Process for the continuous production of acetylene diurea

A process for continuous production of acetylene diurea that takes place by means of the reaction of glyoxal with urea in the presence of mineral acids is disclosed, wherein the reaction is carried out in a cascade of reactors, where the cascade of reactors consists of at least two reactors which are stirred reaction vessel, where at least one reactor is continuously charged which glyoxal, urea, and mineral acid, and where water is discharged in steam-form from at least one reactor and a suspension of acetylene diurea in mother liquor is discharged for one reactor, wherein the discharged acetylene diurea is mechanically removed from the mother liquor, and the remaining mother liquor is recycled back into the reactor, in whole or in part.