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The design of flow reactors for heterogeneous photocatalysis is key to enhancing the control, efficiency, and scalability of chemical reactions. However, conventional designs such as slurry reactors and fixed bed reactors often suffer from poor light penetration, challenging catalyst attachment to the support, and difficult separations. We report an efficient and robust methodology for the functionalization of perfluoroalkoxy (PFA) coil reactors with different fluorinated photocatalysts [a perylene diimide (F-PDI) and poly(p-phenylene ethynylene) polymers (PPEST and POLPDI)] through fluorophilic interactions. We have evaluated the efficiency of photocatalyst-functionalized coil reactors in continuous flow experiments through the [2 + 2] photocycloaddition of 9-vinylcarbazole (VCZ) using blue and green light (440 and 525 nm). The conversion of VCZ to the product 1,2-trans-dicarbazylcyclobutane (t-DCZCB) was continuously monitored by in-line nuclear magnetic resonance (NMR) spectroscopy, and we found that PPEST was the most robust photocatalyst coating of those studied, leading to high conversions with different lamp powers and residence times. Further experiments proved that PPEST-functionalized coil reactors were stable and efficient after 18 h of continuous flow with conversions from around 50 to 75%. 

H₂S/CH₄and CO₂/CH₄separations show opposing trends, making simultaneous improvement challenging. This is addressed by increasing free volume to enhance competitive sorption effects and boosting diffusion selectivity throughin situcrosslinking. 

We report a scalable synthesis of high-molecularweight poly(arylene ether)s (PAEs) using decafluorobiphenyl under SNAr reaction conditions and the preparation of enantiopure (R,R)-6,11-di(tert-butyl)triptycene-1,4-hydroquinone. The nonfluorinated biphenyl-based PAE was also synthesized using Pdcatalyzed C−O coupling methods, and structure−property comparisons were made from the different biphenyl-based polymers. The integration of free-volume-promoting triptycene moieties on the main chain gives rise to intrinsic porosity, which can be further modulated by incorporating biphenyl or perfluorobiphenyl comonomers. The nonfluorinated PAE exhibited a BET surface area of 270 m2 g−1, whereas the racemic and enantiopure fluorinated PAEs showed higher BET surface areas of 454 and 368 m2 g−1, respectively. WAXS analysis revealed that all of the polymers tested have a greater disruption of chain packing compared to related polyimides, with the fluorinated PAEs having the highest average interchain spacing. The fluorinated PAEs also demonstrated high gas permeability as a result of their free volume. The triptycene-based PAEs also were resistant to plasticization even at CO2 pressures of ∼31 bar. 

Elevated levels of ammonia in breath can be linked to medical complications such as chronic kidney disease (CKD) that disturb the urea balance in the body. However, early-stage CKD is usually asymptomatic and mass screening is hindered by high instrumentation and operation requirements, accessible and reliable detection methods for CKD biomarkers, such as trace ammonia in breath. Enabling methods would have significance in population screening for early-stage CKD patients. We herein report a method to effectively immobilize transition metal selectors in close proximity to single-walled carbon nanotube (SWCNT) surface using pentiptycene polymers containing metal-chelating backbone structures. The robust and modular nature of the pentiptycene metallopolymer/SWCNT complexes create a platform that accelerates sensor discovery and optimization. Using these methods, we have identified sensitive, selective, and robust copper-based chemiresistive ammonia sensors displaying low parts per billion detection limits. We have added these hybrid materials into the resonant radio frequency circuits of commercial near-field communication (NFC) tags to achieve robust wireless detection of ammonia at physiologically relevant levels. The integrated devices offer a non-invasive and cost-effective approach for early detection and monitoring of CKD.