1911 Encyclopædia Britannica/Carvacrol
CARVACROL, or Cymophenol, C10H13OH, or , a constituent of the ethereal oil of Origanum hirtum, oil of thyme, oil obtained from pepperwort, and wild bergamot. It may be synthetically prepared by the fusion of cymol sulphonic acid with caustic potash; by the action of nitrous acid on 1-methyl-2-amino-4-propyl benzene; by prolonged heating of 5 parts of camphor with 1 part of iodine; or by heating carvol with glacial phosphoric acid. It is extracted from Origanum oil by means of a 10% potash solution. It is a thick oil which sets at -20°C. to a mass of crystals of melting point 0°C, and boiling point 236–237°C. Oxidation with ferric chloride converts it into dicarvacrol, whilst phosphorus pentachloride transforms it into chlorcymol.