The values of inhibition efficiencies (η %) and corrosion rates (Cr) obtained from weight loss measurements using Eqs. (1) and (2) for the synthesized inhibitors at different concentrations in 1 M HCl are listed in Table 2. It is obvious that corrosion rate (Cr) decreases with increasing the inhibitor concentration (Table 2), while inhibition efficiency increases with increasing inhibitor concentration. The inhibition of carbon steel corrosion reaction can be attributed to the adsorption of the inhibitors at the carbon steel/acid solution interface. The adsorption of the inhibitor molecules on the carbon steel surface decreases the interaction between the metal surface and the corrosive ions increases the inhibition efficiency. The alkyl chains presented at the inhibitors play an important role on their inhibition efficiencies for the dissolution reaction of carbon steel and also on the corrosion rate of this reaction. Increasing the alkyl chain length decreases the corrosion rate of the carbon steel and therefore the inhibition efficiency of the inhibitors increases. That can be attributed to the increase of the adsorption tendency of these inhibitors due to their amphipathic structure [29] and [30], i.e., the presence of hydrophobic part (alkyl chain) and the hydrophilic part. The amphipathic structure of the inhibitors is responsible for their adsorption at the different interfaces including metal/solution interface.