Propargyl Amine Synthesis Catalysed by Gold and Copper Thin Films by Using Microwave‐Assisted Continuous‐Flow Organic Synthesis (MACOS)

Shore, Gjergji; Yoo, Woo‐Jin; Li, Chao‐Jun; Organ, Michael G.

doi:10.1002/chem.200902396

Cited by 113 publications

(53 citation statements)

References 74 publications

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“…Consistent with this view, Figure 16b shows that a considerable yield increase was achieved when a CuZn-based heterogeneous catalyst was used in the fixed- 24 bed reactor. Although for low residence times (< 60 min) no major improvement was obtained, at longer residence times two-fold yield increases were achieved for both singlemode and multimode systems.…”

Section: Figure 16supporting

confidence: 66%

“…The authors employed the concepts of "Novel Process Windows", as introduced by Hessel et al, and discussed the multiple opportunities for operating and controlling organic reactions at elevated temperatures and pressures [22,23]. Organ and co-workers also contributed to state-of-art microwave-assisted capillary-type flow-reactors for metal-catalyzed organic reactions [24,25]. Many examples have been reported of dedicated flow systems being used in combination with microwave heating for large-scale synthesis and industrial applications [26].…”

Section: Introductionmentioning

confidence: 99%

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Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Benaskar

Patil

Engels

et al. 2012

Chemical Engineering Journal

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The combination of milli-scale processing and microwave heating has been investigated for the Cu-catalyzed Ullmann etherification in fine-chemical synthesis, providing improved catalytic activity and selective catalyst heating. Wall-coated and fixed-bed milli-reactors were designed and applied in the Cu-catalyzed Ullmann-type C-O coupling of phenol and 4-chloropyridine. In a batch reactor the results show clearly increased yields for the microwave heated process at low microwave powers, whereas high powers and catalyst loadings reduced the benefits of microwave heating. Slightly higher yields were found in the Cu/ZnO wallcoated as compared to the Cu/TiO 2 fixed-bed flow-reactor. The benefit here is that the reaction occurs at the surface of the metal nanoparticles confined within a support film making the nano-copper equally accessible. Catalyst deactivation was mainly caused by Cu oxidation and coke formation; however, at longer process times leaching played a significant role. Catalyst 2 activity could partially be recovered by removal of deposited by-product by means of calcination. After 6 h on-stream the reactor productivities were 28.3 and 55.1 kg prod /(m R 3 •hr)for the fresh Cu/ZnO wall-coated and Cu/TiO 2 fixed-bed reactor, respectively. Comparison of single-and multimode microwaves showed a three-fold yield increase for single-mode microwaves. Control of nanoparticles size and loading allows to avoid high temperatures in a single-mode microwave field and provides a novel solution to a major problem for combining metal catalysis and microwave heating. Catalyst stability appeared to be more important and provided two-fold yield increase for the CuZn/TiO 2 catalyst as compared to the Cu/TiO 2 catalyst due to stabilized copper by preferential oxidation of the zinc. For this catalyst a threefold yield increase was observed in single-mode microwaves which, to the best of our knowledge, led to a not yet reported productivity of 172 kg prod /(m R 3 •hr) for the microwave and flow Ullmann C-O coupling.

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Section: Figure 16supporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Benaskar

Patil

Engels

et al. 2012

Chemical Engineering Journal

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“…Selective heating can also occur through coupling with immobilized catalysts, which are either deposited on the reactor walls or used as a packed bed. 62,96 The use of microwave heating can be beneficial for heating mesoscale flow reactors (> 1 mm) as the efficiency of microwave energy transfer increases with larger diameters. 97,98 Induction heating can heat packed-bed reactors very fast due to generation of eddy currents in electrically conducting objects via a constantly changing electromagnetic field (Joule heating).…”

Section: Heat Transport Phenomenamentioning

confidence: 99%

Beyond Organometallic Flow Chemistry: The Principles Behind the Use of Continuous-Flow Reactors for Synthesis

Noël

Hessel

2015

Organometallic Flow Chemistry

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Flow chemistry is typically used to enable challenging reactions which are difficult to carry out in conventional batch equipment. Consequently, the use of continuous-flow reactors for applications in organometallic and organic chemistry has witnessed a spectacular increase in interest from the chemistry community in the last decade. However, flow chemistry is more than just pumping reagents through a capillary and the engineering behind the observed phenomena can help to exploit the technology's full potential. Here, we give an overview of the most important engineering aspects associated with flow chemistry. This includes a discussion of mass-, heat-, and photon-transport phenomena which are relevant to carry out chemical reactions in a microreactor. Next, determination of intrinsic kinetics, automation of chemical processes, solids handling and multistep reaction sequences in flow are discussed. Safety is one of the main drivers to implement continuous-flow microreactor technology in an existing process and a brief overview is given here as well. Finally, the scale-up potential of microreactor technology is reviewed.

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“…Organ and co-workers used a different alternative. They coated thin metal films on the inner surface of capillaries as immobilized nanometer-sized catalysts and also microwave antenna [70][71][72][73][74][75][76][77]. The continuous flow reactor (Figure 25.15) consisted of a stainless-steel holding/mixing chamber with three or four inlet ports that merge into one or two outlets.…”

Section: Solid-supportedmentioning

confidence: 99%

Microwave‐Assisted Continuous Flow Organic Synthesis (MACOS)

Alcázar¹,

Muñoz²

2012

Microwaves in Organic Synthesis

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Propargyl Amine Synthesis Catalysed by Gold and Copper Thin Films by Using Microwave‐Assisted Continuous‐Flow Organic Synthesis (MACOS)

Cited by 113 publications

References 74 publications

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Microwave-assisted Cu-catalyzed Ullmann ether synthesis in a continuous-flow milli-plant

Beyond Organometallic Flow Chemistry: The Principles Behind the Use of Continuous-Flow Reactors for Synthesis

Microwave‐Assisted Continuous Flow Organic Synthesis (MACOS)

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