Cu^I–USY as a Ligand-Free and Recyclable Catalytic System for the Ullmann-Type Diaryl Ether Synthesis

Abstract

The catalytic potential of copper(I)-exchanged zeolites was evaluated in the Ullmann-type synthesis of diaryl ethers. Among four investigated zeolites (i.e., USY, MOR, β, and ZSM5), Cu(I)-USY was the best catalyst and proved efficient under ligand-free conditions in toluene at 120 °C. Cu(I)-USY was also easy to recover and was recyclable up to five times without significant loss of activity.

CuI/Oxalamide Catalyzed Couplings of (Hetero)aryl Chlorides and Phenols for Diaryl Ether Formation

“…[1] Thedevelopment of useful methods for preparing diaryl ethers has thus received continuous attention from the synthetic community. [2][3][4][5][6][7] Among the existing methods,m etal-catalyzed coupling reactions between aryl halides and phenols represent one of the most reliable approaches and have been intensively applied in both academia and industry. [2] Initially,t his transformation required harsh conditions (ca.…”

Copper nanoparticles supported on 2‐methoxy‐1‐phenylethanone‐functionalized MCM‐41: An efficient and recyclable catalyst for one‐pot three‐component C–S coupling reaction of aryl halides with benzyl bromide and thiourea

“…To overcome these problems, immobilization of homogeneous metal catalysts by anchoring on various substrates, such as polymers, silica, zeolites and carbon nanotubes can be used for minimizing toxic species from chemical processes. These substrates facilitate work‐up of the reaction and recycling of the catalyst, which recently have been introduced as an important research field to achieve green catalyst systems.…”

“…Although these materials facilitated the C-S crosscoupling reaction by transition copper catalysts, the Sarylation of aryl halides with these thiol surrogates has been catalyzed using homogeneous catalysts that remain environmental concerns and have other issues in a homogeneous media (such as separation and purification of the target product from the reaction mixture, thermal sensitive, high toxicity, difficult and expensive recovery for reuse of the catalyst). [13][14][15] To overcome these problems, immobilization of homogeneous metal catalysts by anchoring on various substrates, [16][17][18][19] such as polymers, [20][21][22] silica, [11,23,24] zeolites [25,26] and carbon nanotubes [27,28] can be used for minimizing toxic species from chemical processes. These substrates facilitate work-up of the reaction and recycling of the catalyst, which recently have been introduced as an important research field to achieve green catalyst systems.…”

Ullmann Coupling Reaction of Nitro‐Substituted Aryl Halides with Phenols under Mild Conditions: Micro‐/Mesoporous Hierarchical LaAlPO‐5 Zeolite Catalyst

“…Ullmann coupling reactions can be catalyzed efficiently by Pd II , Cu I , and Ni II[16] compounds with ligands, such as N ‐dimethylglycine, salicylaldimine, and atropisomeric dipyridyl diphosphine, in the presence of organic additives under mild conditions (90–120 °C). Simple and ligand‐free catalytic systems that are recoverable and reusable have received increasing attention, for example, copper fluorapatite, copper oxide on alumina, copper ferrite nanoparticles, nano‐CuO, Au‐Pd alloy nanoclusters, and Cu‐USY …”

“…Simple and ligand-free catalytic systemst hat are recoverable and reusable have received increasinga ttention, for example, copperf luorapatite, [17] copper oxide on alumina, [18,19] copperf errite nanoparticles, [20] nano-CuO, [21,22] Au-Pd alloy nanoclusters, [23] andC u-USY. [24] Zeolite molecular sieves are solid porousm aterials with ah igh stability that are used widely as adsorbents and catalysts. [25][26][27] Compared with microporous aluminosilicate zeolites, aluminophosphate zeolites (AlPO-n) exhibit more attractive properties, and its Al and/or Pa toms can be replaced by Si to form SAPO-n materials, and by other metals to form metaldoped aluminophosphate (MeAlPO-n) materials.…”