Polymeric Fiber Sorbents Embedded with Porous Organic Cages

Reversible Switching and Recycling of Thermoresponsive 1,2,4-Triazolium-Based Poly(ionic liquid) Catalysts for Porous Organic Cage Synthesis in Organic Media

Homogeneous catalysts of high activity and selectivity often face challenges in the separation from feedstocks and products after reactions. In contrast, heterogeneous catalysts are easier to separate, usually at the cost of compromised catalytic performance. By designing catalysts capable of switching between homogeneous and heterogeneous states for catalysis and separation, the merits of both could be synergistically combined. In this study, a thermoresponsive 1,2,4-triazolium-based poly(ionic liquid) (PIL) was applied as a temperature-switchable organocatalyst for the controlled synthesis of porous organic cages in methanol. Variation of the reaction temperature induced a phase transition of the PIL, causing the polymer chains to dissolve or collapse in methanol, thereby exposing or shielding the catalytically active sites to proceed or retard the reaction, respectively. To note, at a sufficiently low temperature, the PIL as a catalyst precipitated out of its methanol solution and could be separated by centrifugation or filtration for reuse, similar to common heterogeneous catalysts. Such switchable and recyclable properties of polymeric catalysts will inspire the design of efficient and adaptable organic or hybrid nanoreactors in liquid media.

Construction of a novel ursolic acid-based supramolecular gel for efficient removal of iodine from solution

Pentacyclic triterpenes is a natural amphipathic product which possess a rigid backbone and several polar functional groups such as hydroxyl, carbonyl and carboxyl groups. The amphipathic character makes it easy to realize self-assemble into complex nano structure and therefore attract extensive attention due to the simple synthetic processes and renewable raw materials. Hence, a novel Ursolic acid-based hydrogel was prepared successfully via a simple self-assembly of triterpenoid derivative in methanol by capture water molecule in air. The resulting hydrogel show a porous morphology and good elasticity including strong heat resistance. Based on the characteristic above, the hydrogel showed a good iodine adsorption capacity and can removal 75.0% of the iodine from cyclohexane solution and 66.3% from aqueous solution within 36 h. Data analysis indicate that all the iodine adsorption process are dominated by chemisorption and belongs to the multi-site adsorption on heterogenous surfaces. In addition, the obtained hydrogel also possesses a good recyclability which can maintain more than 82% of its capacity after 5 cycles. The simple preparation method and easily available raw materials endow it a great potential in future pollutant treatment.

Recent advances in the applications of porous organic cages

Porous organic cages (POCs) have emerged as a new sub-class of porous materials that stand out by virtue of their tunability, modularity, and processibility. Similar to other porous materials such...