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How does isomerization change an unbranched alkane into a branched alkane?

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structures of common hydrocarbon compounds — hydrocarbon Structures assumed by hydrogen (H) and carbon (C) molecules in four common hydrocarbon compounds.

Isomerization is the chemical process that transforms a compound into one of its isomeric forms—molecules that share the same chemical composition but possess a different structure or configuration.1

In the context of alkanes, this process converts an unbranched (straight-chain) alkane into a branched-chain isomer. This transformation is achieved by heating the unbranched alkane to temperatures of 100 °C or higher in the presence of a catalyst, such as aluminum chloride.12

A primary example is the conversion of n-butane, which has its four carbon atoms joined in a continuous chain, into its branched-chain isomer, isobutane. This reaction is a critical component of a process known as reforming in the gasoline industry, as branched-chain hydrocarbons are more effective as motor fuels than their straight-chain counterparts.132