Search results for "Methanol"
showing 10 items of 1026 documents
2,4,6-Tris(1-oxo-2-pyridylsulfanylmethyl)mesitylene methanol solvate
2008
In the title compound, C(27)H(27)N(3)O(3)S(3)·CH(4)O, the dihedral angles formed by the mesitylene ring with the three oxopyridyl rings are 89.6 (1), 75.5 (1) and 80.69 (1)°, indicating that all three are nearly perpendicular to the mesitylene ring. Intra-molecular C-H⋯S hydrogen bonds generate S(6) ring motifs. The crystal structure is stabilized by intra-molecular C-H⋯S and inter-molecular C-H⋯O hydrogen bonds and weak C-H⋯π inter-actions.
The different kinetic and mechanistic behaviors of molybdenum and tungsten in the reduction of tris(benzene-1,2-dithiolato)Mo(VI) and W(VI) complexes…
2011
The mono-electronic reduction of tris(benzene-1,2-dithiolato)Mo(VI) and W(VI) complexes (ML3: M = Mo, W; L = S2C6H2−4, S2C6H3CH2−3) to their anionic forms ML−3 by L(+)-ascorbic acid (H2A) has been studied in tetrahydrofurane (THF):water and THF:methanol by means of diode-array, stopped-flow, and mass spectrometry–electrospray ionization (MS-ESI) spectroscopy. The kinetic study in methanol demonstrates that the reaction is first order in each reactant, the electron transfer being rate limiting. This fact was assessed by the absence of a primary saline effect and by the correlation observed between the activation free enthalpy (ΔG≠) and the reduction potentials measured by cyclic voltamperome…
Near infrared spectroscopic study on the adsorption of methanol on silica gel
2013
Author's version of an article in the journal: Advanced Materials Research. Also available from the publisher at: http://dx.doi.org/10.4028/www.scientific.net/AMR.650.150 The silanol groups on Silica gel surface are sites for adsorption of polar molecules. Alcohols and other polar molecules are easily adsorbed by forming hydrogen bondings with OH groups on silica gel surface. A study on the adsorption of methanol on silica gel was carried out by using NIR spectroscopy in combination with ssecond derivative techniques. Four of the well characterised silica gel samples were used in this study. Each of the silica gel (0.25g) samples with different surface areas and silanol number was pressed i…
Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells
2020
The use of nanotechnology along with the consideration of a functionalization and stabilization approach to poly(vinyl alcohol) (PVA) is considered useful for the preparation of cost-effective polyelectrolyte membranes. A set of nanocomposite and crosslinked membranes based on PVA/sulfosuccinic acid (SSA)/graphene oxide (GO) are prepared and analyzed as polyelectrolytes in direct methanol fuel cells (DMFCs). The crosslinking and sulfonation by the use of SSA enhances the stability and increase the proton-conducting sites in the PVA structure. The presence of GO augments the stability, remarkably decreases the methanol crossover, and enhances power density curves. An optimum value for proton…
HPLC determination of volatile phenols in wines
1993
An alternative to the traditional solvent extraction method used to extract and rapidly quantify ethyl-and vinylphenol and ethyl-and vinylgaiacol from wine is presented. The method is based on retention of volatile phenols on adsorbants. Among the tested resins, the most efficient, AG 2-X8 (anion exchange resin), worked as well with a synthetic solution as with wines. The percolation of clarified wine adjusted to pH 9 on this resin permits, in particular, the elimination of organic acids. Phenols are not eluted after rinsing the column with 1N HCl, but are eluted with methanol after this treatment. Good recovery (91 %) and good repeatability are observed. The eluate is directly analysed by …
Liquid–liquid equlibria of the system dimethyl carbonate+methanol+water at different temperatures
2006
Abstract In this work, experimental liquid–liquid equilibria (LLE) data of the dimethyl carbonate + methanol + water system are presented. The LLE of this system has been measured from 283 to 333 K. On the other hand, LLE and LVE of the binary system dimethyl carbonate + water have been measured. The equilibrium data presented are correlated using NRTL and UNIQUAC equations. The reliability of these models is tested by comparison with experimental results. Finally, the VLE for the system DMC + water at 101.3 kPa was predicted using the UNIQUAC model, with the adjusted parameters obtained from the LLE data. This prediction was successful when is compared with the experimental VLE data.
Complete basis set prediction of methanol isotropic nuclear magnetic shieldings and indirect nuclear spin–spin coupling constants (SSCC) using polari…
2009
Efficient B3LYP and BHandH density functionals were used to estimate methanol's nuclear magnetic isotropic shieldings and spin–spin coupling constants in the basis set limit. Polarization‐consistent pcS‐n and pcJ‐n (n = 0, 1, 2, 3 and 4), and segmented contracted XZP, where X = D, T, Q and 5, basis sets were used and the results fitted with simple mathematical formulas. The performance of the methods was assessed from comparison with experiment and higher level calculations. 1J(CH) and 3J(HH) values were determined from very diluted solutions in deuterochloroform and compared with theoretical predictions. The agreement between complete basis set (CBS) density functional theory (DFT) predict…
2,7-Di-tert-butyl-9,9-dimethyl-4,5-bis(4-tritylanilinocarbonyl)-9H-xanthene methanol trisolvate monohydrate
2006
The title compound, C75H68N2O3·3CH3OH·H2O, was synthesized starting from the corresponding acid and p-tritylaniline. Single crystals were obtained from a methanol solution as a solvate, with three methanol molecules and one water molecule. The solid-state structure proves the existence of an intramolecular bifurcated hydrogen bond between one amide H atom and the carbonyl and xanthene O atoms. The packing is stabilized by intermolecular hydrogen bonds.
1-(3′,6′-Dihydroxy-3-oxo-3H-spiro[isobenzofuran-1,9′-xanthen]-5-yl)-3-[4-({4-[1-(4-fluorophenyl)-1H-imidazol-5-yl]pyridin-2-yl}amino)phenyl]thiourea …
2016
The title compound, which crystallized as a methanol monosolvate, C41H27FN6O5S·CH3OH, was synthesized as a probe for a fluorescence polarization-based competition binding assay. The isobenzofuran fused-ring system is close to planar and orientated almost perpendicular to the central ring of the xanthene system. The dihedral angle between the benzene rings of the xanthene system is 10.0 (2)°, indicating a butterfly-like orientation. A short intramolecular C—F...π contact [F...π = 3.100 (4) Å and C—F...π = 139.9 (3)°] to the six-membered ring of the isobenzofuran system may influence the molecular conformation. The methanol solvent molecule is disordered over two orientations in a 0.6:0.4 rat…
Impact of lipid extraction on the dearomatisation of an Eisenia foetida protein powder
2010
www.elsevier.com/locate/foodchem ; FSTA:2010-Sp0197; International audience; Delipidation was studied as a way to dearomatise a non-conventional protein powder obtained from Eisenia foetida earthworms. In the first step, we studied the impact of several factors such as solvent type, extraction method and particle size on the yield of extracted lipids. Lipid extraction from samples was considerably improved using an ultrasound method with a chloroform/methanol mixture and small particle size. In the second step, the volatile compounds were extracted from the delipidated protein powder by the SAFE extraction method and by the HS-SPME method, and were further analysed by GC-MS. The chloroform/…