ALKYLATION OF ANILINE WITH ALPHA-METHYLSTYRENE AND SEPARATION OF CLOSE BOILING AROMATIC-AMINES THROUGH REACTION WITH ALPHA-METHYLSTYRENE, USING ACID-TREATED CLAY CATALYSTS

Alkylation of aniline with alpha-methylstyrene was carried out using a cid-treated clay catalyst, Engelhard F-24, to produce mixture of mono- and dialkylated aniline. Alkylation occurred at the ortho- and para-p ositions of aniline and there was no N-alkylation. Mono and dialkylate d anilines were separated from the reaction mixture and characterized by H-1 NMR. Reaction conditions to obtain high selectivity of the dial kylated product were studied. The extent of reusability of the acid-tr eated clay catalyst was also checked. Separation of close boiling comp ounds by physical methods like distillation is difficult. ortho-Toluid ine/para-toluidine/meta-toluidine and ortho-cumidine/para-cumidine are close boiling aromatic amines of industrial importance. For the separ ation of these compounds, various techniques such as dissociation extr action, use of different adsorbents have been attempted by earlier res earchers. In the present work, an alternative strategy was developed f or the separation of ortho-toluidine/para-toluidine, meta-toluidine/pa ra-toluidine and ortho-cumidine/para-cumidine through selective alkyla tion with alpha-methylstyrene followed by dealkylation of alkylated pr oduct(s). The alkylation/dealkylation reactions were catalyzed by acid -treated clay catalyst Engelhard F-24.