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Feedstock Chemistry in the Refinery
Published in James G. Speight, Refinery Feedstocks, 2020
The effect of hydrogen on naphthene hydrocarbon derivatives is mainly that of ring scission followed by immediate saturation of each end of the fragment produced. The ring is preferentially broken at favored positions, although generally all the carbon–carbon bond positions are attacked to some extent. For example, methyl-cyclopentane is converted (over a platinum–carbon catalyst) to 2-methylpentane, 3-methylpentane, and n-hexane.
Shape Selective Catalysis
Published in Subhash Bhatia, Zeolite Catalysis: Principles and Applications, 2020
Table 4 shows examples of both reactant and product-type selectivities. Cracking conversions of 3-methylpentane and normal hexane are compared over four catalysts. Virtually no reaction occurs over silica; but over the amorphous silica alumina catalyst, both normal hexane and 3-methyl pentane react at a significant rate.
Butane and Naphtha Hydroisomerization
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 isomerization equilibrium of the C6 hydrocarbons is considerably more complex than those of C4 and C5 hydrocarbons. There are two sets of equilibria. The first is the equilibrium between n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane. The second is the equilibrium between cyclohexane and methylcyclopentane. At hydroisomerization conditions, little ring opening or ring closure takes place. Equilibration of the acyclic and cyclic species consequently takes place independently.
VOC and trace gas measurements and ozone chemistry over the Chesapeake Bay during OWLETS-2, 2018
Published in Journal of the Air & Waste Management Association, 2023
Joel Dreessen, Xinrong Ren, Daniel Gardner, Katherine Green, Phillip Stratton, John T. Sullivan, Ruben Delgado, Russ R. Dickerson, Michael Woodman, Tim Berkoff, Guillaume Gronoff, Allison Ring
Both 2 and 3-methylpentane were used to identify and distinguish gasoline combustion emissions from fugitive emissions (Rubin et al. 2006). Rubin et al. found 2 and 3-methylpentane to be among the most abundant compounds in liquid gasoline, headspace vapors, and tunnel emissions, but noted that strongly enhanced isopentane to methylpentane was indicative of headspace vapors. In that study, isopentane was roughly a factor of 7–10 greater than methylpentanes in headspace vapors but was ~2–4 times greater in tunnel emissions. At HMI, linear fits of isopentane and 2 and 3-methylpentane had ratios of 11.3 and 12.8 (R2 <0.08). The median 2 and 3-methypentane to isopentane concentration ratios were 8.1 and 8.6. These ratios indicated gasoline headspace vapors, though other sources cannot be ruled out. For example, methylhexane was identified as evaporative emissions from oil and condensate tanks (Hendler et al. 2009) but also as a non-trivial component of non-road, 2-stroke engine exhaust (Reichle et al. 2015) while 2,3-dimethylpentane has been observed in mobile emissions (Sagebiel et al. 1996).