Solvent-Free Selective Condensations Based on the Formation of the Olefinic (C=C) Bond Catalyzed by Organocatalyst

Pyrrolidine and its derivatives were used to catalyze aldol and Knoevenagel condensations for the formation of the olefinic (C=C) bond under solvent-free conditions. The 3-pyrrolidinamine showed high activity and afforded excellent yields of α,β-unsaturated compounds. The aldol condensation of aromatic/heterocyclic aldehydes with ketones affords enones in high conversion (99.5%) and selectivity (92.7%). Good to excellent yields of α,β-unsaturated compounds were obtained in the Knoevenagel condensation of aldehydes with methylene-activated substrates

Peroxymonosulfate Activation by Iron Sulfide Minerals for Degradation of Various Thiol Collectors in Mineral Processing Wastewater: Performance, Mechanism, and Structure–Activity Relationship

The quantity of mineral processing wastewater (MPW) is large and contains residual thiol collectors, which easily cause environmental pollution. Herein, we systematically investigated the catalytic performances and underlying mechanisms of iron sulfide minerals (pyrite, marcasite, and pyrrhotite) for the activation of peroxymonosulfate (PMS) to treat MPW containing various thiol collectors (ethyl xanthate (EX), butyl xanthate (BX), diethyldithiocarbamate (DDTC)). Density functional theory (DFT) calculation results indicated that electron-rich Fe atoms in pyrite and marcasite acted as electron donors for PMS adsorption and cleavage, while pyrrhotite with electron-deficient Fe atoms has no PMS adsorption site. In particular, pyrite has stronger reactivity in comparison with marcasite due to more electron transfer and the lower thermodynamic and kinetic energy barrier of the reaction. Meanwhile, the efficient electron transfer of pyrite with strong F–S covalent bonds facilitated the regeneration of Fe(II), thus improving the catalytic performance. As a result, pyrite exhibited the highest total organic carbon (TOC) removal efficiency for real MPW, which was 1.12-fold and 1.63-fold of that on marcasite and pyrrhotite, respectively. This study highlights the structure–activity relationship of iron sulfide minerals and provides new insights into the PMS activation mechanism of sulfur-containing catalysts for MPW treatment

Efficient methoxycarbonylation of diisobutylene over functionalized ZSM-5 supported cobalt complex catalysts

By grafting nitrogen-containing complexes onto ZSM-5 mesoporous material and then supporting a cobalt catalyst in situ, the methoxycarbonylation of diisobutylene (DIB) was achieved. Moreover, a series of functionalized ZSM-5 mesoporous materials containing different nitrogen complexes were synthesized and characterized by FT-IR, N2 adsorption–desorption isotherms, XRD, SEM, and X-ray photoelectron spectroscopy (XPS). Subsequently, the catalytic activity of functionalized ZSM-5 mesoporous materials and the reaction parameters in the methoxycarbonylation of DIB were investigated. The results revealed that the conversion of DIB was 88.3% and the selectivity for methyl isononanoate was 93.4% under solvent-free conditions at 6.0 MPa and 140 °C for 10 h by using the catalyst ZSM-5iCPdPy@Co2(CO)8. The potential mechanism for this catalytic reaction was also put forth. Admittedly, these inexpensive and easy-to-recover heterogeneous catalysts can replace the noble metal palladium complexes on a laboratory scale to achieve partial olefin carbonylation reactions

THE INFLUENCE OF HUMIDITY ON THE SHEAR FORCE BETWEEN TIP AND SAMPLE IN NSOM USING PIEZOELECTRIC FORK

The distance between tip and sample can be regulated using piezoelectric quartz fork glued with micro optic fiber probe. A biquadrate vibration equation for the fork–probe–sample system is established to theoretically analyze the relations of the electric current flow through fork versus tip–sample (T–S) distance (I–d). The I–d curve and the action distance for shear force are influenced by environmental humidity. The results reinforce the opinions in the earlier works by other researches that the physical origin of the shear force is due to a material filling the tip–sample gap. Furthermore, the intrinsic reasons for shear force damping between tip and sample have been confirmed and developed, i.e. the water and hydrocarbon coupled between optic fiber probe and sample due to the capillary cohesion force.NSOM, shear force, piezo-electric quartz fork

“Water‐in‐Eutectogel” Electrolytes for Quasi‐Solid‐State Aqueous Lithium‐Ion Batteries

The development of high safety lithium-ion batteries (LIBs) is greatly impeded by the flammability and leakage concerns of typical organic solvent-based electrolytes. As one of the alternative classes of electrolytes, hydrogel electrolytes exhibit high safety, high flexibility, low cost, and are benign to the environment. However, the narrow electrochemical stability window (ESW) of typical hydrogel electrolytes restricts the operating voltage of battery cells. Here, a new class of “water-in-eutectogel (WiETG)” electrolyte is reported, fabricated by combining a hydrogel with a “deep eutectic solvent” (LiTFSI in acetamide). The obtained WiETG electrolyte exhibits non-flammability, high ionic conductivity, and a wide ESW. LiMn2O4||Li4Ti5O12 cells with the WiETG electrolyte exhibit good cycling stability, high flexibility, and high safety. This newly developed WiETG electrolyte not only broadens the ESW of typical hydrogel electrolytes, but also opens a new perspective on future directions and guidance for the design of high safety electrolytes for flexible LIBs and beyond