The effect of solvents on the oxidation of butyraldehyde catalysed by ferrocene

1981 ◽  
Vol 46 (1) ◽  
pp. 201-218 ◽  
Author(s):  
Jaroslav Včelák
Keyword(s):  
Oxidation Rate ◽  
Kinetic Equations ◽  
Reaction Medium ◽  
Solvent Polarity ◽  
Dielectric Constants ◽  
Effect Of Solvents ◽  
Nonpolar Solvents ◽  
Similar Dependence ◽  
Donor Ability ◽  
Solubility Of Oxygen

Oxidation of butyraldehyde to butyric acid catalysed by ferrocene in 10 solvents has been described by kinetic equations for autocatalysis. Rate constants of these equations were correlated with the properties of solvents. The oxidation rate was found to be independent of viscosity and fluidity of the reaction medium, electrophilicity expressed by ETfunction and the donor ability of solvents. Only in nonpolar solvents the oxidation rate depended on (nD)-2s. The rate of the title oxidation reaction was dependent on the polarity of reaction medium which was characterized by dipole moment and by functions of dielectric constants and increased with increasing solvent polarity. A similar dependence was also obtained with the use of solubility parameter and cohesion pressure of solvents. The rate of the oxidation increase with increasing solubility of oxygen in solvents. These dependences were used to discuss some steps of the mechanism of this oxidation.

Solvent and temperature effects on the tautomerization of a carbonitrile molecule: A conductor-like polarizable continuum model (CPCM) study

2021 ◽  
Vol 20 (1) ◽  
pp. 59-68
Author(s):  
Zohreh Khanjari ◽  
Bita Mohtat ◽  
Reza Ghiasi ◽  
Hoorieh Djahaniani ◽  
Farahnaz Kargar Behbahani
Keyword(s):  
Gas Phase ◽  
Solvent Effects ◽  
Continuum Model ◽  
Solvent Polarity ◽  
Polarizable Continuum Model ◽  
Dielectric Constants ◽  
Frontier Orbitals ◽  
Reaction Field ◽  
Polarizable Continuum ◽  
Homo Lumo

This research examined the effects of solvent polarity and temperature on the tautomerization of a carbonitrile molecule at CAM-B3LYP/6-311G (d,p) level of theory. The selected solvents were n-hexane, diethyl ether, pyridine, ethanol, methanol, and water. The solvent effects were examined by the self-consistent reaction field theory (SCRF) based on conductor-like polarizable continuum model (CPCM). The solvent effects were explored on the energy barrier, frontier orbitals energies, and HOMO-LUMO gap. Dependencies of thermodynamic parameters (ΔG and ΔH) on the dielectric constants of solvents were also tested. Specifically, the temperature dependencies of the thermodynamics parameters were studied within 100–1000 K range. The rate constant of the tautomerism reaction was computed from 300 to 1200 K, in the gas phase.

Solvent effect on simple and high yield synthesis of polydichlorophosphazene precursor Cl3PNSiMe3

2021 ◽  
Author(s):  
Elif Büşra Çelebi ◽  
Ferda Hacıvelioğlu
Keyword(s):  
Solvent Effect ◽  
Room Temperature ◽  
Solvent Polarity ◽  
High Yield ◽  
Effect Of Solvent ◽  
Nonpolar Solvents

The effect of solvent polarity on the reaction of PCl5 with (Me3Si)2NH has been investigated and it is found that nonpolar solvents promote the formation of Cl3PNSiMe3, whereas the more polar chloroform gives unusual phosphazenes at room temperature.

scholarly journals High colloidal stability ZnO nanoparticles independent on solvent polarity and their application in polymer solar cells

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Woojin Lee ◽  
Jiwoo Yeop ◽  
Jungwoo Heo ◽  
Yung Jin Yoon ◽  
Song Yi Park ◽  
...  
Keyword(s):  
Solar Cells ◽  
Zno Nanoparticles ◽  
Colloidal Stability ◽  
Polymer Solar Cells ◽  
Atmospheric Condition ◽  
Solvent Polarity ◽  
Zno Nps ◽  
Long Term Stability ◽  
Nonpolar Solvents ◽  
Efficient Route

Abstract Significant aggregation between ZnO nanoparticles (ZnO NPs) dispersed in polar and nonpolar solvents hinders the formation of high quality thin film for the device application and impedes their excellent electron transporting ability. Herein a bifunctional coordination complex, titanium diisopropoxide bis(acetylacetonate) (Ti(acac)2) is employed as efficient stabilizer to improve colloidal stability of ZnO NPs. Acetylacetonate functionalized ZnO exhibited long-term stability and maintained its superior optical and electrical properties for months aging under ambient atmospheric condition. The functionalized ZnO NPs were then incorporated into polymer solar cells with conventional structure as n-type buffer layer. The devices exhibited nearly identical power conversion efficiency regardless of the use of fresh and old (2 months aged) NPs. Our approach provides a simple and efficient route to boost colloidal stability of ZnO NPs in both polar and nonpolar solvents, which could enable structure-independent intense studies for efficient organic and hybrid optoelectronic devices.

Pyridinium N-phenoxide betaines and their application to the determination of solvent polarities, XXIV. Syntheses and UV-vis spectroscopic properties of new lipophilic tert-butyl- and 1-adamantyl substituted, negatively solvatochromic pyridinium N-phenolate betaine dyes

1998 ◽  
Vol 76 (6) ◽  
pp. 686-694 ◽  
Author(s):  
Christian Reichardt ◽  
Stefan Löbbecke ◽  
Abdol Mohammed Mehranpour ◽  
Gerhard Schäfer
Keyword(s):  
Solvent Polarity ◽  
Spectroscopic Properties ◽  
Tert Butyl ◽  
Nonpolar Solvents ◽  
Phenyl Rings

Syntheses and negative solvatochromism of two new lipophilic pentaphenyl pyridinium N-phenolate betaine dyes, substituted with seven tert-butyl groups (9) or with three tert-butyl and two 1-adamantyl groups (13) in the peripheral phenyl rings, are described in order to get zwitterionic dyes that are more soluble in nonpolar solvents such as the standard betaine dye, 1, which has been used for the construction of an empirical scale of solvent polarity, called the ET(30) scale.Key words: betaine dyes, ET(30) values, lipophilic dyes, pyridinium N-phenolate betaine dyes, solvatochromism, solvent polarity.

Water-Soluble Paracyclophane Fluorophores with Large Two-Photon Action Cross Sections

2005 ◽  
Vol 871 ◽  
Author(s):  
Han Young Woo ◽  
Dmitry Korystov ◽  
Alexander Mikhailovsky ◽  
Guillermo C. Bazan
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Solvent Polarity ◽  
Water Soluble ◽  
Photon Absorption ◽  
Significant Drop ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Donor Ability ◽  
Fine Tune

AbstractA series of tetradonor substituted [2.2]paracyclophane-based two-photon absorption (TPA) fluorophores were designed, synthesized and characterized. Different substituents were chosen to modulate the conjugation and the donor strength and to allow the molecules to be neutral (N series, organic-soluble) or charged (C series, water-soluble). The overall set of compounds series allows us to examine the correlation among the solvent polarity, donor ability of the substituents, and TPA action cross section (ηδd, where δ is the TPA cross section and η is the quantum yield). In water, a significant drop of both δ and η is observed, approximately one-third relative to those in toluene. Weaker donors and/or weaker acceptors with enhanced conjugation are a better choice due to a minimized quenching related to strong charge transfer (CT) upon excitation. One thus needs to fine-tune the magnitude of CT and find an optimal balance among CT,δ and η.

THE EFFECT OF SOLVENTS UPON EQUILIBRIA, SPECTRA, AND REACTION RATES

1960 ◽  
Vol 38 (9) ◽  
pp. 1590-1596 ◽  
Author(s):  
S. Brownstein
Keyword(s):  
Solvent Polarity ◽  
Reaction Rates ◽  
Effect Of Solvent ◽  
Effect Of Solvents ◽  
Spectral Shifts

It is shown that the effect of solvent upon a wide variety of equilibria, reaction rates, and spectral shifts may be described by the equation log (ksolvent/kethanol) = SR. S is a constant related to the polarity of the solvent and R is a measure of the sensitivity of the system to change in solvent polarity. Tables of S and R are included.

The Electric Dipole Moments of Methine Dyes – Comparison of Experimental Results with Theoretical Predictions

1982 ◽  
Vol 37 (9) ◽  
pp. 1024-1026
Author(s):  
Z. Salamon ◽  
A. Skibiński ◽  
K. Celnik
Keyword(s):  
Dipole Moments ◽  
Stokes Shift ◽  
Emission Spectra ◽  
Solvent Polarity ◽  
Electronic Charge ◽  
Excited Singlet ◽  
Nonpolar Solvents ◽  
Singlet States ◽  
Theoretical Predictions ◽  
Excited Singlet States

Abstract Absorption and emission spectra of methine dyes in polar and nonpolar solvents were measured. From the Stokes shift as a function of solvent polarity the dipole moments of excited singlet states have been estimated and compared with the quantum chemical predictions. Also the π-electronic charge distribution in the ground and first excited singlet electronic states and bond orders of the dyes were calculated. All investigated methines showed an increase in dipole moment upon excitation to the first excited emitting state.

2-S-Methyl-5,5-dimethylimidazolin-4-one: chemical behaviour and crystal structure of its Δ1 tautomer

1991 ◽  
Vol 69 (3) ◽  
pp. 383-390 ◽  
Author(s):  
Franco Cristiani ◽  
Francesco A. Devillanova ◽  
Angelo Diaz ◽  
Francesco Isaia ◽  
Gaetano Verani ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chloroform Solution ◽  
Solvent Polarity ◽  
Ultraviolet Spectrum ◽  
Dielectric Constants ◽  
Quantum Mechanical ◽  
Monoclinic Space Group ◽  
Acid Base ◽  
Chemical Behaviour ◽  
Hydantoin Derivatives

2-S-Methyl-5,5-dimethylimidazolin-4-one can be crystallized as Δ1 or Δ2 tautomers, depending on the solvent polarity. The structure, solved on crystals obtained from benzene, showed it to be the Δ1 tautomer in the anti configuration. Δ1-2-S-Methyl-5,5-dimethylimidazolin-4-one is monoclinic, space group P21/c, with a = 8.347(1), b = 10.121(1), c = 9.996(3) Å, β = 107.20(2)°, R = 0.037 for 1395 independent reflections with I > lσ(I). The quantum mechanical (MNDO, PM3, and AMI) calculations indicate that among the four conformers the anti-Δ1 tautomer has both the lowest dipole moment and the lowest enthalpy of formation. The ultraviolet spectrum of the title compound has been recorded in solvents with different dielectric constants. The infrared spectra of the Δ1 and Δ2 solid samples are discussed relative to the v(NH) and v(CO) absorptions and in comparison with those recorded in carbon tetrachloride and in chloroform solution. Its acid–base behaviour has been studied by determining the pKa in aqueous solutions and the results are compared with those obtained for some related hydantoins. Key words: 2-S-methyl-5,5-dimethylimidazolin-4-one, tautomerism, hydantoin derivatives, crystal structure.

Influence of Decreasing Solvent Polarity (Dioxane-Water Mixtures) on the Stability of Metal Ion Complexes Formed with Phosphate Monoesters

1989 ◽  
Vol 44 (5) ◽  
pp. 538-542 ◽  
Author(s):  
Guogang Liang ◽  
Nicolas A. Corfù ◽  
Helmut Sigel
Keyword(s):  
Metal Ion ◽  
Equilibrium Constants ◽  
Solvent Polarity ◽  
Bulk Water ◽  
Dielectric Constants ◽  
Metal Ion Binding ◽  
Nitrophenyl Phosphate ◽  
Phosphate Monoesters ◽  
The Stability ◽  
Straight Lines

The acidity constants of H(R-MP)-, where R-MP2- = 4-nitrophenyl phosphate (NPhP2-), phenyl phosphate (PhP2-) and D-ribose 5′-monophosphate (RibMP2-), and the stability constants of the binary Cu(R-MP) complexes were determined by potentiometric pH titrations in aqueous solution and in 20, 30, 40 and 50% (v/v) dioxane-water mixtures. The solvent influence on the corresponding equilibrium constants is compared with the same influence on previously studied systems containing uridine 5′-triphosphate, formate or acetate. The influence of the solvent composition on the various ligand (L) systems was evaluated by constructing log KM(L) versus pKH(L)H plots; in all cases straight lines are obtained with slopes close to 1. This indicates that in all these systems, despite the different negative charges of the involved ligands, the solvent effect on proton binding and on metal ion binding is approximately of the same size: A decreasing solvent polarity resulting from the addition of increasing amounts of organic solvent to the aqueous solutions favors the affinity of the negatively charged ligands for protons and metal ions as well. Information of this type is considered important because the ‘effective’ or ‘equivalent solution’ dielectric constants in active-site cavities of enzymes are reduced compared with the dielectric constant of bulk water; i. e., in protein cavities also a decreased ‘solvent polarity’ is occurring and this is expected to affect the stability of metal ion-ligand bonds.

scholarly journals A Combined Synthetic and DFT Study on the Catalyst-Free and Solvent-Assisted Synthesis of 1,3,4-Oxadiazole-2-thiol Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Soleiman-Beigi ◽  
Reza Aryan ◽  
Maryam Yousofizadeh ◽  
Shima Khosravi
Keyword(s):  
Field Theory ◽  
Ab Initio ◽  
Solvent Effects ◽  
Reaction Medium ◽  
Theoretical Studies ◽  
Product Selectivity ◽  
Efficient Catalyst ◽  
Reaction Field ◽  
Effect Of Solvents ◽  
Catalyst Free

A novel practical and efficient catalyst-free method for the synthesis of 5-substituted 1,3,4-oxadiazole-2-thiols has been developed, which is assisted by reaction solvent (DMF). The solvent effects on product selectivity were studied based on Onsager’s reaction field theory of electrostatic solvation. The ab initio theoretical studies on the effect of solvents on the process also supported the suitability of DMF as the reaction medium for the preparation of 1,3,4-oxadiazole-2-thiol derivatives.

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