Process for preparing N-alkylpiperazines

• Main Authors: BOU CHEDID, ROLAND, STEIN, BERND, DE WINNE, HENDRIK, MELDER, JOHANN-PETER, ABEL, ULRICH, DOSTALEK, ROMAN
• Format: Patent
• Language: Chinese; English
• Published: 16.03.2015
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING

A process for preparing an N-alkylpiperazine of formula I in which R1 is hydrogen (H), methyl, or ethyl, and R2 is C1 to C5 alkyl, by reacting an N-substituted diethanolamine of the formula II with ammonia or a primary amine of the formula H2N-R1 (III) in the presence of hydrogen and of a supported metallic catalyst, wherein the catalytically active composition of the catalyst prior to its reduction with hydrogen comprises from 20 to 85 wt% of oxygen-containing compounds of zirconium, calculated as ZrO2, from I to 30 wt% of oxygen-containing compounds of copper, calculated as CuO, from 14 to 70 wt% of oxygen-containing compounds of nickel, calculated as NiO, and from 0 to 5 wt% of oxygen-containing compounds of molybdenum, calculated as MoO3, and the reaction is carried out in the liquid phase at an absolute pressure in the range from 160 to 240 bar, at a temperature in the range from 180 to 230 DEG C, using ammonia or primary amine Ill in a molar ratio, with respect to diethanolamine II employed, of 5 to 50