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Elaborated flow synthesis of sodium diclofenac involving sequential amination, chlorination, and hydrolysis protocols. Reprinted with permission from (Wang et al., 2022). Copyright (2022) Wiley-VCH GmbH.
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Industrial organic synthesis is time and energy consuming, and generates substantial waste. Traditional conductive heating and mixing in batch reactors is no longer competitive with continuous-flow synthetic methods and enabling technologies that can strongly promote reaction kinetics. These advances lead to faster and simplified downstream process...
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... From unsaturated organic substrates to heterocycle synthesis and metal-catalyzed chemistry, this technology has played a central role in the development of sustainable multigram preparations that meet the dual requirement of process intensification and reduced production costs. It has proven to be a promising hybrid technique that can link lab-scale investigations and pilot processes, and thus meet industrial challenges [87][88][89][90][91][92][93][94]. In addition, the FDA and the European Medicines Agency (EMA) have strongly encouraged the study and implementation of this innovative, sustainable and environmentally friendly technology in API synthesis [95,96]. ...
Meropenem is currently the most common carbapenem in clinical applications. Industrially, the final synthetic step is characterized by a heterogeneous catalytic hydrogenation in batch mode with hydrogen and Pd/C. The required high-quality standard is very difficult to meet and specific conditions are required to remove both protecting groups [i.e., p-nitrobenzyl (pNB) and p-nitrobenzyloxycarbonyl (pNZ)] simultaneously. The three-phase gas-liquid-solid system makes this step difficult and unsafe. The introduction of new technologies for small-molecule synthesis in recent years has opened up new landscapes in process chemistry. In this context, we have investigated meropenem hydrogenolysis using microwave (MW)-assisted flow chemistry for use as a new technology with industrial prospects. The reaction parameters (catalyst amount, T, P, residence time, flow rate) in the move from the batch process to semi-continuous flow were investigated under mild conditions to determine their influence on the reaction rate. The optimization of the residence time (840 s) and the number of cycles (4) allowed us to develop a novel protocol that halves the reaction time compared to batch production (14 min vs. 30 min) while maintaining the same product quality. The increase in productivity using this semi-continuous flow technique compensates for the slightly lower yield (70% vs. 74%) obtained in batch mode.
... Hence, alternate heating method was advised for efficient and time saving process. In this regard, ultrasonic method has shown advantages in extraction and transesterification processes; nonetheless, the technology still requires longer reaction time and higher quantities of solvents [20], possibly with excessive energy usage as reported by Yadav et al., [21] and Goh et al., [22]. Recently, the whole scientific community has been inclined towards a cleaner, time efficient and energy saving method for chemical synthesis. ...
Limited crude petroleum and growing awareness of fossil fuel depletion have enabled the development of alternative fuels and new energy sources. Biodiesel, also known as fatty acid methyl esters (FAME), has received a lot of attention due to its biodegradability, renewability, cost effective and nontoxicity. The purity of biodiesel production and uniform heating are the major hurdles for large scale biodiesel production. Recent microwave energy-based heating method has proved the potential for cleaner chemical production, short time duration, uniform heating, and purity over conventional heating method. The goal of this review is to discuss the biodiesel production using microwave-assisted heating. The different feedstocks used for biodiesel production, effects of microwave irradiation, factors affecting the rate of microwave-assisted transesterification to produce biodiesel were comprehensively discussed. Microwave irradiation has been compared to other technologies aiming to enhance the efficiency of overall process. The primary knowledge gaps in biodiesel production can be identified based on this research, ensuring the biodiesel industry's long-term sustainability.
... Hence, alternate heating method was advised for efficient and time saving process. In this regard, ultrasonic method has shown advantages in extraction and transesterification processes; nonetheless, the technology still requires longer reaction time and higher quantities of solvents [20], possibly with excessive energy usage as reported by Yadav et al., [21] and Goh et al., [22]. Recently, the whole scientific community has been inclined towards a cleaner, time efficient and energy saving method for chemical synthesis. ...
In this work, we introduce a microfluidic chip reactor based on a complementary split ring resonator (CSRR) for conducting microscale organic reactions with the aid of microwave irradiation. This microwave-microfluidic...
In the realm of flow chemistry, Do-It-Yourself (DIY) flow setups represent a versatile and cost-effective alternative to expensive commercially available reactors. Not only they are budget friendly, but also unlock a world of possibilities for researchers to explore and create customized setups tailored to their specific needs. This minireview serves as a short compendium of DIY flow systems to assist flow researchers in the challenging task of finding a suitable setup for their experiments and facilitate the transition from batch to flow chemistry. Our goal is to demonstrate that flow chemistry can be affordable, easy-to-build, and reproducible at the same time. Therefore, herein we review and describe selected illustrative examples of easily assembled/constructed DIY flow setups, with a particular emphasis on how to select the most suitable one based on the specific chemistry of interest, ranging from simple homogeneous monophasic reactions to more complex systems for photo-, electrochemistry, and so on. In addition, we briefly comment on the significance of DIY approach on education, particularly its integration into the standard undergraduate curriculum as a key educational tool for young chemists. Ultimately, we hope this mini review will help and encourage the reader to go with the flow and get started with the fine art of flow chemistry.
Polymer production in the 21stcentury will require alternative approaches that do not impact the environment negatively. We recently reported that the synthesis of hypercrosslinked polymers (HCPs) via continuous flow synthesis required less than 99% of the time required in conventional batch reactions. However, the impact of deploying flow synthesis of HCPs and their application on the environment remain unknown. Here, we assessed the environmental impacts of HCP synthesis via batch and flow reactions and their application in water treatment through life-cycle assessment (LCA). These impacts were represented as normalized scores in four end point impact categories: Human health, Ecosystem quality, Climate change, and Resources. Yielding the same amount of HCPs, flow synthesis demonstrated lower end point impacts in all categories. This was due to consuming only 5% of the electricity required for batch reactions. As the specific surface areas of flow-produced HCPs were lower than those of batch-produced HCPs, 36% more flow-produced HCPs were required to remove Rhodamine B (RB) and Uniblue A (UA) dyes from water. Despite this limitation, using flow-produced HCPs for water treatment still scored lower overall negative environmental impacts when compared to batch-produced HCPs. Outcomes from this work showed that flow synthesis could enhance the sustainability of scale-up HCP production.
Catalysis under continuous flow operation is industrially more relevant compared to reactions carried out in batch reactors. But catalysis with metal‐organic frameworks (MOFs) is largely restricted to batch reactions, especially in case of semi hydrogenation reactions. We anchored Pd nanoparticles (NPs) on robust UiO‐66(Hf) MOF to develop effective catalyst for semi hydrogenation of phenylacetylene into styrene. We investigated catalytic performance of Pd/UiO‐66(Hf) in a continuous‐flow liquid‐phase semi‐hydrogenation of phenylacetylene (PA). In this study, Pd/UiO‐66(Hf) catalyst exhibited good catalytic performance with a rare combination of high PA conversion (99.0 %) and high styrene selectivity (90.0 %). Additionally, Pd/UiO‐66(Hf) demonstrated lower deactivation rate in contrast to many reported materials to date. The higher stability of metal NPs over UiO‐66(Hf) aroused from the strong metal‐support interaction (between Brønsted acidic μ3‐OH of MOF and Pd). The Pd/UiO‐66(Hf) retained its catalytic activity even after four recycles.
