Correlation between the structure of aromatic compounds and the rate of their biological degradation

1984 ◽  
Vol 49 (12) ◽  
pp. 2891-2896 ◽  
Author(s):  
Pavel Pitter
Keyword(s):  
Aromatic Compounds ◽  
Electrophilic Substitution ◽  
Degradation Rate ◽  
Biological Degradation ◽  
Electronic Effects ◽  
Aromatic System ◽  
Limiting Stage ◽  
Reaction Constant ◽  
Substituent Constants ◽  
Linear Correlations

Linear relations have been obtained between the logarithms of the biological degradation rate of phenol and aniline derivatives and the substituent constants σ accounting for their electronic effects. The reaction constant in the Hammett equation is negative; the biological degradation rate is negatively affected by electron-withdrawing substituents. Of the OH, CH3, Cl, NO2, and NH2 substituents tested, only amino group led to deviations from the linear correlations for monosubstituted phenols. The rate of degradation of the aromatic system seems to be controlled by electronic effects, the limiting stage being the electrophilic substitution; correlations using the steric or lipophilic constants failed.

Infrared spectra of aqueous sodium benzoates and salicylates in the carboxyl-stretching region: chelation in aqueous sodium salicylates

1969 ◽  
Vol 47 (24) ◽  
pp. 4577-4588 ◽  
Author(s):  
G. E. Dunn ◽  
R. S. McDonald
Keyword(s):  
Salicylic Acid ◽  
Carbon Tetrachloride ◽  
Infrared Spectra ◽  
Aromatic Compounds ◽  
Deuterium Oxide ◽  
Substituent Effects ◽  
Good Evidence ◽  
Frequency Region ◽  
Aqueous Sodium ◽  
Substituent Constants

Infrared spectra in the frequency region 1300–1760 cm−1 are reported for 41 substituted sodium benzoates and 10 substituted sodium salicylates in deuterium oxide solution, and for 9 substituted salicylic acids in chloroform and carbon tetrachloride solutions. Carboxylate stretching frequencies of benzoates and salicylates correlate poorly with substituent constants, but the asymmetric frequencies of benzoates and salicylates correlate well with each other, and the asymmetric frequencies of benzoates correlate well with the asymmetric frequencies of the corresponding nitrobenzenes. It is suggested that, among substituted aromatic compounds, group vibrations which couple with the ring vibrations may correlate well with similar vibrations of other groups, but not with coupled vibrations of different symmetry, uncoupled vibrations, or substituent constants. Chelation in chloroform solutions of salicylic acid dimers can be detected by its influence on substituent effects, but infrared spectra provide no good evidence for chelation in aqueous sodium salicylates.

scholarly journals Simultaneous Adsorption and Biodegradation of Reactive Dyes using Jatropha Deoiled Cakes

2019 ◽  
Vol 8 (12) ◽  
pp. 3246-3250
Keyword(s):  
Biological Treatment ◽  
Degradation Rate ◽  
Human Life ◽  
Reactive Dyes ◽  
Poor Quality ◽  
Effluent Treatment ◽  
Biological Degradation ◽  
Scientific Communities ◽  
The Poor ◽  
Effect Of Glucose

Endemic pollution problems due to discharge of wastewaters are affecting all the aspects of human life. The poor quality effluents coming from industries is destroying the fragile ecosystem, leading to various apprehensions amongst researchers and scientific communities. Treatment of wastewaters have become an urgent need of the society, which cannot be ignored. Incineration, absorption on solid matrices and biological treatment are some of the effluent treatment methods available. These methods, however, have their own disadvantages. This work explores the application of jatropha deoiled cakes on the concurrent adsorption and biological degradation of reactive dyes. Reactive blue, reactive yellow, reactive red were used for the experiments. The combined experiments were tested for effect of glucose concentrations as well as initial concentrations. Glucose concentrations of 1 g/l, 2 g/l and 3 g/l were taken. All the dyes were varied from 100 ppm to 600 ppm. It was observed that combined degradation yielded higher degradation compared to biological degradation alone. The degradation rate varied with the variation of glucose concentration and it also varied with the initial concentration.

Inductive Effects on Molecular Ionization Potentials, XVIII Alkylpyridines and Alkylthiophenes. Molecular Orbital Calculations on Alkylbenzenes and Alkylpyridines

1977 ◽  
Vol 32 (10) ◽  
pp. 1160-1164 ◽  
Author(s):  
Cyril Párkányi ◽  
Leonard S. Levitt
Keyword(s):  
Molecular Orbital ◽  
Linear Correlation ◽  
Molecular Orbitals ◽  
Ionization Potentials ◽  
Molecular Orbital Calculations ◽  
Alkyl Groups ◽  
Inductive Effects ◽  
Substituent Constants ◽  
Linear Correlations ◽  
Molecular Ionization

Models of alkylbenzenes were treated by the HMO and SCF—MO methods and excellent linear correlations were found between the experimental ionization potentials, EI, and the energies of the highest occupied π-molecular orbitals calculated by the above-mentioned methods. A similar linear correlation was obtained for a group of methylpyridines. Also, the experimental ionization potentials of methylpyridines and alkylthiophenes have been linearly correlated with the sum of TAFT'S inductive substituent constants, ΣσI of the alkyl groups.

Electronic effects in cations of aza-aromatic compounds

1975 ◽  
Vol 11 (7) ◽  
pp. 859-861
Author(s):  
K. V. Veksler ◽  
G. M. Trakhnova ◽  
T. M. Sipenkova ◽  
S. S. Zhitenev ◽  
G. A. Odoeva
Keyword(s):  
Aromatic Compounds ◽  
Electronic Effects

Separation of the Enthalpic and Entropic Contributions to Substituent Effects for the Equilibrium Constants of Aromatic Acids

1975 ◽  
Vol 53 (23) ◽  
pp. 3622-3633 ◽  
Author(s):  
T. M. Krygowski ◽  
W. R. Fawcett
Keyword(s):  
Substituent Effect ◽  
Equilibrium Constants ◽  
Substituent Effects ◽  
Point Of View ◽  
Aromatic Acids ◽  
Resonance Effects ◽  
Equation Analysis ◽  
Reaction Constant ◽  
Enthalpy And Entropy Changes ◽  
Substituent Constants

Separation of the substituent effect ρσ into entropie ρSσS and enthalpic ρHσH contributions is presented within the framework of the general Hammett equation. Analysis of the experimental data for aromatic acids shows that, in general, entropie effects are the major contribution to the total substituent effect, the entropic reaction constant being approximately equal to the normal Hammett ρ A comparison of the present results with those based on a separation of inductive and resonance effects shows that the entropie and inductive effects are directly related. On the other hand, strongly resonance interacting substituents were found to be enthalpy controlled. The substituent effect on enthalpy and entropy changes is discussed from a molecular point of view and related to inductive and resonance effects. A list of 16 enthalpic (σH) and entropie (σS) substituent constants are presented.

Structure and Bonding in Hexa-tert-butyl-hexa-peri-hexabenzocoronene Sandwich Complexes of Ruthenium

2018 ◽  
Vol 71 (4) ◽  
pp. 222
Author(s):  
Matthias Lein
Keyword(s):  
Electronic Interaction ◽  
Polyaromatic Hydrocarbon ◽  
Electronic Effects ◽  
Aromatic System ◽  
Tert Butyl ◽  
Coordination Sites ◽  
Site Selectivity ◽  
Sterically Demanding ◽  
Close Proximity ◽  
Steric Influence

We evaluate the balance of steric and electronic effects in the site selectivity of the binding of [Rh(Me5Cp)]+ ([RhCp·]+) to the three possible coordination sites of the polyaromatic hydrocarbon (PAH) hexa-tert-butyl-hexa-peri-hexabenzocoronene (HBBC). We find that despite the close proximity of sterically demanding tert-butyl groups to the methyl groups of the Cp* ligand, the extent of steric repulsion is minor compared to electronic interaction from bond formation and that the site selectivity is best explained in terms of the electronics of the (poly) aromatic system. This is in contrast to previous investigations on similar systems with a COD ligand where steric influence has been shown to dominate selectivity.

scholarly journals Theoretical Study of the Electronic Effects in the Intramolecular Ketene-Styrene [2+2] Cycloaddition

2019 ◽  
Vol 54 (4) ◽  
Author(s):  
Manuel Fernando Rubio ◽  
Federico Jiménez-Cruz ◽  
Guillermo Ramírez-Galicia
Keyword(s):  
Transition State ◽  
Theoretical Study ◽  
Positive Charge ◽  
Ring Structure ◽  
Experimental Results ◽  
Electronic Effects ◽  
Hartree Fock ◽  
Reaction Constant ◽  
Remote Substituent

DFT (B3LYP/6-31+G*) and post-Hartree-Fock (MP2/6-31+G*//B3LYP/6-31G*) calculations were carried out in order to explain the effect of a remote substituent in the intramolecular ketene-styrene [2+2] cycloaddition of p-substituted 2-methyl-7-arylhepta- 1,6-dien-1-one which produces the bicycle[3.1.1] or the bicycle [3.2.0] heptanones according to Bèlanger experimental results. The transition state geometries were found as an asynchronous process with a three-member ring structure and an incipient positive charge development. Kinetic and thermodynamic controls were proposed at B3LYP/6-31+G* to determine which product is most likely to form in a competence reaction. In addition, the value of the ρ experimental reaction constant was reproduced, ρ ~ -1.34.

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