Method for removing HCN from crude dinitro toluene

US9428441B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Yuan Shen Dai · Mannheim, DE
• Katharina Spuhl · Forest, BE
• Renate Hempel · Ruhland, DE

Key dates

• Filing date: Sep 1, 2014
• Grant date: Aug 30, 2016
• Expiry date: Sep 1, 2034

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C205/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of dintrotoluene which comprises (a) nitrating toluene with a nitrating acid, wherein said nitrating acid is a mixture of nitric acid and sulfuric acid, in one or more nitration steps, and separating the nitrating acid from the process stream thus formed, wherein a crude mixture comprising dinitrotoluene and a fraction of said nitrating acid dissolved therein is obtained, said crude mixture further comprising at least 50 ppm of HCN, and (b) washing the crude dinitrotoluene containing mixture in one or more washing steps, wherein, before the first washing step is carried out, the crude mixture is distilled and/or stripped to remove HCN therefrom, wherein a crude dinitrotoluene containing mixture which is essentially free of HCN is obtained.