The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 10, 2006
Filed:
Feb. 17, 2004
Erwin Dieterich, Köln, DE;
Anke Hielscher, Leverkusen, DE;
Berthold Keggenhoff, Krefeld, DE;
Manfred Keller-killewald, Brunsbüttel, DE;
Jürgen Münnig, Kaarst, DE;
Dietmar Wastian, Dormagen, DE;
Erwin Dieterich, Köln, DE;
Anke Hielscher, Leverkusen, DE;
Berthold Keggenhoff, Krefeld, DE;
Manfred Keller-Killewald, Brunsbüttel, DE;
Jürgen Münnig, Kaarst, DE;
Dietmar Wastian, Dormagen, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
The invention relates to a process for the production of dinitrotoluene by the two-stage nitration of toluene. In the first stage of this process, toluene was reacted adiabatically with nitrating acid so that at least 90% of the toluene was reacted off and no more than 70% of the toluene formed dinitrotoluene. The resulting organic phase containing mononitrotoluene and the aqueous acid phase containing sulfuric acid were separated, and the aqueous acid phase containing sulfuric acid was concentrated by flash evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage, and/or into the reaction in the second stage, and/or into the concentration in the second stage. In the second stage, the organic phase containing mononitrotoluene from the first stage was completely reacted isothermally with nitrating acid. The organic phase and the aqueous acid phase containing sulfuric acid were then separated, and the aqueous acid phase containing sulfuric acid was concentrated by vacuum evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage and/or the second stage.