Some studies of the chlorination of aromatic hydrocarbons

Abstract

The products of chlorination of naphthalene and phenanthrene in acetic acid have been examined. Analytical and chromatographic methods have been developed to determine and isolate the reaction products. The work on naphthalene was of a preliminary nature. It was shown that chlorine addition products and acetoxy-chloroadducts were formed in the reaction. The chlorination of phenanthrene was examined in greater detail. The effect of the presence of electrolytes on the product composition was investigated by volumetric analysis and isotope dilution. One of the reaction products was shown to be 9-acetoxy 10-chloro-9,10-dihydrophenanthrene. One of the geometrical isomers of this compound was isolated. It is considered to be the trans-isomer, from the products of its reaction with silver acetate in acetic acid. The significance of these observations is discussed in relation to the reaction paths involved in the chlorination, and to addition-elimination sequences leading to aromatic substitution.