Photomodulation on Active Sites of Adsorbents: Controllable Adsorption Processes with Improved Efficiency.

Adsorption is a widely applied technique in producing high-purity chemicals with advantages of low energy consumption, high selectivity, and mild operating conditions. However, traditional adsorbents have inflexible properties and suffer from the trade-off between selective adsorption and efficient desorption. Recently, the emerging photoresponsive adsorbents have provided new avenues for adsorption techniques. Active sites of photoresponsive adsorbents can be regulated through steric hindrance or tunable adsorbent-adsorbate interactions. Therefore, variation in adsorptive capacity is able to readily achieve through photomodulation, and the corresponding adsorption/desorption cycles are energy-saving. This concept mainly summarizes recent efforts on the fabrication and application of photoresponsive adsorbents with tunable active sites. Also, the future opportunities and critical challenges of photoregulation on adsorptive sites are presented.

Homogeneous base catalyst with high activity and stability for synthesis of dimethyl carbonate by transesterification.

In the synthesis of dimethyl carbonate (DMC) by transesterification, CH3ONa has been commonly applied as a homogeneous catalyst due to its high catalytic activity, but its stability is unsatisfactory. Here, by studying the influence of ionic liquid base strength on transesterification, we prepared an organic base catalyst, potassium imidazole (KIm), with high catalytic activity and stability, which solved the problem of catalyst deactivation in transesterification. The results showed that when KIm was used in the synthesis of DMC from propylene carbonate (PC) and methanol (MeOH), the chemical equilibrium could be reached within 3 minutes and the yield of DMC reached 73.03%, indicating that KIm performed better in transesterification than the majority of previously reported catalysts. In addition, the activity of the catalyst had hardly decreased after ten cycles of reaction, which can well meet the requirements of industrial production.

High-efficiency catalyst CuSO4/SBA-15 toward butylated hydroxytoluene synthesis in a heterogeneous system.

An SBA-15 loaded CuSO4 catalyst was designed and prepared for the highly selective production of 2,6-di-tert-butyl-p-cresol (BHT) from p-cresol and isobutylene. The acidity of solid acid catalysts was altered by varying the loading amount of CuSO4. Among them, 10% CuSO4/SBA-15 exhibited the greatest catalytic performance in the alkylation reaction with a BHT yield of 85.5%. After four cycles, the yield of BHT exceeded 70%. Overall, the catalyst has excellent catalytic performance and can be utilized as a catalyst for efficient BHT production.