Biomass ethanol is regarded as a renewable resource but it is not economically viable to transform it to high-value industrial chemicals at present. Herein, a simple, green, and low-cost CuCl2–ethanol complex is reported for ethanol dehydration to produce ethylene and acetal simultaneously with high selectivity under sunlight irradiation. Under N2 atmosphere, the generation rates of ethylene and acetal were 165 and 3672 μmol g–1 h–1, accounting for 100% in gas products and 97% in liquid products, respectively. An outstanding apparent quantum yield of 13.2% (365 nm) and the maximum conversion rate of 32% were achieved. The dehydration reactions start from the photoexcited CuCl2–ethanol complex, and then go through the energy transfer (EnT) and ligand to metal charge transfer (LMCT) mechanisms to produce ethylene and acetal, respectively. The formation energies of the CuCl2–ethanol complex and the key intermediate radicals (e.g., ·OH, CH3CH2·, and CH3CH2O·) were validated to clarify the mechanisms. Different from previous CuCl2-based oxidation and addition reactions, this work is anticipated to supply new insights into the dehydration reaction of ethanol to produce useful chemical feedstocks.
Water scarcity has become a global problem and caused a lot of conflicts. Atmospheric water harvesting (AWH) is a promising way to address water shortage issue. However, traditional adsorbent materials such as silica gels and zeolites suffer from low water productivity and high regeneration temperature. Hygroscopic salts like LiCl are regarded as a perspective substitution. Salt-modified metal organic frameworks (MOFs) and hydrogels are employed to alleviate the salt aggregation but they are limited to expensive fabrication or sluggish adsorption kinetics. Herein, we demonstrate an asymmetric double-layer design of LiCl@CC (carbon cloth)/PAM with separated function of water adsorption/desorption and water storage in different layer. This double-layer design not only enhances the mechanical properties but also shows an improved water adsorption kinetics compared to common salt-composite hydrogels. In experimental test, the LiCl@CC/PAM exhibits excellent water uptake of 1.5 g g −1 under 60 % RH in 4 h and fast water desorption under sunlight in 1.5 h. In outdoor test, LiCl@CC/PAM based device presents a daily water uptake of 5.12 g g −1 day −1 . Meanwhile, all the materials used and fabrication process are feasible to scale up, which provides a possible solution to the global crisis of water scarcity.
危险品化学品经营许可证（带存储）