Sustainable Adipic Acid Production via Paired Electrolysis of Lignin-Derived Phenolic Compounds with Water as Hydrogen and Oxygen Sources.

Adipic acid (AA) is an important feedstock for nylon polymers and is industrially produced from fossil-derived aromatics via thermocatalysis. However, this process consumes explosive H2 and corrosive HNO3 as reductants and oxidants, respectively. Here, we report the direct synthesis of AA from lignin-derived phenolic compounds via paired electrolysis using bimetallic cooperative catalysts. At the cathode, phenol is hydrogenated on PtAu catalysts to form ketone-alcohol (KA) oil with 92% yield and 43% Faradaic efficiency (FE). At the anode, KA is electrooxidized into AA on CuCo2O4 catalysts, achieving a maximum of 85% yield and 84% FE. Experimental and theoretical studies reveal that the excellent catalytic activity can be ascribed to the enhanced absorption and activation capability of reactants on the bimetallic cooperative catalysts. A two-electrode flow electrolyzer for AA synthesis realizes a stable electrolysis at 2.5 A for over 200 h as well as 38.5% yield and 70.2% selectivity. This study offers a green and sustainable route for AA synthesis from lignin via paired electrolysis.

Clickable APEX2 Probes for Enhanced RNA Proximity Labeling in Live Cells.

Although APEX2-mediated proximity labeling has been extensively implemented for studying RNA subcellular localization in live cells, the biotin-phenoxyl radical used for labeling RNAs has a relatively low efficiency, which can limit its compatibility with other profiling methods. Herein, a set of phenol derivatives were designed as APEX2 probes through balancing reactivity, hydrophilicity, and lipophilicity. Among these derivatives, Ph_N3 exhibited reliable labeling ability and enabled two biotinylation routes for downstream analysis. As a proof of concept, we used APEX2/Ph_N3 labeling with high-throughput sequencing analysis to examine the transcriptomes in the mitochondrial matrix, demonstrating high sensitivity and specificity. To further expand the utility of Ph_N3, we employed mechanistically orthogonal APEX2 and singlet oxygen (1O2)-mediated strategies for dual location labeling in live cells. Specifically, DRAQ5, a DNA-intercalating photosensitizer, was applied for nucleus-restricted 1O2 labeling. We validated the orthogonality of APEX2/Ph_N3 and DRAQ5-1O2 at the imaging level, providing an attractive and feasible approach for future studies of RNA translocation in live cells.