In many applications, the ionic resistance of an ion-exchange membrane shows a strong dependency on the external solution concentration and hydrodynamic environment. It is critical to understand the insights of ion exchange membrane process if its ionic resistance can be simulated accurately. In this paper, we have developed a new model by taking into account both the membrane properties that affect the membrane bulk resistance and hydrodynamic environment that affects the non-ohmic behavior of membrane resistance. The new model not only explains external solution concentration dependency, but also explicitly establishes a relationship between the measured membrane resistance and current density. The modeling results on the direct current (DC) and alternating current (AC) resistance of membranes are compared with experimental data measured under different external solution concentrations and applied to current densities. We demonstrate that the model accurately predicts the behaviors of sulfonated polypoly (2,6-dimethyl-1,4-phenylene oxide) membranes and fumasep ®-FKS and FAS membranes in all cases. The integrative modeling and experimental study provides insights into the ion-exchange membrane synthesis as well as reverse and conventional electrodialysis processes.

Aerobic visible-light induced intermolecular SÀ N bond construction has been achieved without the addition of photosensitizer, metal, or base. With this strategy, 1,2,4-thiadiazoles can be obtained from thioamides. Preliminary mechanistic investigation suggested that the excited state of thioamides undergoes a single-electron-transfer (SET) process to afford thioamidyl radicals, which can be further transformed into a 1,2,4-thiadiazole through desulfurization and oxidative cyclization. The reaction has good functional group tolerance and represents a green method for the construction of SÀ N bonds.

CÀ N bond formation is crucial for the preparation of synthetic organic nitrogen-containing heterocyclic compounds. This work provides a facile and highly efficient strategy (ca. ∼ 92 %) for the synthesis of quinazoline compounds, which involves tandem CÀ H/NÀ H bond functionalization using metal-free conditions without the need for an external oxidant. Mean-while, the reaction system exhibits good functional group tolerance and a wide substrate scope. Furthermore, our corresponding isotope tracking experiments have shown that dimethyl sulfoxide acts as a carbon source. Finally, this work affords a new strategy toward the further design and synthesis of heteroaromatic rings.

An efficient visible‐light‐induced catalyzed dehydrogenation coupling of quinoxalin‐2(1H)‐ones with azoles was developed, a protocol that did not require prefunctionalization of the substrates and produced hydrogen (H2). Meanwhile, this reaction proceeded without the addition of other metal and oxidant and provided a broad range of 3‐aminoquinoxalin‐2(1H)‐ones in medium to good yield. Furthermore, this protocol provided advantages of easy and simple operation, high chemoselectivity, and a recyclable catalyst. A preliminary mechanistic investigation revealed that the reaction involved a radical process.

An efficient quinazoline-assisted ortho-halogenation of 2-arylquinazolines has been developed using N-halosuccinimides as halogen sources with Pd(II)-catalyzed CÀ H bond activation. No additional ligand and oxidant are required. This protocol is highly regioselective and applicable to a broad range of quinazoline substrates bearing different functional groups, giving yields of up to 98 %. The mechanism of the quinazoline ortho-halogenation was investigated by comprehensive experimentation.