Green chemistry : dense carbon dioxide and water as environmentally benign reaction media

(cont.) was investigated in scCO₂, and the cycloaddition between cyclopentadiene and methyl vinyl ketone (MVK) was studied in an scCO₂/liquid water environment. Nitrogen chemistry, specifically the synthesis of nitrogen heterocycles from amines, was also studied in scCO₂ and scCO₂/liquid water systems. The objective of studying the Diels-Alder cycloaddition of 9-hydroxymethylanthracene with N-ethylmaleimide in scCO₂ was to demonstrate the ability of scCO₂ to dramatically accelerate the rate of this reaction when compared to conventional solvents. Using spectroscopy to track the disappearance of the 9-hydroxymethylanthracene peak, it was found that this reaction proceeds at rates in scCO₂ that are significantly faster than in traditional organic solvents. It was also observed that the reaction rate constant increased with decreasing density, opposite the trend normally observed for most reactions conducted in scCO₂. On the basis of the low solubility of 9-hydroxymethylanthracene in scCO₂ and similar results observed in fluorocarbon solvents (fluorocarbons and scCO₂ are known to behave similarly as solvents), a solvophobic mechanism was inferred as the cause of the rate acceleration observed for this particular reaction in scCO₂. In order to utilize the complementary solvation powers of scCO₂ and water, a second Diels-Alder reaction, cyclopentadiene with MVK, was studied in an scCO₂/liquid water mixture. Specifically, the effect of MVK concentration on the selectivity and conversion was studied under both silent and sonicated conditions ...

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

• Allen, Andrew J. (Andrew John), 1978-

Advisor dc:contributor.advisor

• Jefferson W. Tester.

• 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

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/28656

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28656