Search

The separation of chamazulene from hydrophilic contaminants present in blue tansy oil provides a visually engaging example of two common techniques: extraction and thin-layer chromatography (TLC). This application uses liquid CO[subscript 2] as a lipophilic solvent to pull a brilliant blue hydrocarbon molecule, chamazulene, out of or through a common hydrophilic material, cellulose. Yellow-green, hydrophilic components remain in a cotton ball or at the lower end of a paper strip. In dramatic fashion, the separation of colored components of blue tansy oil is accomplished with an environmentally sustainable solvent, CO[subscript 2], and an innocuous support material, cellulose. We believe this is the first reported use of liquid CO[subscript 2] in centrifuge tubes to conduct TLC.

We believe that students should have opportunities--early and often--to learn about science and math activities in fun and recreational ways. As a result, we try to provide many science enrichment activities to the surrounding community. In doing so, we hope to inspire young students to become future scientists and mathematicians. Here we describe some annual science outreach events that we have hosted, share a few demonstrations and activities we have tried at these events, and discuss how we plan to connect our outreach in 2011 to the themes of the International Year of Chemistry. (Contains 4 tables and 3 figures.)

In "JCE" Activity #67, "Flame Tests: Which Ion Causes the Color?", Michael Sanger describes how to conduct flame tests with household items. We have used this activity in outreach settings, and have extended it in a variety of ways. For example, we have demonstrated large-scale strontium (red), copper (green), and carbon (blue) flames using only household items, and have helped children investigate the chemistry of sparklers and colored flame birthday candles. (Contains 2 tables, 1 figure and 7 notes.)

The use of Amado P lipoprotein lipase allows effective separation of remote diol and triol stereoisomers via stereoselective acetylation (in organic media) or hydrolysis of their peracetates (in aqueous media). The enzyme is selective towards (R)-stereogenic centers, converting only (R,R)- and meso- diols to their acetates, or their (R,R)-peracetates to diols. A series of alpha-dimethylaryl and trimethylaryl dimethanols and trimethanols are subsequently separated as a demonstration of this method. Each of the diols' stereochemical purity is established by spectroscopic studies.

The separation of the contents of an activated lightstick using a chromatography column is described. The experiment teaches the role played by intermolecular forces in the separation of components from a mixture and is applicable for teaching students at all levels.

The use of Pasteur pipes for microscale column chromatography is reported. The materials used in the manual pressurization apparatus are proved to be hazardous.

Separation of glow stick dyes adhered to a cotton swab using liquid CO2 provides an engaging demonstration of several chemical concepts including polarity, kinetics, chemiluminescence, and the importance of CO2 a green solvent. The simple protocol allows access to a broad range of students. Differential polarities of the glow stick dyes allow certain dyes to be preferentially dissolved in liquid CO2, leaving other dyes adhered onto cotton. Both TCPO (bis(2,4,6-trichlorophenyl)oxalate) and H2O2, which together provide the necessary reaction for chemiluminescence, are present in both the extracted liquid and cotton upon dissipation of CO2. Thus, it is possible to compare the emission spectrum of the extracted fluid to that of the original glow stick and the residue left on the cotton swab. Emission peaks resulting from the presence of polar dyes in the original glow stick and on the cotton are routinely observed to be missing in the extracts. [ABSTRACT FROM AUTHOR]

Separation of glow stick dyes adhered to a cotton swab using liquid CO2 provides an engaging demonstration of several chemical concepts including polarity, kinetics, chemiluminescence, and the importance of CO2 a green solvent. The simple protocol allows access to a broad range of students. Differential polarities of the glow stick dyes allow certain dyes to be preferentially dissolved in liquid CO2, leaving other dyes adhered onto cotton. Both TCPO (bis(2,4,6-trichlorophenyl)oxalate) and H2O2, which together provide the necessary reaction for chemiluminescence, are present in both the extracted liquid and cotton upon dissipation of CO2. Thus, it is possible to compare the emission spectrum of the extracted fluid to that of the original glow stick and the residue left on the cotton swab. Emission peaks resulting from the presence of polar dyes in the original glow stick and on the cotton are routinely observed to be missing in the extracts. [ABSTRACT FROM AUTHOR]

The separation of chamazulene from hydrophilic contaminants present in blue tansy oil provides a visually engaging example of two common techniques: extraction and thin-layer chromatography (TLC). This application uses liquid CO2 as a lipophilic solvent to pull a brilliant blue hydrocarbon molecule, chamazulene, out of or through a common hydrophilic material, cellulose. Yellow-green, hydrophilic components remain in a cotton ball or at the lower end of a paper strip. In dramatic fashion, the separation of colored components of blue tansy oil is accomplished with an environmentally sustainable solvent, CO2, and an innocuous support material, cellulose. We believe this is the first reported use of liquid CO2 in centrifuge tubes to conduct TLC. [ABSTRACT FROM AUTHOR]

Making triboluminescent crystals using a microwave oven is an example of an activity in which the compound will dazzle undergraduate chemistry students and introduce them to use of a device they might not think of as laboratory equipment. In this exercise, students get background on microwave oven amidation, recrystallization, and triboluminescence by using basic combinations introduced by Erikson, then the amidation of anthranilic acid with acetic anhydride, an amidation which takes one minute.