Structural Analysis of Polymerization Product of Naphthalene

Abstract

Naphthalene was polymerized by the use of anhydrous aluminum chloride-cupric chloride at a reaction temperature of 90 C without solvent.The polymerization prQductwas separated into five fractions(No, 1.to No. 5) by extraction with a series of binary solvents consisting of n-hexane and benzene.The Product yield of polymeriz.ation of naphthalepe was a.bout 40 9% on the, basis of raw naphthalene. Fraction No. 1 soluble in n-hexane was obtained in abbut 400/oyield based on the total product. The added yield of fraction No.1 through No.3 was about 90 /e of the product. It is suggested that the product had a relatively low average degree of polymerlzation.The average molecular structure of each fraction was estimated by the average moleculat weight, gel permeation chroMatography, elementary analysis, IR-, UV- and NMR-spectra.IR- and NMR-spectra showed that product contained some aliphatic struqtures in addition-, to. the aromatic structure, Moreover, the aliphatic structure was found to contain a cycloparaffinic structure.The results of structural analysis of each fraction are as follows. (1) With the descending order of fraction, the average molecular weight increased from 260 for No. 1 to 900 for No.5 and the aromaticity (A) of the fraction a1so showed an increase. (2) Since the numbers of the aromatic carbon (C.) increased gradually, the degree of polymerization of naphthalene was considered to increase with the descending order of fractions.In summary the polymerization product was fractionated to a considerable extent byil the. present fractionation methodwith binary solvents.