Synthesis of heterocycles catalyzed by mesoporous silica MCM nanoparticles

3-(Sulfamic acid)-propyltriethoxysilane on biochar nanoparticles as a practical, biocompatible, recyclable and chemoselective nanocatalyst in organic reactions

Recyclable and inexpensive catalysts, waste regeneration, use of available and safe solvents are important principles of green chemistry. Therefore, in this project, biochar nanoparticles (BNPs) were synthesized by the pyrolysis method from chicken manure. Then, 3-(sulfamic acid)-propyltriethoxysilane (SAPES) was immobilized on the surface of BNPs (SAPES@BNPs). The prepared catalyst (SAPES@BNPs) was used as a commercial, practical, biocompatible and reusable catalyst in the selective oxidation of sulfides to sulfoxides. Further, the catalytic application of SAPES@BNPs was explored in the multicomponent synthesis of tetrahydrobenzo[b]pyrans under mild and green conditions. BNPs were characterized using SEM, TGA and XRD techniques. SAPES@BNPs were characterized using SEM, FT-IR spectroscopy, WDX, EDS, TGA, and XRD techniques. Particle size distribution was obtained by histogram graph. SAPES@BNPs can be recovered and reused several times. The purity of the products was studied using NMR spectroscopy.

A Schiff base complex of lanthanum on modified MCM-41 as a reusable nanocatalyst in the homoselective synthesis of 5-substituted 1H-tetrazoles

In this work, mesoporous MCM-41 was modified by a new Schiff-base formed from the condensation of triethylenetatramine and 5-bromosalicylaldehyde. Then, it was used for the stabilization of lanthanum metal (La-Schiff base@MCM-41) as a homoselective, reusable, efficient and biocompatible catalyst in the synthesis of 5-substituted 1H-tetrazole derivatives. The synthesized tetrazoles were characterized using ¹H NMR and FT-IR spectroscopy and methods to measure their physical properties. La-Schiff base@MCM-41 was characterized by using various techniques such as ICP, CHN, XRD, TGA, BET, FT-IR spectroscopy, SEM, EDS and WDX. This catalyst has good stability and a heterogeneous nature, enabling it to be easily recovered and reused several times without significant loss in catalytic activity. This present strategy has important advantages such as utilizing PEG as a green solvent, short reaction times, excellent yields, easy recycling of the catalyst and pure separation of the products. The recovered La-Schiff base@MCM-41 catalyst was characterized by using FT-IR spectroscopy, SEM and AAS.

Electro-osmotic flow of surfactant assisted zeta potential tuned silica frits

The choice of surfactant is vital for tailoring the zeta potential of silica which in turn improves the electro-osmotic performance.