Supercooled micro flows and application for asymmetric synthesis.

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.

[1]  Takehiko Kitamori,et al.  Continuous-flow chemical processing on a microchip by combining microunit operations and a multiphase flow network. , 2002, Analytical chemistry.

[2]  Takehiko Kitamori,et al.  Fast and high conversion phase-transfer synthesis exploiting the liquid–liquid interface formed in a microchannel chip , 2001 .

[3]  Takehiko Kitamori,et al.  Spectroscopic analysis of liquid/liquid interfaces in multiphase microflows. , 2003, Journal of the American Chemical Society.

[4]  M. Kameda,et al.  Design of N-spiro C2-symmetric chiral quaternary ammonium bromides as novel chiral phase-transfer catalysts: synthesis and application to practical asymmetric synthesis of alpha-amino acids. , 2003, Journal of the American Chemical Society.

[5]  P. Yager,et al.  Microfluidic Diffusion-Based Separation and Detection , 1999, Science.

[6]  Hideaki Hisamoto,et al.  Phase-transfer alkylation reactions using microreactors. , 2003, Chemical communications.

[7]  T. Leisner,et al.  Homogeneous ice nucleation observed in single levitated micro droplets , 1996 .

[8]  T Kitamori,et al.  Determination of carcinoembryonic antigen in human sera by integrated bead-bed immunoassay in a microchip for cancer diagnosis. , 2001, Analytical chemistry.

[9]  Paul Watts,et al.  The application of micro reactors to synthetic chemistry , 2001 .

[10]  G. Whitesides,et al.  Microfabrication inside capillaries using multiphase laminar flow patterning , 1999, Science.

[11]  Manabu Tokeshi,et al.  Peer Reviewed: Thermal Lens Microscopy and Microchip Chemistry , 2004 .

[12]  A Manz,et al.  Chemical amplification: continuous-flow PCR on a chip. , 1998, Science.