SELECTIVE N-ALKYLATION OF ANILINE BY MICELLAR CATALYSIS

Reactions of aniline with 1-bromobutane to form N-butylaniline and N,N -dibutylaniline were performed in single-phase aqueous surfactant syst ems. Reaction rate, yield, and selectivity of the N-alkyl product were monitored for different initial compositions, and much higher reactio n rate, yield, and selectivity were observed in comparison to reaction s of neat components. Excess aniline increased yield and selectivity, while excess 1-bromobutane had the opposite effect. The lipophilic rea ctant (1-bromobutane) and both products are solubilized almost entirel y in the surfactant micelles. The formation of relatively small amount s of N,N-dibutylaniline effectively inhibited further alkylation of N- butylaniline, so that high selectivities (>20) of the N-alkyl were obt ained. Added sodium hydroxide caused small decreases in yield and sele ctivity and showed that pi-I-dependent dissociation equilibria of the various amine species do not have a major influence on reaction charac teristics. (C) 1997 Academic Press.