Hydrodehalogenation of Polyhalogenated Aromatics Catalyzed by NiPd Nanoparticles Supported on Nitrogen‐Doped Graphene

Abstract

Ni Pd nanoparticles supported on nitrogen-doped graphene (NG) acts as a catalyst for the hydrodehalogenation of halogenated aromatics under mild reaction conditions. It reduces mono- or dichloroarenes to the corresponding dehalogenated arenes in >90 % yield in 10 % aqueous isopropanol solvent at or below 50 °C within 5 h. Tests on a variety of substrates containing various functional groups show that the catalyst is selective for reduction of C-Cl and C-Br bonds. In addition, this catalyst completely hydrodehalogenates high-concentration solutions of dioxin, polychlorinated biphenyls, chloroaromatic constituents of the defoliant agent orange, and polybrominated diphenyl ethers in 12 h. The catalyst is reusable and shows no morphological or compositional changes after 5 cycles. This methodology offers a powerful, low-cost, and safe technology for the degradation of polyhalogenated aromatics, and may be useful for preventing proliferation of these toxins in the environment from causing serious health issues.

Highly Dispersed Pt Nanoparticles on N-Doped Ordered Mesoporous Carbon as Effective Catalysts for Selective Hydrogenation of Nitroarenes

“…Moreover, other reducible groups such as -COOCH 2 CH 3 , -COOH, -CN, and -CHO on the nitrobenzene were also well tolerated to give the corresponding amines in high selectivity (entries [14][15][16][17]. Also, for heterocyclic nitroarenes containing N element, full conversion and high selectivity of >99.0% was achieved (entries [19][20][21][22]. In contrast, the hydrogenation of p-chloronitrobenzene over Pt/CMK-3 showed not only low catalytic activity but also poor selectivity (entry 23).…”

“…Generally, the catalytic performance is closely linked to the metal particle sizes, the structure or surface properties of the support, and the interaction effect between the metal and support. The activity and selectivity of the catalyst for the hydrogenation of nitroarenes could be modified by preparation method, thermal treatment, and element doping [20][21][22].…”

Photochemical Dehalogenation of Aryl Halides: Importance of Halogen Bonding

“…The transformation of haloarenes into the corresponding arenes has great relevance to organic synthesis, industrial processes as well as environmental remediation. 1 Conventional methods for dehalogenation of aryl halides usually involve high H2 pressures, reduction by tin or silicon hydrides, 2 or catalytic systems including transition metals like Pd, [3][4][5][6][7] Rh, 8 Ru, 9-10 Mo 11 , Co 12 , Ni. 5,13 More recent examples study the use of light to catalyze the reaction in the presence of organic 14 or inorganic 15 photocatalysts.…”

Self‐Assembly of Nanoparticles into Two‐Dimensional Arrays for Catalytic Applications

“…It has a hydrogen content of 19.6 % (by weight) and is soluble/stable in aqueous solutions. Hydrogen is released via AB hydrolysis, or methanolysis,, both of which can be catalyzed by a nanostructured catalyst. In aqueous solution, AB hydrolysis releases hydrogen (H 2 ) via the reaction: H 3 N ⋅ BH 3 (aq)+2H 2 O→NH 4 BO 2 (aq)+3H 2 (g), in which the ammonium salt can further give NH 3 via deprotonation NH 4 + NH 3 +H + .…”