# Aromatisation of Six-Membered Rings

## Aromatization of Six-Membered Rings: Industrial Applications

### Catalytic dehydrogenation

Aromatic compounds, such as benzene, toluene (methylbenzene) and xylene (dimethylbenzene), are synthesized from hydrocarbons of the C6-8 gasoline fraction obtained during petroleum refining by a process called catalytic reforming. In this process, gaseous hydrocarbons are dehydrogenated to at temperatures of 450-550$°C$ and hydrogen pressure of 1000-5000 $kPa$ with platinum on aluminum oxide as catalyst. In spite of the fact that hydrogen is a product of reforming, excess hydrogen is necessary to prevent the deposition of high-molecular compounds and carbon on the catalyst leading to deactivation.

Fig.1
Industrial synthesis of o-xylene

Addition of aromatic compounds to gasoline increases the octane number and therefore the quality. Some of the aromatics also find applications as solvents or basic organic chemicals.

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