The invention relates to a process for the synthesis of cyclic alkylene ureas comprising reacting a difunctional amine A having two primary amino groups, and an aliphatic organic carbonate component C selected from the group consisting of dialkyl carbonates CD and of alkylene carbonates CA, wherein the ratio of the amount of substance n(-NH2) of primary amino groups -NH2 in the difunctional amine A to the sum n(C) of the amount of substance n(CD) of carbonate groups of a dialkyl carbonate CD and the amount of substance n(CA) of carbonate groups in an alkylene carbonate CA, is at least more than 2, and to the product obtained by this process.