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Getting Ring‐Closing Metathesis off the Bench: Reaction‐Reactor Matching Transforms Metathesis Efficiency in the Assembly of Large Rings
Author(s) -
Monfette Sebastien,
Eyholzer Markus,
Roberge Dominique M.,
Fogg Deryn E.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001210
Subject(s) - continuous stirred tank reactor , plug flow reactor model , catalysis , metathesis , plug flow , selectivity , batch reactor , substrate (aquarium) , chemical engineering , chemistry , ethylene , salt metathesis reaction , materials science , organic chemistry , thermodynamics , polymerization , physics , oceanography , engineering , geology , polymer
Reported is the first study of the influence of reactor configuration on the efficiency of a challenging ring‐closing metathesis (RCM) reaction. With the intention of increasing the generality of RCM scaleup and reducing its dependence on substrate modification, macrocyclization of an unmodified, low effective‐molarity diene was explored using different reactor types, in conjunction with a commercial, homogeneous Grubbs catalyst. Optimized performance is compared for a conventional batch reactor (BR), a continuous plug‐flow reactor (PFR), and a continuous stirred‐tank reactor (CSTR). In the PFR, maximum conversion is achieved most rapidly, but product yields and selectivity are adversely affected by co‐entrapment of ethylene with the catalyst, substrate, and product in the traveling “plug”. Use of the CSTR, in which ethylene is efficiently swept out, affords an order‐of‐magnitude increase in total turnover numbers, and reduces the required catalyst loadings by 25× relative to the BR (to 0.2 mol %), while improving RCM yields and selectivity to quantitative levels. Continuous‐flow methodologies that support liberation of the ethylene co‐product thus show great promise for industrial uptake of RCM.