Search results for "Methanol"
showing 10 items of 1026 documents
Formation of the Cationic [(2‐Aminoethenyl)carbine]iron Complexes by Treatment of (2‐Methoxyethenyl)carbene Complexes with Primary Amines:Synthesis a…
1997
Cationic (2-methoxyethenyl)methoxycarbene iron complexes 2, [Cp(CO)2Fe(C(OMe)CHCR(OMe))+][PF6−], are obtained by the addition of methanol to the corresponding (alkynyl)-methoxycarbene complexes 1, [Cp(CO)2Fe(C(OMe)CCR)+][PF6−]. Primary amines, H2NR', react with these 1,3-dimethoxy-substituted (alkenyl)carbene complexes, 2, through an addition/elimination process to yield cationic (2-aminoethenyl)methoxycarbene iron complexes, 3, [Cp(CO)2Fe(C(OMe)CHCR(NHR'))+][PF6−] in an isolated yield of 71–90%. The complexes 3a–c were characterized by X-ray structural analyses. Thus, previously isolated products, from the reaction, of the (alkynyl)methoxycarbene complexes 1a and 1c, with aniline at room t…
Photochemie elektronenreicher 1,3‐Distyrylbenzole
1988
Die 1,3-Distyrylbenzole 3 mit bis zu sieben Alkoxygruppen werden der oxidativen Photocyclisierung unterworfen. Bei der Bildung der Produkte 6, 7 und 8 konnen als Konkurrenz- bzw. Folgeprozesse die Abspaltung von Methanol (3bb 7bb, 3bf 7bf) und die Chinonoxidation (3cf 8) auftreten. Die eigensensiblisierte Erzeugung von Singulettsauerstoff kann bei 6bf zur Endoperoxidbildung fuhren (6bf 11). Photochemistry of Electron-Rich 1,3-Distyrylbenzenes The 1,3-distyrylbenzenes 3, containing up to seven alkoxy groups, are subjected to the oxidative photocyclization. Elimination of methanol (3bb 7bb, 3bf 7bf) and quinone oxidation can occur as competitive or consecutive reactons in the formation of the…
Oxygen atom transfer reaction involving oxomolybdenum complexes with sterically bulky thiocarboxylate ligands and biochemical interesting substrates …
1999
Abstract Oxidation–reduction reactions of substrates in systems containing the complex [Mo VI O 2 (O 2 CC(S)CH 3 Ph) 2 ] 2− in methanol have been investigated as models of oxo-transfer reactions. At neutral pH, the [Mo VI O 2 (O 2 CC(S)CH 3 Ph) 2 ] 2− reacts with Me 2 PhP or n -butanethiol to yield a [Mo IV O(O 2 CC(S)CH 3 Ph) 2 ] 2− species and Me 2 PhPO or disulfide, respectively. The Mo IV O complex reduces a variety of substrates XO = Me 2 SO and pyridine N-oxide conducing formation of X = Me 2 S and pyridine. The occurrence of these reactions produces a catalytic system Me 2 PhP + XO → Me 2 PhPO + X and 2BuSH + XO → [BuS] 2 + X + H 2 O. In this work we have also included the study of …
Di-n-butyltin(IV)-catalyzed dimethyl carbonate synthesis from carbon dioxide and methanol: An in situ high pressure 119Sn{1H} NMR spectroscopic study
2011
The reactivity of five di-n-butyltin(IV) complexes, n-Bu2Sn(OR)(2) (1), n-Bu2SnO (3), [n-Bu2Sn(OR)](2)O (4), (n-Bu2SnO)(2)(CO2) (6) and (n-Bu2SnO)(6)[(n-Bu2SnOR)(2)(CO3)](2) (7) (R = CH3), with CO2, suggested as possible catalyst precursors and key-intermediates for the direct synthesis of dimethyl carbonate from carbon dioxide and methanol, has been investigated using high-pressure Sn-119{H-1} NMR (HP-NMR) spectroscopy. Four of the five precursors studied, i.e. 3, 4, 6 and 7 give rise to an identical Sn-119{H-1} NMR pattern which can be explicitly attributed to the fingerprint of the dimeric form of the 1-methoxy-3-methylcarbonatotetrabutyldistannoxane {5}(2). However, with 1, a new pair o…
Bismuth trihalide complexes with nitrogen and phosphorus chelating ligands
1985
Abstract Bismuth(III) halides react with 1,10-phenanthroline, 2-pyridinecarboxaldehyde-2-pyridylhydrazone and diphenylphosphynoethane in methanol. A stoichiometry differing from 1:1 is found only for BiCl 3 (Phen) 1.33 and BiCl 3 (Dpe) 1.5 . Characterization of these compounds, which are not very soluble in common solvents, follows from analytical, mass and IR spectral data. In the low frequency region, the IR spectra proved to be useful to ascertain the presence of bridging halogens.
Determination of urea-derived pesticides in fruits and vegetables by solid-phase preconcentration and capillary electrophoresis
2001
A multiresidue analytical method based on solid-phase extraction (SPE) enrichment combined with capillary electrophoresis (CE), using micellar electrokinetic capillary chromatography (MEKC), was developed to determine ten substituted urea pesticides in orange and tomato samples. Several factors such as pH, composition and concentration of the buffer, concentration of surfactant, addition of organic solvent, and working voltage were optimized to obtain the best compound separation in the shortest time. Separation can be achieved in 7 min using a micellar aqueous pH 9 buffer composed of 4 mM borate and 35 mM sodium dodecyl sulfate. After an SPE procedure, which provided a 10-fold enrichment, …
Thermophysical properties of binary mixtures of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ionic liquid with alcohols at several tempera…
2018
Abstract Densities, speeds of sound, and refractive indices for the binary systems made up by 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate and methanol, ethanol, 1-propanol, or 2-propanol, as well as for the pure components, have been measured covering the whole range of compositions at atmospheric pressure and T = (278.15–338.15) K. From densities and speeds of sound, isentropic compressibilities were calculated using the Newton-Laplace equation. Liquid ideal-mixture properties have been defined and calculated, and they have been used to determine excess molar volumes, excess isentropic compressibilities, and deviations in refractive indices. Excess and deviations in properties …
Volumetric and Ultrasonic Studies of 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate Ionic Liquid with Methanol, Ethanol, 1-Propanol, and Water…
2007
The speed of sound and density of mixtures of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][triflate]) with methanol, ethanol, 1-propanol, and water, as well as of the pure components have been experimentally measured over the whole range of compositions at T = (278.15 to 338.15) K and atmospheric pressure. From these experimental data, the excess molar volume, excess isentropic compressibility, and excess speed of sound have been calculated and fitted to an extended version of the Redlich−Kister equation, which takes into account the dependence on composition and temperature simultaneously. The Prigogine−Flory−Patterson theory has also been used to explain the behavior of t…
Influence of culture conditions on production of flavour compounds by 29 ligninolytic Basidiomycetes
1990
The odorous volatile metabolites produced by 29 ligninolytic Basidiomycete strains (identified by gas chromatography coupled to mass spectroscopy — GC-MS) and the flavour quality of their cultures were investigated on 6 different liquid media tested with and without agitation. 113 compounds were identified, the most numerous being alcohols (2-methyl 1-propanol, 2-methyl 1-butanol, 3 methyl 1-butanol, 2 phenyl ethanol, 3,4, dimethoxy phenyl methanol, 4 vinyl phenol), aldehydes (3, 4 dimethoxybenzaldehyde) and ketones (4-hydroxy 3-methyl 2-phenyl 2-cyclopentene 1-one). One third of these compounds possessed an aromatic skeleton. The influences of medium composition and agitation conditions on…
On the Nucleophilic Reactivity of 4,6-Dichloro-5-nitrobenzofuroxan with Some Aliphatic and Aromatic Amines: Selective nucleophilic substitution
2020
The reaction rates for the nucleophilic aromatic substitution of 4,6-dichloro-5-nitrobenzofuroxan 1 with eight aliphatic amines (characterized by very different basicities/ nucleophilicities) and three anilines have been measured in both methanol and toluene. The obtained rates have been related to the basicity (pKaH in water and Kb in benzene) or nucleophilicity (N Mayr constants) of the tested amines. The whole of the obtained kinetic data has furnished useful information on the high nucleophilic reactivity of benzofuroxan derivatives, which has been related essentially to two factors: the high electron-drawing ability/power of the condensed furoxan ring and the low aromatic character of …