Process for acidic scrubbing of dinitrotoluene in the presence of hydrocyanic acid

US9688606B2 · kind B2 · utility

Assignees

• BASF SE
• JOSEF MEISSNER GMBH & CO. KG · DE

Inventors

• Samuel Neto · Brussels, BE
• Rüdiger Fritz · Bernsdorf, DE
• Renate Hempel · Ruhland, DE
• Holger Allardt · Schwarzheide, DE
• Yuan Shen Dai · Mannheim, DE
• Barbara BECKER · Ludwigshafen am Rhein, DE
• Sebastian Ahrens · Wiesloch, DE
• Julia Leschinski · Mannheim, DE
• Henrich Hermann
• Mirko Haendel · Neunkirchen, DE
• Jürgen Pöhlmann · Cologne, DE

Key dates

• Filing date: Oct 22, 2014
• Grant date: Jun 27, 2017
• Expiry date: Oct 22, 2034

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C02F2103/36
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Process for scrubbing a crude mixture which is obtained in the nitration of toluene after separating off the nitrating acid and comprises dinitrotoluene, nitric acid, nitrogen oxides and sulfuric acid, which comprises two scrubbing steps (WS-I) and (WS-II), whereini) in a first scrubbing step (WS-I), the crude mixture is extracted with a scrubbing acid I comprising nitric acid, nitrogen oxides and sulfuric acid in a scrub comprising at least one extraction stage, where the scrubbing acid discharged from the first extraction stage (WS-I-1) of the first scrubbing step (WS-I) has a total acid content of from 10 to 40% by weight and a content of from 80 to 350 ppm of hydrocyanic acid, giving a prescrubbed crude mixture,ii) in a second scrubbing step (WS-II), the prescrubbed crude mixture comprising dinitrotoluene is extracted with a scrubbing acid II in a scrub comprising at least one, preferably at least 2, extraction stage(s), where the scrubbing acid discharged from the first extraction stage (WS-II-1) of the second scrubbing step (WS-II) has a pH of less than or equal to 4, giving a dinitrotoluene-comprising mixture which is essentially free of nitric acid, sulfuric acid, nitrogen …