Coupling of the exothermic catalytic oxidative conversion and endothermic thermal cracking (noncatalytic) reactions of propane to propylene and ethylene over the SrO/La2O3/SA5205 catalyst in the presence of steam and limited oxygen was investigated at different process conditions (temperature, 700-850 degrees C; C3H8/O-2 ratio in feed, 2.0-8.0; H2O/C3H8 ratio, 0.5-2.5; space velocity, 2000-15000 cm(3) g(-1) h(-1)). In the presence of steam and limited O-2, the endothermic thermal cracking and exothermic oxidative conversion reactions occur simultaneously and there is no coke formation on the catalyst. Because of the direct coupling of exothermic and endothermic reactions, this process occurs in a most energy efficient and safe manner. The propane conversion, selectivity for propylene, and net heat of reaction (Delta H-r) in the process are strongly influenced by the temperature and concentration of O-2 relative to the propane in the feed. The C3H6/C2H4 product ratio is also strongly influenced by the temperature, C3H8/O-2 feed ratio, and space velocity. The net heat of reaction can be controlled by manipulating the reaction temperature and C3H8/O-2 ratio in the feed; the process exothermicity is reduced drastically with increasing the temperature and/or C3H8/O-2 feed ratio.