Axial dispersion in coiled tubular reactors

Leclerc, D.; Smith, Carr J.; Toren, E. Clifford

doi:10.1016/s0003-2670(00)84764-9

Cited by 12 publications

(4 citation statements)

References 11 publications

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“…These results show that shaking is more efficient at low flow rates in contrast to coiling or knotting that work better at higher values. 6,9 Hence, for the disturbed straight reactor, reducing the flow rate at a constant reactor length is a way to increase the number of times the flow direction is changed. An analogy with current strategies (coiled, knotted reactors) can be found when the coiling factor or the number of knots per unit length is increased.…”

Section: Discussionmentioning

confidence: 99%

“…Different types of reactors such as packed, helically coiled and three-dimensional disoriented (serpentines, knotted or knitted) have been reported, showing different advantages and disadvantages depending on the operational conditions. [4][5][6][7][8][9] Some strategies other than the modification to the reactor shape and dimensions have been reported. Cardwell et al 10 used a vibrating reed mixer for improving the mixing of sample and reagents in the determination of the acidity of wines by discontinuous flow analysis.…”

Section: Introductionmentioning

confidence: 99%

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Oscillatory control of sample dispersion in a continuous flow system

Bruno

Andrade

Iñón

et al. 2001

Analyst

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A new strategy for the instrumental control of sample dispersion in continuous flow systems is presented. The method is based on shaking a loosely held straight reactor while the sample travels through the flow injection manifold. This external disturbance yields a sample transport more similar to the plug flow type because of the changes promoted on the flow pattern. Up to a three-fold increase in peak height, a comparable reduction in peak width and a more Gaussian peak profile are observed when the signals obtained with the shaken reactor are compared with those obtained with the same reactor but static. Improvements in the analytical performance as a function of different operational variables are shown for systems with or without a chemical reaction. Analytical implications and possible uses are discussed since this strategy allows the control of dispersion by simply selecting the frequency and amplitude of oscillation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oscillatory control of sample dispersion in a continuous flow system

Bruno

Andrade

Iñón

et al. 2001

Analyst

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“…It affects the sample integrity and sample dilution and thus decreases the detection sensitivity. In a paper studying dispersion in coiled tubes (Leclerc, Bloxham, and Toren 1986;Leclerc, Smith, and Toren 1987), it was found to be related to theoretical plate height. Plate heights at higher fluid velocities were found to be much lower for coiled than for ideal (straight) tubes.…”

Section: Introductionmentioning

confidence: 99%

“…It has been shown that the geometry of the deformed tubes affects the dispersion in open tubular reactors (Trivedi and Vasudeva 1975;van den Berg et al 1986;Leclerc, Smith, and Toren 1987). As the fluid velocity and aspect ratio (ratio of the tube radius to that of the coil) increase, a stronger secondary flow developed and the band broadening was reduced.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Helically Coiled and Knitted Open Tubular Reactors for the Efficient Post-Column Determination of Tetrodotoxin by High-Performance Liquid Chromatography

et al. 2016

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A post-column fluorescence reaction system for the high-performance liquid chromatographic (HPLC) determination of tetrodotoxin in the silver-cheeked toadfish Lagocephalus sceleratus is discussed theoretically and investigated experimentally. Ion-pair chromatography with volatile ammonium perfluoroheptanoate was used for the separation of tetrodotoxin and 4, 9-anhydrotetrodotoxin. The post-column reaction was based on tetrodotoxin conversion to a quinazoline fluorescent compound in strong alkaline conditions. All post-column parameters were optimized that affected the sensitivity, dispersion, and stability. Helically coiled and knitted open tubular reactors composed of polyetheretherketone were constructed and characterized in detail. The performance of these reactors was evaluated on the bases of sensitivity and dispersion. Their optimal design is reported. The knitted reactors were more efficient than the relevant helically coiled reactors when higher reaction times are required. A 1,500 μL polyetheretherketone knitted coil with 0.010″ internal diameter was optimum exhibiting higher pressure tolerances than Teflon coils. The HPLC post-column reaction method was evaluated in Downloaded by [University of Arizona] at 09:01 08 June 20163 terms of linearity, sensitivity, accuracy, precision, and ruggedness. The linear dynamic ranges for tetrodotoxin and 4, 9-anhydrotetrodotoxin were 40 to 3,000 ppb and 80 to 3,000 ppb, respectively. The limits of detection and quantification were 12 and 41 ppb for tetrodotoxin and 26 and 85 ppb for 4, 9-anhydrotetrodotoxin. The accuracy was evaluated by recovery measurements and the values for tetrodotoxin were between 90.7% and 93.6%. The use of a volatile perfuorocarboxylic acid as an ion-pair reagent allowed confirmation of by highperformance liquid chromatography -tandem mass spectrometry using identical mobile phase conditions.

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Reactor design and selection for effective continuous manufacturing of pharmaceuticals

2021

J Flow Chem

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Pharmaceutical production remains one of the last industries that predominantly uses batch processes, which are inefficient and can cause drug shortages due to the long lead times or quality defects. Consequently, pharmaceutical companies are transitioning away from outdated batch lines, in large part motivated by the many advantages of continuous manufacturing (e.g., low cost, quality assurance, shortened lead time). As chemical reactions are fundamental to any drug production process, the selection of reactor and its design are critical to enhanced performance such as improved selectivity and yield. In this article, relevant theories, and models, as well as their required input data are summarized to assist the reader in these tasks, focusing on continuous reactions. Selected examples that describe the application of plug flow reactors (PFRs) and continuous-stirred tank reactors (CSTRs)-in-series within the pharmaceutical industry are provided. Process analytical technologies (PATs), which are important tools that provide real-time in-line continuous monitoring of reactions, are recommended to be considered during the reactor design process (e.g., port design for the PAT probe). Finally, other important points, such as density change caused by thermal expansion or solid precipitation, clogging/fouling, and scaling-up, are discussed.

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Axial dispersion in coiled tubular reactors

Cited by 12 publications

References 11 publications

Oscillatory control of sample dispersion in a continuous flow system

Oscillatory control of sample dispersion in a continuous flow system

Evaluation of Helically Coiled and Knitted Open Tubular Reactors for the Efficient Post-Column Determination of Tetrodotoxin by High-Performance Liquid Chromatography

Reactor design and selection for effective continuous manufacturing of pharmaceuticals

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