scholarly journals Weaving a web of reliable thermochemistry around lignin building blocks: phenol, benzaldehyde, and anisole

2021 ◽  
Author(s):  
Sergey P. Verevkin
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Chemical Method ◽  
Value Added ◽  
Building Blocks ◽  
Enthalpies Of Formation ◽  
Quantum Chemical Method ◽  
Substituted Benzenes ◽  
Energy Balances

Abstract Substituted benzenes such as phenol, benzaldehyde, and anisole are the simplest fragments from the lignin separation feedstocks. We have collected available primary experimental results on vapour pressures, enthalpies of phase transition, and enthalpies of combustion of phenol, benzaldehyde, and anisole. The resulting data on the gas-phase standard molar enthalpies of formation were validated using the quantum chemical method G4. The consistent sets of evaluated thermodynamic data are essential for calculating the energy balances of lignin conversion in the value-added chemicals and materials. Graphic abstract

Solvation of ions by dipolar aprotic solvents and water. A CNDO/2 study

1985 ◽  
Vol 50 (11) ◽  
pp. 2493-2508 ◽  
Author(s):  
Petr Kyselka ◽  
Zdeněk Havlas ◽  
Ivo Sláma
Keyword(s):  
Binary Mixtures ◽  
Quantum Chemical ◽  
Chemical Method ◽  
Molecular Structures ◽  
Dimethyl Sulphoxide ◽  
Ternary Mixtures ◽  
Aprotic Solvents ◽  
Quantum Chemical Method ◽  
Solvation Of Ions ◽  
Dipolar Aprotic Solvents

Solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions has been studied in binary mixtures with dimethyl sulphoxide, dimethylformamide, acetonitrile and water, and in ternary mixtures of the organic solvents with water. The CNDO/2 quantum chemical method was used to calculate the energies of solvation, molecular structures and charge distributions for the complexes acetonitrile...ion (1:1, 2:1, 4:1), dimethyl sulphoxide...ion (1:1), dimethylformamide...ion (1:1), and acetonitrile (dimethyl sulphoxide, dimethylformamide)...ion...water (1:1:1).

The optoelectronic properties of π-conjugated organic molecules based on terphenyl and pyrrole for BHJ solar cells: DFT / TD-DFT theoretical study

2021 ◽  
Vol 10 (4) ◽  
pp. 489-502 ◽  
Author(s):  
M. Raftani ◽  
T. Abram ◽  
W. Loued ◽  
R. Kacimi ◽  
A. Azaid ◽  
...  
Keyword(s):  
Solar Cells ◽  
Quantum Chemical ◽  
Chemical Method ◽  
Chemical Reactivity ◽  
Optoelectronic Properties ◽  
Oscillator Strengths ◽  
Frontier Molecular Orbital ◽  
Bandgap Energy ◽  
Quantum Chemical Method ◽  
Td Dft

In the present paper, four π-conjugated materials, based on terphenyl and pyrrole, with A–D–A structure have been theoretically studied to propose new organic compounds to be used in the organic solar cell field. Moreover, the geometrical and optoelectronic properties of the designed molecules M1, M2, M3 and M4 have been computed after optimization in their fundamental states, using the quantum chemical method DFT / B3LYP/ 6−311G (d, p). Different parameters including HOMO and LUMO energy levels, bandgap energy, frontier molecular orbital (FMO), chemical reactivity indices, the density of states (DOS), Voc, electrostatic potential (ESP), and thermodynamic parameters at several temperatures in the range of 0-500 K have been determined. The absorption properties including the transition energy, the wavelengths (λmax), the excitation vertical energy, and the corresponding oscillator strengths of these molecules have been studied using the quantum chemical method TD−DFT / CAM–B3LYP / 6–311G (d, p). The obtained results of our studied compounds show that M3 (with 2H, 2'H-1, 1'-biisoindole moiety) as a donor group has special optoelectronic, absorption, and good photovoltaic characteristics. Thus, they can be utilized as an electron-donating in organic solar cells BHJ type.

scholarly journals Standard Molar Enthalpies of Formation of Halomethanes Based on Quantum Chemical Computations

2020 ◽  
Author(s):  
Konstantinos Kalamatianos
Keyword(s):  
Gas Phase ◽  
Quantum Chemical ◽  
Halogen Bond ◽  
Chemical Processes ◽  
Enthalpies Of Formation ◽  
Isodesmic Reaction ◽  
Gold Standard Method ◽  
Ozone Destruction ◽  
Quantum Chemical Computations ◽  
Reaction Schemes

Accurate calculations of standard molar enthalpies of formation (ΔΗf°)m(g) and carbon-halogen bond dissociation enthalpies, BDE, of a variety of halomethanes with relevance on several atmospheric chemical processes and particularly to ozone destruction, were performed in the gas phase at 298.15 K. The (ΔΗf°)m(g) of the radicals formed through bond dissociations have also been computed. Ab initio computational methods and isodesmic reaction schemes were used. It is found that for the large majority of these species, the gold standard method of quantum chemistry (CCSD(T)) and even MP2 are capable to predict enthalpy values nearing chemical accuracy provided that isodesmic reaction schemes are used. New estimates for standard molar enthalpies of formation and BDE are suggested including for species that to our knowledge there are no experimental (ΔΗf°)m(g) (CHCl2Br, CHBr2Cl, CHBrCl, CHICl, CHIBr) or BDE values (CHCl2Br, CHBr2Cl, CHBrCl, CHICl, CHIBr) available in the literature. The method and calculational procedures presented may profitably be used to obtain accurate (ΔΗf°)m(g) and BDE values for these species.

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