Anionic Surfactants as Corrosion Inhibitors in Co2 -Containing Environments

The results of studies on the synthesis of anionic substances based on a mixture of higher carboxylic acids isolated from linseed oil as well as individual linolenic acid (C18:3) are presented. Potassium, sodium and calcium salts were obtained based on synthesised sulphonic acids at a ratio of 1 : 2 : 1 at room temperature. The synthesised compounds are characterised by the necessary physicochemical, surface-active and anticorrosive functional properties. It is shown that the maximum surface activity is observed in the sodium salt of sulphated linolenic acid (the surface tension at the kerosene-water interface decreases from 42.4 to 4.1 mN/m). This fact indicates the surface activity of the compound the molecules of which are diphilic and include a large hydrocarbon fragment. The maximum efficiency of the compounds in protecting against carbon dioxide corrosion is 98.7 % at a concentration of sodium salt obtained from linolenic acid 100 ppm. As a result of the conducted studies, it was established that based on polyunsaturated fatty acids contained in linseed oil as well as individual linolenic acid, the synthesised surfactants are effective inhibitors of corrosion of low-carbon steels when protecting against carbon dioxide corrosion in mineralised environments at elevated temperatures.