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

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 -memylnaphthalene.