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Inter‐ und intramolekulare Umlagerung der Sulfogruppe in 2‐Naphtol‐1‐sulfonsäure
Author(s) -
Fisher P. B.,
Zollinger H.
Publication year - 1970
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19700530607
Subject(s) - chemistry , sulfuric acid , intramolecular force , sulfonic acid , acetic acid , medicinal chemistry , aqueous solution , salt (chemistry) , isomerization , inorganic chemistry , polymer chemistry , organic chemistry , catalysis
The isomerisation of 2‐naphthol‐1‐sulfonic acid (potassium salt) into 2‐naphthol‐6‐sulfonic acid has been studied using labelled sulfuric acid (H 2 35 SO 4 ). In 40 to 50% aqueous sulfric acid the reaction takes place exclusively by an intermolecular mechanism (protio‐desulfonation and resulfonation). In glacial acetic acid, in the presence of an excess of sulfuric acid, the rearrangement is partly intramolecular. With an equimolar amount of sulfuric acid the rearrangement is completely intramolecular. This reaction is first order with respect to 2‐naphthol‐1‐sulfonic acid and zeroth order with respect to excess of sulfuric acid. A mechanism for the reaction is proposed.