The review addresses the main approaches to desulfurization of hydrocarbon products by adsorption methods. Examples of the use of various supports (metal-organic frameworks, various porous carbons, silica, and alumina) for the removal of acidic sulfur components from gas and liquid hydrocarbons are presented. Modification of the supports with transition metals, oxides, salts, and complex compounds to remove hydrogen sulfide and thiols from hydrocarbon raw materials is substantiated. The environmental friendliness and lower energy consumption for the use of silica gel modified with Zn(II), Co(II), Ni(II), and Cu(II) carboxylates to refine hydrocarbon fuel are demonstrated. A comparison of the theoretical calculations (DFT) with experimental results attests to good agreement between the data. The choice of the parameters for silica gel surface modification with metal carboxylates is discussed, including pore size of the support, time and power of the ultrasonic treatment for the support impregnation with solutions of complexes, optimal concentration of transition metal complexes, effect of the geometry of complexes on their adsorption and on the absorption of acidic sulfur components, and so on. According to quantum chemical calculations and experimental results, metal sulfides are formed as the final products of reactions of both hydrogen sulfide and thiols with metal carboxylates. Zinc pivalate is proposed as the most promising modifier for silica, which not only efficiently removes sulfur impurities, but also gives rise to nontoxic zinc sulfide supported on silica gel.

Theoretical and experimental methods were used to model the adsorption desulfurization process of hydrocarbon fuels with the pivalates Zn(II), Co(II), Ni(II) deposited on silica gel of various porosities via ultrasonic action. The proposed adsorbents make it possible to reduce the content of toxic sulfur components to 4 ppm.

The removal of acidic sulfur components (hydrogen sulfide, alkanethiols) with zinc (II), cobalt (II) and copper (II) acetates deposited on silica gel under the influence of ultrasound was investigated. The efficiency of adsorption desulfurization in relation to hydrogen sulfide and alkanethiols is shown by the example of model analogues of gasoline fractions. Cobalt acetate shows the greatest affinity for hydrogen sulfide (90%). The studied adsorbents showed the same adsorption activity (79-81%) to isopropylthiol. For the gasoline fraction (62-180 degrees C) cobalt (II) and zinc (II) acetates showed higher adsorption capacity compared to copper acetate (II). The degree of desulfurization, in the case of the use of cobalt (II) acetate, is 90%, which makes it possible to obtain fuel that meets regulatory requirements. The mechanism of retention of the acetates under consideration on the silica gel surface has been studied and quantum chemical calculations modeling the adsorption of zinc (II), cobalt (II) and copper (II) acetates on silica gel has been performed. The values of the adsorption energy of zinc (II), cobalt (II) and copper (II) acetates are quite close and equal to -99.2, -103.3 and -84.1 kJ/mol, respectively. The estimation of the energy of possible ways of transformations of sulfur-containing compounds in the process of adsorption desulfurization is given. The decomposition of hydrogen sulfide and alkanethiols, with the formation of metal sulfide, is more likely from an energy point of view. The values of Delta E for the reactions of cobalt (II) acetate with methanethiol, ethanethiol, propanethiol are equal to 65.3, 57.5, 58.4 kJ/mol, respectively. The difference between the formation energies of metal thiolates and metal sulfides is 15-20 kJ/mol. Silica gel modified with zinc (II) acetate, after the adsorption of sulfur impurities can be recommended, as a means for treating tracks and sports grounds, since the resulting zinc sulfide has an antifungal effect.

A method of synthesis of organic mono-, di-, and polysulfides based on electrochemical reactions of unsubstituted and alkyl–substituted cycloalkanes C5–C8 with di(n-butyl)disulfide (di(tert-butyl)disulfide) and hydrogen sulfide is developed. Three–component electrosynthesis is carried out in methylene chloride under atmospheric pressure, at the room temperature under the conditions of anodic H2S activation to a cation radical fragmented to a proton and a thiyl radical. The suggested approach with application of oxidative conversion initiation allows obtaining asymmetric mono-, disulfides and symmetric disulfides. The yield of biologically active organic sulfur derivatives depends on the electrosynthesis duration, structure of isomeric dibutyl sulfides, alicycle size and saturation degree.

Hydrogen sulfide and alkanethiols are toxic compounds containing in the production of wells in many oil and gas condensate fields. Because the policy of hydrocarbon processing enterprises aimed at the development of new fundamental research, processes and technologies in order to find rational use of raw materials, the conversion of hydrogen sulfide and alkanethiols into valuable compounds is one of the strategic goals of the oil and gas industry. The methods of "green" chemistry are perspective processes for converting hydrogen sulfide and alkantiols into valuable organic compounds, which allow working in environmentally friendly conditions with minimal energy and resource costs. The reactions of direct nucleophilic substitution of butanol-2, pentanol-1 and hexanol-1 to HS- and RS- group by single-electron reduction of hydrogen sulfide and alkanthiol in acetonitrile and ionic liquid at room temperature and atmospheric pressure with a single by-product - H2O were described. The possibility of conducting an experiment without electrolyte due to the intrinsic electrical conductivity of the ionic liquid allows not only lowering the consumption of reagents, but also facilitating the isolation of the target product. Due to the structuring and the matrix effect in ionic liquids, the duration of electrolysis in the reactions under consideration is 2-3 times less than in the case of aprotic solvents.

Most methods of obtaining aromatic thiols are based on nucleophilic substitution reactions at halogen derivatives of aromatic hydrocarbons when used as nucleophilic reagents sodium thiolate, thiourea or potassium xanthate at high temperatures, pressure and in the presence of catalysts. The direct reaction of nucleophilic substitution of OH-groups in the phenols, pyrocatechol and benzyl alcohol to the HS-group in conditions of one-electron reducrion of hydrogen sulfide in acetonitrile and pyridinium ionic liquid was investigated for the first time. The proposed reactions proceed at room temperature and atmospheric pressure. The use of "green" solvent - ionic liquid - reduces the syntheses time in а half, improves ecological safety friendliness of the process and reduces the consumption of reagents. The main positive feature of these studies is not only ecological safety of reactions of nucleophilic substitution (due to the lack of harmful byproducts), but the use of electrochemical reactions in ionic liquid media, that is very relevant in modern science in terms of new environmental technologies development. For citation: Okhlobystina A.V., Okhlobystin A.O., Berberova N.T., Burmistrova D.A. Hydrogen sulfide in nucleophilic substitution reactions of hydroxy groups in aromatic alcohols. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 36-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conditions for the extraction of sulfur compounds from model hydrocarbon mixtures and real fuels (gasoline and fuel oil) with pyridinium and imidazolium ionic liquids were optimized to provide the maximum degree of desulfurization of fuels.

Electrochemical properties of ionic liquids (pyridinium and imidazolium salts) and the effect of additives of organic solvents on the electrochemical determination of organic compounds in ionic liquids have been studied. Transformations of aromatic and aliphatic sulfur compounds in ionic liquids in the presence of aromatic substrates are discussed. A new method has been proposed for identification of organic sulfur compounds–gas chromatography on columns with ionic liquid as the active phase.

Electrochemical behavior of [1,2-b]selenophenes and 4H-selenochromenes in organic media and their interaction with hydrogen sulfide have been studied. In aprotic solvents (CH2Cl2 and CH3CN), the organoselenium compounds are oxidized at anode to give cation-radicals. In the presence of hydrogen sulfide, at its oxidation potential (1.60 V) [1,2-b]selenophenes and 4H-selenochromenes undergo recyclization into corresponding thiophenes and thiochromenes. The recyclization yielding sulfur analogs have been studied in the presence of organic electromediators, including the transition metal complex with redox-active ligands, as well.

We consider the possible application of pyridinium ionic liquids to desulfurize hydrocarbon raw products and to transform the extracted toxic admixtures into promising sulfur compounds. Anodic oxidation of the extracted thiols as well as oxidation in the presence of electron mediators ( N,N,N′,N′ -tetramethyl-1,4-phenylenediamine, tri- p -bromophenylamine, and tri- p -tolylamine) leads to the corresponding disulfides.

Initiation of the reaction between hydrogen sulfide and aliphatic, aromatic, and heteroaromatic hydrocarbons in acetonitrile using the binary system organic base-anode is described. The reaction of hydrogen sulfide with nitrogen-containing organic bases is studied by means of cyclic voltammetry. The reaction of hydrogen sulfide with triethylamine leads to the formation of thiolate anion. The next step o reaction is electrochemical oxidation of the thiolate anion that to lead thiyl radical formation in situ thiyl radicals. In the presence of binary system on the basis of hydrogen sulfide aliphatic, aromatic, and heteroaromatic thiols and sulfides are formed at room temperature.

The chromium(III) tris- o -semiquinolate complex Cr(L SQ ) 3 (L SQ is 3,6-di- tert -butyl- o -semiquinone) and the monoanionic paramagnetic nickel(II) complex [ n -Bu 4 N][Ni(L S SQ )(L S DT )] (L S SQ is o -thiosemiquinone, L S DT is benzene-1,2-dithiolate) are considered as electromediators of hydrogen sulfide oxidation in the presence of various organic substrates (hex-1-ene, oct-1-ene, benzene, toluene, and benzoic acid). It is revealed that the electrolysis of hydrogen sulfide at the oxidation potential of the mediators in the presence of the substrates affords the corresponding aliphatic and aromatic thiols in a yield of 62–75%.

The reactions of hydrogen sulfide with transition metal complexes containing redox-active ligands are studied. A combination of electrochemical and spectral data indicates that the one-electron process affording the hydrogen sulfide radical and monoanionic complexes is an elementary act for the most part of the reactions studied. The accessibility of the metal center in the Co, Ni, Zn, and Pt complexes allows hydrogen sulfide to preliminary coordinate to the metal followed by the inner-sphere electron transfer in the hydrogen sulfide-metal-organic ligand system. Active intermediates (radical cation, thiyl radical, and proton) formed due to oxidation react with aromatic substrates. The substitution reaction in the aromatic ring produces a mixture of isomeric thiols and dimerization products of organylthiyl radicals (disulfides).

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The reaction of 2-hydroxy-6-methylpyridine (HL, 1) with nonanuclear nickel trimethyl-acetate Ni9(OH)6(OOCCMe3)12(HOOCCMe3)4 (2) in MeCN with a ratio M: L = 1: 1 under mild conditions (20 °C, 15 min) led to degradation of the metal core to form the hexanuclear complex (HL)2(µ 2-HL)2Ni6(µ3-OH)2(µ2-H2O)2(µ-OOCCMe3)8(η-OOCCMe3)2 (3). Further heating of 3 in acetonitrile at 80 °C for 4 h afforded the (HL)Ni6(µ 3-OH)(µ3,η2-L)3(µ,η2-L)(µ3-L)(µ 3-OOCCMe3)(µ-OOCCMe3)4(η2-OOCCMe3) complex. The reaction with the use of a 2: 1 THF-EtOH mixture instead of acetonitrile at 50 °C gave the decanuclear complex [Ni10(µ 3-O)2(µ3-OH)4(µ-OOCCMe3)6(µ3,η 2-L)6(EtOH)6](H2O)2, which is also produced from compounds 1 and 2 in ethanol. The structures of the resulting complexes were established by X-ray diffraction.