Chemistry:Methylcyclopentane

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Methylcyclopentane is an organic compound with the chemical formula CH3C5H9. It is a colourless, flammable liquid with a faint odor. It is a component of the naphthene fraction of petroleum usually obtained as a mixture with cyclohexane. It is mainly converted in naphthene reformers to benzene.[1]

As of early 1990s, it was present in American[2] and European[3] gasoline in small amounts, and by 2011 its share in US gasoline varied between 1 and 3%.[4] It has a research octane number of 103 and motor octane number of 95.[5]

The C6 core of methylcyclopentane is not perfectly planar and can pucker to alleviate stress in its structure.[6]

The conversion of methylcyclopentane to benzene is a classic aromatization reaction, specifically a dehydroisomerization. This platinum (Pt)-catalyzed process is practiced on scale in the production of gasoline from petroleum.

History

Methylcyclopentane was first synthesized in 1888 by Paul Caspar Freer ({{{2}}}) and W. H. Perkin Jr. by a Wurtz reaction of sodium and 1,5-dibromohexane.[7] They named it methylpentamethylene since the modern nomenclature wasn't developed until 1892 Geneva Rules.

In 1895, Nikolai Kischner discovered that methylcyclopentane was the reaction product of hydrogenation of benzene using hydriodic acid. Prior to that, several chemists (such as Marcellin Berthelot in 1867,[8][9] and Adolf von Baeyer in 1870[10]) had tried and failed to synthesize cyclohexane using this method.

References

  1. ↑ M. Larry Campbell (2012). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_209.pub2. 
  2. ↑ Doskey, Paul V.; Porter, Joseph A.; Scheff, Peter A. (November 1992). "Source Fingerprints for Volatile Non-Methane Hydrocarbons" (in en). Journal of the Air & Waste Management Association 42 (11): 1437–1445. doi:10.1080/10473289.1992.10467090. ISSN 1047-3289. Bibcode: 1992JAWMA..42.1437D. https://www.tandfonline.com/doi/full/10.1080/10473289.1992.10467090. 
  3. ↑ Östermark, Ulf; Petersson, Göran (1992-09-01). "Assessment of hydrocarbons in vapours of conventional and alkylate-based petrol". Chemosphere 25 (6): 763–768. doi:10.1016/0045-6535(92)90066-Z. ISSN 0045-6535. Bibcode: 1992Chmsp..25..763O. https://publications.lib.chalmers.se/records/fulltext/local_72590.pdf. 
  4. ↑ "Hydrocarbon Composition of Gasoline Vapor Emissions from Enclosed Fuel Tanks". United States Environmental Protection Agency. 2011. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100GPED.TXT. 
  5. ↑ Lokachari, Nitin; Wagnon, Scott W.; Kukkadapu, Goutham; Pitz, William J.; Curran, Henry J. (2021-03-01). "An experimental and kinetic modeling study of cyclopentane and dimethyl ether blends". Combustion and Flame 225: 255–271. doi:10.1016/j.combustflame.2020.10.017. ISSN 0010-2180. Bibcode: 2021CoFl..225..255L. https://www.sciencedirect.com/science/article/abs/pii/S0010218020304375. 
  6. ↑ Carey, Francis; Giuliano, Robert (2014). "3". Organic Chemistry (9 ed.). McGraw-Hill. pp. 97–131. ISBN 978-0073402741. 
  7. ↑ Freer, Paul C.; Perkin, W. H. (1888). "The synthetical formation of closed carbon-chains. Part IV. Some derivatives of hexamethylene" (in en). Journal of the Chemical Society, Transactions 53: 202–215. doi:10.1039/CT8885300202. ISSN 0368-1645. https://books.google.com/books?id=xvRi1OdwXbAC&pg=PA202. 
  8. ↑ Bertholet (1867). "Nouvelles applications des méthodes de réduction en chimie organique" (in fr). Bulletin de la Société Chimique de Paris series 2 (7): 53–65. https://books.google.com/books?id=YVgSAAAAYAAJ&pg=PA53. 
  9. ↑ Bertholet (1868). "Méthode universelle pour réduire et saturer d'hydrogène les composés organiques" (in fr). Bulletin de la Société Chimique de Paris series 2 (9): 8–31. https://books.google.com/books?id=r1sSAAAAYAAJ&q=Bertholet&pg=PA17. "En effet, la benzine, chauffée à 280° pendant 24 heures avec 80 fois son poids d'une solution aqueuse saturée à froid d'acide iodhydrique, se change à peu près entièrement en hydrure d'hexylène, C12H14, en fixant 4 fois son volume d'hydrogène: C12H6 + 4H2 = C12H14 … Le nouveau carbure formé par la benzine est un corps unique et défini: il bout à 69°, et offre toutes les propriétés et la composition de l'hydrure d'hexylène extrait des pétroles.". 
  10. ↑ Adolf Baeyer (1870). "Ueber die Reduction aromatischer Kohlenwasserstoffe durch Jodphosphonium". Annalen der Chemie und Pharmacie 55: 266–281. https://books.google.com/books?id=RJU8AAAAIAAJ&pg=PA266. "Bei der Reduction mit Natriumamalgam oder Jodphosphonium addiren sich im höchsten Falle sechs Atome Wasserstoff, und es entstehen Abkömmlinge, die sich von einem Kohlenwasserstoff C6H12 ableiten. Dieser Kohlenwasserstoff ist aller Wahrscheinlichkeit nach ein geschlossener Ring, da seine Derivate, das Hexahydromesitylen und Hexahydromellithsäure, mit Leichtigkeit wieder in Benzolabkömmlinge übergeführt werden können.". 



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