The invention relates to a process for preparing
2,3,5,6-tetrahaloxylylidene compounds of formula (I)
##STR1##
where each Hal is independently fluorine or chlorine, and X is fluorine,
chlorine, bromine, --O--R, or --O--C(.dbd.O)R, where R is hydrogen, a
straight-chain or branched C.sub.1 -C.sub.12 -alkyl- or a C.sub.6
-C.sub.14 -aryl radical, by reacting 2,3,5,6-tetrahaloxylylidenediamines
of formula (II)
##STR2##
with an alkyl nitrite and/or nitrous acid in HX as a solvent.