P140: Straightforward procedure using bleach for the green oxidation of alcohols

Author: Hamish Christie, University of Arizona, USA

Co-Author: Edon Vitaku, University of Arizona, USA

Date: 8/4/14

Time: 11:10 AM11:30 AM

Room: LMH 114

Related Symposium: S7

Alcohol oxidation is an essential transformation in organic chemistry. The well-known chromium based oxidants are notorious for their toxicity and environmentally harmful effects, yet are still used in many teaching laboratories. It is well-established that hypochlorous acid (often generated from bleach) can oxidize many alcohols to the corresponding aldehydes or ketones. However, several inconvenient aspects of the known procedures limit their utility in teaching laboratories. In this presentation a straightforward, easy to execute procedure will be described. The reaction occurs rapidly at room temperature using household bleach. In many cases highly pure products are obtained simply using liquid-liquid extraction. This procedure uses ethyl acetate (a comparatively green organic solvent), an acid, and bleach; the reaction byproducts are innocuous inorganic salts suitable for drain disposal. Importantly, the principles of green chemistry can be demonstrated to students by analyzing (on paper) the differences between the bleach and chromium reaction procedures

P47: Safe, easily constructed apparatus for liquid CO2 extractions

Author: Hamish Christie, University of Arizona, USA

Co-Author: Pitambar Khanal, University of Arizona, USA

Date: 8/3/14

Time: 4:40 PM5:00 PM

Room: LMH 114

Related Symposium: S7

Supercritical carbon dioxide is well-known as an excellent solvent for extraction of organic compounds. The properties of CO2 itself, and the processes using it, make it a good green alternative to organic solvents. Perhaps less well known is the use of liquid CO2 as a solvent. Liquid CO2 can be generated at relatively moderate pressure (>5 atm), compared to that required to form supercritical CO2 (>70 atm). Building on a previously reported extraction procedure, we present a simply constructed, robust, apparatus for the extraction of organic materials. Students can readily observe the melting of dry-ice and the extraction process through the transparent walls of the pressure vessel. The pressure is safely controlled by an automatic release valve and a gauge allows the actual pressure to be known. This apparatus enables the rapid extraction of organic compounds from a range of materials including citrus zest, cumin, cloves, and star anise.