Synthesis and Evaluation of Acid‐base Bi‐functional MOFs Catalyst Supported on PVDF Membrane for Glucose Dehydration to 5‐HMF

Zn(II)/Cd(II)-Based Metal-Organic Frameworks as Bifunctional Materials for Dye Scavenging and Catalysis of Fructose/Glucose to 5-Hydroxymethylfurfural

Functional neutral metal-organic frameworks (MOFs) {[M(5OH-IP)(L)]}_n [M = Zn(II) for ADES-4; Cd(II) for ADES-5; 5OH-IP = 5-hydroxyisophthalate; L = (E)-N'-(pyridin-3-ylmethylene)nicotinohydrazide) have been synthesized by a diffusion/conventional reflux/mechanochemical method and characterized by various analytical techniques. Crystals were harvested by a diffusion method, and single-crystal X-ray diffraction (SXRD) analysis revealed that an adjacent [M₂(COO)₂]_n ladder chain generates isostructural two-dimensional network motifs by doubly pillaring via L. The bulk-phase purity of ADES-4 and ADES-5 synthesized by a versatile synthetic approach has been recognized by the decent match of powder X-ray diffraction patterns with the simulated one. Both ADES-4 and ADES-5 showed selective adsorption of cationic dyes methylene blue (MB), methyl violet (MV), and rhodamine B (RhB) over anionic dye methyl orange (MO) from water with good uptake and rapid adsorption. Utilization of ADES-4 as a chromatographic column filler for adsorptive removal of individual cationic dyes as well as a mixture of dyes has been demonstrated from the aqueous phase. Interestingly, ADES-4 is reusable with good stability, and it showed a dye desorption phenomenon in methanol. The probable mechanism of cationic dye removal based on insight from structural information and plausible supramolecular interactions has also been explored. Both MOFs also showed efficient catalytic transformation of fructose and glucose into the high-value chemical intermediate 5-hydroxymethylfurfural of industrial significance.

High-throughput monitoring of biomass conversion reaction with automatic time-resolved analysis

Reactions of biomass conversions are of great importance in fine chemistry for substantial development. While numerous studies have been performed to search for functional materials to catalyze biomass conversions, a robust and high-throughput analytical method is rather limited, which may hamper further integration and automation of the reactions. Here we propose an automatic and sequential method for the investigation of glucose conversion. By combining sequential sample injection and high-speed capillary electrophoresis (HSCE) techniques, we can monitor the glucose conversion from the beginning toward the end with a good temporal resolution. The HSCE assays are performed using short capillaries (effective length of 10 cm, i.d./o.d. of 50 μm/365 μm), and the analytes are separated at an electric field of 467 V/cm and are detected by UV-absorption at 200 nm with mixed 0.2 mM CTAB, 10 mM borate, 20 mM sorbic acid (pH 12.2) as the background electrolyte. All compounds involved in the reaction, including all products (fructose, 5-hydroxymethylfurfural, formic acid and levulinic acid) and the remaining substrate glucose, are efficiently separated and simultaneously detected from just one analysis with a temporal resolution of one minute. The method exhibits high-resolution separation, a wide linear range with limit-of-detection down to μg/mL-level, as well as excellent repeatability in sequential analysis. It is indicated that the proposed method is of great value in the analysis of complicated biomass conversion and could be potentially applied in various catalytic chemical reactions.