title: Reaction rates as a function of scale within ionic liquids: microscale in droplet microreactors versus macroscale reactions in the case of the Grieco three-component condensation reaction.
abstract: Task-specific ionic liquids (TSILs) and more specifically binary task-specific ionic liquids (BTSILs), a unique subclass, have been shown to be excellent supports for solution-phase chemistry. The negligible volatility of ionic liquids enables their use as stable droplet microreactors in atmospheric environments without oil protection or confinement. These droplets can be moved, merged and mixed by electrowetting on a chip. Solution-phase synthesis can be performed on these open digital microfluidic labs-on-a-chip as illustrated by a study of the Grieco three-component reaction in [tmba][NTf(2)]-droplet (tmba=N-trimethyl-N-butylammonium NTf(2)=bis(trifluoromethylsulfonyl)imide) microreactors. A detailed study of matrices and scale effects on conversion and kinetic rates of this three-component condensation is presented in this paper. Reactions have been shown to be slower in droplets than in batches in the absence of additional mixing. Also, a significant influence of the ionic-liquid matrix has been observed. Finally, an increase of droplet's temperature resulted in a kinetics enhancement so as to reach macroscale reaction rates, probably because of a much better mixing of reaction's components involving a Marangoni's effect.
authors.affiliation: CEA Léti-MINATEC, Department of Technology for Biology and Health, 17 rue des Martyrs 38054 Grenoble, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Dubois
authors.forename: Gilles
authors.initials: G
authors.lastname: Marchand
authors.forename: Said
authors.initials: S
authors.lastname: Gmouh
authors.forename: Michel
authors.initials: M
authors.lastname: Vaultier
mesh_terms: D007094:Imides / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D007700:Kinetics; D046208:Microchip Analytical Procedures / Q000379:methods; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D007094:Imides; D052578:Ionic Liquids; D000644:Quaternary Ammonium Compounds