Isomerization

Source: Wikipedia, the free encyclopedia.

In

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]

Examples and applications

Alkanes

Skeletal isomerization occurs in the

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

photochemical reaction.[5]

Resveratrol photoisomerization

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

Other examples

saccharide chemistry.[citation needed
]

An example of an

linkage isomer.[7][8]

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

See also

References

  1. doi:10.1351/goldbook.I03295
  2. ISBN 978-3-527-33995-2
    .
  3. doi:10.1021/jo062446p
  4. 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. doi:10.1021/ja00535a056
    .
  7. doi:10.1039/C39900000408
    .
  8. doi:10.1071/CH9950851
    .
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