Alkanes potential isomers

In alkanes or alkyl systems, an infinite number of conformations is possible as a result of rotation about CC single bonds, and each conformation has a certain potential energy. Two conformational extremes, one of low (minimal steric interaction between bond substituents) and one of high (maximal steric interaction) potential energy, have been described for these systems. These are depicted as Newman projections in Fig. 17. A more recent nomenclature system for conformational isomers arising from energy barriers associated with rotation about a CC single bond is shown in Fig. 18. In this case, the most stable conformer is... 

Several physical-chemical properties of alkanes, polyaromatic hydrocarbons, alkylben-zenes, polychlorobenzenes, polymethylphenols and polychlorophenols were determined using various software packages. The ionization potentials calculated by the MOPAC program was the most suitable property with which to adjust the capacity ratios of polychlorobenzene, polymethylphenol and polychlorophenol isomers . 

The number of hydrocarbons in the atmosphere is potentially very large, since vapor pressures are favorable and the heavier species admit many isomers. In urban areas several hundred different hydrocarbons have been identified by gas chromatography (Appel et al, 1979 Louw el al, 1977). They include saturated compounds (alkanes) unsaturated species with one carbon-carbon double bond (alkenes) or two double bonds (alkadienes), acetylene type compounds (alkynes), and benzene derivatives or aromatic compounds (arenes). To separate that many different compounds requires... 

As a result of the above constraints, VOCs that for all practical purposes do not produce organic aerosol in the atmosphere include all alkanes with up to six carbon atoms (from methane to hexane isomers), all alkenes with up to six carbon atoms (from ethene to hexene isomers), and most other low-molecular-weight compounds. An important exception is isoprene, a five-carbon atom molecule with two double bonds (see Section 6.11) isoprene photooxidation produces SOA in laboratory chambers (Kroll et al. 2005, 2006) and its oxidation products have been detected in ambient aerosols (Claeys et al., 2004a Edney et al. 2005). In general, large VOCs containing one or more double bonds are expected to be good SOA precursors. A set of structure-SOA formation potential relationships have been proposed by Keywood et al. (2004) for cycloalkenes ... 

In a theoretical work, we compared cationic Ni202H2 [134] with Ni202H2 [135], which are the (potential) products of the reaction of Ni202 and Ni202 with H2 or with alkanes. They also could be regarded as products of the NiO/NiO" " + H2O reaction. The analysis of these systems completes the comparison of neutral and cationic nickel oxides. The lowest lying isomer of Ni202H2" has a rhombic... 

Similarly, 2-methylpentane runs through the column faster than its linear isomer n-hexane, while 2,2-dimethylbutane, the isomer of hexane with the shortest linear chain, elutes even faster. Thus, mixtures of 2-methylbutane, n-pentane, 2,2-dimethylbutane, 2-methylpentane, and n-hexane can be easily separated with this new type of microporous MOF column. The potential applications of this mi-croporous MOF column in the efficient GC separation of natural gas and alkane mixtures are remarkable and foreseeable. The column could be used to identify the impurities in natural gas, and to monitor the amounts of mono- and multibranched alkanes formed in cracking reactions. 

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