Inhibition of Carbon Steel CO2 Corrosion in High Salinity Solutions

Corrosion inhibitors designed to prevent general carbon dioxide corrosion in carbon steel were investigated. The environment considered were two high salinity solutions, denominated as W1 and W2, which were kept at room temperature and had a pH of 4.8 and 5.6, respectively. The performance of 2-mercaptopyrimidine and 4,6-diamine-2-mercaptopyrimidine was assessed using electrochemical and weight loss tests. Mercaptopyrimidines were revealed to be mixed-type inhibitors that predominantly influenced the anodic process on the interface. The inhibition efficiency can be monitored by corrosion potential measurements. It was concluded that 2-mercaptopyrimidine presented better inhibition than 4,6-diamine-2-mercaptopyrimidine in the tested conditions.