| 摘要 |
A process for the selective preparation of alpha - or beta -naphthol, respectively, by acid (Lewis or Bronsted, or superacidic mixtures thereof) catalyzed hydroxylation of naphthalene with hydrogen peroxide. Conventional (non-superacidic) acid systems, such as hydrogen fluoride, pyridine-hydrogen fluoride complexes (i.e., pyridinium polyhydrogen fluoride), anhydrous aluminum chloride, and the like give alpha -naphthol regioselectivity in isomeric purity of 92 to 98+%. The use of superacidic systems, such as fluorosulfuric acid, fluorosulfuric acid-antimony pentafluoride, hydrogen fluoride-boron trifluoride, hydrogen fluoride-antimony pentafluoride, hydrogen fluoride, tantalum pentafluoride, and the like, result, on the other hand, in the formation of beta -naphthol in 92-98% isomeric purity.
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