Adiabatic process for producing dinitrotoluene

US6528690B2 · kind B2 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Uwe Klingler · Dormagen, DE
• Hans-Georg Pirkl · Leverkusen, DE
• Thomas Schieb · Rösrath, DE
• Dietmar Wastian · Dormagen, DE

Key dates

• Filing date: Oct 10, 1998
• Grant date: Mar 4, 2003
• Expiry date: Oct 10, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C201/08
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Dinitrotoluene (DNT) is produced by the adiabatic nitration of toluene with nitric acid at a temperature of from about 60 to about 200° C. and at a molar ratio of toluene to nitric acid of from about 1:1.5 to about 1:3.0. The reaction mixture thus-obtained is concentrated to a water content of up to 30% by weight. The dinitrotoluene which is present in the reaction mixture is at least partially (if not completely) removed from the reaction mixture either before or after concentration of the reaction mixture. The DNT which is still present in the vapor generated during the concentration of the reaction mixture is kept liquid by the addition of a solvent to the vapors generated during concentration of the reaction mixture. The solvent added to vapor, together with any DNT present in the vapor is recovered. This solvent/DNT mixture may be recycled directly to the reaction vessel. The solvent/DNT mixture may also be separated. The separated solvent may be recycled to the solvent addition step. The separated DNT may be combined with the recovered DNT product or it may be recycled to the nitration reaction mixture.