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

US6156945A · kind A · utility

Assignee

• Occidental Chemical Corporation · US

Inventors

• Viesturs Lesins · Buffalo, US
• Arthur H. Morth · Grand Island, US
• Frank P. Bermel · Orchard Park, US
• David Y. Tang · East Amherst, US
• Mark E. Lindrose · Buffalo, US
• William L. Rueter · Niagara Falls, US
• Dean R. Lagerwall · Amherst, US
• Pravin M. Khandare · Amherst, US
• Hang Chen · Getzville, US
• Mark F. Lechner · Sanborn, US

Key dates

• Filing date: Oct 28, 1999
• Grant date: Dec 5, 2000
• Expiry date: Oct 28, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C17/395
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

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.