Trihalomethane

Trihalomethanes (THM ) are organic compounds in which exactly three hydrogen atoms are replaced by halogens in methane. Trihalomethanes are among the haloalkanes.

According to the nomenclature recommendations of the IUPAC is the systematically correct name trihalomethanes. Haloforms is a common name for the simple CHX3 representative with three identical halogen atoms.

Representative

There are known by all the halogens corresponding trihalomethanes: trifluoromethane ( fluoroform ), trichloromethane (chloroform ), tribromomethane ( bromoform ), triiodomethane ( iodoform ).

In addition, there are a number of mixed trihalomethanes, for example, bromodichloromethane or dibromochloromethane.

Astatoform as trihalomethane of astatine is radioactive and thus unstable.

Trihalomethanes (THMs ) in water treatment

As a by- product of the disinfection of drinking water or water treatment in swimming pools with chlorine or chlorine bleach to form trihalomethanes. Health significance of trichloromethane, bromodichloromethane, dibromochloromethane and tribromomethane. For these substances, limits are set as a sum parameter (THM ) content, compliance must be monitored analytically.

The limit for drinking water, a level of 0.05 mg / L. If the limit is exceeded for THM, a disinfection with chlorine dioxide offers, in which virtually no halogenation occurs.

Extraction

Chloroform can be obtained by radical substitution of methane. A known method for the production of chloroform, bromoform and iodoform, the haloform reaction.