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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.


Effects of the residence time on the outcome of the reaction shown on Scheme 3 b with the catalyst shown in Scheme 4. ▼: conversion; ▪: yield of cyclopropanes; •: yield of trans-cyclopropanes; ▲: yield of cis-cyclopropanes. Reproduced with permission from ref. 32. Copyright 2015, American Chemical Society.
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fig12: Effects of the residence time on the outcome of the reaction shown on Scheme 3 b with the catalyst shown in Scheme 4. ▼: conversion; ▪: yield of cyclopropanes; •: yield of trans-cyclopropanes; ▲: yield of cis-cyclopropanes. Reproduced with permission from ref. 32. Copyright 2015, American Chemical Society.

Mentions: The monolithic catalyst was synthetized by the polymerization of the starting 4-vinyl derivative. Through fine-tuning of the residence time, the chemoselectivity of the reaction was changed. At a residence time of 14 min, the yield for trans-cyclopropanes was ∼15 %, while for the cis isomers it was ∼6 %; while at a residence time of 35 min, the corresponding yields were ∼40 % and ∼10 %, respectively. Consequently, upon increase of the residence time by ∼20 min, the yield of the trans-derivatives almost tripled, whereas that of the cis-derivative did not even double. Thus, at longer residence times the selectivity is shifted towards the trans-derivative (Figure 12).


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

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

Effects of the residence time on the outcome of the reaction shown on Scheme 3 b with the catalyst shown in Scheme 4. ▼: conversion; ▪: yield of cyclopropanes; •: yield of trans-cyclopropanes; ▲: yield of cis-cyclopropanes. Reproduced with permission from ref. 32. Copyright 2015, American Chemical Society.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig12: Effects of the residence time on the outcome of the reaction shown on Scheme 3 b with the catalyst shown in Scheme 4. ▼: conversion; ▪: yield of cyclopropanes; •: yield of trans-cyclopropanes; ▲: yield of cis-cyclopropanes. Reproduced with permission from ref. 32. Copyright 2015, American Chemical Society.
Mentions: The monolithic catalyst was synthetized by the polymerization of the starting 4-vinyl derivative. Through fine-tuning of the residence time, the chemoselectivity of the reaction was changed. At a residence time of 14 min, the yield for trans-cyclopropanes was ∼15 %, while for the cis isomers it was ∼6 %; while at a residence time of 35 min, the corresponding yields were ∼40 % and ∼10 %, respectively. Consequently, upon increase of the residence time by ∼20 min, the yield of the trans-derivatives almost tripled, whereas that of the cis-derivative did not even double. Thus, at longer residence times the selectivity is shifted towards the trans-derivative (Figure 12).

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.