Benzene can be readily converted to chlorobenzene by
nucleophilic aromatic substitution via a
benzyne intermediate. Chlorobenzene is treated with aqueous
sodium hydroxide at 350 °C and 300 bar or molten sodium hydroxide at 350 °C to convert it to
sodium phenoxide, which yields phenol upon acidification. When 1-[14C]-1-chlorobenzene was subjected to aqueous NaOH at 395 °C,
ipso the substitution product 1-[14C]-phenol was formed in 54% yield, while the
cine substitution product 2-[14C]-phenol was formed in 43% yield. This indicates that an elimination-addition (benzyne) mechanism is predominant, with perhaps a small amount of product from addition-elimination (SNAr). ==References==