Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermore, it is recognized as a possible future energy carrier achieving safer operation, storage and transportation. The photochemical production of H2O2 serves as a promising alternative to the waste- and energy-intensive anthraquinone process. Following green and sustainable chemistry principles, we demonstrated a sustainable photocatalyst utilizing earth-abundant iron and biobased sources only. These iron oxide nanoparticles (FeOx NPs) facilitated effective H2O2 production under batch conditions. Here, through the design of a modular photo-flow reactor, we achieved continuous and enhanced production of H2O2 by minimizing Fenton degradation. After detailed investigation of Fenton chemistry, we designed a reactor tailored to optimize the performance of our catalyst system. Optimal reaction conditions balancing production and energy efficiencies allowed a remarkable increase in production of >14x and productivity by >3x when compared to batch conditions. The produced H2O2 was concentrated to 0.02 wt% via rotary evaporation, approaching commercially relevant concentrations. The reactor design also allowed other chemical transformations, such as photoclick chemistry, as well as the processing of biomass waste into valuable products.

This guidebook aims to improve lab users’ everyday practices to become more sustainable. Specifically, this guidebook provides practical suggestions on how to effectively use lab instruments and resources and on how to acquire data. We provide advice to labs covering disciplines such as biology, chemistry, computational science, engineering, life sciences, materials sciences, medicine, pharmacy, and physics. As every lab is different, it may occur that alternative measures are required, advice may be outdated or not applicable, and sometimes laboratories may not be able to comply with measures of other laboratories.

Scientists are of key importance to the society to advocate awareness of the climate crisis and its underlying scientific evidence and provide solutions for a sustainable future. As much as scientific research has led to great achievements and benefits, traditional laboratory practices come with unintended environmental consequences. Scientists, while providing solutions to climate problems and educating the young innovators of the future, are also part of the problem: excessive energy consumption, (hazardous) waste generation, and resource depletion. Through their own research operations, science, research and laboratories have a significant carbon footprint and contribute to the climate crisis. Climate change requires a rapid response across all sectors of society, modeled by inspiring leaders. A broader scientific community that takes concrete actions would serve as an important step in convincing the general public of similar actions. Over the past years, grassroots movements across the sciences have recognized the overlooked impact of the scientific enterprise, and so-called Green Lab initiatives emerged seeking to address the environmental footprint of research. Driven by the voluntary efforts of researchers and staff, they educate peers, develop sustainability guidelines, write scientific publications and maintain accreditation frameworks. With this perspective we want to advocate for and spark leadership to promote a systemic change in laboratory practices and approach to research. Comprehensive evidence for the environmental impact of laboratories and their root-causes is presented, expanded with data from a current case study of the University of Groningen showcasing annual savings of 398 763 € as well as 477.1 tons of CO2e. This is followed by guidelines for sustainable lab practices and hands-on advice on how to achieve a systemic change at research institutions and industry. How can we expect industry, politics, and society to change, if we as scientists are not changing either? Scientists should lead by example and practice the change they want to see.

We describe the optimization and scale-up of two consecutive reaction steps in the synthesis of bio-derived alkoxybutenolide monomers that have been reported as potential replacements for acrylate-based coatings (Sci. Adv., 2020, 6, eabe0026). These monomers are synthesized by (i) oxidation of furfural with photo-generated singlet oxygen followed by (ii) thermal condensation of the desired 5-hydroxyfuranone intermediate product with an alcohol, a step which until now has involved a lengthy batch reaction. The two steps have been successfully telescoped into a single kilogram-scale process without any need to isolate the 5-hydroxyfuranone between the steps. Our process development involved FTIR reaction monitoring, FTIR data analysis via 2D-visualization and two different photo-reactors (i) a semi-continuous photo-reactor based on a modified rotary evaporator where FTIR and 2D-correlation spectroscopy (2D-COS) revealed the loss of the methyl formate co-product and (ii) our fully continuous Taylor Vortex photo-reactor which enhanced the mass transfer and permitted the use of near-stoichiometric equivalents of O2. The use of inline FTIR monitoring and modelling greatly accelerated process optimization in the Vortex reactor. This led to scale up of the photo-oxidation with an 85% yield and a projected productivity of 1.3 kg day-1, with a space time yield of 0.06 mol day-1 mL-1. Higher productivities could be achieved whilst sacrificing yield; e.g. 4 kg day-1 at 40% yield. The second step, the thermal condensation of 5-hydroxyfuranone, was transformed from a 20 h batch reflux reaction to a < 1 minute thermal flow reaction in a reactor only 3 mL in volume operating at 200 oC with projected productivities of >700 g day-1. Proof of concept for telescoping the two steps was established with an overall two-step yield of 67%, producing a process with projected productivity of 1.1 kg day-1 of the methoxybutenolide monomer without any purification of the 5-hydroxyfuranone intermediate.

Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermore, it is recognized as a possible future energy carrier achieving safe operation, storage and transportation. The photochemical production of H2O2 serves as a promising alternative to the waste- and energy-intensive anthraquinone process. Following the 12 principles of Green Chemistry, we demonstrate a facile and general approach to sustainable catalyst development utilizing earth-abundant iron and biobased sources only. We developed several iron oxide (FeOx) nanoparticles (NPs) for successful photochemical oxygen reduction to H2O2 under visible light illumination (445 nm). Achieving a selectivity for H2O2 of >99%, the catalyst material could be recycled for up to four consecutive rounds. An apparent quantum yield (AQY) of 0.11% was achieved for the photochemical oxygen reduction to H2O2 with visible light (445 nm) at ambient temperatures and pressures (9.4–14.8 mmol g−1 L−1). Reaching productivities of H2O2 of at least 1.7 ± 0.3 mmol g−1 L−1 h−1, production of H2O2 was further possible via sunlight irradiation and in seawater. Finally, a detailed mechanism has been proposed on the basis of experimental investigation of the catalyst's properties and computational results.

Photoclick reactions combine the selectivity of classical click chemistry with the high precision and spatiotemporal control afforded by light, finding diverse utility in surface customization, polymer conjugation, photocross-linking, protein labeling, and bioimaging. Nonetheless, UV light, pivotal in prevailing photoclick reactions, poses issues, especially in biological contexts, due to its limited tissue penetration and cell-toxic nature. Herein, a reliable and versatile strategy of activating the photoclick reactions of 9,10-phenanthrenequinones (PQs) with electron-rich alkenes (ERAs) with near infrared (NIR) light transduced by spectrally and structurally customized upconversion nanoparticles (UCNPs) is introduced. Under NIR irradiation, the UCNPs become UV/blue nanoemitters uniformly distributed in the reaction system. Enabled by the customized UCNPs, 800 or 980 nm light effectively activates the photocycloaddition reactions via radiative energy transfer in both general and triplet-triplet energy transfer (TTET)-mediated PQ-ERA systems. In particular, the novel sandwich structure UCNPs achieve the click reaction with up to 76% production yield in 10 min under NIR light irradiation. Meanwhile, the tricky side effect of photoclick product absorption-induced quenching is successfully circumvented from the fine-tuning of the upconversion spectrum. Moreover, through-tissue irradiation experiments, the authors show that the UCNP-PQ-ERA reaction unlocks the full potential of photoclick reactions for in vivo applications. A reliable and versatile strategy to near-infrared (NIR) light-induced 9,10-phenanthrenequinones (PQs) - electron-rich alkenes (ERAs) photoclick reactions enabled by upconversion nanoparticles (UCNP) was presented. By capitalizing on favorable absorption and emission spectra overlaps between PQs/photosensitizers and UCNPs, the emitted light from UCNPs effectively triggers PQ-ERA reaction. Additionally, successful in vivo application is demonstrated via deep tissue penetration.image

Photocatalytic hydrogen peroxide formation is an advancing field with various approaches motivated by the promise of a green oxidant and energy carrier for a sustainable future. An assessment on quantification methods, sacrificial agents and best practices is provided to avoid false positives and support progress in the field.

A complete biobased process towards polymers and coatings using starting materials derived from renewable resources and implementing sustainable synthetic steps.

Lignin is the largest natural source of functionalized aromatics on the planet, therefore exploiting its inherent structural features for the synthesis of aromatic products is a timely and ambitious goal. While the recently developed lignin depolymerization strategies gave rise to well-defined aromatic platform chemicals, the diversification of these structures, especially toward high-end applications is still poorly addressed. Molecular motors and switches have found widespread application in many important areas such as targeted drug delivery systems, responsive coatings for self-healing surfaces, paints and resins or muscles for soft robotics. They typically comprise a functionalized aromatic backbone, yet their synthesis from lignin has not been considered before. In this contribution, we showcase the synthesis of a novel light-driven unidirectional molecular motor from the specific aromatic platform chemical 4-(3-hydroxypropyl)-2,6-dimethoxyphenol (dihydrosynapyl alcohol) that can be directly obtained from lignocellulose via a reductive catalytic fractionation strategy. The synthetic path takes into account the principles of green chemistry and aims to maintain the intrinsic functionality of the lignin-derived platform molecule.

For almost a century, petrochemical-based monomers like acrylates have been widely used as the basis for coatings, resins, and paints. The development of sustainable alternatives, integrating the principles of green chemistry in starting material, synthesis process, and product function, offers tremendous challenges for science and society. Here, we report on alkoxybutenolides as a bio-based alternative for acrylates and the formation of high-performance coatings. Starting from biomass-derived furfural and an environmentally benign photochemical conversion using visible light and oxygen in a flow reactor provides the alkoxybutenolide monomers. This is followed by radical (co) polymerization, which results in coatings with tunable properties for applications on distinct surfaces like glass or plastic. The performance is comparable to current petrochemical-derived industrial coatings.