Search results for "Anhydrous"
showing 8 items of 48 documents
Molecular dynamics of electrosprayed water nanodroplets containing sodium bis(2-ethylhexyl)sulfosuccinate
2013
The behavior of aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) subject to electrospray ionization (ESI) has been investigated by molecular dynamics (MD) simulations at three temperatures (350, 500 and 800 K). We consider several types of water nanodroplets containing AOTNa molecules and composed of a fixed number of water molecules (1000), N(AOT)(0) AOT(-) anions (N(AOT)(0) = 0, 5, 10) and N(Na)(0) sodium ions (N(Na)(0) = 0, 5, 10, 15, 20): in a short time scale (less than 1 ns), the AOTNa molecules, initially forming direct micelles in the interior of the water nanodroplets, are observed in all cases to diffuse nearby the nanodroplet surface, so that the hydrophilic …
Photoiodocarboxylation of Activated C═C Double Bonds with CO2 and Lithium Iodide
2018
The photolysis at 254 nm of lithium iodide and olefins 1 carrying an electron-withdrawing Z-substituent in CO2-saturated (1 bar) anhydrous acetonitrile at room temperature produces the atom efficient and transition metal-free photoiodocarboxylation of the C═C double bond. The reaction proceeds well for terminal olefins 1 to form the new C-I and C-C σ-bonds at the α and β-positions of the Z-substituent, respectively, and is strongly inhibited by polar protic solvents or additives. The experimental results suggest that the reaction channels through the radical anion [CO2•-] in acetonitrile, yet involves different intermediates in aqueous medium. The stabilizing ion-quadrupole and electron don…
ChemInform Abstract: Epoxidation of Olefins with a Silica-Supported Peracid.
2012
Anhydrous [2-percarboxyethyl] functionalized silica (2a) is an advantageous oxidant for performing the epoxidation of olefins 1. Epoxides 3 do not undergo the ring-opening reactions catalyzed by the acidic silica surface, except for particularly activated cases such as styrene oxide. The hydrophilic and acidic character of the silica surface does not interfere with the directing effects exerted by allylic H-bond acceptor substituents. The alkenes 1 carrying hydroxyl groups react with silica-supported peracid 2a faster than unsubstituted alkenes, thus reversing the trend known for reactions with soluble peracids. These results are attributed to the H-bond interactions of substrate 1 with the…
A novel synthesis of 2-aryl-4-piperidones by mannich cyclization of iminoketals
1983
2-Aryl-4-piperidones have been synthesized by condensation between an aromatic aldehyde and a β-aminoketone ethylene ketal, and further cyclization of the resulting iminoketal with dry hydrogen chloride or anhydrous p-toluensulfonic acid. Alternatively, reaction of the above iminoketals with methyl fluorosulfonate followed by dry hydrogen chloride treatment and acid hydrolysis gives directly N-methyl-4-piperidones. The application of these reactions to the synthesis of some 2-aryl-3-acetylpyrrolidine systems is also described.
Electrochemical Syntheses of Carboxylic Acids from Carbon Dioxide
1987
The first report on the reduction of carbon dioxide is due to the venerable name of Hermann Kolbe, who, in 1861, published with R. Schmitt the reduction of carbon dioxide to formate with metallic potassium (1). Seven years later he introduced to the Chemical Society in London his assistant E. Drechsel, who “after many unsuccessful experiments, made during several years” (2) at the end succeeded in reducing carbon dioxide to oxalate with metallic sodium or with potassium amalgam in anhydrous conditions. Soon afterwards Beketov (3) and Royer (4) opened the series of papers dealing with the direct involvement of carbon dioxide in electrolytic processes. Since then the reduction of carbon dioxi…
Acetylhydroxamic acid
2017
There is one independent molecule in the asymmetric unit of the title compound (alternatively namedN-hydroxyacetamide), C2H5NO2. It crystallizes in the noncentrosymmetric space groupP43. The structure is an anhydrous form of acetylhydroxamic acid with typical geometry that corresponds well with the hydrated structure described by Bracher & Small [Acta Cryst.(1970), B26, 1705–1709]. In the crystal, N—H...O and O—H...O hydrogen bonds connect the molecules into chains in thec-axis direction.
Viscoelastic properties of acid milk gel as affected by fat nature at low level
2005
International audience; The viscoelastic properties of acid milk gels containing small amounts of different fats were investigated. Skim milk was reconstituted from ultra low-heat skim milk powder and emulsions made with 2% (v/v) sunflower oil, olive oil, groundnut oil, or anhydrous milk fat using a pressure homogenizer. Acidification at 20 °C for 14 h to pH ∼4.6 was achieved by adding glucono-δ-lactone to the emulsion. Stress relaxation testing enabled determination of the firmness and the solid-like properties, i.e., elasticity. Regardless of the physical state of the fat, emulsion gels exhibited higher firmness than fat-free gels, despite the low fat level used. The firmness of the gels …
Catalytic activity of solvated and unsolvated lanthanide halides in Friedel–Crafts acylations
2000
Abstract Anhydrous lanthanide halides — chlorides and bromides — can act as homogeneous catalysts of Friedel–Crafts acylations. The catalytic activity is related to the solubility of these anhydrous salts. More soluble THF or dioxane (Diox.) neodymium and samarium adducts are more active catalysts.