Laser-induced fluorescence and mass spectrometric studies of the Cu. Formation of HCuCl+HCl reaction over a wide temperature range

The kinetics and products of the Cu + HCl reaction have been studied using high-temperature fast-flow reactors (HTFFR). The rate coefficient measurements were made using laser-induced fluorescence (LIF) of Cu atoms and yielded k(680-1500 K) = 1.2 x 10(-10) exp(-7719 K/T) cm(3) molecule(-1) s(-1). Product analysis was achieved by coupling a specially designed HTFFR to a chopped molecular beam quadrupole mass spectrometer. Those observations, which covered the approximately 1150-1500 K temperature range, showed formation of CuCl and the previously unknown species HCuCl. Confirmation of the latter assignment was made using DCl. Increasing pressure and decreasing temperature favor the HCuCl formation. These findings and this molecular structure are supported by ab initio calculations. These also indicate passage through a CuClH --> HCuCl transition state as the rate-controlling step for formation of both products, in agreement with the observed pressure independence of the overall, Cu disappearance, rate coefficients.