A process is described for the preparation of s-triazine derivatives of the formula in which R is a C1-C12-alkyl radical, by reacting a cyanuric acid halide with a p-aminobenzoic acid ester, which comprises a C6-C12-alkyl radical as radical of the ester alcohol, in a molar ratio of 1:3 to 1:5 in a xylene isomer mixture as solvent. 10 The process is characterized in that the solvent is used in amounts of from 0.6 to 2.1 mol/l.
