Synthesis of zinc oxide nanotiles by wet chemical route assisted by microwave heating

Bull. Chem. React. Eng. Catal.

El-Idreesy

2019

This paper reported a scientific approach adopting microwave-assisted synthesis as a synthetic route for preparing highly active palladium nanoparticles stabilized by polyvinylpyrrolidone (Pd/PVP) and supported on reduced Graphene oxide (rGO) as a highly active catalyst used for Suzuki, Heck, and Sonogashira cross coupling reactions with remarkable turnover number (6500) and turnover frequency of 78000 h -1 . Pd/PVP nanoparticles supported on reduced Graphene oxide nanosheets (Pd-PVP/rGO) showed an outstanding performance through high catalytic activity towards cross coupling reactions. A simple, reproducible, and reliable method was used to prepare this efficient catalyst using microwave irradiation synthetic conditions. The synthesis approach requires simultaneous reduction of palladium and in the presence of Gaphene oxide (GO) nanosheets using ethylene glycol as a solvent and also as a strong reducing agent. The highly active and recyclable catalyst has so many advantages including the use of mild reaction conditions, short reaction times in an environmentally benign solvent system. Moreover, the prepared catalyst could be recycled for up to five times with nearly the same high catalytic activity. Furthermore, the high catalytic activity and recyclability of the prepared catalyst are due to the strong catalyst-support interaction. The defect sites in the reduced Graphene oxide (rGO) act as nucleation centers that enable anchoring of both Pd/PVP nanoparticles and hence, minimize the possibility of agglomeration which leads to a severe decrease in the catalytic activity.one of the main interests that attracted researchers' attention is transition metals based materials, especially when using palladium nanoparticles [5][6][7][8][9][10]. It is well established that palladium-based catalysts have been widely used in homogeneous and heterogeneous catalysis due to their several outstanding properties that combine between those of single metal atoms and other bulk metals [11][12][13][14][15][16]. In order to design new compounds with tailored chemical and

Section: Introductionmentioning

confidence: 99%

Polyvinylpyrrolidone - Reduced Graphene Oxide - Pd Nanoparticles as an Efficient Nanocomposite for Catalysis Applications in Cross-Coupling Reactions

Bull. Chem. React. Eng. Catal.

El-Idreesy

2019

“…Over the past few decades, micro-reaction technology has been emerged as an ideal route newly adopted approach could achieve a significant improvement via using safer micro-reactor processes [17][18][19][20][21][22][23][24][25][26]. This will definitely improve the capability of producing smaller scale synthetic chemicals on demand and on site at which those products are urgently needed as well [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

“…Palladium-catalyzed coupling reactions are among the most widely applied reactions in the field of organic synthesis although there are some disadvantages of using palladium in such reactions including its high price and also the high toxicity of the metal residue which is considered as a critical issue, especially in the field of pharmaceutical industry [30][31][32][33][34][35]. Those disadvantages could be minimized by using very small amounts of palladium catalysts, however, there will be still some issues associated with homogeneous catalysis like the lack of recyclability and contamination from residual metals in the reaction products [20][21][22][24][25][26][27][28]. The key for solving this technical problem could be simply by using heterogenized homogeneous catalyst or heterogeneous catalyst as it is widely known.…”

Section: Introductionmentioning

confidence: 99%

Pd-Fe3O4/RGO: a Highly Active and Magnetically Recyclable Catalyst for Suzuki Cross Coupling Reaction using a Microfluidic Flow Reactor

Bull. Chem. React. Eng. Catal.

Siamaki

Gupton

et al. 2019

There are several crucial issues that need to be addressed in the field of applied catalysis. These issues are not only related to harmful environmental impact but also include process safety concerns, mass and heat transfer limitations, selectivity, high pressure, optimizing reaction conditions, scale-up issues, reproducibility, process reliability, and catalyst deactivation and recovery. Many of these issues could be solved by adopting the concept of micro-reaction technology and flow chemistry in the applied catalysis field. A microwave assisted reduction technique has been used to prepare well dispersed, highly active Pd/Fe3O4 nanoparticles supported on reduced graphene oxide nanosheets (Pd-Fe3O4/RGO), which act as a unique catalyst for Suzuki cross coupling reactions due to the uniform dispersion of palladium nanoparticles throughout the surface of the magnetite -RGO support. The Pd-Fe3O4/RGO nanoparticles have been shown to exhibit extremely high catalytic activity for Suzuki cross coupling reactions under both batch and continuous reaction conditions. This paper reported a reliable method for Suzuki cross-coupling reaction of 4-bromobenzaldehyde using magnetically recyclable Pd/Fe3O4 nanoparticles supported on RGO nanosheets in a microfluidic-based high throughput flow reactor. Organic synthesis can be performed under high pressure and temperature by using a stainless steel micro tubular flow reactor under continuous flow reaction conditions. Optimizing the reaction conditions was performed via changing several parameters including temperature, pressure, and flow rate. Generally, a scalable flow technique by optimizing the reaction parameters under hightemperature and continuous reaction conditions could be successfully developed.to solve several critical issues in many aspects including organic chemistry and applied catalysis [1][2][3][4][5][6][7][8]. This new technology has created new promising horizons for chemical synthesis and industry via performing chemistry under continuous flow reaction conditions instead of the conventional batch chemistry [9][10][11][12][13][14][15][16]. This

“…The main advantage of using those types of nano-sized particles is that they largely increase the surface area of the active ingredient of the used catalyst, hence causing a huge enhancement of the contact between reactants and catalyst to be nearly like that of the homogeneous catalysts (Chattopadhyay et al., 2009; Hoseini et al., 2017; Hosseini-Sarvari and Razmi, 2015; Mandali and Chand, 2013). This also led to some innovative ideas regarding the use of nanocatalysis for green chemistry development including the possibility of using the concept of microwave-assisted synthesis combined with nanocatalysis (Bondioli et al., 2008; Ceylan et al., 2011; Fukui et al., 2012; Glasnov et al., 2009; Gupta et al., 2011; Kirschning et al., 2012; Malewicz et al., 2009; Nishioka et al., 2011; Pourmortazavi et al., 2012; Shviro and Zitoun, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…It allows the synthesis of the nanoparticles with controlled size. The important remarkable advantage of the microwave dielectric heating over the convective heating is that the reactants can be added at room temperature (or slightly higher temperatures) without the need for high-temperature injection (Bondioli et al., 2008; Fukui et al., 2012; Glasnov et al., 2009; Kirschning et al., 2012; Malewicz et al., 2009). In this manuscript, we report on a green efficient method to prepare highly active palladium nanoparticles supported on copper oxide as a highly efficient catalyst for Suzuki cross-coupling.…”

Section: Introductionmentioning

confidence: 99%

Microwave-assisted synthesis of palladium nanoparticles supported on copper oxide in aqueous medium as an efficient catalyst for Suzuki cross-coupling reaction

Adsorption Science & Technology

Sadek

El-Idreesy

2018

We report here a reliable green method for the synthesis of palladium nanoparticles supported on copper oxide as a highly active and efficient catalyst for Suzuki cross-coupling reaction. The experimental synthetic approach is based on microwave-assisted chemical reduction of an aqueous mixture of palladium and copper salt simultaneously using hydrazine hydrate as reducing agent. The catalyst was fully characterized using various techniques showing well-dispersed palladium nanoparticles. The catalytic activity and recyclability of the prepared catalyst were experimentally explored in the ligand-free Suzuki cross-coupling reaction with a diverse series of functionalized substrates. The synthesized Pd/CuO catalyst shows many advantages beside its high catalytic efficiency such as the recyclability of up to five times with negligible loss of catalytic activity, short reaction times, use of environmentally benign solvent systems, and mild reaction conditions.