METHOD FOR PRODUCING MIXTURES CONSISTING OF DIPHENYLMETHANE DIISOCYANATES AND POLYPHENYLENE-POLYMETHYLENE-POLYISOCYANATES CONTAINING A REDUCED AMOUNT OF CHLORINATED SECONDARY PRODUCTS AND WITH A REDUCED IODINE COLOR INDEX

US6576788B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Ulrich Penzel · Lauscha, DE
• Volker Scharr · Senftenberg - Zły Komorow, DE
• Dieter Starosta · Schwarzheide, DE
• Hilmar Boesel · Senftenberg - Zły Komorow, DE
• Eckhard Ströfer · Mannheim, DE
• Joachim Pfeffinger · Ludwigshafen, DE
• Frank Poplow · Overath, DE
• Jürgen Dosch · Ludwigshafen, DE
• Hans Volkmar Schwarz · Waterloo, BE
• Fritz Näumann · Bensheim, DE
• Peter Van Den Abeel · Brasschaat, BE
• Jan Jacobs · Hoogerheide, NL
• Filip Nevejans · Sint-Niklaas, BE
• Willy van Pee · Neukirchen-Vluyn, DE

Key dates

• Filing date: Oct 13, 2000
• Grant date: Jun 10, 2003
• Expiry date: Oct 13, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C263/20
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In a process for preparing mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced content of chlorinated by-products and a reduced iodine color number by two-stage reaction of the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, separation of the excess phosgene and solvent after the phosgenation is complete and thermal treatment of the reaction product, the mass ratios of phosgene to hydrogen chloride in the residence time apparatus of the second stage of the phosgenation are at the same time 10-30:1 in the liquid phase and 1-10:1 in the gas phase.