To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

From Wikipedia, the free encyclopedia

In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure.[1] Enolization is an example of isomerization, as is tautomerization.[2] When the isomerization occurs intramolecularly it may be called a rearrangement reaction.[citation needed]

When the activation energy for the isomerization reaction is sufficiently small, both isomers will exist in a temperature-dependent equilibrium with each other. Many values of the standard free energy difference, , have been calculated, with good agreement between observed and calculated data.[3]

YouTube Encyclopedic

  • 1/3
    Views:
    23 072
    532 636
    7 357
  • C.2 Isomerisation (SL)
  • Isomers | Properties of carbon | Biology | Khan Academy
  • Chemistry of Isomerization for Gasoline Isomerates (Lecture 142)

Transcription

Examples and applications

Alkanes

Skeletal isomerization occurs in the cracking process, used in the petrochemical industry. As well as reducing the average chain length, straight-chain hydrocarbons are converted to branched isomers in the process, as illustrated the following reaction of n-butane to i-butane.[citation needed]

Fuels containing branched hydrocarbons are favored for internal combustion engines for their higher octane rating.[4]

Alkenes

Trans-alkenes are about 1 kcal/mol more stable than cis-alkenes. An example of this effect is cis- vs trans-2-butene. The difference is attributed to unfavorable non-bonded interactions in the cis isomer.

Terminal alkenes isomerize to internal alkenes in the presence of metal catalysts. This process is employed in the Shell higher olefin process to convert alpha-olefins to internal olefins, which are subjected to olefin metathesis. In certain kinds of alkene polymerization reactions, chain walking is an isomerization process that introduces branches into growing polymers.[citation needed]

The trans isomer of resveratrol can be converted to the cis isomer in a photochemical reaction.[5]

Resveratrol photoisomerization

Thermal rearrangement of azulene to naphthalene has been observed.[6]

Other examples

Aldose-ketose isomerism, also known as Lobry de Bruyn–van Ekenstein transformation, provides an example in saccharide chemistry.[citation needed]

An example of an organometallic isomerization is the production of decaphenylferrocene, [(η5-C5Ph5)2Fe] from its linkage isomer.[7][8]

Formation of decaphenylferrocene from its linkage isomer
Formation of decaphenylferrocene from its linkage isomer

See also

References

  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "isomerization". doi:10.1351/goldbook.I03295
  2. ^ Antonov L (2016). Tautomerism: Concepts and Applications in Science and Technology (1st ed.). Weinheim, Germany: Wiley-VCH. ISBN 978-3-527-33995-2.
  3. ^ How to Compute Isomerization Energies of Organic Molecules with Quantum Chemical Methods Stefan Grimme, Marc Steinmetz, and Martin Korth J. Org. Chem.; 2007; 72(6) pp 2118 - 2126; (Article) doi:10.1021/jo062446p
  4. ^ Karl Griesbaum; Arno Behr; Dieter Biedenkapp; Heinz-Werner Voges; Dorothea Garbe; Christian Paetz; Gerd Collin; Dieter Mayer; Hartmut Höke (2002). "Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_227. ISBN 3-527-30673-0.
  5. ^ Elyse Bernard, Philip Britz-McKibbin, Nicholas Gernigon (2007). "Resveratrol Photoisomerization: An Integrative Guided-Inquiry Experiment'". Journal of Chemical Education. 84: 1159.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ Becker, Juergen; Wentrup, Curt; Zeller, Klaus; Katz, Ellen (July 1, 1980). "Azulene-naphthalene rearrangement. Involvement of 1-phenylbuten-3-ynes and 4-phenyl-1,3-butadienylidene". J. Am. Chem. Soc. 102 (15): 5110. doi:10.1021/ja00535a056.
  7. ^ Brown, K. N.; Field, L. D.; Lay, P. A.; Lindall, C. M.; Masters, A. F. (1990). "(η5-Pentaphenylcyclopentadienyl){1-(η6-phenyl)-2,3,4,5-tetraphenylcyclopentadienyl}iron(II), [Fe(η5-C5Ph5){(η6-C6H5)C5Ph4}], a linkage isomer of decaphenylferrocene". J. Chem. Soc., Chem. Commun. (5): 408–410. doi:10.1039/C39900000408.
  8. ^ Field, L. D.; Hambley, T. W.; Humphrey, P. A.; Lindall, C. M.; Gainsford, G. J.; Masters, A. F.; Stpierre, T. G.; Webb, J. (1995). "Decaphenylferrocene". Aust. J. Chem. 48 (4): 851–860. doi:10.1071/CH9950851.
This page was last edited on 26 December 2023, at 03:55
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.