Thymol

2-isopropyl -5-methyl -phenol, 2 - (1 -methylethyl )-5- methyl-phenol

Colorless, spicy -scented thyme, burning taste panels

Fixed

0.97 g · cm -3

51.5 ° C

233 ° C

1.3 hPa ( 65 ° C)

• Poorly in water ( 0.98 g · l -1) and glycerol
• Well in sodium hydroxide solution, ethanol, diethyl ether, carbon disulfide, and chloroform

Risk

640 mg · kg -1 ( LD50, mouse, oral)

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Thymol is a monoterpene and next to its isomer carvacrol, a component of the essential oils from ajwain seeds, thyme, oregano and savory.

History

In ancient Egypt, thymol and carvacrol in the form of thyme preparations were used because of the bactericidal and fungicidal properties for preservation of mummies.

The crystalline substance thymol was discovered in 1719 by Caspar Neumann and illustrated purely by M. Lallemand in 1842 and characterized by elemental analysis. He was able to determine the proper ratio of the elements carbon, hydrogen, and oxygen that make up this substance. Also keep Ferdinand Runge dealt with the chemistry of this substance. The crystal structure analysis using the accurate determination of the atomic positions was published only in 1980 by Alain Thozet and M. Perrin.

Production and representation

Thymol may be via the reaction of m-cresol and propylene in the presence of acid catalysts such as Zeolite can be prepared.

Properties

The solid melts at 51.5 ° C and boils at 233 ° C. The density is 0.97 g / cm ³. The vapor pressure is 1.3 hPa at 65 ° C. The flash point is 104 ° C.

As Thymol is a phenol derivative, it shows the typical behavior of phenol. That is, it dissolves in sodium hydroxide solution or potassium hydroxide solution and again, is liberated by acidification. Also in ethanol, ether and chloroform, it is readily soluble in one liter of ethanol dissolve at 25 ° C 1000 g thymol, in one liter of chloroform about 1428 g of thymol. In water it is only sparingly soluble, in one liter of water is approximately one gram of thymol dissolves.

In contrast to phenol, thymol is no color reaction with iron ( III) chloride.

Thymol may be hydrogenated to menthol.

The bromination of thymol with elemental bromine in acetic acid leads exclusively to the 4- bromothymol.

Use

Thymol is characterized by a strong disinfectant fungicidal and bactericidal effect and is used because of its pleasant taste in mouthwashes, toothpaste and a 5 -percent alcohol solution for skin disinfection or locally against skin fungi, such as a component of vaginal or for the treatment of oral fungal in AIDS patients. In veterinary medicine, thymol is also used for many years for the treatment of fungal skin infections, but also as a digestive conveyor. In the bee takes care thymol application as a drug against mite infestation ( Varroose ).

For the storage and preservation of extracted teeth before further processing for scientific study thymol can also be used.