Isomerisation

In chemistry isomerization (also isomerisation) is the process by which one molecule is transformed into another molecule which has exactly the same atoms, but the atoms have a different arrangement e.g. A-B-C → B-A-C (these related molecules are known as isomers ). In some molecules and under some conditions, isomerization occurs spontaneously. Many isomers are equal or roughly equal in bond energy, and so exist in roughly equal amounts, provided that they can interconvert somewhat freely; that is, the energy barrier between the two isomers is not too high. When the isomerization occurs intramolecularly it is considered a rearrangement reaction.

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

Isomerization in hydrocarbon cracking is usually employed in organic chemistry, where fuels, such as diesel or pentane, a straight-chain isomer, are heated in the presence of a platinum catalyst. The straight- and branched-chain isomers in the resulting mixture then have to be separated. Another industrial process is the isomerisation of n-butane into isobutane.

"Trans-cis isomerism" is where, in certain compounds, an interconversion of cis and trans isomers can be observed. For instance, with maleic acid and with azobenzene, often by photoisomerization. Another example is the photochemical conversion of the trans isomer to the cis isomer of resveratrol:

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