Properties that can be determined are boiling point, density, refractive index, ir, nmr, gas chromatographic retention times, very careful smell determinations and optical rotations. For the optical rotations, we supply polarimeter tubes already filled with the two carvones as polarimetry usually requires more material than the students obtain. The very high reported toxicity of d-carvone was unexpected and was hard to believe especially in light of its use as a flavoring. This apparent discrepancy led me to make an inquiry to the FDA and they responded that a typographical error from the original data has been sustained during subsequent publications of the data. Have students select a partner and give one student spearmint oil and the other caraway oil.
Students then compare the properties of each product and are asked to make appropriate conclusions.
A shorter option involves supplying each partner with one of the two carvones. Relatively pure samples of both carvones are commercially available at costs that are not prohibitive. For this option, each student then does all the property determinations eliminating the not too trivial separation and purification portion of the experiment. Another option is to use the two limonenes instead of the carvones however the smell differentiation is questionable. R. H. Mitchell and P. R. West, J. Chem.