Chemistry · Aromatic hydrocarbons: Nomenclature, benzene - structure and aromaticity, mechanism of electrophilic substitution, halogenation, nitration
1,4-dimethylbenzene on heating with anhydrous and produces :
1,4-dimethylbenzene on heating with anhydrous \( A l C l_{3} \) and \( H C l \) produces :
- A. 1,2 -dimethylbenzene
- B. 1, 3-dimethylbenzene
- C. 1,2,3 -trimethylbenzene
- D. ethylbenzene
Step-by-step solution
Under Friedel-Crafts conditions (anhydrous AlCl3 and HCl), 1,4-dimethylbenzene (p-xylene) undergoes acid-catalyzed rearrangement to the more stable 1,3-dimethylbenzene (m-xylene). This isomerization occurs via a carbocation intermediate, where the methyl groups shift to achieve greater thermodynamic stability (meta isomer is more stable than para and ortho due to steric and electronic effects).
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