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Strategic Application of Residence-Time Control in Continuous-Flow Reactors.

Mándity IM, Ötvös SB, Fülöp F - ChemistryOpen (2015)

Bottom Line: As a sustainable alternative for conventional batch-based synthetic techniques, the concept of continuous-flow processing has emerged in the synthesis of fine chemicals.Systematic tuning of the residence time, a key parameter of continuous-reaction technology, can govern the outcome of a chemical reaction by determining the reaction rate and the conversion and by influencing the product selectivity.Such a fine reaction control cannot be performed in conventional batch reaction set-ups.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pharmaceutical Chemistry, University of Szeged Eötvös u. 6, H-6720, Szeged, Hungary.

ABSTRACT
As a sustainable alternative for conventional batch-based synthetic techniques, the concept of continuous-flow processing has emerged in the synthesis of fine chemicals. Systematic tuning of the residence time, a key parameter of continuous-reaction technology, can govern the outcome of a chemical reaction by determining the reaction rate and the conversion and by influencing the product selectivity. This review furnishes a brief insight into flow reactions in which high chemo- and/or stereoselectivity can be attained by strategic residence-time control and illustrates the importance of the residence time as a crucial parameter in sustainable method development. Such a fine reaction control cannot be performed in conventional batch reaction set-ups.

No MeSH data available.


Effluent concentrations as a function of residence time in the hydrogenation of 3-methyl-1-pentyn-3-ol in ethanol over a 0.02 wt % Pd catalyst operated in segmented flow at 24 °C. The dashed line shows the maximum obtainable yield. Reproduced with permission from ref. 23.Copyright 2011, Wiley-VCH Verlag GmbH / Co. KGgA, Weinheim.
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fig10: Effluent concentrations as a function of residence time in the hydrogenation of 3-methyl-1-pentyn-3-ol in ethanol over a 0.02 wt % Pd catalyst operated in segmented flow at 24 °C. The dashed line shows the maximum obtainable yield. Reproduced with permission from ref. 23.Copyright 2011, Wiley-VCH Verlag GmbH / Co. KGgA, Weinheim.

Mentions: Kinetic modelling showed that the maximum possible yield is 78–81 %, which is obtained only at precisely the right residence time. The dependence of the selectivity of the reaction on the residence time has been investigated. There is an optimum value where the formation of P1 displays a maximum value, and the overhydrogenation to P2 is still low. Any further variation of the residence time reduces the yield (Figure 10). At a shorter residence time, the conversion is lower in general, but at longer residence times, the formation of P2 increases, while the concentration of P1 decreases. In a one-day optimization, the theoretical optimum yield of P1 was achieved by using segmented flow.


Strategic Application of Residence-Time Control in Continuous-Flow Reactors.

Mándity IM, Ötvös SB, Fülöp F - ChemistryOpen (2015)

Effluent concentrations as a function of residence time in the hydrogenation of 3-methyl-1-pentyn-3-ol in ethanol over a 0.02 wt % Pd catalyst operated in segmented flow at 24 °C. The dashed line shows the maximum obtainable yield. Reproduced with permission from ref. 23.Copyright 2011, Wiley-VCH Verlag GmbH / Co. KGgA, Weinheim.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522171&req=5

fig10: Effluent concentrations as a function of residence time in the hydrogenation of 3-methyl-1-pentyn-3-ol in ethanol over a 0.02 wt % Pd catalyst operated in segmented flow at 24 °C. The dashed line shows the maximum obtainable yield. Reproduced with permission from ref. 23.Copyright 2011, Wiley-VCH Verlag GmbH / Co. KGgA, Weinheim.
Mentions: Kinetic modelling showed that the maximum possible yield is 78–81 %, which is obtained only at precisely the right residence time. The dependence of the selectivity of the reaction on the residence time has been investigated. There is an optimum value where the formation of P1 displays a maximum value, and the overhydrogenation to P2 is still low. Any further variation of the residence time reduces the yield (Figure 10). At a shorter residence time, the conversion is lower in general, but at longer residence times, the formation of P2 increases, while the concentration of P1 decreases. In a one-day optimization, the theoretical optimum yield of P1 was achieved by using segmented flow.

Bottom Line: As a sustainable alternative for conventional batch-based synthetic techniques, the concept of continuous-flow processing has emerged in the synthesis of fine chemicals.Systematic tuning of the residence time, a key parameter of continuous-reaction technology, can govern the outcome of a chemical reaction by determining the reaction rate and the conversion and by influencing the product selectivity.Such a fine reaction control cannot be performed in conventional batch reaction set-ups.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pharmaceutical Chemistry, University of Szeged Eötvös u. 6, H-6720, Szeged, Hungary.

ABSTRACT
As a sustainable alternative for conventional batch-based synthetic techniques, the concept of continuous-flow processing has emerged in the synthesis of fine chemicals. Systematic tuning of the residence time, a key parameter of continuous-reaction technology, can govern the outcome of a chemical reaction by determining the reaction rate and the conversion and by influencing the product selectivity. This review furnishes a brief insight into flow reactions in which high chemo- and/or stereoselectivity can be attained by strategic residence-time control and illustrates the importance of the residence time as a crucial parameter in sustainable method development. Such a fine reaction control cannot be performed in conventional batch reaction set-ups.

No MeSH data available.