Petroleum sulphonates: Production and evalution as corrosion inhibitors

Abstract

Sodium and calcium petroleum sulphonates have been prepared by sulphuric acid treatment of the Egyptian Morgan 350-450 "C petroleum fraction. Extraction and purification of the sulphonates from the sulphonated oil and the residual acid sludge is described. Corrosion studies revealed that the sodium petroleum sulphonates are more effective as corrosion inhibitors than the calcium salts in a neutral as well as in an acid medium. A maximum inhibition efficiency of about 75% was obtained by the sodium salt in an acid and a neutral medium, while the rclevant value obtained by the calcium salt is 60 and 23% in an acid and a neutral medium respectively. It has been also found that both salts accelerated corrosion when used at relatively high concentration in a neutral medium. Results are discussed according to the current views of corrosion inhibition.