Facile synthesis of hierarchical porous catalysts for enhanced conversion of fructose to 5-hydroxymethylfurfural

CoFe2O4@SiO2-NH2@MOF-5 magnetic nanocatalyst for the synthesis of biologically active quinazoline derivatives

Metal-organic frameworks (MOFs) offered excellent catalytic activity due to their superior porosity, and high densities of catalytic sites in remarkable specific surfaces. In this research, we prepared a magnetic nanocomposite based on MOF-5 which is one of the prominent and practical structures that have been reported in many applications, and investigated the advantages of it as a catalyst. The multi-functional catalyst was prepared in five steps including (1) preparation of cobalt ferrite nanoparticles (CoFe2O4), (2) surface modification of cobalt ferrite using tetraethyl orthosilicate, (3) surface functionalization using 3-aminopropyl triethoxysilane, (4) preparation of MOF-5, (5) preparation of CoFe2O4@SiO2-NH2@MOF-5 nanocomposite. The resulting catalyst was evaluated by FTIR, FESEM, EDX, XRD, and VSM analyses. The CoFe2O4@SiO2-NH2@MOF-5 nanocomposite was applied as a catalyst for the quinazoline derivatives' synthesis. Various products were prepared with significant yields (90-98%) in short reaction times (20-60 min) without difficult work-up. In addition, the magnetic behavior of the catalyst allows it to be collected and recycled by a magnet and applied for six consecutive cycles without significantly reducing its efficiency. Quinazoline derivatives showed significant biological activities so their antioxidant activity was between 23.7% and 88.9% and their antimicrobial activity was in contradiction of E. coli, S. enterica, L. monocytogenes, S. aureus, and E. faecalis.

High-efficiency synthesis of 5-hydroxymethylfurfural and 2,5-diformylfuran from fructose over magnetic separable catalysts

In this work, a sulfonic acid-functionalized magnetic separable solid acid (Fe₃O₄@SiO₂-SO₃H) was synthesized, characterized, and tested for fructose conversion to 5-hydroxymethylfurfural (HMF). Results indicated that the prepared catalyst had a good efficacy for fructose dehydration to HMF due to its larger specific surface area, appropriate acid amount and homogeneous acid distribution. The maximum HMF yield of this work was 96.1 mol%. It was obtained at 120 °C for 1.5 h with 100 mol% fructose conversion. More importantly, the produced HMF could be further in-situ oxidized into 2,5-diformylfuran (DFF) after the replacing of the Fe₃O₄@SiO₂-SO₃H with a ZnFeRuO₄ catalyst, and the highest DFF yield of 90.2 mol% (based on initial fructose) was obtained after reaction another 8.5 h. The production of DFF from fructose through the above two consecutive steps avoids the intermediate HMF separation, which saves time and energy. In addition, both Fe₃O₄@SiO₂-SO₃H and ZnFeRuO₄ catalysts exhibited satisfied stability in the recycling experiments, which can be reused at least for five times with the HMF and DFF yield loss<5.3% and 3.3%, respectively. Finally, the plausible reaction mechanisms for fructose conversion to HMF or DFF over Fe₃O₄@SiO₂-SO₃H or/and ZnFeRuO₄ catalysts were also proposed in this work.

Recent advances on preparation and environmental applications of MOF-derived carbons in catalysis

Carbon materials derived from metal organic frameworks (MOFs) have excellent properties of high surface area, high porosity, adjustable pore size, high conductivity and stability, and their applications in catalysis have become a rapidly expanding research field. In this review, we have summarized the synthesis strategies of MOF-derived carbons with different physical and chemical properties, obtained through direct carbonization, co-pyrolysis and post-treatment. The potential applications of derived carbons, especially monometal-, bimetal-, nonmetal-doped and metal-free carbons in organo-catalysis, photocatalysis and electrocatalysis are analyzed in detail from the environmental perspective. In addition, the improvement of catalytic efficiency is also considered from the aspects of increasing active sites, enhancing the activity of reactants and promoting free electron transfer. The function and synergy of various species of the composites in the catalytic reaction are summarized. The reaction paths and mechanisms are analyzed, and research ideas or trends are proposed for further development.

Metal organic frameworks for biomass conversion

This review narrates the recent developments on the catalytic applications of pristine metal–organic frameworks (MOFs), functionalized MOFs, guests embedded over MOFs and MOFs derived carbon composites for biomass conversion into platform chemicals.

Functionalised heterogeneous catalysts for sustainable biomass valorisation

Functionalised heterogeneous catalysts show great potentials for efficient valorisation of renewable biomass to value-added chemicals and high-energy density fuels.