Biomass-to-biomass strategy: sulphonic acid functionalized covalent organic frameworks for metal-free esterification of biomass-derived acids.
- 1Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda Vadodara 390 002 India [email protected].
- 2Research and Development Cell (RDC), Parul University Vadodara 391760 India.
- 3Department of Chemistry, Parul Institute of Applied Sciences, Parul University Waghodia Vadodara Gujarat 391760 India [email protected].
Abstract
A sulphonic acid functionalized Covalent Organic Framework (COF-SO₃H) was synthesized via an ultrasound-assisted aqueous-phase Schiff base condensation, providing a green and efficient route to incorporate Brønsted acidic sites directly into the framework. Characterisation techniques showed that the resulting material exhibits a partially crystalline, hierarchically porous structure with a surface area of 185 m² g⁻¹. DFT calculations performed using B3LYP reveal a well-defined hexagonal pore topology with uniformly distributed -SO₃H groups along the framework edges. The catalytic activity of COF-SO₃H was evaluated for the esterification of biomass-derived molecules, levulinic acid (LA) and succinic acid (SA), with butyl alcohol. Under optimized conditions, the metal-free catalyst afforded excellent conversion (96%) of LA with 99.7% selectivity toward n-butyl levulinate, while SA esterification showed tunable selectivity between mono- and diesters depending on reaction parameters. The catalytic performance is attributed to the accessible -SO₃H sites and efficient mass transport within the porous framework. The catalyst demonstrated good stability and recyclability over multiple cycles with minimal loss of activity. The scope of the esterification catalysis could also be extended to various other alcohols, including secondary alcohols and cyclohexanol. It was observed that the chain length and structure of alcohols have significant influence on conversion and selectivity. This study establishes the potential utilization of -SO₃H functionalized COFs as sustainable metal-free heterogeneous acid catalysts for the valorization of biomass-derived acids into value-added esters.
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BibTeX
@article{samal2026biomasstobiomass,
title = {{Biomass-to-biomass strategy: sulphonic acid functionalized covalent organic frameworks for metal-free esterification of biomass-derived acids.}},
author = {Shradhanjali Samal and Muskan Memon and Entesar Alhousin and Soyeb Pathan and Sonal Thakore},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra06829d},
url = {https://europepmc.org/article/MED/42846356},
note = {CC BY},
}
RIS
TY - JOUR
TI - Biomass-to-biomass strategy: sulphonic acid functionalized covalent organic frameworks for metal-free esterification of biomass-derived acids.
AU - Shradhanjali Samal
AU - Muskan Memon
AU - Entesar Alhousin
AU - Soyeb Pathan
AU - Sonal Thakore
PY - 2026
DA - 2026/10/07
JO - RSC advances
DO - 10.1039/d6ra06829d
UR - https://europepmc.org/article/MED/42846356
AB - A sulphonic acid functionalized Covalent Organic Framework (COF-SO₃H) was synthesized via an ultrasound-assisted aqueous-phase Schiff base condensation, providing a green and efficient route to incorporate Brønsted acidic sites directly into the framework. Characterisation techniques showed that the resulting material exhibits a partially crystalline, hierarchically porous structure with a surface area of 185 m² g⁻¹. DFT calculations performed using B3LYP reveal a well-defined hexagonal pore topology with uniformly distributed -SO₃H groups along the framework edges. The catalytic activity of COF-SO₃H was evaluated for the esterification of biomass-derived molecules, levulinic acid (LA) and succinic acid (SA), with butyl alcohol. Under optimized conditions, the metal-free catalyst afforded excellent conversion (96%) of LA with 99.7% selectivity toward n-butyl levulinate, while SA esterification showed tunable selectivity between mono- and diesters depending on reaction parameters. The catalytic performance is attributed to the accessible -SO₃H sites and efficient mass transport within the porous framework. The catalyst demonstrated good stability and recyclability over multiple cycles with minimal loss of activity. The scope of the esterification catalysis could also be extended to various other alcohols, including secondary alcohols and cyclohexanol. It was observed that the chain length and structure of alcohols have significant influence on conversion and selectivity. This study establishes the potential utilization of -SO₃H functionalized COFs as sustainable metal-free heterogeneous acid catalysts for the valorization of biomass-derived acids into value-added esters.
SN - 2046-2069
ER -