Fractional distribution of graphene oxide and its potential as an efficient and reusable solid catalyst for esterification reactions

Graphene oxide (GrO) prepared by the Hummers method was separated into three different fractions (GrO₅₀₀₀, GrO₂₀₀₀, and GrO_res) on the basis of their dispersion stability in the water. Infrared, nuclear magnetic resonance, X‐ray photoelectron spectroscopy, and elemental analyses revealed that GrO₅₀₀₀ possesses a high degree of oxygen functionalities including phenolic, carboxylic, and ?OSO₂H groups, compared with the other fractions. The GrO₅₀₀₀ was found to be a highly efficient and reusable solid catalyst for the esterification of various carboxylic acids with a variety of alcohols to furnish corresponding esters in high to excellent yields. The catalytic activity of the GrO₅₀₀₀ was attributed to the ability of highly polar GrO₅₀₀₀ scaffold to adsorb/attract reactants, where the acid functionalities of GrO₅₀₀₀ facilitated the esterification process efficiently. The chemical and structural features of GrO₅₀₀₀ were discussed to understand the improved catalytic activity compared with GrO₂₀₀₀ and conventional solid acid catalysts. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis of New Benzosubstituted Dioxaphosphonines Containing Quinoxaline Subunit

A simple and efficient synthesis of previously unknown benzosubstituted dioxaphosphonines containing a quinoxaline subunit is described. Reasonably good yields of the products, mild reaction conditions, and convenient work-up are the advantages of this method. The procedure does not require any catalyst or activator and can be efficiently achieved via dianion cyclization. All the synthesized compounds have been characterized by satisfactory elemental analyses and spectral (IR, ¹H, ¹³C, ³¹P NMR, and mass) studies.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis of nanoplate bismuth oxychloride—a visible light active material

We have synthesized bismuth oxychloride (BiOCl) by wet chemical route. Characterization of the synthesized samples has been carried out using XRD, SEM with EDAX, HRTEM, FT-IR, Raman Spectroscopy, PL and UV. XRD and SEM analysis confirms crystallite size varying from 20–40 nm. FTIR spectrum indicates that the prepared material is highly pure and there is no water molecule present. Raman and photoluminescence spectrum of the bismuth oxychloridenanoplate demonstrated strong blue light emission which brings them in a special class of materials which work under visible light exposure. UV-Vis spectroscopy shows very less charge carriers transit time under visible light thus confirming excellent photocatalytic properties of material.     

An Efficient,Basic Resin-Mediated,One-Pot Synthesis of Dithiocarbazates Through Alcoholic Tosylates

A quick and efficient, one-pot synthesis of dithiocarbazates was accomplished in high yields by the reaction of various alcoholic tosylates of primary, secondary, and tertiary alcohols, with substituted hydrazines using an Amberlite IRA 400 (basic resin)/CS ₂ system. The reaction conditions are mild with simpler work-up procedures than previously reported methods.     

Selective Oxidation of Sulfides to Sulfones Using H2O2 and Anderson-Type Hexamolybdochromate(III) as Catalyst

An Anderson-type hexamolybdochromate(III) is found to be an effective catalyst for the selective oxidation of sulfides to their corresponding sulfones. The reaction was carried out in 60% aq. acetonitrile (v/v) using 30% H₂O₂ at 60°C. Various dialkyl, alkyl-aryl, and diaryl sulfides were selectively oxidized, giving high yields of sulfones after a simple workup procedure.     

Synthesis and Characterization of Dichlorotin(IV)trithiophosphates and Their Adducts with Nitrogen Donor Bases

Abstract

Dichlorotin(IV)trithiophosphates [(RO)P(S)S ₂ ]SnCl ₂ were prepared by the reaction of methanolic solution of SnCl ₄ and dipotassium salt of trithiophosphates in a 1:1 molar ratio and their adducts [(RO)P(S)S ₂ ]SnCl _2.N ₂ C ₁₂ H ₈ and [(RO)P(S)S ₂ ]SnCl _2.N ₂ C ₁₀ H ₈ were prepared by the reaction of methanolic solution of [(RO)P(S)S ₂ ]SnCl ₂ and N-donor bases in a 1:1 molar ratio. These newly synthesised derivatives have been characterized by elemental analysis; molecular weight measurements; and IR, ¹³ C, ³¹ p and ¹¹⁹ Sn NMR spectral studies. Coordination number of four and six was suggested for dichlorotin (IV)trithiophosphates and their adducts with N-donor bases respectively.     

Synthesis and Antibacterial Studies of Some Novel 2-(Coumarin-3-yl)-5-mercapto-1,3,4-oxadiazoles Containing 2,4,6-Trisubstituted s-Triazine Derivatives

A new series of 2-(coumarin-3-yl)-5-mercapto-1,3,4-oxadiazoles based on various aryl thiourea/ureas incorporating a 1,3,5-s-triazine moiety is reported. The components of this series have been obtained by the reaction of cyanuric chloride (1) with 2-(coumarin-3-yl)-5-mercapto-1,3,4-oxadiazole (2). The prepared 2-{(coumarin-3-yl-1,3,4-oxadiazolyl)-5-thio}-4,6-dichloro-s-triazine (3) was subsequently treated with morpholine (4) to form 2-{(coumarin-3-yl-1,3,4-oxadiazolyl)-5-thio}-4-(morpholino)-6-chloro-s-triazine (5). This was further treated with various substituted aryl urea/thioureas (6a–k/7a–k) to afford the title compounds 8a–k and 9a–k, which were and tested for their antibacterial activity (MIC) against different microorganisms. The structures of the novel synthesized compound have been established on the basis of ¹H NMR and FT-IR data together with elemental analysis.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.