Theoretical study on thermochemical parameters and IR spectra of chlorinated isomers of nitrobenzene

2013 ◽  
Vol 91 (10) ◽  
pp. 999-1008 ◽  
Author(s):  
Ibrahem Altarawneh ◽  
Mohammednoor Altarawneh ◽  
Saleh Rawadieh
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Ir Spectra ◽  
Theoretical Study ◽  
Enthalpies Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Calculated Enthalpy ◽  
Standard Enthalpies Of Formation ◽  
Thermochemical Parameters

Thermochemical and geometrical parameters and internal rotation barriers of all chlorinated nitrobenzene isomers were calculated with the G3MP2B3 composite method. Standard entropies, standard Gibbs free energies of formation, standard enthalpies of formation, and heat capacities were calculated and compared with their corresponding available experimental data. Our calculated enthalpy values agree well with the corresponding experimental data. The temperature dependence of entropy and heat capacity has been analysed. All isomers with ortho-chlorine substituents were found to be less stable than other corresponding isomers. Rotational barriers and distortions of the benzene rings were incorporated in the calculations of values for entropy and heat capacity. The IR spectra were calculated and found to be in reasonable agreement with the experimental spectra.

scholarly journals A Thermochemical Parameters and Theoretical Study of the Chlorinated Compounds of Thiophene

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Ibrahim A. M. Saraireh ◽  
Mohammednoor Altarawneh ◽  
Jibril Alhawarin ◽  
Mansour H. Almatarneh
Keyword(s):  
Enthalpies Of Formation ◽  
Geometrical Parameters ◽  
Reactivity Descriptors ◽  
Relative Preference ◽  
Fukui Indices ◽  
Calculated Enthalpy ◽  
Standard Enthalpies Of Formation ◽  
Complete Series ◽  
Thermochemical Parameters ◽  
Experimental Values

This contribution sets out to compute thermochemical and geometrical parameters of the complete series of chlorinated isomers of thiophene based on the accurate chemistry model of CBS-QB3. Herein, we compute standard entropies, standard enthalpies of formation, standard Gibbs free energies of formation, and heat capacities. Our calculated enthalpy values agree with available limited experimental values. The DFT-based reactivity descriptors were used to elucidate the site selectivity for the chlorination sequence of thiophene. The relative preference for chlorination was found to be in accord with the thermodynamic stability trends inferred based on the H scale. Calculated Fukui indices predict a chlorination sequence to ensue as follows: 2-chloro → 2,5-dichloro → 2,3,5-trichloro → 2,3,4,5-tetrachlorothiophene.

A Theoretical Study of Substituted Stepwise Fluorinated Cyclopropanone Keto-Enol System

2003 ◽  
Vol 58 (12) ◽  
pp. 749-755
Author(s):  
Abdullah El-Alali ◽  
Ali A. Marashdeh ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Isodesmic Reactions ◽  
Orbital Energies ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Complete Optimization

MINDO-Forces calculations have been performed with complete optimization of the geometries on stepwise fluorinated cyclopropanones and their enols. Increase in the number of fluorine atoms causes destabilization of cyclopropanone. Perfluorinated enol was found to be present in substantial concentration, as was mentioned in previous work. This is supported by calculations of Gibbs free energies and isodesmic reactions. Geometrical parameters, heats of formation, electron densities, dipole moments and orbital energies (HOMO-LUMO) are reported.

scholarly journals A Theoretical Study of Substituted Cyclopentanones and their Enols

2003 ◽  
Vol 58 (12) ◽  
pp. 738-748 ◽  
Author(s):  
Meisa S. Al-Noeemat ◽  
Reem A. Al-Ma’ani ◽  
Salim M. Khalil
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Geometry Optimization ◽  
Density Functional Theory Calculations ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Strong Electron ◽  
Functional Theory ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on cyclopentanone and its enol counter part, perfluorination of cyclop entanone and its enol counterpart and X-cyclopentanones and their X-enols, where X is NO2, CF3, CN, OH, NH2 and O−. It was found that ketone is more stable than its enol counterpart. Perfluorination destabilizes ketone on the expense of enol. These results agree with the experimental results and density functional theory calculations. All substituents are destabilizing except O− in the case of cyclopentanone. It was found that NO2 and CF3 behave as strong electron withdrawing groups, CN and NC show amphielectronic behavior, and the substituents OH,NH2 and O− behave as electron releasing groups with O− being strongest. Geometrical parameters, heats of formation, entropies, and Gibbs free energies are reported

The Standard Enthalpies of Formation of Energetic 4,5-dinitroimidazole derivatives: A Theoretical Study

2013 ◽  
Vol 774-776 ◽  
pp. 484-487 ◽  
Author(s):  
Xin Fang Su ◽  
Jing Hua Wei ◽  
Hai Ying Wu
Keyword(s):  
Nitro Group ◽  
Theoretical Study ◽  
Enthalpies Of Formation ◽  
Isodesmic Reactions ◽  
Standard Enthalpies Of Formation ◽  
Derivatives Of

The standard enthalpies of formation for 7 derivatives of 4,5-dinitroimidazole in gas at 298 K were determined using isodesmic reactions at B3LYP/6-311G** and B3P86/6-311G** levels. The results indicate that the substitution of nitro group can increase the enthalpies of formation. The more the number of nitro group, the higher the enthalpies of formation. The standard enthalpies of formation of –NO2 and –CH3 substitution compounds on N atom are larger than corresponding ones on C atom.

THEORETICAL STUDY OF THE EFFECT OF GEOMETRICAL PARAMETERS AND LOCATION OF ROTOR IMPACT ELEMENTS OF AN IMPACT-CENTRIFUGAL GRINDER ON SPEED AND ANGLES OF CRUSHED PARTICLES FLIGHT

2020 ◽  
Keyword(s):  
Granulometric Composition ◽  
Theoretical Study ◽  
Process Efficiency ◽  
Geometrical Parameters ◽  
Grinding Process ◽  
Main Work ◽  
Impact Element ◽  
The Impact ◽  
Positive Effect ◽  
Efficiency Indicators

One of efficiency indicators of grain grinders is grain granulometric composition. The basis of mixed fodder is crushed grain, the particles of which must have a leveled granulometric composition for subsequent mixing and obtaining a high-quality feed mixture. In agricultural production, hammer crushers are widely used, in which the destruction of grain occurs due to the impact of a hinged hammer. The main disadvantage of these crushers is that not the entire surface of the hammers is involved in grinding, thus reduces grinding process efficiency. A slightly different principle of material destruction is laid down in the basis of the proposed design of the shock-centrifugal grinder. Main work is performed by flat impact elements located on the rotor, which serve to accelerate crushed particles with subsequent impact of them on the bump elements. An important step in the design of new constructions of shock-centrifugal grinders is to determine size and location of the impact elements on the rotor, without which the grinding process is not possible. In the calculation method presented, the dependencies for determining the velocities and angles of a single particle flight from the surface of a flat impact element for its specified dimensions are proposed. Two variants of an impact element location on the rotor are considered and analyzed: radial and at an angle in the direction of rotor rotation. As a result of research carried out, it is noted that in the case of inclined position of an impact element on the rotor an increase in flight speed and flight angles change in crushed particles, which gives the opportunity to have a positive effect on grinding process.

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