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of Aquated Sulfur Dioxide Autoxidation by Aliphatic, Acyclic, Aromatic, and Heterocyclic Volatile Organic Compounds

Meena

Dhayal

Rathore

et al. 2017

Int J of Chemical Kinetics

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The oxidation of dissolved sulfur dioxide, sulfur(IV), by oxygen proceeds through the involvement of sulfoxy radicals among which sulfate radical anion is the main chain carrier. When organics are present, they inhibit the oxidation of sulfur(IV) via scavenging of SO4− radicals. In contrast to previous studies, which were limited mostly to aliphatic compounds, this paper presents the results of the effect of 13 new volatile organic compounds (VOCs) including aromatic and heterocyclic on uncatalyzed sulfur(IV) autoxidation at pH 8.2 and 25°C. In all cases, the kinetics was first order in the presence and absence of VOCs and experimental rate law was Eq. (1). trueright−d[normalSfalse( IV false)]/normaldt=k obs []normalSfalse( IV false)=ko[]normalSfalse( IV false)/{}1+Bfalse[ Inh false]where −d[S(IV)]/dt is the rate of sulfur(IV) disappearance, kobs is the first‐order rate constant in the presence of inhibitor, ko is the first‐order rate constant in the absence of inhibitor, [S(IV)] is concentration of sulfur(IV) at time, t, and B is an inhibition parameter. VOCs cause inhibition by scavenging sulfate radical anions, which propagate the autoxidation chain. An analysis of B (Eq. (1)) and kinh (Eq. (2)) values for 21 aliphatic, aromatic, acyclic, and heterocyclic organic compounds showed that these to be related by Eq. (3) for a subgroup and Eq. (4) for b subgroup. trueright SO 4−+ VOC 0.33em⟶k inh 0.33em SO 42−+ VOC a subgroup (benzamide, 2,2‐dimethyl‐1‐propanol, 1‐hexanol, methanol, ethanol, 1‐propanol, 2‐ propanol, 1‐butanol, 2‐butanol, ethylene glycol, rebaudioside A) truerightB=()0.87±0.21×10−30.16emk inh b subgroup (o‐toluic acid, m‐toluic acid, p‐toluic acid, 4‐hydroxybenzoic acid, 1‐heptanol, glycerol, sucralose, acesuifame K, glycine, 3‐pentanol) truerightB=()1.2±0.3×10−30.16emk inh

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Kinetics of copper(II)‐catalyzed oxidation of S(IV) by atmospheric oxygen in ammonia buffered solutions

Cited by 15 publications

References 64 publications

Inhibition of Atmospheric Aqueous Phase Autoxidation of Sulphur Dioxide by Volatile Organic Compounds: Mono-, di- and Tri-Substituted Benzenes and Benzoic Acids

Inhibition of Atmospheric Aqueous Phase Autoxidation of Sulphur Dioxide by Volatile Organic Compounds: Mono-, di- and Tri-Substituted Benzenes and Benzoic Acids

Co2O3 Catalyzed Oxidation of SO2 in Aqueous Solution Differing Effect of Benzamide in Alkaline Medium

Inhibition of Aquated Sulfur Dioxide Autoxidation by Aliphatic, Acyclic, Aromatic, and Heterocyclic Volatile Organic Compounds

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