Ewoud

Renewable thiophenes: Thiophene synthesis can now be realized with a greener approach. Two renewable thiophene diesters were prepared from biomass-derived methyl levulinate and elemental sulfur as a cheap by-product of the fossil industry.

Abstract

Heterocyclic compounds are pivotal building blocks in petrochemical and renewable fine chemical synthesis. The production of bio-based heterocyclic compounds is limited to furans and pyrroles, while thiophenes are rarely prepared from bio-based feedstock in a real renewable method. Current research on the “pseudo-renewable” thiophene synthesis strongly relies on unwieldy Lawesson's Reagent, which makes the process unsustainable. The present work describes for the first time that, two thiophene diesters were synthesized from biomass-derived methyl levulinate and elemental sulfur, a cheap, surplus by-product of the fossil industry that is causing potential pollution. The condensation and sulfurization steps in this process all involved multiple reaction pathways, leading to a much more intricate mechanism than previous research in its type. The footprint of sulfur in this system was tracked throughout the process, and the chemistry of this multi-step reaction provided a new orientation for the real sustainable thiophene synthesis based on elemental sulfur.

Pressure-sensitive adhesives (PSAs) were synthesized from spruce tree lignin via depolymerization, amination, acrylamidation, and copolymerization with n-butyl acrylate, achieving a peel strength of up to 4.4 N cm⁻¹ and a tack strength of up to 3.9 N cm⁻¹. This approach offers a sustainable route for producing widely demanded PSA products, surpassing several commercial alternatives.

Abstract

This study presents a novel approach for fabricating high-performance pressure-sensitive adhesives (PSAs) using spruce tree lignin. Through a lignin-first strategy, lignin is selectively depolymerized into 4-propanol-tethered guaiacol, followed by amination, acrylamidation, and copolymerization with n-butyl acrylate (BA) to generate polymeric materials. The resulting lignin-derived PSAs exhibit excellent mechanical properties, achieving a peel strength of up to 4.4 N cm⁻¹ and a tack strength of up to 3.9 N cm⁻¹, surpassing those of several commercial products. This work provides a unique pathway to sustainable, high-performance PSA solutions to meet growing industrial demand.

Nature, Published online: 19 March 2025; doi:10.1038/d41586-025-00746-4

Nature, Published online: 18 March 2025; doi:10.1038/d41586-025-00771-3

Nature, Published online: 12 March 2025; doi:10.1038/d41586-025-00763-3

Nature, Published online: 07 March 2025; doi:10.1038/d41586-025-00383-x

Green chemistry assessment of an environmentally friendly microwave-assisted (MW) esterification of levulinic acid to obtain medium- and long-chain alkyl levulinates. Synthesis of biofuels and fuel additives from renewable sources in high yields (>90 mol %).

Abstract

Alkyl levulinates (ALs) represent a family of bio-compounds derived from levulinic acid (LA), a platform chemical obtained from lignocellulosic biomass. Medium- and long-chain ALs (pentyl levulinate or longer) have shown potential as biofuel and fuel additives due to their relatively low oxygen content and resemblance to biodiesel. This study reports a fast and environmentally friendly method for synthesizing ALs via microwave (MW)-assisted LA esterification, laying emphasis on medium- and long-chain ALs. By combining p-toluenesulfonic acid (5 wt % loading) as catalyst and MW radiation as heating source for a short time (5 minutes), excellent yields of ALs (≥89 mol %) were achieved for a wide range of primary and secondary alcohols (2–10 carbons), overcoming the expected lower reactivity of long chain alcohols. Additionally, formation of undesired side products, such as dialkyl ethers or LA aldol condensation products, was significantly minimized. The feasibility of recovering the unreacted alcohol was successfully proved by simple distillation (88 wt % recovery). The green chemistry metrics assessment proved that this approach aligns with the green chemistry principles and the United Nations Sustainable Development Goals, offering a more sustainable pathway for biofuel and fuel additive production.