Ullmann reaction for the synthesis of diaryl ethers

In a process for the preparation of a diaryl ether by reacting an unactivated halobenzene with an alkali metal phenolate in the presence of a copper catalyst, the improvement which comprises conducting said reaction in the presence of an effective amount of at least one tertiary amine sequestering agent having the formula:

• N--CHR.sub.1 --CHR.sub.2 --O--CHR.sub.3 --CHR.sub.4 --O).sub.n R.sub.5 ].sub.3 (I)
• in which n is an integer which is greater than or equal to 0 and less than or equal to about 10, R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which are identical or different, each represent a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms and R.sub.5 represents an alkyl or cycloalkyl radical having from 1 to 12 carbon atoms, a phenyl radical or a radical --C.sub.m H.sub.2m --.phi. or C.sub.m H.sub.2m+1 --.phi.--, wherein .phi. is phenyl and in which m is between 1 and 12.