Green Chemistry最新文献

A palladium-catalyzed reductive carbonylative benzannulation of 1,4-enynes with carbon dioxide (CO₂) as carbonyl source has been developed for the first time, offering an efficient approach to a wide range of multi-substituted phenols in high yields. The success of this transformation hinges on a synergistic dual silane reduction system: one silane acts as a reductant for the conversion of CO₂ to CO, while the other serves as a hydrogen source to generate Pd–H species. This method is operationally simple, exhibits broad substrate scope, and can be applied to the late-stage modification of complex pharmaceutical molecules as well as the synthesis of bioactive compounds such as thymol.

Rifamycin O (RO), a key intermediate in the antibiotic drug rifaximin synthesis, faces several production challenges including low yield, purity issues, and environmental concerns. Here, we report an electrochemical synthesis strategy for achieving RO production via electrooxidation of rifamycin B (RB), resulting in a 92% high yield. Trace water addition improves the functional-group compatibility during RB electrooxidation, substantially elevating the RO yield by 10%. Mechanistic studies reveal that trace water regulates methanol's hydrogen bond network, facilitates the dissociation of the hydroxyl group in the carboxylic acid, and enriches RB at the electrode/electrolyte interface, thereby achieving thermodynamic and kinetic synergistic optimization of RB electrooxidation. Systematic optimization of flow electrolyzer parameters further improves the performance. The scale-up experiment with an electrode area of 400 cm² demonstrates high yield and space–time yield. The present work establishes the electrochemical synthesis of RO, providing a sustainable paradigm for pharmaceutical electrosynthesis.

Lignin can significantly promote gel formation and enhance the properties of the resulting gels due to its rigid structure and abundant functional groups. Herein, high-purity (91.28%) lignin with a low and uniform molecular weight (M_w = 4071 g mol⁻¹, M_n = 2770 g mol⁻¹, PDI = 1.46) was effectively separated from natural bamboo using deep eutectic solvents (DESs). The obtained DES-separated bamboo lignin (DESL) was dissolved in different DES systems, including betaine/ethylene glycol (Bet/EG) DES and choline chloride/ethylene glycol (ChCl/EG) DES via a green and mild one-pot approach to fabricate two kinds of DES gels, Fe-L-GO/PAA and L/PAA, respectively. The abundant active sites and dispersibility of DESL enabled the formation of a dense and uniform hydrogen-bonded network within both Fe-L-GO/PAA and L/PAA. This network enhanced the polymeric structure of two gels, thereby significantly improving their conductivity, toughness, and stability. Meanwhile, the phenolic hydroxyl groups of DESL improved the long-term and repeatable adhesion of gels, while its aromatic structures endowed the gels with UV resistance. These properties extended the service life of the gels. Among the two gels, Fe-L-GO/PAA exhibited a higher tensile strength of 246.3 kPa and a lower glass transition temperature of −117.4 °C, making it suitable for use in flexible electronic devices at low temperatures. Moreover, L/PAA achieved a higher conductivity (7.41 mS cm⁻¹), elongation at break (712.9%), and compressive strength (2.5 MPa). These properties satisfy the requirements for accurate electrical signal transmission for flexible electronic materials under large-scale deformation. In general, this study extracted high-quality bamboo lignin using DES and employed it to fabricate green DES gels, which exhibit outstanding performance outdoors or in harsh environments.

Green hydrogen produced via renewable-powered water electrolysis is widely regarded as environmentally sustainable, yet existing life cycle assessments often differ in their treatment of upstream supply chain processes. This study evaluates four major electrolysis technologies—alkaline, proton exchange membrane, solid oxide electrolysis cell, and anion exchange membrane —using a harmonized cradle-to-gate framework that systematically incorporates all relevant upstream emission categories. Across all technologies, upstream supply chain emissions (scope 3) contribute 15–49% of total greenhouse gas burdens, underscoring their substantial influence on life cycle outcomes. Environmental performance is shaped by material requirements, operational efficiency, and component manufacturing intensity, with critical raw materials such as platinum, nickel, and high-temperature alloys emerging as major upstream drivers. Under a net-zero mitigation scenario in which conventional grid electricity is replaced with renewable electricity, total life cycle emissions decrease by 79–90% across all electrolysis technologies. Nevertheless, upstream supply chain processes remain significant contributors, indicating that electricity decarbonization alone is insufficient. Material efficiency, low-carbon manufacturing routes, durability improvements, and recycling strategies are essential to meaningfully reduce the carbon footprint of green hydrogen. Emerging technologies such as AEM demonstrate promising environmental potential owing to their balanced material profiles and reduced dependence on supply-constrained critical materials. This study provides a harmonized methodological foundation for evaluating the environmental performance of water electrolysis systems and highlights that achieving truly sustainable green hydrogen requires coordinated advances in supply chain decarbonization, technological efficiency, and renewable electricity integration.

The growing demand for sustainable extraction approaches has positioned deep eutectic systems (DESs) as promising, and often greener, alternatives to conventional solvents for valorizing algal and cyanobacterial biomass. This systematic review, supported by quantitative data integration and multivariate statistical analysis, analyzes peer-reviewed studies on the recovery of proteins, carbohydrates, lipids, fatty acids, phytosterols, polyphenols, and pigments from microalgae, macroalgae, and cyanobacteria, and highlights the main challenges in applying DESs to biomass processing. To ensure comparability, extraction conditions, DES composition, biomass origin, and assisted extraction techniques were systematically examined, with results normalized across studies. Hydrophilic DESs, typically based on choline chloride, sugars, or glycerol, generally show high efficiency for proteins and phycobiliproteins, whereas hydrophobic systems derived from fatty acids or terpenes favor the extraction of lipids and lipophilic pigments. However, water content, viscosity, and biomass-solvent interactions can significantly modulate these trends, and deviations are reported. Ultrasound-assisted extraction is among the most frequently employed techniques to enhance DES extraction. Principal component analysis revealed clear clustering of algal species and DES formulations according to compound class, confirming polarity-driven selectivity for specific macronutrients, pigments and phenolics. Beyond selective extraction, DESs and natural DESs (NADESs) support biomass pretreatment and stabilization, and can mitigate off-flavors and odors, thus reducing both energy and solvent consumption while aligning with circular-economy principles. Although further research is required to address scalability and standardization, DES-based algal processing holds strong potential as a practical and sustainable route to producing functional ingredients.

Photochemical organic synthesis has emerged as a prominent and important synthetic methodology in recent years. However, conventional photosensitizers are often expensive and require multi-step synthesis for their preparation. This study utilizes natural flavonoids extracted from citrus peel (Tangeretin, Nobiletin, and Sinensetin) as photocatalysts to achieve the photooxidation of alkenes. Conversion rates of 53.7% for styrene and 66.1% for cyclohexene were attained. Reaction Mechanism Generator (RMG) simulations revealed that alkenes undergo reaction pathways mediated by singlet oxygen or oxygen-free radicals to form the corresponding products, a finding corroborated by a series of control experiments and EPR. These flavonoid compounds exhibit Aggregation-Induced Emission (AIE) characteristics. Upon encapsulation with saponins to form nanoparticles, the conversion rate for cyclohexene was further enhanced to 86.0%. Furthermore, this system successfully achieved the efficient oxidation of benzyl alcohol in an aqueous solvent (52.4% conversion, >99% selectivity). This work establishes a comprehensive green chemistry system encompassing the light source, catalyst, and solvent. The proposed strategy offers a novel approach to the development of natural photocatalysts and sustainable organic synthesis.

Reduction of carbonate salts by transfer hydrogenation, utilizing glycerol as a sacrificial hydrogen donor, to generate formate and lactate is an attractive reaction to produce value-added products from chemical waste. Iridium complexes have emerged as highly active catalysts for this transformation. Herein, we report the synthesis of a series of iridium(I) bis-carbonyl complexes, supported by neutral chelating bis-N-heterocyclic carbene (bis-NHC) ligands, which define 7-membered ring metallacycles. A rigid ortho-phenylene-bis(N-methylimidazol-2-ylidene (Ph-bis-mim) and a flexible ethylene-bis(N-methylimidazol-2-ylidene (C₂H₄-bis-mim) were utilized as chelating ligands. We performed a comparative study with the analogue complex bearing a bis-NHC with an imidazolium bridging group (1,3-dimethyl-imidazolium-4,5-bis(N-methylimidazol-2-ylidene), Im-bis-mim), and found that this positively charged ligand enables high selectivity towards the generation of formate, and high activity at low catalyst loadings. Our study reveals general design principles for iridium bis-N-heterocyclic carbene catalysts that can guide further designs for fast and selective carbonate transfer hydrogenation with glycerol at low catalyst concentrations.

Biopolymers, particularly polysaccharides, are a renewable feedstock with the potential to reduce reliance on petrochemicals and enable decarbonization and circularity efforts. Their sustainable chemical modification is essential to expand their use in the industry, yet this goal has proven hard to achieve because of their poor processability attributed to low solubility in most solvents. Mechanochemistry is a fast-emerging technique enabling the effective chemical transformation of materials in the solid state. It is effective for the chemical modification of biopolymers and composites with lower reagent, solvent and energy use compared to solution phase methods. Herein, we review recent progress in the development of mechanochemical methodologies for polysaccharide transformations, including depolymerization, nano-extraction, and chemical functionalization. We compare in detail the different techniques and their outcomes in terms of the functional properties of the final products, as well as the green metrics of each method based on reported parameters. Conclusions are then drawn to direct future research directions to expand the range of new functional biomaterials mechanochemistry that can be produced in a more sustainable manner.