We have measured the thermal explosion times of nitromethane at 1, 10, and 50 kbar and between 160 and 380 C. At constant pressure, the explosion time decreases as the temperature increases. At constant temperature, the explosion time decreases as the pressure is increased. For a constant explosion time of 10 seconds, at 1 kbar the required temperature is 369 C, at 10 kbar it is 327 C, and at 50 kbar it is 225 C. The increase in decomposition rate with increasing temperature is explainable by Arrhenium-type kinetics. The reasons for the increase in decomposition rate with increasing pressure remain to be determined. We have also measured the thermal explosion times of some isomeric dinitropropanes at a constant pressure of 10 kbar in the temperature range 130 to 310 C. For a constant thermal explosion time of 20 seconds, the dinitropropanes that do not have a hydrogen atom on the same carbon as the dinitro group require a higher temperature than those that have such a hydrogen. Specifically, the temperatures corresponding to a 20 second explosion time at 10 kbar pressure at 2-2-dinitropropane 269 C; 1-1-1-fluorodinitropropane 242 C; 1-1-dinitropropane 172 C; 1-2-dinitropropane 162 C. (Author).