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Copper, aluminum-based composite metal oxides was prepd. by copptn. method and as the catalyst in synthesis of the N-methylpiperazinewhile the starting materials are diethanolamine and methylamine. Compared the activity of the catalysts in autoclave and found that copper, aluminum and nickel composite metal oxides has the highest activity. The molar ratio of copper, aluminum and nickel, different coprecipitators, precipitants order and the calcining temp. have been optimized. Experimented results showed that: the ideal molar ratio of copper, aluminum and nickel is 1 : 1 : 3.2, coprecipitator is NaOH, precipitants order is cocurrent, and the best calcining temp. lies around 500 C. Under this condition the conversion of diethanolamine and the yield of N-methylpiperazine were 89.8% and 27.7% resp. Meanwhile, the reason of deactivation for the catalysts was that some oligomeric compds. deposited on the catalyst surface and blocked active site via comparing the catalyst unused and used by token analyzing.
N-Methylpiperazineis important intermediate for organic synthesis. It can be used to produce antibacterial rifampicin, antipsychotic trifluoperazine, ofoxacin, etc in pharmaceutical industry.