Halex catalyst for reactions

A catalyst for halogen-fluorine exchange reactions of aromatic compounds essentially consists of a mixture of one or more compounds (a) and at least one compound (b), (c) and/or (d). (a) is an amidophosphonium salt of formula (I), in which A , A , A , A , A , A , A and A are the same or different and independently represent a straight- or branched-chain alkyl or alkenyl with 1 to 12 carbon atoms, cycloalkyl with 4 to 8 carbon atoms, aryl with 6 to 12 carbon atoms, aralkyl with 7 to 12 carbon atoms, or A A , A A , A A , A A are independent, the same or different and are joined together directly or via O or N-A into a ring with 3 to 7 members; A stands for an alkyl with 1 to 4 carbon atoms and B represents a monovalent acid radical or the equivalent of a polyvalent acid radical; (b) is a quaternary ammonium salt; (c) is a quaternary phosphonium salt; (d) is a crown ether or polyether of formula (IV) R -(O-CxH2x)r-OR , in which R and R are the same or different and represent a linear or branched alkyl radical with 1 to 16, preferably 1 to 8, carbon atoms; x is an integer from 2 to 6, preferably 2 to 3; and r is an integer from 0 to 20, preferably 1 to 18, in particular 4 to 14.