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Gupta, K. C.; Bhargava, Pinky; Manoj, Sreedharan V.

doi:10.1023/a:1007195721986

Cited by 5 publications

(7 citation statements)

References 17 publications

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“…and its rearranged form Eq. , which are same as reported previously

\begin{matrix} true \\ right k_{obs} = k_{0} / ({}, 1 + B ([], Inh)) \end{matrix}

\begin{matrix} true \\ right 1 / k_{obs} = 1 / k_{0} + B ([], Inh) / k_{0} \end{matrix}

…”

Section: Resultssupporting

confidence: 87%

“…The role of organics, which is mostly inhibitive, has been studied by several workers in case of Fe(II)/Fe(III) , Mn(II) , Ag(I) , Pd(II) , and transition metal oxide–catalyzed sulfur(IV) autoxidation. Because of addition of metal catalysts from outside, these results do not mimic the environmental aqueous systems.…”

Section: Introductionmentioning

confidence: 99%

“…SO 3 − , SO 4 − , and SO 5 − as intermediates as discussed later. The autoxidation of sulfur(IV) is strongly inhibited by organics due to scavenging of SO 4 − radicals (1) .…”

Section: Introductionmentioning

confidence: 99%

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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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“…and its rearranged form Eq. , which are same as reported previously

\begin{matrix} true \\ right k_{obs} = k_{0} / ({}, 1 + B ([], Inh)) \end{matrix}

\begin{matrix} true \\ right 1 / k_{obs} = 1 / k_{0} + B ([], Inh) / k_{0} \end{matrix}

…”

Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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 experimental procedure was exactly the same as described earlier [19][20][21][22][23] and is briefly given here. All chemicals used were of reagent grade and their solutions were prepared in double distilled water.…”

Section: Methodsmentioning

confidence: 99%

“…The kinetics was followed by withdrawing the aliquot samples periodically and titrating the unreacted S(IV) iodometrically in slightly acidic medium as described earlier [19][20][21][22][23].…”

Section: Methodsmentioning

confidence: 99%

Kinetics of iron(III)-catalyzed autoxidation of sulfur(IV) in acetate buffered medium

Manoj

Mudgal

Gupta

2007

Transition Met Chem

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The kinetics of the environmentally important oxidation of sulfur(IV) by oxygen in acetate buffered medium in the presence of Fe(III) and the pH range 5.27-5.70 has been studied. The results were in agreement with the rate law:The role of iron(III) appears to be that of production of SO 3 -radicals in Fe(III)SO 3 2-complex by an internal 1-equivalent redox reaction. Subsequently, a radical mechanism involving oxysulfur radicals, viz., SO 3 -, SO 4 -, and SO 5 -operates. Addition of ethanol leads to the introduction of an induction period and decrease in reaction rate, most likely due to scavenging of SO 4 -radicals. The value of apparent energy of activation is 45.4 kJ mol -1 .

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The influence of hydroxyl volatile organic compounds on the oxidation of aqueous sulfur dioxide by oxygen

Dhayal

Chandel

Gupta

2014

Environ Sci Pollut Res

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Although the effect of volatile organic compounds (VOCs) on the oxidation of dissolved sulfur dioxide by oxygen has been the subject of many investigations, this is the first study which examines the effect of a large number of precisely 16 hydroxy compounds. The kinetics both in the absence and the presence of VOCs was defined by rate laws (A and B): -d[S(IV)]dt = R₀ = k₀[S(IV)] (A) -d[S(IV)]dt = R(i) = k(i)[S(IV)] (B) where R₀ and k₀ are the initial rate and first-order rate constant, respectively, in the absence of VOCs, R(i), and k(i) are the initial rate and the first-order rate constant, respectively, in the presence of VOCs, and [S(IV)] is the concentration of dissolved sulfur dioxide, sulfur(IV). The nature of the dependence of k(i) on the concentration of inhibitor, [Inh], was defined by Eq. (C). [k(i) = k₀/(1 + B[Inh]) (C) where B is an empirical inhibition parameter. The values of B have been determined from the plots of 1/k(i) versus [Inh]. Among aliphatic and aromatic hydroxy compounds studied, t-butyl alcohol and pinacol were without any inhibition effect due to the absence of secondary or tertiary hydrogen. The values of inhibition parameter, B, were related to k(inh), the rate constant for the reaction of SO₄(-) radical with the inhibitor, by Eq. (D). B = (9 ± 2) x 10⁻⁴ x k(inh) (D) Equation (D) may be used to calculate the values of either of B or k(inh) provided that the other is known. The extent of inhibition depends on the value of the composite term, B[Inh]. However, in accordance with Eq. (C), the extent of inhibition would be sizeable and measurable when B[Inh] > 0.1 and oxidation of S(IV) would be almost completely stopped when B[Inh] ≥ 10. B[Inh] value can be used as a guide whether the reaction step: SO4 (-) + organics → SO₄(2-) + non-chain products: should be included in the multiphase models or not.

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Untitled

Cited by 5 publications

References 17 publications

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

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

Kinetics of iron(III)-catalyzed autoxidation of sulfur(IV) in acetate buffered medium

The influence of hydroxyl volatile organic compounds on the oxidation of aqueous sulfur dioxide by oxygen

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