Aluminum metal is produced by the electrolytic reduction of aluminum oxide (Al2O3), mainly extracted from bauxite ore digested in a hot caustic soda solution. This solution is supersaturated with respect to sodium aluminate and silicate, which react together to form sodalite (3[Na2O⋅Al2O3⋅2SiO2⋅2H2O]⋅Na2CO3) at high temperatures. Heat exchanger tubes are scaled with this compound, which serious...

Sulfuric acid hydrate has been proposed as an important species on Europa’s surface, the acid being produced by radiolysis of surficial sulfur compounds. We investigated the spectral properties of disordered and crystalline forms of sulfuric acid and suggest that the hydration properties of Europa’s hypothesized sulfuric acid lie between two end members: liquid sulfuric acid and its higher crys...

The aryl-(Z)-N-[2-amino-1,2-dicyanovinyl]formamidine 2 cyclize in solvent-free conditions and in the presence of a base to give a 5-amino-1-aryl-4-cyanoimidazoles 3. Silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 through reaction with aromatic amines at room temperature and in good to excellent yields. ...

The aryl-(Z)-N-[2-amino-1,2-dicyanovinyl]formamidine 2 cyclize in solvent-free conditions and in the presence of a base to give a 5-amino-1-aryl-4-cyanoimidazoles 3. Silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 through reaction with aromatic amines at room temperature and in good to excellent yields. ...

Neat 3,5-dinitro-1H-1,2,4-triazole was obtained in quantitative yield from potassium 3,5-dinitro-1,2,4-triazolate and sulfuric acid. The compound was purified by sublimation in vacuo at 110 °C. Pure HDNT is a hygroscopic white solid that is impact and friction sensitive and decomposes explosively upon heating to 170 °C. However, the presence of impurities might lower the decomposition temperatu...

Periana et al. [Science 1998, 280, 560] previously reported two catalysts for lowtemperature methane activation to methanol: PtCl2(NH3)2 and PtCl2(bpym). It was shown that the ammine catalyst is much more active, but it decomposes rapidly in sulfuric acid to form a PtCl2 precipitate, while the bpym system is long-lived. To have a basis for developing new catalysts that would not decompose, we u...

β-Cyclodextrin sulfuric acid as a green Lewis acid catalyst has been applied for the preparation of bis(indolyl)methanes, tris(indolyl)methanes and 3,3'-diindolyloxindole derivatives by the condensation of indoles with various carbonyl compounds in aqueous media with high to excellent yields.

The complex H2SO4-H2O has been observed by rotational spectroscopy in a supersonic jet. A-type spectra for 18 isotopic forms have been analyzed, and the vibrationally averaged structure of the system has been determined. The complex forms a distorted, six-membered ring with the water unit acting as both a hydrogen bond donor and a hydrogen bond acceptor toward the sulfuric acid. One of the H2SO...