Abstract
1) Various alkanolamines were heated under a high pressure, with Raney nickel as a catalyst, and piperazines were prepared; piperazine from ethanolamine, 1, 4-dimethylpiperazine from 2-methylaminoethanol, and trans- and cis-2, 5-dimethylpiperazine from 1-amino-2-propanol. 3-Amino-2-butanol failed to undergo the reaction under a pressure of 600 lb./in2.
2) Reaction of ethylenediamine and various glycols in an autoclave, with Raney nickel as a catalyst, affords various C-alkylpiperazines in a good yield. Reaction of ethylenediamine with ethyleneglycol, 1, 2-propanediol and 2, 3-butanediol respectively afforded piperazine, 2-methylpiperazine, and trans- and cis-2, 3-dimethylpiperazine. 2-Methyl-1, 2-propanediol and pinacol failed to undergo this reaction.
3) Piperazines were also prepared by the reaction of N-(2-hydroxyalkyl)ethylenediamine in vapor phase catalysis and in liquid phase under high pressure.
