Reaction Environment Design for Multigram Synthesis via Sonogashira Coupling over Heterogeneous Palladium Single-Atom Catalysts.

Single-atom heterogeneous catalysts (SACs) attract growing interest in their application in green chemistry and organic synthesis due to their potential for achieving atomic-level precision. These catalysts offer the possibility of achieving selectivity comparable to the traditionally applied organometallic complexes, while enhancing metal utilization and recovery. However, an understanding of SAC performance in organic reactions remains limited to model substrates, and their application as drop-in solutions may not yield optimal activity. Here, we investigate the previously unaddressed influence of the reaction environment, including solvent, base, cocatalyst, and ligand, on the performance of a palladium SAC in Sonogashira-Hagihara cross-couplings. By examining the effects of different solvents using the established criteria, we find that the behavior of the SAC deviates from trends observed with homogeneous catalysts, indicating a distinct interplay between heterogeneous systems and the reaction environment. Our results illustrate the satisfactory performance of SACs in cross-couplings of aryl iodides and acetylenes with electron-withdrawing and -donating groups, while the use of bromides and chlorides remains challenging. Extending the proof-of-concept stage to multigram scale, we demonstrate the synthesis of an intermediate of the anticancer drug Erlotinib. The catalyst exhibits high stability, allowing for multiple reuses, even under noninert conditions. Life-cycle assessment guides the upscaling of the catalyst preparation and quantifies the potential environmental and financial benefits of using the SAC, while also revealing the negligible impact of the PPh3 ligand and CuI cocatalyst. Our results underscore the significant potential of SACs to revolutionize sustainable organic chemistry and highlight the need for further understanding the distinct interplay between their performance and the reaction environment.

Low-carbon diets can reduce global ecological and health costs.

Potential external cost savings associated with the reduction of animal-sourced foods remain poorly understood. Here we combine life cycle assessment principles and monetarization factors to estimate the monetary worth of damage to human health and ecosystems caused by the environmental impacts of food production. We find that, globally, approximately US$2 of production-related external costs were embedded in every dollar of food expenditure in 2018-corresponding to US$14.0 trillion of externalities. A dietary shift away from animal-sourced foods could greatly reduce these 'hidden' costs, saving up to US$7.3 trillion worth of production-related health burden and ecosystem degradation while curbing carbon emissions. By comparing the health effects of dietary change from the consumption versus the production of food, we also show that omitting the latter means underestimating the benefits of more plant-based diets. Our analysis reveals the substantial potential of dietary change, particularly in high and upper-middle-income countries, to deliver socio-economic benefits while mitigating climate change.

Global environmental and nutritional assessment of national food supply patterns: Insights from a data envelopment analysis approach.

The global food system inextricably connects human health and environmental integrity. It holds the transformative capability to significantly reduce levels of environmental degradation, caused by current food production practices, and alleviate the 'triple burden' of malnutrition, existing due to food consumption patterns. System-wide transitions are therefore paramount to tackling environmental and nutritional challenges that are exacerbated by a rapidly growing population. This work presents a novel application of Data Envelopment Analysis (DEA) to study the sustainability of food supply patterns around the world and appraise the potential to lower environmental pressure without compromising the supply of calories and nutritional quality. By relating environmental impacts to caloric availability and nutritional adequacy, DEA computes a relative performance score for 139 countries and identifies only 18 countries with per capita food supplies that are 'efficient' in transforming five environmental inputs (land use, greenhouse gas emissions, acidification potential, eutrophication potential and freshwater withdrawals) into calories and nutrition. The widespread extent of 'inefficiency' stresses that the significant opportunity and need to reduce environmental impacts from food is truly global and extensive. Results of this analysis also provide quantitative information on the varying degrees of potential to improve the ways in which each nation's population is fed and therefore offers country-specific insight for decision-makers into the integration of environmental and nutritional outcomes for sustainable development.