Doebner–von Miller reaction catalyzed by mesoporous polymeric solid acid: an efficient route to produce 1,10-phenanthroline

Abstract

Exploring environmentally friendly, highly economical, resource-saving, and recyclable low-temperature heterogeneous catalysts for liquid-phase organic reactions is of great significance for the realization of green and sustainable development. In this study, mesoporous polydivinylbenzene (PDVB)-based solid acid (PDVB-SO₃H) has been successfully prepared from sulfonation of mesoporous PDVB. And the sulfonated polymeric solid acid PDVB-SO₃H was used as for catalyzing Doebner–von Miller reaction for the synthesis of 1,10-phen with choline chloride as the co-catalyst for the first time. FT-IR and XPS confirmed successful sulfonate group grafting onto PDVB. N₂ sorption isotherms, SEM, and TG curves revealed the mesoporous PDVB-SO₃H possesses a high BET surface area, superior pore structure, and thermal stability. Besides, the results of acid–base titration and elemental analysis indicate that the extremely high acid capacity. Finally, the catalytic tests show that PDVB-SO₃H exhibits excellent catalytic activities and good recyclability in synthesis of 72% yield of 1,10-phen and the 1,10-phen yield did not decrease obviously after the PDVB-SO₃H catalyst was reused for 5 times. This work highlighted the excellent catalytic activity and good recyclability of PDVB-SO₃H, and provides a method and references to produce 1,10-phenanthroline.