One-pot synthesis of chromenes in the presence of magnetic nanocomposite based on NH2-UiO-66(Zr), graphene oxide and Fe3O4

Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Immobilization of lipase on hydrophobic MOF synthesized simultaneously with oleic acid and application in hydrolysis of natural oils for improving unsaturated fatty acid production

The hydrolysis of natural oils (vegetable oils and fats) by lipase has significant applications in food and medicine. However, free lipases are usually sensitive to temperature, pH and chemical reagents in aqueous solutions, which hinders their widespread industrial application. Excitingly, immobilized lipases have been widely reported to overcome these problems. Herein, inspired by lipase interface activation, a hydrophobic Zr-MOF (UiO-66-NH₂-OA) with oleic acid was synthesized for the first time in an emulsion consisting of oleic acid and water, and the Aspergillus oryzae lipase (AOL) was immobilized onto the UiO-66-NH₂-OA through hydrophobic interaction and electrostatic interaction to obtain immobilized lipase (AOL/UiO-66-NH₂-OA). ¹H NMR and FT-IR data indicated that oleic acid was conjugated with the 2-amino-1,4-benzene dicarboxylate (BDC-NH₂) by amidation reaction. As a result, the V_max and K_cat values of AOL/UiO-66-NH₂-OA were 179.61 μM﹒min^-1 and 8.27 s^-1, which were 8.56 and 12.92 times higher than those of the free enzyme, respectively, due to the interfacial activation. After treated at 70 °C for 120 min, the immobilized lipase maintained 52 % of its original activity, but free AOL only retained 15 %. Significantly, the yield of fatty acids by the immobilized lipase reached 98.3 % and still exceeded 82 % after seven times of recycling.