Corrosion inhibitors are widely used to guarantee asset integrity from oil exploration and production stages (e.g. drilling equipment and metal piping in producing wells) to refinery, as well as during transportation of produced fluids and finished by-products. The major forms of corrosion found among the oil and gas industry include chemical, electrochemical, mechanical, and microbiologically induced. Corrosion inhibition by organic compounds is applied mostly in electrochemical corrosion due to acidic gases (H2S and CO2), from which CO2 corrosion is considered one of the major threats in oil and gas producing assets. According to the literature, amide and amine/diamine are the main classes of corrosion inhibitors used to combat sweet corrosion (CO2) in oilfields. However, the constant need to overcome new challenges makes it possible to create novel chemicals or to identify well-known molecules that can be improved in order to meet both the market demands and technical requirements, for example: guaranteed inhibitory capacity under several conditions, low emulsion and foaming tendency. In the present work, evaluations of different alkoxylation degrees and types of diamines were carried out in order to analyze the influence on the corrosion behavior of a carbon steel surface (SAE 1020 and API 5L X65), as well as emulsion and foaming tendencies. For these studies, the corrosion measurements were either performed by linear polarization resistance (LPR) or by weight loss measurements. The data revealed that their corrosion protection of carbon steel depended critically on the alkoxylation type and degree. Therefore, a suitable choice of molecule can create a tailor-made product to achieve specific requirements. The chemicals developed have shown good corrosion inhibiton performance and have satisfied defined pratical requirements to avoid emulsion and foaming tendencies.

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