Designing of a magnetically separable Fe3O4@dopa@ML nano-catalyst for multiple organic transformations (epoxidation,reduction, and coupling) in aqueous medium

A copper(II) macrocyclic Schiff base complex (ML) was synthesized by condensation between 2,2-dimethylpropane-1,3-diammine and 2,6-diformyl-4-butylphenol with the aim to modify the surface of widely used magnetically separable nanocatalyst Fe₃O₄@dopa. ML was characterized by physicochemical techniques and single crystal X-ray diffraction. The newly synthesized heterogeneous catalyst Fe₃O₄@dopa@ML was characterized by SEM, TEM, PXRD, EDX, TGA, etc. ML showed stability in aqueous medium and utilizing this unique property, the heterogeneous catalyst Fe₃O₄@dopa@ML was used for catalyzing epoxidation, nitroarene reduction and C–C coupling (Henry reaction) in aqueous medium. The separation method of the prepared nano-catalyst is very easy and can be done with an external magnetic field. The experimental findings suggest that Fe₃O₄@dopa@ML is a versatile “green catalyst.”     

Palladium nanoparticles supported on mesoporous natural phosphate: An efficient recyclable catalyst for nitroarene reduction

We report the preparation of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) using a wetness impregnation method. The prepared catalyst was characterized using various techniques. Furthermore, the reduction and preparation of the palladium nanoparticles was followed using UV–visible spectra. Based on the Scherrer equation, the crystallite size of the as‐synthesized palladium nanoparticles was 10.88 nm. The performance of the synthesized catalyst was investigated in the reduction of 4‐nitrophenol as a model substrate to 4‐aminophenol using NaBH₄ as a hydrogen source. Moreover, catalytic reduction of various nitroarenes was studied and monitored using UV–visible spectroscopy and gas chromatography. The Pd@NP catalyst showed a high activity for the selected reaction and could be recycled.     

甲醇为氢源的连续化催化转移加氢合成芳胺

开发了一种温和高效的以甲醇为氢源，以Ru-Fe双金属为催化剂的硝基芳烃连续化转移加氢方法。采用浸渍法制备Ru-Fe双金属催化剂，通过电感耦合等离子体-质谱(ICP-MS)、透射电子显微镜(TEM)、X射线衍射(XRD）、氢气程序升温还原(H₂-TPR)对催化剂进行表征。结果表明催化剂具有较小的粒径和较好的分散性。在Ru-Fe双金属催化剂上，成功实现了硝基芳烃与甲醇在无外加氢源条件下的连续化转移加氢合成芳胺。通过对反应条件的调控，成功得到了一系列产率较高的胺类化合物。特别地，该方法对不饱和基团(醛基、羰基或炔基)取代的硝基芳烃的加氢表现出优异的选择性和转化率。