Process for preparing 1,4-diazobicyclo(2,2,2)octane from ethylenediamine and oxirane

The invented process for preparing 1,4-diazabicyclo(2,2,2)octane from ethylenediamine and oxirane is characterized in that it comprises two reaction zones and a rectification reaction mixture from the second reaction zone, whereby in the first reaction zone ethylenediamine and a piperazine fraction form rectification are treated with oxirane at a temperature ranging from 20 to 150 degC and a mixture obtained in the first reaction zone is then fed in the second reaction zone. In this second reaction zone dehydrating and deamination reaction takes place on acid heterogeneous catalyst in gaseous phase and at a temperature ranging from 300 to 400 degC. The reaction mixture from the second reaction zone being freed from ammonia is then separated by rectification into water fraction, piperazine fraction, raw DABCO fraction and fraction of higher-boiling substances, whereby the piperazine fraction, containing also ethylenediamine, morpholine and N-ethylpiperazine is returned back into the first reaction zone and the fraction of the higher-boiling substances is returned back into the second reaction zone. From the raw DABCO fraction a pure product is then isolated by employing some of known processes. The dehydrating and deamination reaction proceeds preferably in the presence of water and/or ammonia. The heterogeneous catalyst in the second reaction zone is preferably represented by zeolite ZSM 5 or ZSM 5 with partially replaced ions He+ for ions of alkali metals, or calcium, barium, strontium and aluminium hydrogen phosphate or diphosphate. In the first reaction zone it is preferred to treat both the ethylenediamine and piperazine fraction with oxirane separately and to mix both the intermediates prior their entry the second reaction zone. In the first reaction zone it is preferred to have molar ration of oxirane/amines in the range of 0.3 to 1.2, preferably 0.6 to 0.8. It is preferred in the first reaction zone to treat with oxirane amines containing 1 to 20 percent by weight water. It is also suitable that the mixture entering the second reaction zone contains 0 to 20 moles ammonia and 1 to 10 moles water per 1 mole of amines.