Process for preparing essentially formic acid-free N-alkyl-N′-methylalkyleneureas

US6554966B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Andreas Kramer · Zürich, CH
• Johann-Peter Melder · Schifferstadt, DE
• Heinz Rutter · Hochdorf-Assenheim, DE
• Günter Riewe · Schifferstadt, DE
• Wolfgang Siegel · Schifferstadt, DE
• Hans-Jurgen Weyer · Frankenthal (Pfalz), DE

Key dates

• Filing date: Jun 26, 2000
• Grant date: Apr 29, 2003
• Expiry date: Apr 15, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D239/10
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for preparing essentially formic acid-free N-alkyl-N′-methylalkyleneureas of the formula with R1=H or CH3, R2=CnH2n+1 with n=1-4 and x=0 or 1, from the corresponding alkyleneureas by reaction with monomeric or polymerized formaldehyde in the presence of formic acid. This entails feeding the mixture, obtained in the reaction, of N-alkyl-N′-methylalkyleneurea and formic acid to the upper region of a distillation column, distilling without further additions and removing essentially formic acid-free N-alkyl-N′-methylalkyleneurea in the lower region of the column. The process parameters are set so that the pressure in the upper region of the column is at a higher level than in the lower region of the column, and the difference in pressure between the upper and lower regions of the column is from 10 to 100 mbar, and the temperature in the lower region of the column is higher than in the upper region of the column, with the difference in temperature between the upper and lower regions of the column being from 40° C. to 210° C.