Confinement effect as a tool for selectivity orientation in heterogeneous synthesis of 4,4′-diamino-3,3′-dibutyl-diphenyl methane over montmorillonite catalysts

Montmorillonite was successfully employed as a heterogeneous catalyst in the condensation of o-tert-butylaniline with paraformaldehyde for its significant confinement effect on the synthesis of 4,4′-MBTBA.