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Revisado por pares
Copper(II) Catalysis in Cyanide Conversion into Ethyl Carbamate in Spirits and Relevant Reactions
2001; American Chemical Society; Volume: 49; Issue: 6 Linguagem: Inglês
10.1021/jf001346w
ISSN1520-5118
AutoresMichele Aresta, Maurício Boscolo, Douglas Wagner Franco,
Tópico(s)Isotope Analysis in Ecology
ResumoThe role of copper(II) species in the oxidation of inorganic cyanide to cyanate and in the conversion of cyanate or urea into ethyl carbamate was investigated. The oxidation process has been shown to be independent from the dissolved oxygen. Elemental analysis and infrared spectroscopy have shown the formation of a mixed copper carbonate/hydroxide in the process of oxidation of cyanide to cyanate in water/ethanol. The complexation to CuII of cyanate formed upon cyanide oxidation makes the former more susceptible to nucleophilic attack from ethanol, with conversion into ethyl carbamate. Comparatively, urea has a minor role with respect to cyanide in the formation of ethyl carbamate. Therefore, the urea present in some samples of Brazilian sugar cane spirit (cachaça) has been shown to have almost no influence on the ethyl carbamate content of cachaças, which comes essentially from cyanide. FeII,III affords results similar to those found with CuII. Some suggestions are presented to avoid ethyl carbamate formation in spirits during distillation. Keywords: Cyanate; cyanide; urea; ethyl carbamate; spirits; alcoholic beverages
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