This work synthesizes the results of three kinds of experiment performed in order to investigate the molecular and temperature aspects of short residence time catalytic partial oxidation (CPO) of natural gas (NG), and the reaction at low- and high-pressure conditions. Experiments performed in a reaction chamber equipped with IR and mass spectrometry have shown that CO and H-2 can be produced as primary reaction products with a selectivity close to 100% by alternating flowing streams of CH4 and O-2. IR thermography and thermocouple measurements have measured large temperature gradients between the surfaces and the gaseous phase illustrating non-local thermal equilibrium conditions. These and other information have been useful for the design, construction and test of a bench-scale reactor where the possibility to perform the CPO reactions at pressures till 20 atm has been demonstrated. (C) 2001 Elsevier Science B.V. All rights reserved.