Early Production Methods
Phenol was first manufactured commercially by
distillation from coal tar, but the energy required and quantities
produced meant this method could not be sustained. Synthesis by
the sulphonation of benzene was implemented by BASF in 1899 and
continued until the 1960s. One of its main disadvantages is the
poor atom economy
of the reaction, a factor that has become increasingly important
as the chemical industry seeks to develop more sustainable processes.
For more details of the atom economy of this process, click here.
The sulphonation route produced large
quantities of waste, and used aggressive reagents, and so several
other methods, mostly using benzene as the starting point, were
developed, though these also used reagents like chlorine, sodium
hydroxide and hydrogen gas and so are not in use.