The use of M@p(4-VP) and M@p (VI) (M:Co, Ni, Cu) cryogel catalysts as reactor in a glass column in the reduction of p-nitrophenol to p-aminophenol under gravity

In this study, metal@p(4-Vinyl pyridine) (M@p(4-VP)) and metal@p (vinyl imidazole) (M@p (VI)) (M: Co, Ni, and Cu) cryogel catalysts as continuous reactor were used in reduction of p-nitrophenol (p-NP) to p-amino phenol (p-AP). The aqueous solution of p-NP passed through these super porous cryogel catalysts under gravity, and reaction kinetic for p-AP generation was investigated. The effect of metal species, amount of p-NP solution, amount of metal nanoparticle (increased by loading/reducing cycles), and temperature on the reduction reaction for p-NP to p-AP catalyzed by M@p(4-VP) and M@p (VI) cryogel catalysts were investigated. It was found that Co@p(4-VP) and Co@p (VI) cryogel catalysts provided the best catalytic performances than the other used metal species with 2.19 and 1.37 mol p-NP/(mol catalyst.min)(-1) turn-over frequency (TOF) values. Furthermore, in addition better TOF values, low Ea values of the prepared Co@p(4-VP) and Co@p (VI) cryogel catalysts with the values of 18.9 +/- 1.3, and 25.4 +/- 1.8 kJ/mol were found to be better than most of the similar works reported in the literature.