Chloroform (CHCl3) is used as an anesthetic during surgical procedures We have come a long way since the primitive days of medicine when calling a doctor and undergoing surgery was a last resort, the alternative being certain death. Whilst even today few people relish a trip to hospital, surgery is no longer such a life–threateningor unduly painful experience because of organohalogen compounds. Halogenation of methane
The substitution of a chlorine atom into a molecule of the organic family known as the alkanes results in a compound with anesthetic properties – trichloromethane (chloroform) was a clear example. Increasing the number of chlorine atoms in the compound increases the depth of anesthesia given, but unfortunately also increases the toxicity of the compound.
Carbon–fluorine bonds are very stable and so their presence in a compound leads to non–flammable, non–toxic and unreactive properties. Halothane, 2–bromo–2–chloro–1,1,1–trifluoroethane is an effective compound giving deep yet safe anesthesia.
Halothane, a deceptively simple molecule, has allowed to make surgeries safer for the patient. It has also enabled an enormous range of other surgical procedures, ranging from operations carried out through minute openings made in the body wall to massive transplant operations involving many hours in the theater.
An organohalogen has a hydrocarbon skeleton with a halogen functional group. The hydrocarbon skeleton may be aliphatic or aromatic, and the halogen may be fluorine, chlorine, bromine or iodine. The properties of an organohalogen compound are therefore affected by three things:
- the type of hydrocarbon skeleton
- the halogen or halogens attached
- the position of the halogen in the molecule.
There are three main types of organohalogen molecules – the halogenoalkanes, the halogenoarenes (aromatic halogens) and the acid halides. The names tell us the basic structure of the molecules in the different families.