Chemistry in your cupboard

Antiseptics and disinfectants

Before the mid-1800s, major surgery was often a death sentence. Amputations of damaged limbs were carried out as a last resort but patients frequently died from post-operative infections.

This changed in the 1860s when Joseph Lister developed antiseptic surgery using carbolic acid to sterilise wounds and instruments. Lister was aware of the germ theory of infections developed by Louis Pasteur and others, and knew that carbolic acid (which we now call phenol) was able to kill germs, Figure 1.

Figure 1: An operation in the 1870s. Doctors are using a carbolic acid spray as an antiseptic. Notice that they appear to be wearing their everyday clothes! (Wellcome Photo Library, Wellcome Images)

It is reputed that phenol’s germ-killing power first came to notice in a bizarre way. Sailors who underwent amputations at sea appeared to have a higher survival rate than patients in hospital. This seemed to be due to the practice at sea of dipping the stump into molten tar to seal the wound. Tar contains, among other things, phenol, Figure 2.

Figure 2: Structure of phenol

Nowadays, disinfectants are just as important for germ-killing in hospitals, homes and elsewhere. Many products are still based on phenol derivatives as the active ingredient. This site looks at Dettol, made by Reckitt Benckiser.