Ethyltoluene

Ethyltoluene describes organic compounds with the formula CH₃C₆H₄CH₂CH₃. Three isomers exist: 1,2- 1,3-, and 1,4-. All are colorless liquids, immiscible in water, with similar boiling points. They are classified are aromatic hydrocarbons. The ring bears two substituents: a methyl group and an ethyl group.^[1]

Cymenes
Name	2-ethyltoluene	3-ethyltoluene	4-Ethyltoluene
Structural formula
CAS number	611-14-3	620-14-4	622-96-8
melting point (°C)	−80.8	−95.5	−62.3
boiling point (°C)	165	161.3	162

Production and reactions

Ethyltoluenes are prepared by alkylation of toluene with ethylene:

CH₃C₆H₅ + CH₂=CH₂ → CH₃C₆H₄CH₂CH₃

These alkylations are catalyzed by various Lewis acids, such as aluminium trichloride.

3- and 4-Ethyltoluenes are mainly of interest as precursors to methylstyrenes:

CH₃C₆H₄CH₂CH₃ → CH₃C₆H₄CH=CH₂ + H₂

This dehydrogenation is conducted in the presence of zinc oxide catalysts.^[1]