Acoustic emulsions of liquid, near-critical carbon dioxide and water : application to synthetic chemistry through reaction engineering

Supervised by The need to eliminate hazardous solvents, such as methanol, toluene, and dichloromethane, in specialty and pharmaceutical chemical synthesis applications has motivated the development of alternative approaches. Because of its environmental compatibility, low cost, and favorable physicochemical properties, supercritical carbon dioxide (scCO2) has been actively considered to replace conventional hydrocarbon solvents. Progress towards this objective has been impressive, for example scCO2 is used as a selective extraction solvent in several commercial processes. By comparison, development of scCO2 as a reaction solvent has been much less successful due to its limited solvation power. Furthermore, the rates of reactions conducted in scCO2 tend to be slower than and their selectivities are comparable to those observed in hydrocarbon solvents. This research focused on development of water/carbon dioxide biphasic reaction systems as an engineering solution to increase reaction rates and manipulate selectivity while preserving environmental compatibility of scCO2. Emulsification by power ultrasound was selected as an additive-free means to bring near-critical liquid carbon dioxide and water into intimate contact and increase interphase transport. With this approach, the complementary solvation powers of the two solvents could be utilized to expand the range of potential chemical transformations. Carbon dioxide was envisioned as a delivery solvent, allowing access to the unique abilities of water to accelerate organic reactions while influencing their product spectrum. First, the partitioning behavior of organic solutes was investigated with the objective of developing empirical correlations for estimating partition coefficients.

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

• Timko, Michael T., 1974-

Advisor dc:contributor.advisor

• Jefferson W. Tester and Kenneth A. Smith.

• 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/1721.1/29375

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29375