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Organic Chemistry
Published in Armen S. Casparian, Gergely Sirokman, Ann O. Omollo, Rapid Review of Chemistry for the Life Sciences and Engineering, 2021
Armen S. Casparian, Gergely Sirokman, Ann O. Omollo
In skeletal structures (also known as line notation), lines are used to denote shared electrons between carbon atoms. One shared electron pair is denoted using a single line (single bond). Two lines (double bond) represent two pairs of shared electrons (C=C), and three lines (triple bond) represent three pairs of shared electrons (C≡C).
Solar irradiation-driven synthesis of biodiesel from composite oil using biomass catalyst and process parameters optimization
Published in Biofuels, 2023
Balamurugan S, Seenivasan D, Veera Kumar A, Pritam S. Kalos
The FTIR results of egg shell powder is shown in Figure 4(a). The uncalcined eggshell’s major peaks are observed at 1411.89 cm−1, 871.82 cm−1 and 709.80 cm−1, but this asymmetric stretching disappears in the calcined eggshells. The broad infrared wave is observed between 1250 cm−1 and 1500 cm−1 wavenumbers. This represents weak double bond carbon and carbon aromatic functional group present in the eggshell powder [18]. A medium and narrow infrared wave is observed between 800 cm−1 and 900 cm−1 wavenumbers. This represents carbon and fluorine single bond functional group. Drawing insights from the FTIR analysis, it is observed that the eggshell powder accommodates 100% calcium carbonate (CaCO3) in the form of calcite, since the infrared spectrum is observed at variable 1411 cm−1, variable 871 cm−1, and variable 709 cm−1 wavenumbers [19].
An Experimental and Kinetic Study of Phenylacetylene Ignition at High Temperatures
Published in Combustion Science and Technology, 2023
Tao Ding, Weixin Tang, Rui Wang, Ping Xu, Dongxian Li, Changhua Zhang
Upon comparing the pathways shown in Figures 4 and 7, we observed that the side chains attached to the aromatic ring have a significant impact on C8 aromatics’ fuel consumption during oxidation. The main difference lies in the character of the C-C bonds within the side chain: a single bond in ethylbenzene, a double bond in styrene, and a triple bond in phenylacetylene. The C-C bond within the ethyl branched chain is the weakest (74 kcal/mol), resulting in the dominant consumption of decomposition into benzyl and methyl radical, with minor contributions from H-abstraction reactions. In contrast, for styrene, the C-C bond between the phenyl and side chain is much weaker than the C-C bond within the side chains. Thus, the major consumption pathways of styrene are H-abstraction and addition reactions. For phenylacetylene, addition reactions contribute the most. As these addition reactions have a strong promoting effect on phenylacetylene ignition, they lead to shorter ignition delay times for phenylacetylene.
A TDDFT study of some dinuclear compounds containing CpM(CO)3 or CpM(CO)2 groups
Published in Molecular Physics, 2020
Apart from the cited references, there are other papers with more current DFT calculations about similar compounds. Bing Xu [9] studied cyclopentadienyldirrenium carbonyls using DFT, finding its geometry and energy to be dependent on different multiplicities and different isomers. Another paper [10] studied Cp2Mo2(CO)x. For x = 6, there is a single bond between both molybdenes, and for x = 4 there is a triple bond. Thus, for x = 5 it there should be a double bond. For the purposes of this paper, some calculations were performed about this compound which was not known when the paper was written. A further paper [11] studied the structures and dynamics of Cp2M2(CO)4 (M=Fe, Ru) using DFT as well. None of these papers mentioned the electronic spectroscopy of these compounds.