Dimeric 1,3,5-triazinane-based derivatives as corrosion inhibitors for Q235 carbon steel in 1.0 mol per L HCl

In this work, 5,5'-(propane-1,3-diyl)bis-(1,3,5-triazinane-2-thione) (PBT) was successfully prepared by a three-component condensation method using thiourea, formaldehyde and 1,3-diaminopropane. The inhibition properties of PBT in 1.0 mol per L HCl were investigated by gravimetric measurement, electrochemical analysis, surface analysis and quantum chemical methods. The results show that the inhibition efficiency of PBT is close to 90% at 298.15 K in the concentration range of 0.005-1.0 mmol L^-1, where the maximum inhibition efficiency of PBT is 92.1% at a concentration of 1.0 mmol L^-1. In addition, the adsorption of PBT on the carbon steel surface is consistent with the Langmuir isothermal model. Both experimental and theoretical calculations show that PBT exhibits excellent corrosion inhibition performance in strong acidic media.