Abstract: The present invention relates to a process for the selective preparation of 4,4-methylene-bis-(N-phenylalkylcarbamate) which comprises condensing N-phenylalkylcarbamate with a methylating agent in the presence of an acidic ion-exchange resin or an aqueous acid as a catalyst and a non polar aprotic solvent and filtrating a condensation product at a temperature greater than the melting point of N-phenylalkylcarbamate to separate 4,4-methylene-bis-(N-phenylalkylcarbamate).

Abstract: A process for preparing N,N'-disubstituted urea derivatives of the following formula (I) ##STR1## wherein Ar represents an unsubstituted aromatic radical or an aromatic radical substituted with a halogen atom, an alkyl group, or an alkoxy group, which comprises reacting an aromatic mono-nitro compound, an aromatic primary amine, and synthesis gas in the presence of a catalyst consisting essentially of a divalent palladium compound as a main catalyst component and an ammonium or a phosphonium salt containing halogen atom as a co-catalyst component, and a non-polar solvent.