22 research outputs found
Regio- and Diastereoselective Vicinal Aminobromination of Electron Deficient Olefins via Phosphorus-Based GAP Protocol
No full text© 2021 Rahman, Zarshad, Khan, Faiz, Li and Ali. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Chemical synthesis based on Group-Assisted Purification chemistry (GAP) has been prolifically used as a powerful, greener and ecofriendly tool so far. Herein, we report hypervalent iodine (III) mediated regio- and diastereoselective aminobromination of electron-deficient olefins using group-assisted purification (GAP) method. By simply mixing the GAP auxiliary-anchored substrates with TsNH2–NBS as nitrogen/bromine sources and PhI(OAc)2 as a catalyst, a series of vicinal bromoamines with multifunctionalities were obtained in moderate to excellent yields (53–94%). The vicinal bromoamines were obtained without column chromatography and/or recrystallization simply by washing the crude mixtures with cosolvents and thus avoiding wastage of silica, solvents, time, and labor. The GAP auxiliary is recyclable and reusable
Hypervalent Iodine (III) Catalyzed Regio- and Diastereoselective Aminochlorination of Tailored Electron Deficient Olefins via GAP Chemistry
No full text© Copyright © 2020 Rahman, Zarshad, Zhou, Yang, Li and Ali. cc-byHerein, we report a protocol for highly efficient hypervalent iodine (III) mediated, group-assisted purification (GAP) method for the regioselectivities and stereoselective aminochlorination of electron-deficient olefins. A series of vicinal chloramines with multifunctionalities were acquired in moderate to excellent yields (45–94%), by merely mixing the GAP auxiliary-anchored substrates with dichloramine T and tosylamide as chlorine/nitrogen sources and iodobenzene diacetate as a catalyst. The vicinal chloramines were obtained without any column chromatographic purification and recrystallization simply by washing the reaction mixture with a minimum amount of common inexpensive solvents and thus avoiding wastage of silica, solvents, time, and labor. The GAP auxiliary is recyclable and reusable. This strategy is easy to handle, cost-effective, greener, sustainable, environmentally benign, and mostly suitable for the syntheses of vicinal haloamines from various electron-deficient alkenes
Tailored silica nanospheres: an efficient adsorbent for environmental chromium remediation
No full textAbstract
This manuscript reports the synthesis and characterization of caprylpyrazolone tailored silica nanospheres, synthesized through sol–gel procedure by activating the silica nanospheres with organosilane precursor and grafting with caprylpyrazolone. Its successful attachment to the silica is confirmed by FTIR, TGA and elemental techniques. The feasibility of the synthesized nanospheres as adsorbent was systematically checked by elimination of trace level of Cr(III) from aqueous medium, using radiotracer technique. A number of factors such as effect of pH, agitation time, adsorbent and adsorbate dosage were optimized to guarantee the use of the adsorbent for practical use. Various counter ions were added to the matrix solution to check the selectivity of the synthesized sorbent. Various rate equations and adsorption isotherms such as Freundlich, D-R and Langmuir were employed to suggest the mechanistic pathway of the adsorption process. The Cr(III) extraction was monitored at room and elevated temperatures and thermodynamic parameters such as change in enthalpy, entropy, and Gibbs free energy of the metal ion uptake were computed. The removal of Cr(III) is endothermic (∆H=30.00 J mol−1 K−1) and spontaneous (∆S=105.43 J mol−1 K−1) in nature. Application of the adsorbent to real water samples demonstrated the practical utility of the adsorbent. The sorbent displayed good stability. Its cleaning efficiency is not significantly affected after various adsorption-desorption cycles and so it can be used repeatedly.</jats:p
Complexation of Hg(II) ions with a functionalized adsorbent: A thermodynamic and kinetic approach
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Glycol stabilized magnetic nanoparticles for photocatalytic degradation of xylenol orange
No full textMoisture Sorption by Low-Cost Pyridinium-Based Protic Ionic Liquids: Kinetics and Physico-Electrochemical Properties
No full textWe report the synthesis of two pyridinium-based room temperature protic ionic liquids (PILs), pyridinium bisulfate, [HPyr][HSO4] and pyridinium sulphate, [HPyr]2[SO4] and investigation of the kinetics of their water sorption behaviour and its influence on their density, ionic conductivity, and potential windows. The PILs were synthesized by the reaction of pyridine base with an acid, H2SO4, under solventless conditions, and confirmed by FTIR spectroscopy and 1H NMR spectra. The appearance vibration bands in the 3095–3252 cm−1 range for −NH+ stretching in the FTIR spectra and a peak at a chemical shift of 8.439 ppm in the 1H-NMR of the liquids confirm their synthesis as no such bands/peaks can be seen in that of the pure pyridine spectra. The PILs’ hygroscopic nature was examined by exposing them (5 mL each sample with exposed surface area 3.143 cm2) to air for varied time intervals at a relative humidity, RH=58±5 % and T=20±5 °C. Coulometric Karl-Fischer (KF) titration was used to determine how much moisture each PIL sample absorbed at each time interval. The findings reveal that when the PIL was exposed to air for longer periods of time, more moisture was absorbed, and the results correspond well with the pseudo first-order kinetic model. The densities and conductivities of several samples of the two PILs were examined, and it was discovered that as the percentage water content of the PILs grew, density decreased but conductivities increased. Furthermore, it was discovered that when temperature rose, the conductivity of each of the PILs increased, and the results fit well to the Arrhenius linear equation since the regression coefficient, R2, for each of the samples approached the perfect fit value of one. The electrochemical window (EW) data, the mechanism of moisture oxidation within the EWs of each PIL at Pt and Au electrodes, and the electrocatalytic role played by the Pt and Au surface oxides during ethanol oxidation are evaluated and discussed in light of their future sustainable energy applications.Godkänd;2025;Nivå 0;2025-03-21 (u4);Fulltext license: CC BY</p
Photocatalytic Degradation of Congo Red Dye from Aqueous Environment Using Cobalt Ferrite Nanostructures: Development, Characterization, and Photocatalytic Performance
No full textInternational audienc
Involvement of the Opioidergic Mechanism in the Analgesic Potential of a Novel Indazolone Derivative: Efficacy in the Management of Pain, Neuropathy, and Inflammation Using In Vivo and In Silico Approaches
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