Environmentally friendly hydrogenation of nitrobenzene to p-aminophenol using heterogeneous catalysts

New insight on the mechanism of the catalytic hydrogenation of nitrobenzene to 4-aminophenol in CH3CN–H2O–CF3COOH as a reusable solvent system. Hydrogenation of nitrobenzene catalyzed by precious metals supported on carbon

“…Therefore, removal of H 2 SO 4 use is likely to be the most important target for the improvement of the process. Several researchers have recently proposed the use of a biphasic liquid system (waternitrobenzene) employing Pt supported on solid acid in the presence of surfactant and promoters, which, however, cause problems in the recycle and/or disposal of the aqueous phase [13][14][15].…”

Highly Efficient Au/TiO2 Catalyst for One‐pot Conversion of Nitrobenzene to p‐Aminophenol in Water Media

“…[13,14] Moreover, since NB is not soluble in water, the reaction happens in a four-phase system, i.e. [15][16][17][18][19][20][21] However, for metal-solid acid bifunctional catalysts, the high selectivity of PAP is more difficult to achieve. [13] Although this property makes the separation of reagent and product easier (PAP and its sulphate are water soluble), it hinders the mass transfer process between molecules, and therefore the importation of phase-transfer agents may also improve the catalytic performance.…”

“…gas, solid catalyst, aqueous and organic phases. Only Figueras et al [20] reported the highest selectivity over 90% using the mechanical mixture of supported Pt and sulphated zirconia, but their reaction conditions varied and it was difficult for comparison. Various solid acids have also been applied for this conversion for cleaner synthesis of PAP.…”

Heterogeneous Bifunctional Metal/Acid Catalysts for Selective Chemical Processes

“…[80] The study showed that the competitive full hydrogenation reaction of NB to aniline can be minimized by lowering the Pt loading and by the selection of an optimal calcination temperature, which has a strong effect on the catalyst acidity. [82] The performance of the system was shown to be poorly affected by the support used for Pt. Similar results were reported by Figueras et al with a bifunctional catalytic system composed of a mechanical mixture of supported Pt (Pt/C, Pt/ZrO 2 , Pt/sulfated-ZrO 2 , Pt/TiO 2 , Pt/MgLa) and solid acid catalysts.…”