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Protection of hydroxy groups as trimethylsilyl ethers catalyzed by magnetically recyclable Schiff-base complexes of ruthenium using HMDS

Mehdigholami Somayeh, Koohestanian Esmaeil

Chemical and Process Engineering : New Frontiers

2024

Vol. 45, nr 1

art. no. e52

In this study, a stable and effective magnetically recoverable nanocatalyst was prepared by coating Fe 3O 4 nanoparticles with SiO 2, followed by functionalization with N-(2-aminoethyl)- 3-aminopropyltrimethoxysilane (AEPTMS) and produce Schiff base ligand to linkage Ru(OTf) 2 onto the surface. The nanocatalyst was characterized using various techniques such as FT-IR spectroscopy, SEM, TEM, and VSM to confirm its successful synthesis. The nanocatalyst was used for the trimethylsilylation of various alcohols (primary, secondary, and tertiary alcohols) using hexamethyldisilazane as a silylating agent in dichloromethane at room temperature. The reaction proceeded quickly with a protection time of only 90 seconds, which is a remarkable advantage of this nanocatalyst. The turnover frequency (TOF) values of the catalytic system were estimated to be 1869 h -1. The use of this nanocatalyst offers many advantages, such as excellent yield, catalyst reusability, high acidity, and strong magneticp roperties. These advantages make it a fascinating candidate for green chemistry principles. The simple reprocessing procedure and quick response times are also additional benefits of this nanocatalyst. Overall, this study provides a promising approach for the facile preparation of a stable and effective magnetically recoverable nanocatalyst that can be utilized for the trimethylsilylation of alcohols. The exceptional properties of this catalyst make it an attractive candidate for practical applications in the field of catalysis.

Preparation and characterisation of Pd nanocatalyst supported on nickel mesh

Tomiczek B., Szindler Marek, Łukowiec D., Pawlyta M., Nuckowski P., Lukaszkowicz K., Krzywiecki M., Kříž A., Basiaga M., Polański J.

Journal of Achievements in Materials and Manufacturing Engineering

2023

Vol. 121, nr 2

212--220

The primary aim of the publication is to show the possibility of the synthesis of palladium nanoparticles directly on the nickel molecular mesh. A combination of chemical and physicochemical methods was used. Design/methodology/approach Palladium chloride was chosen as the precursor of palladium nanoparticles, dissolved in alcohol, water or a mixture thereof. Surface topography studies of the prepared nanoparticles were made using a scanning electron microscope, Supra 35 (Zeiss’s company), and transmission electron microscope S/TEM TITAN 80-300 (FEI company). Qualitative studies were performed using spectroscopy of scattered X-ray energy using the Energy Dispersive Spectrometer to define the chemical composition of prepared nanocatalysts. The chemical states of the elements were analysed using X-ray photoelectron spectroscopy. Nanocatalyst structures were identified using X-ray crystallography. Findings Using such methods proved that the obtained material is Pd-Ni synthesised using a mixture of alcohol and water assisted by ultrasound. Nanoparticles with oval shapes and diameters below 10 nm were obtained. Research limitations/implications During the tests, it was decided to abandon the use of the ascorbic acid reducer, which, combined with the temperature, had a negative impact on the nickel substrate. Practical implications Nanocatalyst has been achieving a gradually increasing interest from researchers in environmental areas. The developed materials can be used in low-temperature carbon dioxide methanation. Originality/value The results provide a novel road for designing and developing efficient, low-cost, and low-temperature double metallic catalysts.