isomerizing

Isomerizing, or isomerization, is the process by which a molecule is converted into another molecule that has the same molecular formula but a different arrangement of atoms. Isomerization can be classified into structural (constitutional) isomerization and stereoisomerization.

Structural isomerization involves changes in connectivity and the carbon skeleton. This type includes rearrangements that alter which atoms are bonded to which, such as straight-chain alkanes rearranging into branched isomers or ring-opening and ring-closing processes. These transformations change the overall structure without introducing new atoms.

Stereoisomerization preserves connectivity but changes spatial arrangement. This includes geometric isomerization around carbon–carbon double bonds (cis/trans or E/Z) and transformations at stereocenters that can alter optical activity. Geometric isomerization can occur under thermal or photochemical conditions; enzymatic or chemical catalysts can also drive stereochemical changes. In biological systems, specific enzymes called isomerases catalyze many of these interconversions.

Mechanisms and catalysts vary widely. Isomerization can be driven by heat, light, acids or bases, or metal catalysts. Industrially, isomerization is used to improve fuel quality by converting normal alkanes into branched isomers, which increases octane ratings and enhances process efficiency. In synthesis, controlled isomerization offers routes to selective products from a common starting material.

Biological relevance is prominent: organisms use isomerases to interconvert isomers during metabolism, signaling, and vision. For example, photoisomerization of retinal in the eye is a key step in vision.

In summary, isomerization encompasses interconversions between isomers that differ in connectivity or spatial arrangement, spanning chemical, industrial, and biological contexts.