Research on Chemical Intermediates

Heteropoly acids have attracted great attention as potential solid-state proton-conducting materials owing to their high proton conductivity of 10–2 S cm−1 at room temperature. However, the proton conductivity can be significantly reduced under operating conditions due to the leaching of water molecules out of the acid Keggin structure. In the present study, silicotungstic acid (SiWA) was encapsulated in the mesoporous structure of the chromium (III) terephthalate metal–organic framework (MIL-101) in an attempt to prevent water loss and preserve proton conductivity. This hybrid material was then shaped into a membrane with the aid of polyvinyl alcohol (PVA). This approach of SiWA encapsulation with PVA addition to form a membrane proved to be successful as the proton conductivity of the resulting membranes was found to be of 2.4 × 10–2 S cm−1 at 25 °C and 25% RH. Under low levels of hydration, when the membrane was dried at 80 °C, the proton conductivity still remained high (1.9 × 10–2 S cm−1). This improved proton conductivity is believed to be the result of the continuous channels for facile proton transport created through the immobilisation of the heteropoly acid within the MIL-101 framework.

The development of low-cost, environmental friendliness, outstanding catalytic activity, superior conductivity and good stability counter electrode (CE) catalyst in dye-sensitized solar cells (DSSCs) is important to promote the commercial application of DSSCs. Here, WN/nitrogen-doped reduced graphite oxide hybrids (WN/NrGO) had been synthesized by hydrothermal method followed by nitridation treatment, which used as CE catalysts for catalyzing I3− to I−. The combined WN and nitrogen-doped reduced graphite oxide (NrGO) into WN/NrGO could effectively regulate the catalytic activity for the reduction of I3−, accelerate the charge transfer at the interface, and then the synergistic effect between of them can be fully achieved. When the WN/NrGO served as the CE catalyst in DSSCs, the photoelectric conversion efficiency (PCE) of 7.42% has been obtained, compared to the conventional Pt-based DSSCs (7.71%). Meanwhile, as-prepared WN/NrGO exhibited higher PCE than that of the solo WN (6.19%) and NrGO (5.81%) in parallel. A series of electrochemical measures revealed that the WN/NrGO displayed the higher catalytic activity and charge transfer ability than that of the solo WN and NrGO, so the synthesized low-cost WN/NrGO have an potential to be used as the effectively CE catalysts for the replacement of the noble Pt.

As a kind of volatile organic compound, styrene is a typical industrial pollutant with high toxicity and odorous smell. In this study, the removal of malodorous styrene simulation waste gas was carried out in a self-made wire-tube dielectric barrier discharge reactor. The decomposition efficiency of the reaction was investigated under different applied voltages and flow rates. The results showed that nearly 99.6 % of styrene could be removed with a concentration of 3,600 mg/m3 and the applied voltage of 10.8 kV. However, the selectivity of CO2 and CO showed that the mineralization efficiency of styrene was less than 25 %. The by-products of the reaction, including O3, NO x and other intermediates, were also detected and analyzed under different applied voltages. The relationships between the applied voltage and the quantity of final product (CO2) and by-products (intermediate organics, NO x , O3) were investigated. The reaction mechanism was also described according to the bond energy and the intermediates that formed.

2-Morpholinoethanamine is prepared rapidly mainly in aqueous conditions from inexpensive and commercially accessible starting materials. The process development of an effective synthetic route by utilizing morpholine as the starting material via Michael addition, hydrazinolysis, and Curtius rearrangements was undertaken. The optimal conditions were selected in the experiments. The total yield was 81.8% and it was a convenient process.

Time-resolved fluorescence and steady-state spectroscopic measurements were performed with +4-charged cationic porphyrins adsorbed on an anionic-type clay (Sumecton SA; SSA) surface at a low molecular loading level (10 % vs. cation-exchange capacity of clay) corresponding to an occupied area of ca 50 nm2 per molecule. Absorption spectra indicated no interaction between transition moments of the porphyrins on the clay surface. An efficient energy-transfer process from donor to acceptor porphyrin was observed on the clay surface even under low porphyrin loading conditions. The efficiency of energy transfer obtained from the steady-state measurement was 65 %. Real-time behavior of the porphyrins was successfully captured during energy transfer. The rate constant of the energy transfer obtained from time-resolved fluorescence measurements was found to be 5.3 × 108 s−1. According to the efficiency and the rate constant, it is proposed that the adsorbed porphyrins did not have a uniform and fixed distribution.

Cd x Zn1−x S solid solution photocatalysts were prepared by a hydrothermal process. The photocatalysts were characterized by X-ray diffraction (XRD), UV–vis diffusive reflectance spectroscopy (DRS), and transmission electron microscope (TEM) measurements. Using glucose as an electron donor, photocatalytic hydrogen generation over Pt/Cd x Zn1−x S was investigated. The results show that glucose not only improves the efficiency of photocatalytic hydrogen generation but prevents photocorrosion of Cd x Zn1−x S. Glucose was degraded effectively with the hydrogen generation. The factors which affect photocatalytic hydrogen generation, such as composition and structure of Cd x Zn1−x S solid solutions, irradiation time, initial concentration of the glucose, and concentration of NaOH were studied.

This manuscript describes the preparation and characterization of DBU hydrogen sulfate bonded to chloropropyl-functionalized bilayer silica-nano-Fe3O4 (DHCBSF), as well as its use as a highly effective, heterogeneous, and recyclable catalyst to facilitate a valuable chemical reaction. FTIR, SEM, TEM, TGA, XRD, BET, VSM, and EDS techniques were used to identify the nanomagnetic catalyst. The nanomagnetic catalyst (0.01 g) was successfully used in a multicomponent reaction including 2-thiobarbituric acid (2 mmol), aryl aldehydes (1 mmol), and ammonium acetate (1.4 mmol) at 25 °C in H2O (2 mL), so that it presented ten samples of pyrido[2,3-d:6,5-d']dipyrimidines with yields of 92–98% in 5–10 min. DHCBSF is a heterogeneous catalyst with advantages such as a high specific surface area, low environmental and economic impact, and ease of purification and separation from the reaction mixture. Furthermore, the nano-catalyst was recycled ten times without significantly altering its catalytic properties.

Sulfamic acid pyridinium chloride-functionalized Fe3O4 nanoparticles as a novel organic-inorganic hybrid heterogeneous catalyst was manufactured and characterized by FT-IR, XRD, TGA, SEM, TEM and VSM techniques. The catalytic activity of the nanomagnetic catalyst was investigated in the multicomponent reactions of arylaldehydes, 7-amino-4-methylcoumarin and dialkyl acetylenedicarboxylate that afford the novel N-coumarin-2-furanones. This green nanocatalytic procedure has good reversibility and provides clean production in a short reaction time. Preparation and characterization of sulfamic acid pyridinium chloride-functionalized Fe3O4 nanoparticles as a novel magnetic catalyst for synthesis of novel N-coumarin-2-furanone.