Accession Number:

ADA075263

Title:

Nitrous Acid as an Oxidant in Acidic Media

Descriptive Note:

Final rept. 15 Jul 1976-31 May 1979

Corporate Author:

SRI INTERNATIONAL MENLO PARK CA

Personal Author(s):

Report Date:

1979-09-25

Pagination or Media Count:

21.0

Abstract:

It has been found that benzyl and aliphatic alcohols are rapidly oxidized by nitrous acid to the corresponding carbonyl compound at 25 degrees C in 50-70 sulfuric acid. The oxidations are very rapid, complete within minutes for most substrates the process appears to be quantitative, at least in runs with alcohol concentrations in the 10 to the -14 M range. For the benzyl alcohols, an electron withdrawing para-substituent, such as nitro, retards the rate, while an electron donating group, such as methyl, increases the rate. Thus, some cationic character must be present in the process. The rate increases with increasing acidity, peaking at 60 sulfuric acid, and declining thereafter. Surprisingly, ethers are oxidized as well, with the most unlikely case, the methyl ether of 2-phenyl-2-propanol, cleanly and rapidly yielding acetophenone. For primary and secondary alcohols and their ethers, the proposed mechanism for oxidation includes initial electrophilic attack by NO on oxygen, followed by elimination of HNO. In these cases, the nitrous acid is regenerated, probably through HNO oxidation by dissolved oxygen. Thus, an equivalent of nitrous acid oxidizes more than one equivalent of alcohol. For the tertiary alcohol case, we suggest elimination of alkyl nitrite however, the mechanistic details remain to be fully established. Author

Subject Categories:

  • Inorganic Chemistry
  • Organic Chemistry
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE