The reduction of vanillin to vanillyl alcohol, by sodium borohydride is a common experiment performed in organic chemistry labs. In an effort to adhere to the twelve principles of green chemistry, we have investigated ways to oxidize vanillyl alcohol back to vanillin, so that it may be reused in the lab. The goal is to perform the oxidation in the highest yield possible, while having as little negative impact on the environment as possible.

The four reagents with which we attempted the oxidation of vanillyl alcohol are: pyridinium chlorochromate (PCC), 4-acetamido-2,2,6,6-tetramethyl piperidine 1-oxyl (4-acetamido-TEMPO), commercially-available aryl oxidase enzymes and polymer supported chromic acid-. All of the reagents successfully oxidized the vanillyl alcohol, but the goal, is to maximize greenness and yield together. The chromium (VI)-based reagents, PCC and polymer supported-chromic acid may cause cancer and have adverse consequences on the environment. These are not the best methods for this oxidation, where a green reaction is desired. While 4-acetamido-TEMPO is slightly less green than the enzymatic systems, it produces much higher yields, at about 68% in comparison to an average yield of 36.5% for the enzymes. Also, 4-acetamido-TEMPO is much more cost efficient in comparison to the enzymes. The future of this project includes optimization of 4-acetamido-TEMPO yields and the immobilization of the enzymes, so that they may be reused.