Friedel-Crafts Phenylsulfonylation of o-Xylene, Indan and Tetralin in Nitrobenzene

Abstract

Friedel-Crafts reactions of o-xylene, indan and tetralin with benzenesulfonyl chloride in the presence of aluminum chloride in nitrobenzene were studied about temperature effect on isomer distribution under kinetic conditions. It was found that in indan, the isomer ratio (3-/4-) increased with temperature, while the ratio (3-/4-) were decreased in o-xylene and in tetralin. Differences of activation energies and activation entropies in the 3- and 4-position for o-xylene, indan and tetralin were -0.39kcal/mol, -2.0 e. u./mol, 0.16, -0.2, and -0.31, -1.5, respectively. Isokinetic temperatures were -81 and -62 °C for o-xylene and tetralin, respectively. These results suggest that 3-position of o-xylene or tetralin is more reactive than 4-position, whereas 4-position is more reactive in indan. It was conclued that the reaction proceeded with a concerted mechanism in which strong acid-catalytic effect by aluminum chloride and base-catalyzed deprotonation by solvent and/or AlCl4 on 3-position were observed in o-xylene and tetralin. © 1986, The Chemical Society of Japan. All rights reserved.