Abstract: Acetaldehyde is obtained from an ethyl alcohol "fuel" anodically treated in a fuel cell, and the acetaldehyde (along with any evaporated, unreacted ethanol "fuel") is ultimately recovered in anhydrous or substantially anhydrous form. Further chemical and electrochemical transformation of acetaldehyde in the presence of the fuel cell anode is stopped or minimized to avoid the formation of condensates or polymers or more highly oxidized products (e.g., acetic acid or aldol condensates) which may act as catalyst poisons. For example, ethyl alcohol can be vaporized and fed to the gas side of a gas-permeable fluid-impermeable electrode, in which case up to 60 mole-% or more of the acetaldehyde product stays with the vapor stream and avoids further chemical reactions or side reactions, substantially the balance going into solution in the electrolyte, from which it can be recovered, e.g., by low temperature distillation.