Monitoring of the stoichiometric ratio in the reaction of nitroaromatics with hydrogen

US8895783B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Andreas Raichle · Ludwigshafen, DE
• Stefanie Haase · Pulsnitz, DE
• Holgar Braunsberg · Senftenberg - Zły Komorow, DE
• Johannes Buettner · Ruhland, DE
• Ulrich Penzel · Lauscha, DE
• Samuel Neto · Brussels, BE

Key dates

• Filing date: Feb 5, 2013
• Grant date: Nov 25, 2014
• Expiry date: Feb 5, 2033

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C209/36
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to a continuous process for preparing at least one aromatic amine by hydrogenation of at least one nitroaromatic by means of hydrogen, where a liquid phase comprising at least the aromatic amine and a gas phase comprising at least hydrogen are present, in the presence of a catalyst suspended in the liquid phase at a temperature of from 50 to 250° C. and a pressure of from 5 to 50 bar, wherein the pressure in the reactor is kept essentially constant by continuous adaptation of the amount of hydrogen fed to the reactor, the total amount of hydrogen fed to the reactor is monitored and the introduction of the at least one nitroaromatic is interrupted if the hydrogen uptake in the reactor is not at least 50 mol % of the amount of hydrogen required for stoichiometric reaction of the at least one nitroaromatic to form the at least one aromatic amine.