Abstract Isomerization equilibria have been studied between 1-chloro-3-isopropyl-4- methylbenzene (I) and 1-chloro-2-isopropyl-4-methylbenzene, between 1-chloro-2, 6- diisopropyl-4-methylbenzene (III) and 1-chloro-2, 5-diisopropyl-4-methylbenzene (IV), and between 1-chloro-3, 5-diisopropyl-4-methylbenzene (V) and (IV). The interaction of (IV) with 1-chloro-4-methylbenzene (VI) with the formation of (I) and (II) has also been studied. ...