Aqueous formulations are prepared by a process wherein at least one cyclic compound of the formula I is heated in the presence of water and of an acidic catalyst and, during or after the heating, H—X—R3 is at least partially separated off, where, in formula I, X is selected from oxygen, sulfur and N—R6, R3 and R6 are identical or different and are selected from C1-C12-alkyl, C3-C12-cycloalkyl, substituted or unsubstituted, C7-C13-aralkyl, C6-C14-aryl, substituted or unsubstituted, formyl, CO—C1-C12-alkyl, CO—C3-C12-cycloalkyl, substituted or unsubstituted, CO—C7-C13-aralkyl, CO—C6-C14-aryl, where, if X is N—R6, R3 and R6 may be linked to one another with formation of a ring; R1, R2 and R4 are identical or different and are selected from hydrogen, C1-C12-alkyl, C3-C12-cycloalkyl, substituted or unsubstituted, C7-C13-aralkyl, C6-C14-aryl, substituted or unsubstituted, it being possible in each case for two neighboring radicals to be linked to one another with formation of a ring; n is an integer from 1 to 4; R5 are identical or different and are selected from hydrogen, C1-C12-alkyl, C3-C12-cycloalkyl, substituted or unsubstituted, C7-C13-aralkyl, C6-C14-aryl, substituted or unsubstituted, it being possible for R5 to be linked to R4 or in each case two neighboring radicals R5 to be linked to one another with formation of a ring.