Phenol Hydroxylation with Nitrous Oxide
Catalysis in Industry
, E-ISSN: 2070-0555
||Dihydroxybenzenes, Nitrous oxide, Phenol hydroxylation, Zeolite catalysts
Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Phenol hydroxylation with nitrous oxide opens up a new, promising way to the gas-phase synthesis of dihydroxybenzenes, which are among the most important semiproducts of contemporary organic chemistry. A process based on this reaction could provide an alternative to the existing liquid-phase processes employing hydrogen peroxide as the oxidizer. Here, we report phenol oxidation with nitrous oxide over zeolite MFI at 450–500°C and a residence time of 1.70–3.4 s. The dihydrobenzenes production rate per unit weight of the catalyst is 2.3 mmol/(g h). The process involving nitrous oxide is superior to the other technologies in terms of oxidizer consumption efficiency and dihydroxybenzene isomer proportions. Specifically, the nitrous oxide conversion into dihydroxybenzenes is 74% and hydroquinone-to-catechol ratio in the reaction product is 1.2–1.4.