Process for the preparation of compounds which contain hydantoin groups

A process for the preparation of a hydantoin which comprises reacting at a temperature of 50.degree. to 350.degree.C.

• a. 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 containing 1-20 carbon atoms, an optionally substituted aromatic radical containing 5-12 carbon atoms, a cycloaliphatic radical containing 5-12 carbon atoms, an aliphatic-aromatic radical containing 6-20 carbon atoms or an aromatic or cycloaliphatic heterocyclic radical containing 5-12 ring atoms which contains or is substituted by hetero atoms such as N, O or S, with
• b. at least one .alpha.-halocarboxylic acid selected from the group consisting of ##EQU11## wherein Hal is halogen;
• R.sup.4 is an optionally substituted aromatic radical containing 5-10 carbon atoms, an aliphatic radical containing 1-20 carbon atoms, a cycloaliphatic radical containing 5-10 carbon atoms, hydrogen or 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.6 is an aliphatic radical containing 1-10 carbon atoms, a cycloaliphatic radical containing 5-10 carbon atoms, an aliphatic-aromatic radical containing 6-10 carbon atoms or an aromatic radical containing 5-10 carbon atoms and y is an integer of from 1 to 3.