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Balaev, A. V.; Konshenko, E. V.; Спивак, С. И.; Ismagilov, F. R.; Джемилев, У. М.

doi:10.1023/a:1018812326380

Cited by 8 publications

(3 citation statements)

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“…The kinetics expressions for the homogeneous reactions ,,,, and were provided by the literature papers in which it was evidenced that these reactions follow first-order kinetics with respect to the H 2 S and O 2 concentrations. − …”

Section: Resultsmentioning

confidence: 99%

Oxidative Decomposition of H₂S over Alumina-Based Catalyst

Palma

Vaiano

Barba

et al. 2017

Ind. Eng. Chem. Res.

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An Al 2 O 3 -based catalyst was employed for the first time in the H 2 S oxidative decomposition in order to obtain simultaneous sulfur and hydrogen. The influence of the reaction temperature (in the range of 700−1100 °C) and the contact time (in the range of 17−33 ms) were investigated in terms of H 2 S conversion, H 2 yield, and SO 2 selectivity. Good catalytic performances were obtained at 1000 and 1100 °C with experimental values very close to those ones expected from the thermodynamic equilibrium. At a temperature of 1000 °C, the H 2 S conversion and H 2 yield were, respectively, about 50% and 17%; in particular, the SO 2 selectivity decreased of a magnitude order ∼0.5% with respect to the value observed in the homogeneous case (4%). A predictive mathematical model of H 2 S oxidative decomposition in the presence of a catalyst was developed through the identification of the main reactions occurring in the system. The results obtained from the kinetic investigations evidenced that the catalyst, in addition to the H 2 S decomposition reaction and the partial oxidation reaction to sulfur, was able also to promote the SO 2 conversion by the Claus reaction allowing it to avoid the presence of SO 2 at the reactor outlet.

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Section: Resultsmentioning

confidence: 99%

Oxidative Decomposition of H₂S over Alumina-Based Catalyst

Palma

Vaiano

Barba

et al. 2017

Ind. Eng. Chem. Res.

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“…Let us consider the mechanism of oxidation of hydrogen sulfide, taking into account oxygen and hydrogen sulfide adsorption [8].The chemical reac tion steps corresponding to this mechanism are the following:…”

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Index method of finding the independent routes of complex chemical reactions

Спивак

Ismagilova

2015

Dokl Phys Chem

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The route is a vector such that multiplication of its components by the corresponding step of the complex reaction mechanism with subsequent summation of the steps leads to the overall reaction equation that does not contain intermediates [1].The concept of "reaction route" has been intro duced in classical works by J. Horiuti [1] and M.I. Temkin [2] while developing a steady state reac tion theory. The route theory played an important role in construction of complex reaction kinetics theory [2]. The concept of "route" and its application have again attracted much attention in analysis of complex reactions of metal complex catalysis [3].When formulating the steady state reaction theory, Temkin [2] has suggested graphical interpretation of the complex reaction mechanism. This approach has been used for exclusion of intermediates and con struction of general kinetic equations for the cases when the stationarity equation set is linear with respect to the intermediates. This is the case when all elemen tary reactions are first order in intermediates. This "linearity" has considerably limited the application of the graph theory.A general description of chemical reaction schemes based on the graph theory has been intro duced by A.I. Volpert [4]. A specific feature here is the fact that all results can be used for arbitrary nonlinear reaction mechanisms.Real complex reaction mechanisms often involve a large number of substances and reactions between them [5]. Intermediates are formed and consumed in the course of reaction. At the initial instant of time, their concentrations are zero. The vertex index is the minimum order of the derivative with respect to con centration nonzero at the initial instant of time [4]. In other words, information on indices characterizes intermediates on the basis of the rate of their involve ment in the course of a complex reaction.Any of the sets found according to the algorithm described in [2] can be selected as the route basis. A question arises as to how to select a route basis each component of which is characterized by a part of a complex reaction mechanism that has physicochemi cal meaning. In this context, the rate of involvement of a substance in the reaction provides important specific information for selection of the basic route. This can be of importance for finding a unique solution of inverse problems of identification of complex reaction mechanisms [6].This brings up a question of constructing algo rithms for route selection based on information on vertex indices. The present study is aimed at creating an algorithm for independent route basis selection, using the information on vertex indices of the chemi cal reaction graph. The major result is one to one cor respondence between the graph cycles and index matrix. Thus, taking into account the theorem relating the route basis and the cycle basis [7] leads to the appropriate algorithm.Let us describe the algorithm of searching for inde pendent routes and deriving overall equations of com plex chemical reactions.(1) Construction...

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“…Many sulfur and nitrogen heterocycles possess a biocidal activity [4], and also fi nd application as selective complexing agents [5], extractants, and sorbents for noble metals [6].…”

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Cyclothiomethylation of heterochain α,ω-diamines with formaldehyde and H2S

et al. 2012

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Cyclothiomethylation was performed of heterochain (O, S-S, NH) α,ω-diamines with formaldehyde and H 2 S in aqueous medium at 20-60°С to obtain new α,ω-bis(1,3,5-dithiazinanes). The cyclocondensation of N-(3-aminopropyl)butane-1,4-diamine (spermidine), formaldehyde, and H 2 S proceeds effi ciently in the medium of BuOH-H 2 O at 0°С and leads to the formation of previously unknown O,S-containing macroheterocycle, 1,7-dioxa-3,5,9,11-tetrathiacyclododecane. A fungicidal activity was found in 5,5'-(3,6-dioxaoctane-1,8-diyl)bis-1,3,5-dithiazinane with respect to microscopic fungi affecting agriculture.One-pot methods of synthesis of heterocycles possessing practically useful properties based on the cyclothiomethylation of primary amines with formaldehyde and H 2 S [1-3] are interesting for the development of modern ecologically friendly chemical technology. Many sulfur and nitrogen heterocycles possess a biocidal activity [4], and also fi nd application as selective complexing agents [5], extractants, and sorbents for noble metals [6].It was shown previously [7] that the condensation of α,ω-diamines I with CH 2 O and H 2 S (Scheme 1) at 60°С occurred with the formation of α,ω-bis(1,3,5-dithiazinan-5-yl)-alkanes II, and at 0°С the direction of the reaction changed, and the main reaction products were 3-thia-1,5-diazabicyclo[n.3.1] alkanes III.In extension of the study of the α,ω-diamines cyclothiomethylation and also aiming at testing the possibility to perform the cyclothiomethylation of aliphatic heterochain α,ω-diamines containing C-O, S-S, and С-N bonds and to obtain new classes of heterocycles we investigated the reactions of α,ω-diamines with CH 2 O and H 2 S. The cyclothiomethylation of 3-oxapentane-1,5-diamine (IV) and 3,6-dioxaoctane-1,8-diamine (V) with formaldehyde and H 2 S in the mentioned conditions (molar ratio 1 : 3 : 2 or 1 : 6 : 4, H 2 O, 0-60°С, 3 h) proceeded at the terminal NH 2 groups of the initial diamine giving 5,5'-(3-oxapentane-1,5-diyl)bis-1,3,5-dithiazinane (VI) and 5,5'-(3,6-dioxaoctane-1,8-diyl) bis-1,3,5-dithiazinane (VII) (Scheme 2). All our attempts to direct the cyclothiomethylation of diamines IV and V to the route of the intramolecular condensation by reducing the reaction temperature to -30°С failed (Table 1).Dithiazinanes VI and VII were isolated from the reaction mixture by extraction with chloroform followed by Scheme 1. N N S n H 2 N NH 2 N N S S S S n n 60 o C 0 o C II III I CH 2 O _ H 2 S CH 2 O _ H 2 S n = 1 _ 8.

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Cited by 8 publications

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Oxidative Decomposition of H₂S over Alumina-Based Catalyst

Oxidative Decomposition of H₂S over Alumina-Based Catalyst

Index method of finding the independent routes of complex chemical reactions

Cyclothiomethylation of heterochain α,ω-diamines with formaldehyde and H2S

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Untitled

Cited by 8 publications

References 1 publication

Oxidative Decomposition of H2S over Alumina-Based Catalyst

Oxidative Decomposition of H2S over Alumina-Based Catalyst

Index method of finding the independent routes of complex chemical reactions

Cyclothiomethylation of heterochain α,ω-diamines with formaldehyde and H2S

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Oxidative Decomposition of H₂S over Alumina-Based Catalyst

Oxidative Decomposition of H₂S over Alumina-Based Catalyst