title: Supercooled micro flows and application for asymmetric synthesis.
abstract: Supercooled micro flow in microchannels was demonstrated. In order to clarify fundamental properties of the supercooling state in microchannels, freezing temperature was measured in the microchannels having widths ranging from 70 microm to 300 microm. The freezing temperature decreased with decreasing width of the microchannel when the microchannel wall was chemically modified with octadecylsilane group. The lowest freezing temperature was observed as -28 degrees C for water in the 70 microm wide microchannel. By contrast, the freezing temperature was -15 degrees C and did not depend on width when a microchannel with a bare glass surface was used. Next, the freezing point was measured with flow rates ranging from 0.1 to 2.0 microl min(-1) and no dependence on flow rate was observed. Then, the supercooled micro flow was applied to an asymmetric reaction in micro two-phase flow of aqueous and CH2Cl2 phases. As expected from thermodynamic prediction, enantiomeric selectivity increased in the supercooled state of water.
authors.affiliation: Department of Applied Chemistry, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsuoka
authors.forename: Akihide
authors.initials: A
authors.lastname: Hibara
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ueno
authors.forename: Takehiko
authors.initials: T
authors.lastname: Kitamori
mesh_terms: D002384:Catalysis; D005018:Ethyl Chloride / Q000737:chemistry; D005615:Freezing; D006878:Hydroxides / Q000737:chemistry; D046208:Microchip Analytical Procedures / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D015394:Molecular Structure; D036103:Nanotechnology / Q000379:methods*; D017680:Potassium Compounds / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D006878:Hydroxides; D017680:Potassium Compounds; D014867:Water; D005018:Ethyl Chloride; C029943:potassium hydroxide