Phosphonate functionalized carbon spheres as Br?nsted acid catalysts for the valorization of bio-renewable α-pinene oxide to trans-carveol?

Dalton Transactions Pub Date: 2020-04-30 DOI: 10.1039/D0DT00921K

Abstract

Herein, we report a simple route for the synthesis of phosphonate functionalized Br?nsted solid acid carbon spheres as heterogeneous catalyst for the valorization of bio-derived α-pinene oxide. The Br?nsted acidity was generated via two steps; hydrothermal carbonization of sugar to produce carbon microspheres followed by PCl3 treatment to form phosphonate functionalized carbon. The presence of phosphonate was confirmed by CP-MAS 31P and 13C NMR. In addition, the presence of the P–C, O–P–C and HO–P[double bond, length as m-dash]O bonds of the phosphonate group was confirmed by FT-IR, 31P NMR, and XPS. SEM-EDAX analysis revealed the presence of a phosphorus content of ～1.71 wt% on the surface of the catalyst while elemental mapping showed a uniform dispersion of phosphorus over the carbon spheres. The as-synthesized Br?nsted solid acid catalyst was used for the isomerization of α-pinene oxide which gave 100% conversion with 67% trans-carveol selectivity in highly polar basic solvent in 1 h reaction time. Also, the catalyst showed good recyclable activity even after five cycles.

Graphical abstract: Phosphonate functionalized carbon spheres as Br?nsted acid catalysts for the valorization of bio-renewable α-pinene oxide to trans-carveol
Recommended Literature