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) : Ross, David S ; Hum, Georgina P


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a075263.pdf


Report Date : 25 Sep 1979


Pagination or Media Count : 21


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)


Descriptors :   *NITRIC ACID , *NITROSO COMPOUNDS , *OXIDATION , SUBSTRATES , ETHERS , CARBORANYL RADICALS , BENZYL RADICALS , ALKYL RADICALS , ALCOHOLS , PROPANOLS , METHYL RADICALS , CATIONS , IONS , ELECTRON DONORS


Subject Categories : Inorganic Chemistry
      Organic Chemistry
      Nuclear Physics & Elementary Particle Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE