Search results for "METHANE"
showing 10 items of 1763 documents
Thermal and optical properties of 4H-pyran-4-ylidene fragment and bis-styryl and triphenyl groups containing derivatives
2014
Small D-π-A type organic molecules with incorporated 4H-pyan-4-ylidene (pyranylidene) fragment in their structures show potential in organic photonics - such as materials for organic light emitting diode application studies and organic solid state lasers. Additional incorporation of bulky triphenyl- groups in their structures gives them the ability to form thin amorphous solid films from volatile non-polar organic solvents. Unfortunately, there is still no clear relation between compound organic structures and their thermal and optical properties. In order to investigate the above mentioned regularities we have synthesized a series of tripheyl- group containing derivates of 2,6-bis-styryl-4…
Reaction of 3-Methylamino-1,2-diols with Dihalomethanes. Synthesis of Chiral 4-Substituted 3-Methyltetrahydro-1,3-oxazin-5-ols
2000
Abstract Enantiomerically pure 4,5-disubstituted 3-methyltetrahydro-1,3-oxazines have been obtained by reaction of 3-methylamino-1,2-diols with dichloromethane by regioselective differentiation of hydroxyl groups.
Kronenethersubstituierte 1,4-Distyrylbenzole und ihre Komplexierung mit Alkalipikraten
2000
Crown Ether Substituted 1,4-Distyrylbenzenes and their Complexation with Alkali Picrates The 1,4-distyrylbenzenes 8 and 9, which contain two crown ether units, each, were prepared by Wittig—Horner reactions. Their complexation tendencies with alkali picrates (Li—Cs) in water/dichloromethane were investigated. Potas sium ions give the strongest complexes. Generally monomo-lecular 1:1-complexes are formed; however, [K-8] + [Pik]—, [K-9]+ [Pik]— and [Rb-8] + [Pik]— generate aggregates, for which a stairway structure is proposed.
Crystal structure of 1-hydroxy-2,2,6,6-tetramethylpiperidin-1-ium trifluoromethanesulfonate
2015
In the cation of the title salt, C9H20NO+·CF3O3S−, the six-membered heterocyclic ring displays a chair conformation. In the crystal, centrosymmetric pairs of cations and anions are linked by N—H...O and O—H...O hydrogen bonds to form rings with aR44(14) graph-set motif.
Methyl-Substituted α-Cyclodextrin as Affinity Material for Storage, Separation, and Detection of Trichlorofluoromethane
2018
Abstract The severely ozone‐depleting trichlorofluoromethane is still appearing in several recycling processes or industrial applications. A simple and selective supramolecular complex formation of per‐methylated α‐cyclodextrin (1) with the highly volatile trichlorofluoromethane (2) is reported. This interaction moreover leads to thermally stable crystals. Per‐methylated α‐cyclodextrin is successfully exploited as a reversible and selective adsorption material for liquid and airborne trichlorofluoromethane as well as an affinity material for the chemical sensing and detection of this particular volatile organic component.
Umsetzungen von polyacroleinen mit methylenaktiven verbindungen. Polymere acroleine, 21. Mitt.1
1962
Redoxpolymerisate des Acroleins wurden unter den Bedingungen einer KNOEVENAGEL-Kondensation mit methylenaktiven Verbindungen umgesetzt. Als Katalysatoren dienten Piperidin im essigsauren Medium oder Kaliumfluorid. Mit Malonsauredinitril, Cyanessigsaureathylester, Benzylcyanid, Phenylnitromethan und Acetessigsaureathylester entstehen losliche Polyacrolein-Derivate. Die Reaktionen mit Nitroacetonitril, Malonsaurediathylester, Nitromethan und Acetonitril fuhren zu unloslichen Umsetzungsprodukten. Die Umsetzungen wurden durch Elementaranalysen und IR-Spektren verfolgt. The reaction of redoxpolymers of acrolein with methylenactive compounds was studied under the conditions of a KNOEVENAGEL-conde…
ChemInform Abstract: Addition of Organolithium Reagents to Cinnamic Acids.
2010
Abstract Reaction of tert -butyllithium with p - and m -substituted cinnamic acids at low temperature affords mixtures of 1,4- and 1,3-addition products, whose composition depend on the nature of the substituents. Electron-donating and electron-withdrawing groups favour 1,4- and 1,3-additions, respectively. Linear correlations are obtained with electronic effect and with radical substituent constants.
Preparation of N,O-Aminals as Synthetic Equivalents of H2C=NAr and (H2C=NHAr)+ Ions: Neutral and Acid-promoted Transformations
1988
A general method for the synthesis of N,O-aminals derived from primary aromatic amines is described. The reactivity of these compounds under neutral and acidic conditions has been studied and the title compounds can be envisaged as general purpose H2C=NAr or (H2C=NHAr)+ equivalents. N,O-Aminals have been converted into perhydrotriazines by moderate heating and into bis(4-aminoaryl) methane derivatives or N-benzylarylamines, respectively when heated in acidic media with pH control. Reduction of N, O-acetals with sodium cyanoborohydride has revealed that the C-O bond is broken exclusively in acidic media.
Electrochemistry, spectroelectrochemistry and catalytic activity of biscobalt bisporphyrin dyads towards dioxygen reduction
2011
Three face-to-face biscobalt bisporphyrin dyads, including one incorporating a copper(II) ion inside the linker, were synthesized and characterized both spectroscopically and electrochemically in three non-aqueous solvents, dichloromethane, benzonitrile and pyridine. The electrocatalytic reduction of dioxygen with these derivatives on an electrode surface in 1.0 M HClO4 was also investigated and the results are compared to that obtained with "regular" Pacman biscobalt bisporphyrins under the same experimental conditions. Surprisingly, the tris-metal species ( Cu-bisCo ) catalyzes the reduction of O2 mainly via a 2e- transfer process, leading to H2O2 , while the bis-metal (bisCo) catalyst p…
Biogenic methane in freshwater food webs
2010
SUMMARY 1. It has long been known that substantial amounts of methane are produced in anoxic lake sediments, and the components of the methane cycle in lakes have been well described. At oxic–anoxic interfaces, methane-oxidising bacteria (MOB) convert methane to microbial biomass and can be highly productive. However, only recently has methane been recognised as a potentially important carbon and energy source for lake food webs, and some instances have also been reported of methane contribution to river food webs. Stable isotope analysis (SIA) has provided compelling evidence in this respect and has been supplemented by other lines of evidence. 2. In the benthic food webs of lakes, profund…