Process Analytical Tools for Flow Analysis: A Perspective

Price, Gregory A.; Mallik, Debasis; Organ, Michael G.

doi:10.1556/1846.2017.00032

Cited by 49 publications

(42 citation statements)

References 37 publications

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“…The ease of connection to inline analytical techniques [66] and the possibility to remotely control the individual components of a typical flow system (e.g., temperature/pressure controllers, pumps, injection valves, mass flow controllers) [67] makes flow chemistry amenable to automation. Many automated strategies for screening and optimization in flow, for both discrete (solvents, catalysts, ligands) and continuous (temperature, loading, time) reaction variables, can now be found in the literature.…”

Section: Automated Screening Platforms For Flow Photochemistrymentioning

confidence: 99%

Flow Photochemistry: Shine Some Light on Those Tubes!

Sambiagio

Noël

2020

Trends in Chemistry

295

223

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Continuous-flow chemistry has recently attracted significant interest from chemists in both academia and industry working in different disciplines and from different backgrounds. Flow methods are now being used in reaction discovery/methodology, in scale-up and production, and for rapid screening and optimization. Photochemical processes are currently an important research field in the scientific community and the recent exploitation of flow methods for these methodologies has made clear the advantages of flow chemistry and its importance in modern chemistry and technology worldwide. This review highlights the most important features of continuous-flow technology applied to photochemical processes and provides a general perspective on this rapidly evolving research field. Microflow Technology and Photochemistry: A Perfect MatchThe use of light to promote chemical reactions has been exploited since the 18th century, but only recently a resurgence has been observed in synthetic organic chemistry, in particular due to the development of visible-light photoredox catalysis [1-5]. All transformations involving light (e.g., Figure 1A-D) must consider, besides classical chemical parameters (i.e., reaction conditions), the photophysical aspects of the sensitizer (see Glossary)/photocatalyst (when used), and the reactor design. The latter, although often neglected by chemists, is a critical aspect for the outcome of the studied chemical transformation. This includes, for example, the size, shape, and material of the reaction vessel, the characteristics and positioning of the light source(s), and heat-transfer properties, particularly when high-intensity lamps are used [6,7]. The engineering and technological aspects of photochemical processes are often at the basis of the irreproducibility and non-scalability of such transformations.According to the Beer-Lambert law, light transmittance decreases exponentially with the distance from the light source ( Figure 1F). For a standard batch reactor (diameter at least in the centimeter range), light intensity decreases considerably from the flask walls to the middle of the reaction mixture, resulting in slow reactions and nonhomogeneous irradiation of the reaction mixture. Performing photochemical reactions in microchannels (ID < 1 mm) allows a higher and more homogeneous photon flux, resulting in shorter reaction times and consequently less side-product formation due to over-irradiation, often observed in batch [8,9]. Another advantage of microflow chemistry, correlated with the large surface:volume ratio, is improved heat and mass transfer, with the possibility to perform mass-transfer-limited multiphasic reactions efficiently [10]. Reactive chemicals and intermediates can be handled more safely in flow than in batch, as no accumulation of dangerous components occurs within the confined reactor volume due to the continuous nature of the process. Together, these result in often faster, safer, and higher-yielding reactions, with the possibility to perform reactions under condition...

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Section: Automated Screening Platforms For Flow Photochemistrymentioning

confidence: 99%

Flow Photochemistry: Shine Some Light on Those Tubes!

Sambiagio

Noël

2020

Trends in Chemistry

295

223

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“…The bulk chemical industry has likewise pursued the miniaturization of unit operations (e.g., compact heat exchanger‐reactors) as means of process intensification and modular manufacturing towards concepts of Industry 4.0/Smart Factory, albeit typically at the millimetre‐scale in order to meet production rates . As a result, the literature has expanded from less than 100 articles a year in the early 1990s to 583 articles as of July 2018, with new potential applications, monographs, reviews, and perspective articles, which were written along with dedicated journals or journal sub‐sections (e.g., Lab on a Chip, Journal of Flow Chemistry, Chemical Engineering and Processing: Process Intensification, Chemistry Today ) and conferences (e.g., International Conference on Micro Reaction Technology, International Conference on Nanochannels, Microchannels, and Minichannels).…”

Section: Introductionmentioning

confidence: 99%

Experimental methods in chemical engineering: Micro‐reactors

et al. 2019

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Whereas the bulk chemical industry has historically sought economic advantage through economies of scale, a paradigm shift has researchers developing systems on smaller scales. Nano-cages and nano-actuators increase selectivity and robustness at the molecular scale. In parallel, micro-contactors with sub-millimetre lateral dimensions are decreasing boundary layers that restrict heat and mass transfer and thus meet the objectives of process intensification with great increases in productivity with a smaller footprint. These contactors continue to serve chemical engineers and chemists to synthesize fine chemicals and characterize catalysts; however, they have now been adopted for sensors in biological and biochemical systems. A bibliometric analysis of articles indexed in the Web of Science in 2016 and 2017 identified five major clusters of research: catalysis and bulk chemicals; nanoparticles; organic synthesis and flow chemistry; systems and micro-fluidics applied to biochemistry; and micro-channel reactors and mass transfer. In the early 1990s, less than 100 articles a year mentioned micro-reactors, while over 943 articles mentioned it in 2017. Here, we introduce micro-reactors and their role in the continuous synthesis of fine chemicals across the various scales to commercialization.

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“…Continuous reaction and analysis is a relevant approach for sustainable chemical process [1] [2]. Ideally, techniques should provide scalable data and should be suitable for adaptation to industrial equipment (for ultimate application to process and quality control).…”

Section: Introductionmentioning

confidence: 99%

“…For example, Cu or CuO nanoparticles are effective to remedy a range of bacterial pathogens involved in hospital-acquired infections [9]. Some green paintings are based on copper derivatives [11] as copper acetate, silicates, Cu(Ac) 2 •H 2 O has a simple process under heating, one step of dehydration followed by a step of decomposition giving rise to Cu x O y species as presented by Mansour [5]. Thermal gravimetric analysis (TGA) was a common tool for those studies and was used by some researchers to suggest the obtained copper oxides.…”

Section: Introductionmentioning

confidence: 99%

“…In situ DRIFT of Cu(Ac)2 •H 2 O in KBr under air (a) and Ar (b) between 2600 and 2150 cm −1 . I. Youssef et al DOI: 10.4236/ajac.2019.105014 163 American Journal of Analytical Chemistry oxidized under air but the decomposition of acetate involves the creation of intermediate compounds which is mainly acetic acid under Ar (acetone and ethanol are formed at minor).…”

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confidence: 99%

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Forward Looking Analysis Approach to Assess Copper Acetate Thermal Decomposition Reaction Mechanism

Youssef¹,

Sall²,

Dintzer³

et al. 2019

AJAC

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Thermal decomposition course of copper acetate monohydrate was monitored by combining diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) coupled with µ gas chromatography-mass spectrometry (µGC-MS) with other analytical techniques (thermogravimetry analysis and in situ X-ray diffraction). Non-isothermal kinetic was examined in air and Ar.A complete analysis of the evolution of infrared spectra matched with crystalline phase transition data during the course of reaction allows access to significant and accurate information about molecular dynamics. While thermogravimetry gives broad conclusion about two steps reaction (dehydration and decarboxylation), in line approach (in situ X-ray and in situ DRIFT coupled to µGC-MS) is proposed as an example of a new robust and forward-looking analysis. While decomposition mechanism of copper acetate monohydrate is still not well elucidated yet previously, the present in-line characterization results lead to accurate data making the corresponding mechanism explicit. techniques able to analyze data about different reaction media: powder, solid, liquid and gases. Two strategies could be proposed: continuous sampling coupled with fast analytical technique on one hand and in situ spectroscopic analysis on the other hand. Both approaches are complementary.Metal carboxylates are useful reagents particularly for organic synthesis [3] and applied in several fields of research as solid-state, surface chemistry and catalysis [3] [4] [5] [6]. The thermal decomposition of metal carboxylates is a feasible route to synthesize metal nanoparticles suitable for catalytic purposes [7] [8]

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Process Analytical Tools for Flow Analysis: A Perspective

Cited by 49 publications

References 37 publications

Flow Photochemistry: Shine Some Light on Those Tubes!

Flow Photochemistry: Shine Some Light on Those Tubes!

Experimental methods in chemical engineering: Micro‐reactors

Forward Looking Analysis Approach to Assess Copper Acetate Thermal Decomposition Reaction Mechanism

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