Ir spectra of catalysts and adsorbed molecules. Communication 35. Exchange of protons between different types of oh groups of acidic component of platinized alumina catalyst

1984 ◽  
Vol 33 (2) ◽  
pp. 246-251
Author(s):  
V. N. Gaevskii ◽  
A. K. Potapovich ◽  
L. I. Lafer ◽  
V. I. Yakerson
Keyword(s):  
Ir Spectra ◽  
Alumina Catalyst ◽  
Adsorbed Molecules ◽  
Oh Groups ◽  
Different Types ◽  
Acidic Component

Etude par spectrométrie infrarouge de l'action de solvants aprotiques sur l'association ester–eau et ester–Ba2+. Discussion du rôle catalytique du solvant et de l'ion Ba2+ dans l'hydrolyse alcaline du propionate de methyle

1979 ◽  
Vol 57 (4) ◽  
pp. 400-403 ◽  
Author(s):  
Anne Le Narvor ◽  
Pierre Saumagne
Keyword(s):  
Ir Spectra ◽  
Charge Density ◽  
Carbonyl Group ◽  
Alkaline Hydrolysis ◽  
Experimental Results ◽  
Methyl Propionate ◽  
Orbital Control ◽  
Different Types ◽  
Kinetics Of ◽  
Better Than

The ir spectra of mixtures of methyl propionate/water and methyl propionate/Ba2+ in dimethylsulfoxide and in acetonitrile have been recorded in the region of the νCO mode of the ester. Evidence is presented to indicate the presence of different types of complexes; their concentration was determined as a function of the composition of the medium. The spectroscopic results are compared to those from the kinetics of the alkaline hydrolysis in the same conditions. It is demonstrated that the orbital control explains the experimental results better than does the charge density on the carbon of the carbonyl group. [Journal translation]

Phase diversity in an adsorption model of an additive binary gas mixture for all sets of lateral interactions

2018 ◽  
Vol 20 (15) ◽  
pp. 10359-10368 ◽  
Author(s):  
V. F. Fefelov ◽  
A. V. Myshlyavtsev ◽  
M. D. Myshlyavtseva
Keyword(s):  
Phase Behavior ◽  
Square Lattice ◽  
Complete Analysis ◽  
Gas Mixture ◽  
Lateral Interactions ◽  
Adsorption Model ◽  
Adsorbed Molecules ◽  
Phase Diversity ◽  
Binary Gas Mixture ◽  
Different Types

Complete analysis of phase behavior of an adsorption model of a binary gas mixture on a square lattice was carried out for all possible sets of lateral interactions between nearest adsorbed molecules of the same type and no interaction between adsorbed molecules of different types.

Spectroscopic studies of vanadium biosorption on different types of carbohydrate biomass

2013 ◽  
Vol 91 (3) ◽  
pp. 186-195 ◽  
Author(s):  
Jousy García ◽  
Juan Carlos González ◽  
María Inés Frascaroli ◽  
Silvia García ◽  
Patricia Blanes ◽  
...  
Keyword(s):  
Metal Ion ◽  
Orange Peel ◽  
Spectroscopic Studies ◽  
Visible Range ◽  
Water Molecules ◽  
Main Process ◽  
Paramagnetic Resonance ◽  
Oh Groups ◽  
Surface Level ◽  
Different Types

The biosorption potential of different types of carbohydrate biomass is investigated to evaluate their application to purify water contaminated by vanadium in environmentally relevant oxidation states (VIV and VV). Spectroscopic studies were done by electron paramagnetic resonance (EPR), vanadium nuclear magnetic resonance (51V NMR), circular dichroism (CD), and electronic absorption in the visible range (vis). Both d-galacturonic and d-glucuronic acids are major components of plant cellular wall polysaccharides. The interaction of VIV with the model ligands d-galacturonic and d-glucuronic acids showed that complexation starts at low pH values (pH 3) and that carboxylate and sugar–OH groups, as well as water molecules, are involved in the coordination. At pH > 4.5, coordination promotes the sugar–OH deprotonation and new species form with the ligand chelating the metal ion via oxygen atoms of carboxylate and of adjacent sugar–O− donors. The studies with pectin and citric acid show the ability of both compounds to partially reduce VV to VIV in solution and the EPR parameters suggest coordination of carboxylate, sugar–OH, and water molecules. The interaction of VV with biomass from different sources shows that grapefruit, orange peel, and plane tree fruit are the most suitable candidates for the biosorption of vanadium. Studies with VV and grapefruit (or the grainless stalk of corn) indicate that the reduction takes place at the “surface” of the solid. EPR studies on the interaction of VIV with different carbohydrate biomass show their ability to complex high amounts of VIV. We propose that the biosorption mechanism, when the biomass is in contact with VV species, involves sorption, reduction, and retention at the surface level of VIV coordinated by oxygen donors of the biomass. When the interaction starts with VIV, the main process just involves the uptake of the metal ion at the surface level.

IR Spectra of catalysts and adsorbed molecules

1973 ◽  
Vol 22 (3) ◽  
pp. 504-508
Author(s):  
V. Ya. Danyushevskii ◽  
V. I. Yakerson ◽  
L. I. Lafer ◽  
A. M. Rubinshtein
Keyword(s):  
Ir Spectra ◽  
Adsorbed Molecules

Properties of very dilute alcohol solutions

1977 ◽  
Vol 30 (1) ◽  
pp. 23 ◽  
Author(s):  
F Smith
Keyword(s):  
Dielectric Constant ◽  
Dilute Solution ◽  
Oh Groups ◽  
Correlation Data ◽  
Energy Of Mixing ◽  
Different Types ◽  
Alkane Solvents ◽  
Free Energy Of Mixing ◽  
Degree Of Association ◽  
Dipole Correlation

A detailed study is reported of the association behaviour of normal alcohols in very dilute solution (c < 0.2 mol/dm3) in benzene, carbon tetrachloride and alkane solvents using experimental i.r., N.M.R., dielectric constant, enthalpy and free energy of mixing data. The concentration dependence of the degree of association F(c) has been derived from these data and the results compared and critically assessed. The derived F(c) data have been found to be independent of the property used, while the hydrogen-bonding propensities of the OH groups are found to be independent of the alcohol chain length. The implications of the form of F(c) for association models is discussed and used together with dipole-dipole correlation data g(c) to obtain information on imer structure. An indication has been obtained of the cause of the distinctive forms of the F(c) and g(c) functions found for alcohol solutions in the different types of solvent.

scholarly journals Synthese und Eigenschaften unsymmetrischer Diketopiperazine des Cysteins / Synthesis and Properties of Unsymmetrical Diketopiperazines of Cysteine

1971 ◽  
Vol 26 (11) ◽  
pp. 1144-1151 ◽  
Author(s):  
V. Rossbach, ◽  
H. Wenck
Keyword(s):  
Ir Spectra ◽  
Functional Groups ◽  
Hydrogen Bridge ◽  
Subsequent Reduction ◽  
Oh Groups ◽  
Nucleophilic Reactivity ◽  
Kinetics Of

The synthesis of cyclo (c)-cys-ser, c-cys-asp and c-cys-try via cyclisation of the corresponding cystin-dipeptidesters and subsequent reduction of the disulfides of the diketopiperazines with mercapto-ethanole is described. The ir-spectra of the cyclo-dipeptides and their disulfides were studied with regard to interactions of the functional groups. The spectra indicate a strong hydrogen bridge between the OH-groups of c-cys-ser-disulfide and interactions between the SH and other functional groups of the above mentioned diketopiperazines. The kinetics of the reaction of cysdiketopiperazines with N-ethylmaleimide and p-nitro-phenylacetate were studied. The SH-groug of cys-diketopiperazines has a greater nucleophilic reactivity towards p-nitro-phenylacetate than was expected on the basis of the pKSH-values.

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