Search

• This AgNO 3 /ionic liquid system employs the lowest level metal loading by far. • This AgNO 3 /ionic liquid system works efficiently under 1 bar of CO 2. • This AgNO 3 /IL system could be recycled and reused for at least 5 times. • The AgNO 3 /IL system green metrics' outperforms all reported Ag-catalyzed cases. • NHC-CO 2 adducts and NHC-Ag complexes were detected during the process. Oxazolidinones and α-hydroxyl ketones are two series of fine chemicals that have been generally utilized in biological, pharmaceutical, and synthetic chemistry. Herein, a AgNO 3 /ionic liquid (IL) catalytic system was developed for the simultaneous synthesis of these compounds through the atom-economical three-component reactions of propargyl alcohols, 2-aminoethanols, and CO 2. Notably, this system behaved excellent catalytic activity with the lowermost metal loading of 0.25 mol%. Meanwhile, it is the first reported metal-catalyzed system that could efficiently work under atmospheric CO 2 pressure and be recycled at least five times. Evaluation of the green metrics proved the AgNO 3 /IL-catalyzed processes to be relatively more sustainable and greener than the other Ag-catalyzed examples. Further mechanistic investigations revealed the derivative active species of N-heterocyclic carbene (NHC) silver complexes and CO 2 adducts generated during the process. Subsequently, their reactivity in this reaction was assessed for the first time, which was finally identified as beneficial for the catalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: The reactions occurred and growth process in the preparation of copper aluminum borate (Cu2Al6B4O17) whiskers based on flux method (Al2(SO4)3/CuSO4/H3BO3 as raw materials, K2SO4 as flux) were investigated. The thermogravimetric and differential scanning calorimetry analysis (TG-DSC), inductively coupled plasma atomic emission spectrum analysis (ICP-AES) and X-ray diffraction analysis (XRD) results of reactants mixture quenched at various temperatures and phase diagrams of K2SO4–Al2(SO4)3 system and B2O3–Al2O3 system showed that the reaction process proceeds through three steps: the formation and decomposition of two different kinds of potassium aluminum sulfate (K 3 Al(SO4)3 and KAl(SO4)2); the formation of aluminum borate (Al4B2O9) and decomposition of copper sulfate (CuSO4) and boric acid (H3BO3); growth and formation of copper aluminum borate (Cu2Al6B4O17) whiskers. The scanning electron microscopy (SEM) analysis results indicated that morphology in growth of Cu2Al6B4O17 whiskers develops through three stages: nanoparticles, fan-shaped whiskers and agminate-needlelike whiskers. [Copyright &y& Elsevier]