Ullmann coupling of aryl chlorides in water catalyzed by palladium nanoparticles supported on amine-grafted porous aromatic polymer

A chemically stable porous carbonyl-incorporated aromatic polymer (CBAP-1(EDA)) was post synthetically functionalized with ethylenediamine, and used as a solid support to immobilize the Pd nanoparticles (Pd@CBAP-1(EDA)) with particle size of 2-4 nm using conventional chemical reduction. The synthesized Pd@CBAP-1(EDA) was characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM), thermogravimetric analysis (TGA), N-2 adsorption-desorption isotherms, and inductively coupled plasma optical emission spectrometry (ICP-OES). The obtained material was tested as a solid catalyst for the environmentally-benign Ullmann self-coupling of aryl chlorides in water medium, showing excellent catalytic performance for a series of aryl chlorides without the addition of any external additives. The catalyst was easily recovered by simple filtration and could be reused six times without loss of its initial activity. The high catalyst stability was confirmed by hot filtration and ICP analysis. (C) 2017 Elsevier B.V. All rights reserved.