Zinc dust distillation of 2-naphthol

Chemicals needed

glass beads or coarse sand

2-naphthol GSGESUND.gif (476 Byte) Xn  GSUMWELT.gif (758 Byte)  N    R 20/22-50     S (2)-24/25-61

zinc (dust) GSLEICHT.gif (932 Byte) F    R 10-15    S 7/8-12-43

If 1-naphthol could have also been used as an alternative was not investigated.

Dangerous substance information

naphthalin GSGESUND.gif (476 Byte) Xn  GSUMWELT.gif (758 Byte)  N     R 22-50/53     S 36/37-60-61

Equipment needed

burner (gas or alcohol)
wooden clamp
test tube

Test procedure



Zinc dust acts even under drastic conditions without acid or base catalysis as a strong reducing agent, and is even capable of reducing a (activated) aromatic hydroxyl compound to a hydrocarbon, a synthetic transformation which is otherwise, in contrast to aliphatic alcohols, only possible with very special methods. Since the yield is usually very poor and in addition substantial rearrangements and eliminations within the molecules can occur, this reaction has never had a important preparative significance. It was however previously important in analysis, so for example morphine yielded as a major product phenanthrene, which was of great importance for the structural investigation (which lasted for a good century) of this molecule, and which at the same time shows how dramatic the above mentioned side reactions turn out. The sand or glass beads by the way do act as a cooler in order that the reaction partners have enough time to react with one another.
If someone should find that the product does not smell at all like mothballs, then this could be because the naphthalin for this purpose has been replaced over the last decades by p-dichlorobenzene, which occurs as a cheap by-product in the industrial production of chlorobenzene or o-dichlorobenzene.