โ Scribed by U. Mazzucato; G. Beggiato; G. Favaro
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Aryl and alkyl thiocyanates are known to isomerize to isothiocyanates through an ionization path '. For the benzyl derivative the reaction does not take place in mild conditions (unless electrophilic catalysts lb or an ionic thiocyanate are present: in this last case a direct nucleophilic displacement by the nitrogen and of SCN-ion is operative *); on the other hand under drastic temperature conditions the isomerization is accompanied by extensive decomposition.
It was interesting to examine the possibility of obtaining the isomerizatlon by a photochemical way.
Benzyl thlocyenate wae then irradiated with a low pressure mercury arc, using the 2537 1 line, In n-hexane solutions -10-r N at room temperature; the changes In the system were followed with an Optica CF4 grating spectrophotometer.
By irradiation In the presence of oxygen the initial spectrum of thiocyanate (A_ = 260 me, Emax = 470) evolves regularly towards a spectrum showing a prrncipal intense absorption peak
๐ SIMILAR VOLUMES
THIOCYANIC acid esters have long been known to undergo thermal isomerization to give the corresponding isothiocyanic acid esters. Although the isomerization reaction is believed to be quite general and is frequently used as a synthetic route to isothiocyanates, little is known about its nature and m