The effect of sound-induced reaction rate changes on mass transfer between the reactor wall and the gas was studied in the frequency range 275-1325 Hz and pressures ?165.7 decibel under laminar-flow and steady-state conditions. The catalytic hydrogenation of C2H4 in a tubular reactor is used as a model reaction. Owing to the increased mass transfer, the effective reaction rate consts. increase ?46% with increasing pressure and decreasing frequency of s ound. An empirical equation is derived for the mass transfer as a function of frequency, pressure, and av. gas rate. [on SciFinder (R)]