Henry's law constant and hydrolysis of peroxyacetyl nitrate (PAN)

Abstract

The effect of temperature on the solubility of PAN and on its hydrolysis rate in near-neutral and slightly acidic water were studied in a bubble column apparatus. The results obtained are a Henry's law coefficient H=10-9.04±0.6 exp[(6513±376)/T] M atm-1, and a first-order hydrolysis rate constant k=106.60±1.0 exp[(-6612±662)/T] s-1, which was independent of pH in the range 3.2≤pH≤6.7. The products formed are nitrite and nitrate in approximately equal proportions under near-neutral conditions. At a pH<4, nitrite is oxidized in a secondary reaction, and nitrate becomes the only product at low pH. Previously measured deposition velocities of PAN on stagnant water surfaces are shown to be hydrolysis rate limited. © 1991 Kluwer Academic Publishers.