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Catalytic Naphtha Reforming
Published in Mark J. Kaiser, Arno de Klerk, James H. Gary, Glenn E. Hwerk, Petroleum Refining, 2019
Mark J. Kaiser, Arno de Klerk, James H. Gary, Glenn E. Hwerk
The impact of hydroisomerization and hydrocracking on the octane number of the reformate is different. Paraffins in the heavy naphtha have low octane numbers, unless the paraffins are tri- or tetrabranched. The octane number of the heavy naphtha is nevertheless improved by hydroisomerization, because branched paraffins have higher octane numbers than linear paraffins. For example, n-heptane has a RON = 0 and MON = 0, but 2-methylhexane has a RON = 42 and MON = 46. Although the octane number of 2-methylhexane is still low, it represents a large relative increase in octane number with almost no associated liquid yield loss. The octane number of the heavy naphtha is also improved by hydrocracking, but this is due to the conversion of heavy to light paraffins. The products from hydrocracking of heavy naphtha are in the C3 to C6 range. Hydrocracking is associated with liquid yield loss, but by removing low octane number paraffins from the heavy naphtha, the overall octane number of the remaining liquid is improved. Hydrocracking reactions also consume H2. Thus, although hydrocracking contributes to the increase in the reformate octane number, hydrocracking is responsible for liquid yield loss and H2 yield loss.
Organic Chemicals
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Perbellini et al.81 reported tissue/air partition coefficients for nine aliphatic hydrocarbons: n-pentane, 2,2-dimethylbutane, 2-methylpentane, 3-methylpentane, methylcyclopentane, n-hexane, cyclohexane, 2-methylhexane, and n-heptane. Their mean solubility in different tissues was higher than the solubility in the blood by the following factors: lung 1.4, heart 3.9, liver 5.6, kidney 5.2, brain 6.5, muscle 7.6, and fat 205 (Table 5.32). Because of the tissue differences, a much higher end-organ load that produces an increased total body burden occurs. This increased load, in turn, will exacerbate the chemically sensitive for longer periods of time, resulting in chronic illness until the toxic compounds are cleared.
Contaminants Dissolved in the Mobile Pore Water of the Unsaturated Zone
Published in Warren J. Lyman, Patrick J. Reidy, Benjamin Levy, Chi-Yuan Fan, Mobility and Degradation of Organic Contaminants in Subsurface Environments, 2020
Warren J. Lyman, Patrick J. Reidy, Benjamin Levy, Chi-Yuan Fan
Mobile water of locus no. 12 may become contaminated through contact with polluted water in locus no. 3 as contaminated and pure waters mix. Contact with soil air (locus no. 1) containing volatilized liquid contaminant may also contaminate the mobile water of locus no. 12. The compounds which most readily partition from the air phase to the mobile water phase are those compounds with lower Henry’s law constants (e.g., benzene, toluene, xylenes); those compounds with high Henry’s law constants (e.g., 2-methylhexane, n-pentane, 2,2,5,5-tetramethylhexane) present in the mobile water of locus no. 12 partition more readily into the soil air of locus no. 1. The process of air/water partitioning is discussed in detail in locus no. 3.
Novel cubic silicane nanosheet as an adsorbing medium for dimethylbutane and methylhexane molecules – a first-principles study
Published in Molecular Physics, 2023
M. S. Jyothi, V. Nagarajan, R. Chandiramouli
The 2,2-dimethylbutane is also known as neohexane with the molecular formula C6H14 and is the branched isomer of hexane. This is the only isomer of hexane with quaternary carbon and also with butane backbone. The 2-methylhexane possesses a molecular formula of C7H16 and is commonly known as isoheptane. Both types of VOC vapours are heavier than air and pass along the ground. The agitation and flow of these vapours sometimes even generate electrostatic charges. The acute inhalation of these vapours causes tremors and dipsia, lung aspirations, drowsiness, and dizziness [4]. Hence, there is a need for the removal of these vapour contaminants is the need of the hour.