PURPOSE: To directly and efficiently obtain an oxygen-containing compound, such as alcohols, aldehydes or ketones, useful as chemical industrial products, by reacting ethane with steam while irradiating the reaction system with light and carrying oxidation under mild condition without using a catalyst.

CONSTITUTION: Ethane is reacted with steam in the presence or absence of water or an aqueous solution in the vapor phase at ordinary temperature W 100°C, normally under about ordinary pressure for some ten min W some ten hr while being irradiated with rays of light, such as mercury lamp, at 185W400nm, preferably 185W254nm wavelength thereof and oxidized to afford the aimed oxygen-containing compound, such as alcohols, such as methanol or ethanol, aldehydes, such as formaldehyde or acetaldehyde, ketones, such as acetone or methyl ethyl ketone, or carboxylic acids, such as formic acid or acetic acid.