Amino and imino propionic acids, process of preparation and use

N-alkyl, N-alkenyl, N-cycloalkyl, N-aryl amino or imino propionic acids with an alkyl chain ranging from 6 to 18 carbons, or alkenyl chain from 8 to 30 carbons, are obtained from a reaction process in the absence of solvent at a temperature range from 30 to 180° C. and a time of 1 to 10 hours at atmospheric pressure. Formulations composed of N-alkyl or N-alkenyl or N-cycloalkyl or N-aryl amino or imino propionic acids, polyethers derived from propylene oxide or ethylene oxide or copolymer thereof and a solvent consisting of aromatic compounds such as toluene or xylene, diesel or gasoline or alcohols such as isopropanol and ethanol, or mixtures thereof, are obtained inhibit ferrous metal corrosion of pipelines and storage tanks and transport crude oil and liquid fuels. A method inhibiting corrosion of ferrous metals adds an effective amount of the corrosion inhibitor to a petroleum based material such as crude oil and liquid fuels such as gasoline, diesel fuel, and aviation fuel.