Catalytic synthesis of pyrazine, piperazine, and 1,4-diaza[2,2,2]-bicyclooctane

Abstract

A study is made of the deamination of diethylenetriamine over acidalkali catalysts, i. e., kaolin and alumina with promoters. Promoters which raise the acidity of the catalyst, affect the formation of triethylene diamine favorably. Increasing the amount of additive increases the amount of triethylenediamine, and cuts the optimum temperature at which it is formed. On kaolin or Al2O3+15% B2O3, the yield of triethylenediamine amounts to 30% theory. Addition of MoO3 facilitates dehydrodeamination and hydrogenolysis of the diethylenetriamine. The optimum promoter for preparing pyrazine is MoO3 along with a small amount of acid oxides. On the Al2O3+5% MoO3+1% P2O5, the pyrazine yield is 27.5% theory. Triethylenediamine can be separated from mixtures of it with piperazine by azeotropic distillation with mxylene or a mixture of mesitylene and α-memylnaphthalene.