Palladium supported on ethylenediaminetetraacetic acid functionalized cellulose: synthesis, characterization, and its application in carbon–carbon cross-coupling reactions

Abstract

Through the esterification of cellulose (Cell) with ethylenediaminetetraacetic dianhydride, ethylenediaminetetraacetic acid-functionalized cellulose (Cell-EDTA) was conveniently obtained. Furtherly a novel and efficient Cell-EDTA-supported palladium catalyst (Pd@Cell-EDTA) was easily prepared via coordination of Cell-EDTA with PdCl₂. The as-prepared Pd@Cell-EDTA was fully characterized by inductively coupled plasma atomic emission spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, energy-dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and derivative thermogravimetric analysis techniques. Then Pd@Cell-EDTA was successfully exerted as catalysts in Suzuki reactions and Sonogashira reactions. Due to the interactions of carboxylic groups, nitrogen atoms, and hydroxyl groups on cellulose, the Pd complex showed excellent activity towards these carbon–carbon cross-coupling reactions. The catalyst recycling experiments for Suzuki model reaction showed that the catalyst can be reused at least five times without significant losing its catalytic performance. The present cellulose-based Pd@Cell-EDTA catalyst offers the salient features of wide application, excellent catalytic activity, good reusability, tolerance of broad scope of substrate, and environmental benign.