video tutorial Reduction of vanillin to vanillyl alcohol

Name: video tutorial - Reduction of vanillin to vanillyl alcohol
Uploaded: 2025-12-11T09:03:44.089Z
Duration: 14 min 47 s
Description: can easily be oxidized to the corresponding carboxylic acid, but it can...and 99% pure. As you can see from the structure, vanillin is a phenol

Goal: reduce vanillin to vanilla alcohol by forming the vanillin sodium salt and then carrying out a borohydride reduction.
Setup: 25 g vanillin (99%), 200 mL water; dissolve 7.3 g NaOH (1.1 equivalents) to form the vanillin sodium salt, which turns yellow as it dissolves; chill the solution.
Salt formation: vanillin becomes a water-soluble sodium salt in basic solution; after dissolution, chill to fridge temperature.
Reduction: add 7 g sodium borohydride slowly over ~20 minutes with continuous cooling; expect hydrogen gas evolution; final volume ~350 mL; maintain cold conditions with ice as needed.
Workup: neutralize the mixture gradually with hydrochloric acid (40 mL conc, diluted to about 100 mL total) to decompose residual borohydride and convert the salt to vanilla alcohol; monitor pH and avoid foam; cool during neutralization.
Isolation: allow a white precipitate of vanilla alcohol to form, filter, wash with ice-cold water, and dry; yield 23.9 g (94%) of vanilla alcohol; product shows little to no vanilla aroma.
Notes: keep reaction and neutralization cold; slow borohydride addition is crucial; a large beaker helps control foaming; borohydride is hard to obtain and handling precautions are important; overheating can lead to undesired side products (e.g., quinone-like species).
Further experiments: reactions of pure borohydride with strong acids (50% sulfuric acid, then 68% nitric acid) show vigorous reactions but are not particularly impressive.