Process for the preparation of N,N'-substituted ureas

摘要

A process for the preparation of substituted benzenes or benzenesulfonic acid and its derivatives comprising diazotisation of an aminobenzene or ortho-amino-benzenesulfonic acid derivative followed by homogeneous palladium-catalysed coupling with an olefine and heterogeneous palladium-catalysed hydrogenation of the olefinic substituent, wherein the homogeneous catalyst is reduced and precipitated as metal after the coupling in the reaction mixture and used as a heterogeneous palladium catalyst for the hydrogenation step. The process is particular suitable for the preparation N-benzenesulfon-N'-triazinyl-urea herbicides.