Triazole-functionalized hydrochar-stabilized Pd nanocatalyst for ullmann coupling.

Autor: Pereira GR; Federal University of Viçosa, Chemistry Department-Viçosa/MG, Brazil., Lopes RP; Federal University of Viçosa, Chemistry Department-Viçosa/MG, Brazil. Electronic address: renata.plopes@ufv.br., Wang W; Université de Bordeaux, ISM, UMR CNRS 5255, Talence 33405 Cedex, France., Guimarães T; Federal University of Viçosa, Chemistry Department-Viçosa/MG, Brazil., Teixeira RR; Federal University of Viçosa, Chemistry Department-Viçosa/MG, Brazil., Astruc D; Université de Bordeaux, ISM, UMR CNRS 5255, Talence 33405 Cedex, France.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2022 Dec; Vol. 308 (Pt 1), pp. 136250. Date of Electronic Publication: 2022 Aug 31.
DOI: 10.1016/j.chemosphere.2022.136250
Abstrakt: Biomass valorization is essential, particularly in emerging countries. Here, hydrochar from arabica coffee straw was functionalized with a triazole group (HD-TRz) for use as a support of palladium nanoparticles (PdNPs-HD-TRz) applied in the Ullmann coupling reaction for the first time. It provided remarkably excellent selectivities, conversions at a temperature as low as 45 °C and catalyst recyclability, surpassing previous literature performances. Hydrochar was obtained by one-pot reaction via hydrothermal synthesis, using NaOH solution as activating agent and functionalized with a 1,3-triazole group by CuAAC "click" reaction. The PdNPs were prepared via reduction of hydrochar-bound Pd(II) using NaBH 4 . Hydrochar functionalization was monitored by infrared spectroscopy, and X-ray diffraction (XRD) allowed to observe carbon and palladium planes in hydrochar and PdNPs HD-TRz structures. The PdNPs presented a spherical shape with 2.1 ± 0.1 nm size, homogeneously distributed in the carbon coverslips. The HD-TRz-supported PdNPs were used as a catalyst in the Ullmann reaction of iodobenzene, using ethanol as solvent with 100% of conversion and 91% selectivity at 45 °C. The material was reused, presenting 100% of conversion and selectivities of 92, 84 and 73% for the 1st, 2nd and 3rd cycle, respectively. The scope of the reaction was expanded to other molecules showing the potential of this and other triazole-hydrochar-supported nanocatalysts.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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