Studies of the chlorination of naphthalene and related compounds

Abstract

This thesis describes the studies of chlorination of naphthalene in different solvents, namely acetic acid, chloroform and carbon tetrachloride. More than 50[percent] of the reacted naphthalene is converted into the substitution product, 1-chloronaphthalene, when the chlorination is made in acetic acid. Two naphthalene tetrachlorides, [alpha] and [delta], as well as an acetoxytrichloride are also produced. The variation in the proportion of these products when added electrolytes are present in the solution, as well as their properties and structures, have been studied. A third naphthalene tetrachloride, the previously known y-isomer, was isolated from a chlorination of naphthalene in liquid chlorine. The chlorination of naphthalene in carbon tetrachloride under catalysis by sunlight and benzoyl peroxide yields mainly the y-tetrachloride and a new isomer, not previously reported, that we designate E-naphthalene tetrachloride. The chlorination of naphthalene in chloroform yields all the products characterized from the reactions in acetic acid and in carbon tetrachloride. The chlorinations in acetic acid and in chloroform have also been studied kinotically. In the former solvent, the kinetic follows the usual second-order reaction. The kinetics in chloroform were complicated by the fact that the hydrogen chloride produced in the substitution catalyzed the chlorination. Traces of iodine had also a very important catalytic effect which was determined kinetically. The p.m.r. spectra of the compounds formed in the chlorination of naphthalene, kindly recorded and examined by Dr. M. D. Johnson, have led to knowledge of their stereochemistry and structure.To provide better characterisation of the naphthalene tetrachlorides, their infrared spectra have been recorded and their dipole moments determined. Finally, the mechanisms of chlorination are discussed in order to interpret the formation of the different products, not only forheterolytic reaction in acetic acid but for the homolytic chlorination of naphthalene.