Occidental Chemical Corporation

William L Rueter

David Y Tang

Viesturs Lesins

Mark E Lindrose

Arthur H Morth

Frank P Bermel

Michael J Fifolt

William S Derwin

Hang-Chang Bobby Chen

Dean R Lagerwall

Pravin M Khandare

Mark F Lechner

Disclosed is a method of separating the meta isomer of a haloalkylbenzene having the general formula

Reducing meta content of isomeric mixtures of halo substituted alkylbenzenes

Disclosed is a method of making high purity 2,4- and 3,4-dichlorotoluene from parachlorotoluene that contains some metachlorotoluene. About 0.0001 to about 5 wt % of a Friedel-Crafts catalyst and about 0.5 to about 10 equivalents of a brominating agent are added to the parachlorotoluene. The metachlorotoluene is brominated, but most of the parachlorotoluene is not brominated. Without separating the brominated products from the unbrominated products, about 0.5 to about 1.5 equivalents of a chlorinating agent are added, whereby only the unbrominated products (i.e., the parachlorotoluene) are chlorinated. The resulting 2,4-dichlorotoluene and 3,4-dichlorotoluene can be separated by distillation.

Method of making high purity 2,4- and 3,4-dichlorotoluene

Disclosed is a method of separating the meta isomer of a halotoluene having the general formula ##STR1## from a mixture with at least one other isomer, where X is Cl or Br. About 0.0001 to about 5 wt % of a Friedel-Crafts catalyst is added to the mixture and the mixture is exposed to a brominating agent which preferentially brominates the meta isomer. The mixture is then heated at a temperature above the boiling point of the other isomers but below the boiling point of the brominated meta isomer.

Reducing meta content of isomeric mixtures of halo substituted toluenes

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Niagara Falls, NY, United States of America

William L Rueter