Patent ID: 7767856

Claim:
A method for forming N,N-diphenyl-4-aminobiphenyl, comprising reacting a first reagent with a second reagent at a temperature above 90° C., the first reagent being diphenylamine and the second reagent being 4-bromobiphenyl, the reaction taking place in a presence of a base comprising sodium t-butoxide and a palladium catalyst ligated with tri-t-butylphosphine in a continuous plug flow reactor such that N,N-diphenyl-4-aminobiphenyl is produced, and wherein the steps further comprise: continuously reacting the 4-bromobiphenyl and the diphenylamine in a first solvent in the presence of the palladium catalyst ligated with tri-t-butylphosphine under Buchwald conditions in the continuous plug flow reactor; adding a second solvent with sodium t-butoxide base to the 4-bromobiphenyl and the diphenylamine in the continuous plug flow reactor at a time subsequent to the addition of the first solvent to form a co-solvent system; and continuously reacting the 4-bromobiphenyl and the diphenylamine in the first solvent and the second solvent with the sodium t-butoxide base in the presence of the palladium catalyst ligated with tri-t-butylphosphine under Buchwald conditions in the continuous plug flow reactor such that N,N-diphenyl-4-aminobiphenyl is produced, and wherein all products and by-products remain solubilized; wherein the second solvent is selected from the group consisting of a polyethylene glycol dimethyl ether, a phosphonium-based ionic liquid, and mixtures thereof.