Scalable multiphase microchemical systems for direct fluorination

Microchemical systems or microreactors refer to a new class of continuous reactors that have feature sizes in the submillimeter range. In particular, microfabricated chemical reactors are built using silicon-based photolithographic fabrication techniques that were originally developed to create integrated microelectronic circuits. Because silicon microfabrication allows precise control over the geometry of the reactor features down to the micron scale, as well as the integration of a variety of sensors into the fluidic path, microfabricated reactors are promising as versatile chemical synthesis tools that present capabilities exceeding those of their macroscale counterparts. In addition, small reactor volumes enhance the control of fast exothermic reactions and allow new reaction chemistries deemed too difficult to control in conventional reactors to be carried out safely. One example of such chemistry is the direct fluorination of organic molecules. This thesis addresses the design, fabrication, and application of a gas-liquid microreactor as a discovery tool for the synthesis of fluorinated compounds by direct fluorination. A microfabrication methodology was developed to create microfluidic channels chemically compatible with the highly corrosive direct fluorination environment. Electron-beam evaporated nickel in combination with thermally grown silicon oxide coatings were employed as corrosion barriers for microchannels formed in a silicon substrate. The direct fluorination of toluene was safely demonstrated at room temperature and on preparative yields for substrate concentrations ranging between 0.1 and 1.0 M. The product distribution was studied as a function of the number of fluorine equivalents and solvent type.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• De Mas Valls, Nuria, 1975-

Advisor dc:contributor.advisor

• Klavs F. Jensen and Martin A. Schmidt.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29446

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29446