Reactions of Dichloroethenes with Sulfur in the System Hydrazine Hydrate–KОН

Vinylidene chloride and 1,2-dichloroethene react with sulfur in the system hydrazine hydrate–KОН with the formation of polyvinylenesulfide oligomer of molecular mass 1750–6120 Da containing also vinylenehydrazine and vinylenechloride links in the Z-configuration, and 1,4-dithiine in the yield up to 46%. In aqueous-hydrazine layer polysulfide anions S _n ^2– (n = 1–4), mainly S₂^2– were found. The mechanism of formation of oligomers and 1,4-dithiine is suggested, which includes in the first stage dehydrochlorination of dichloroethenes and generation of chloroacetylene.     

Azo Bond Reduction of N,N＇,diaryl Adipyl Bis-azo Compounds with Hydrazine Hydrate

Reduction of a series of N,N'-diaryl adipyl bis-azo compounds using hydrazine hydrate as reductant was investigated. The products were characterized by elemental analysis, IR and 1H NMR methods and confirmed to be N,N'-diaryl adipyl dihydrazine. The results show that hydrazine hydrate can selectively reduce azo bonds with other potential reducible bonds intact in the N,N'-diaryl adipyl bis-azo compounds. The yields are high up to 92% under mild reaction conditions. According to the previous reports, this reduction process was attributed to an indirect reduction mechanism through an intermediate diimide.     

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron（Ⅲ） Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.     

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron(III) Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron(III) oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.     

Preparation of Sulphur-containing Aromatic Amines by Reduction of the Corresponding Aromatic Nitro Compounds with Hydrazine Hydrate over Iron Oxide Hydroxide Catalyst

The sulphur-containing aromatic amines are an important class of compounds frequently used as key intermediates in the synthesis of pharmaceutical products1,2, dyestuffs3-6 and polymers7. The usual methods for preparing sulphur-containing aromatic amines …     

Electrooxidation of Thiols in the Presence of Halide Ions—A Facile Preparative Method for Synthesis of Disulfides

The aliphatic, aromatic and heteroaromatic disulfides were easily synthesized by the electrolysis of corresponding thiols. The electrochemical method is also convenient for synthesis of unsymmetrically substituted disulfides and “paired” synthesis of disulfide and sulfide.     

Plasma-catalytic Selective Reduction of NO with C2H4 in the Presence of Excess Oxygen

This paper reports observations of significant synergistic effects between dielectric barrier discharge (DBD) plasmas and Cu-ZSM-5 catalysts for C2H4 selective reduction of NOx at 250℃ in the presence of excess oxygen by using a one-stage plasma-over-catalyst (POC) reactor. With the reactant gas mixture of 530 ppm NO, 650ppm C2H4, 5.8% 02 in N2and GHSV = 12000h^-1, the pure catalytic, pure plasma-induced (discharges over fused silica pellets) and plasma-catalytic (in the POC reactor) NOx conversion are 39%, 1.5% and 79%, respectively. The in-situ optical emission spectra of the reactive systems imply some short-lived active species formed from plasma-induced and plasma-catalytic processes may be responsible to the observed synergistic effects in this one-stage POC system.     

New One‐Pot Procedure for the Synthesis of 2‐Substituted Benzimidazoles

A highly selective synthesis of 2‐substituted benzimidazole derivatives from the reaction of o‐phenylendiamine derivatives and aromatic aldehydes in the presence of an organic salt, NH₄OAc, in absolute ethanol is presented. The products were obtained by evaporating the solvent followed by a simple recrystallization with excellent yields.     

Quantum-chemical Study of the Mechanisms of Organic Reactions: VIII. On the Reaction of Ethane-1,2-dithiol with 1,3-Dichlorobut-2-ene in the Hydrazine Hydrate–KOH System

Russian Journal of Organic Chemistry - A mechanism of the reaction of 1,3-dichlorobut-2-ene with 1,2-ethanedithiol in the hydrazine hydrate–KOH system is proposed on the basis of the results...     

Quantum Chemical Study of Mechanisms of Organic Reactions: VII. Reaction of Ethane-1,2-dithiol with 1,3-Dichloropropene in the System Hydrazine Hydrate–KOH

A mechanism has been proposed for the reaction of 1,3-dichloropropene with ethane-1,2-dithiol in the system hydrazine hydrate–potassium hydroxide on the basis of DFT quantum chemical calculations [B3LYP/6-311++G(d,p)]. The proposed mechanism involves several consecutive steps, in particular nucleophilic substitution of chlorine at the sp³-hybridized carbon atom by sulfur, prototropic allylic rearrangement of the monosubstitution product with double bond migration toward the sulfur atom, dithiolane ring closure via nucleophilic attack of the second thiolate group on the carbon atom in the γ-position with respect to the second chlorine atom, and prototropic allylic rearrangement of 2-vinyl-1,3-dithiolane to more stable 2-ethylidene-1,3-dithiolane.     

An Efficient Synthesis of Diaryl Ethers by Coupling Aryl Halides with Substituted Phenoxytrimethylsflane in the Presence of TBAF

A general synthesis of diaryl ethers via coupling of aryl halides with substituted phenoxytrimethylsilane in the presence of TBAF is desedbed. The protocol is simple and mild,and gives good to excellent yields.     

An Efficient Synthesis of Diaryl Ethers by Coupling Aryl Halides with Substituted Phenoxytrimethylsilane in the Presence of TBAF

A general synthesis of diaryl ethers via coupling of aryl halides with substituted phenoxytrimethylsilane in the presence of TBAF is described. The protocol is simple and mild, and gives good to excellent yields.     

1,4-Dichalcogenins: Synthesis from Dichloroethenes and Elemental Chalcogens in a Hydrazine Hydrate–Potassium Hydroxide System

Russian Journal of General Chemistry - A possibility of the synthesis of 1,4-dichalcogenins by the reaction of vinylidene chloride or 1,2-dichloroethene with elemental chalcogenes in a hydrazine...     

Hydrogenation of 1,5,9-Cyclododecatriene in a Three-Phase System in the Presence of Nickel Nanoparticles Supported on NаX Zeolite

Russian Journal of Applied Chemistry - Hydrogenation of 1,5,9-cyclododecatriene in the presence of nanostructured nickel catalysts in a flow-through reactor at atmospheric hydrogen pressure was...     

Mo–Catalyzed One-Pot Synthesis of N-Polyheterocycles from Nitroarenes and Glycols with Recycling of the Waste Reduction Byproduct. Substituent-Tuned Photophysical Properties

A catalytic domino reduction–imine formation–intramolecular cyclization–oxidation for the general synthesis of a wide variety of biologically relevant N-polyheterocycles, such as quinoxaline- and quinoline-fused derivatives, and phenanthridines, is reported. A simple, easily available, and environmentally friendly dioxomolybdenum(VI) complex has proven to be a highly efficient and versatile catalyst for transforming a broad range of starting nitroarenes involving several redox processes. Not only is this a sustainable, step-economical as well as air- and moisture-tolerant method, but also it is worth highlighting that the waste byproduct generated in the first step of the sequence is recycled and incorporated in the final target molecule, improving the overall synthetic efficiency. Moreover, selected indoloquinoxalines have been photophysically characterized in cyclohexane and toluene with exceptional fluorescence quantum yields above 0.7 for the alkyl derivatives.     

A Convenient Procedure for Carboxylation—Robinson Annulations of Ketones Using Triethylamine Base in the Presence of Magnesium Chloride

Carboxylation of ketones with carbon dioxide in the presence of magnesium chloride and triethylamine followed by reaction with methyl vinyl ketone gives satisfactory yields of Michael and Robinson annulation products.     

Influence of NO on the Reduction of NO2 with CO over Pt/SiO2 in the Presence of O2

Reduction of NO2 with CO in the presence of NO and excess oxygen, a model mixture for flue gas, over a 0.1% Pt/SiO2 catalyst was studied. The related reaction mechanisms, such as oxidation of CO and NO, were discussed. It was found that there was a narrow temperature window （180-190 ℃） for the reduction of NO2 by CO. When the temperature was lower than the lower limit of the window, the reduction hardly occurred, while when the temperature was higher than the upper limit of the window, the direct oxidation of CO by O2 occurred and thereby NO2 could not be effectively reduced by CO. The presence of NO shifted the window to higher temperatures owing to the inhibition effect of NO on the activation of O2 on Pt, which made it possible to reduce NO2 by CO in flue gas.     

Participation of Water in the Secondary Transformations of Hydrocarbons on Cobalt–Zeolite Catalysts for the Fischer–Tropsch Synthesis

This review is dedicated to the effect of water as the main by-product of the Fischer–Tropsch synthesis on the process. The reasons for the negative effect of water are analyzed and the possible versions of the control of its participation in the process are considered. As an optimal solution to the problem, the use of zeolites in the H form as the constituents of cobalt catalysts for the Fischer–Tropsch synthesis is proposed. Bibliography: 148 references.