“…1994) and Fe, B, and Ti substituted versions (Salakhutdinov et al, 1993), sulphonated ion exchange polystyrene resins (Wright et al, 1965), perfluorinated sulphonic acid (Olah et al, 1978), clay supported metal nitrates (Laszlo and Vondormeal, 1988;Delaude et al, 1993), Fe 3þ on K10 Montmorillonite (Choudary et al, 1994), modified silica (Smith, 1989), modified silica-alumina, and supported acid (Kameo et al, 1974;Schubert and Wunder, 1978;Suzuki et al, 1987;Riego et al, 1996) versions have been reported. Conventional nitrating agents like nitric acid alone or in combination with acetic anhydride, mixed acids, nitrogendioxide (Radoslaw and Smallridge, 2001), acyl nitrates (benzoyl and acetyl), and alkyl nitrates continue to engage the attention of some researchers (Olah et al, 1989) which resulted in achieving improved para-selectivity (defined as the molar ratio of para-and ortho-nitrotoluenes) although their commercial viability is questionable.…”