One‐Pot Synthesis of Carbon‐Based Solid Acid Polymer Catalyst: Efficient Catalysts for Liquid‐Phase Nitration of Alkanes

Carbon‐based solid acid polymer catalyst was successfully prepared by a facile one‐pot method with sulfonation of naphthalene and crosslinking by formaldehyde. The characterization results showed that the prepared catalysts were flexible soft polycyclic amorphous carbon sheets with abundant ‐SO 3 H, and ‐COOH groups. The catalysts have high acid density (4.68 mmol⋅g −1 ) and a remarkable activity for the liquid‐phase nitration of alkanes. Especially, cyclohexane was effectively nitrated to nitrocyclohexane with a high conversion (47.9%) and a good selectivity (98.4%) over the catalyst at moderate reaction temperature (125 °C). The high activity was due to the high acidic site density and amorphous carbon structure with hydrophilic functional groups. The hydrophilic surface facilitates the adsorption of hydrophilic molecules, including water and nitric acid, despite the low BET surface areas. A possible formation pathway for various products was proposed. Carbon‐based solid acid polymer exhibited good potential as a substitution for the liquid acid catalysts in liquid‐phase nitration.