Production of 15N-enriched nitric acid (H15NO3)

techniques that employ 15n have proved to be an important tool in many areas of the agronomic and biomedical sciences. nevertheless, their use is limited by methodological difficulties and by the price of compounds in the international market. nitric compounds (15no3-) have attracted the interest of researchers. however, these compounds are not currently produced in brazil. thus, in the present work h15no3 was obtained from the oxidation of anhydrous 15nh3. the method we used differs from the industrial process in that the absorption tower is replaced with a polytetrafluoroethylene-lined, stainless-steel hydration reactor. the process output was evaluated based on the following parameters: reaction temperature; ratio of reagents; pressure and flow of 15nh3(g) through the catalyst (pt/rh). the results showed that, at the best conditions (500 oc; 50 % excess o2; 0.4 mpa; and 3.39 g.min-1 of 15nh3), a conversion percentage (n-15nh3 to n-15no3-) of 62.2 %, an overall nitrogen balance (n-15nh3 + n-15no3-) of 86.8 %, and purity higher than 99 % could be obtained.