Process for the preparation of compounds which contain hydantoin rings

A process for the preparation of a compound containing hydantoin groups which comprises reacting at a temperature of 50.degree. to 350.degree.C. at least one compound of the formula

• R.sup.3 (-NCX).sub.z
• wherein X is O or S;
• z is an integer of from 2 to 3 and R.sup.3 is an optionally substituted aliphatic radical having 1-20 carbon atoms, an optionally substituted aromatic radical having 5-12 carbon atoms, a cycloaliphatic radical having 5-12 carbon atoms, an aliphatic-aromatic radical having 6-20 carbon atoms, an aromatic or cycloaliphatic heterocyclic radical containing 5-12 carbon atoms which contains or is substituted by hetero atoms such as N, O or S with (b) at least one .alpha.-halocarboxylic acid amide selected from the group consisting of ##EQU18## wherein Hal denotes halogen;
• R.sup.4 is an optionally substituted aromatic radical having 5-10 carbon atoms, an aliphatic radical having 1-20 carbon atoms, a cycloaliphatic radical having 5-10 carbon atoms, hydrogen or the two radicals R.sup.4 taken together with the carbon atom to which they are attached form a cycloaliphatic ring of 5-7 ring members, R.sup.5 is one of the radicals defining R.sup.3 ;
• R.sup.6 is an aliphatic radical having 1-10 carbon atoms, a cycloaliphatic radical having 5-10 carbon atoms, an aliphatic-aromatic radical having 6-10 carbon atoms or an aromatic radical having 5-10 carbon atoms and x and y are integers from 2 to 3.