Conversion of N-acetyl-D-glucosamine (GlcNAc) to furan derivatives in ionic liquid ([Bmim]Cl) was studied with Amberlyst 45 (Brønsted acid) and B(OH)3 (Lewis acid) additives. A 10 wt% of GlcNAc solution in [Bmim]Cl with additives was loaded into a glass reactor and heated at constant temperature in the range of 110–150°C for 5–30 min. In the presence of Amberlyst 45, 80% conversion of GlcNAc was obtained. With both additives, the formation of 3-acetamide-5-acetylfuran was observed. From the reaction kinetics, the activation energy of GlcNAc conversion was determined to be 43.7 kJ/mol with Amberlyst 45 and 73.6 kJ/mol with B(OH)3.
With a view to constructing a resource circulation system for lithium ion batteries, we attempted to recover lithium and cobalt ions by hydrothermal citric acid leaching into water. Under reaction conditions in the range of 100–200°C, 5–30 min, and 0.1–1.0 M citric acid, leaching efficiency of lithium and cobalt was found to increase with reaction temperature, time and citric acid concentration, and recovery of both metals exceeded 80%. To elucidate the reaction mechanism, leaching rate constants of lithium and cobalt were calculated based on the unreacted core or shrinking core model. It was found that the leaching behavior was expressed by the product layer controlled model in the unreacted core model, and the leaching rate constants of lithium and cobalt are approximately linearly dependent on the proton concentration.
Magnetite/activated carbon composite (MAC) and MAC modified with poly (N-isopropyl acrylamide) (PNIPAM) (PMAC) were synthesized as dye adsorbents, and their structures were evaluated by inductively coupled plasma atomic emission spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption-desorption measurement. As a result, PMAC was found to consist of 16.9 wt% of magnetite loaded on the activated carbon, with 7.6 wt% of PNIPAM modifying the MAC. The amounts of methyl orange (MO) adsorbed by activated carbon, MAC, PMAC (room temperature) and PMAC (50°C) were 271, 285, 178 and 273 µmol/g, respectively. The adsorption of MO by PMAC was remarkably lower at room temperature than at 50°C, which was almost the same as that of activated carbon and MAC. The activated carbon, MAC, PMAC were dispersed in water at room temperature, while PMAC precipitated in water at 50°C. PMAC is effective for dye adsorption, and it self-aggregates above LCST, so it is expected to be effective for recovery by magnetic separation.