Benzoic acid from methyl naphthalene

Zone refining purified naphthalene from anthracene, 2,4-dinitrophenylhydrazine, methyl violet, benzoic acid, methyl red, chrysene, pentacene and indoline. 

Protonation becomes a rapid reaction in protic solvents and in the presence of acids, as demonstrated for, e.g., -butyl acrylate in aqueous solution [207], methyl acrylate in EtOH [208], cinnamates in the presence of phenol in DMF [209], and benzaldehyde in ethanolic buffer solution [210]. Rate constants for protonation of aromatic radical anions (anthracene [211], naphthalene, 2-methoxynaphthalene, 2,3-dimethoxynaphthalene) by a number of proton donors including phenols, acetic acid, and benzoic acids in aprotic DMF were found to vary from 5.0 X 10 M- s-> (for anthracene, in the presence of p-chlorophenol) to 6.2 x lO s (for anthracene, in the presence of pentachlorophenol) [212]. For dimedone, PhOH, or PhC02H the rate of protonation depends on the hydrogen-bond basicity of the solvent and increases in the order DMSO < DMF MeCN [213],... 

The alkyl naphthalenes, such as methyl naphthalene, may be oxidized to phthalic anhydride in the same manner as naphthalene, thus making it possible to use cruder grades of naphthalene. Thus, crude naphthalene obtained by centrifuging the oils from the proper cut from the distillation of coal-tar (whizzed naphthalene) consisting principally of naphthalene to the extent of 50 to 80 per cent and usually containing considerable quantities of alkyl naphthalenes and other ring compounds may be treated in a manner similar to that used in the oxidation of pure naphthalene. The reaction products contain phthalic anhydride, benzoic acid, naphthoic acids and anhydrides, etc.81... 

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