Just like the morphine rule: (1) a benzene ring (2) attached to a quaternary carbon connected by (3) a two‐carbon spacer to (4) a tertiary amine.  Any compound with these structure will have pharmaceutical activity.

Do the same with imidazoline! The other structure feature needed is the length of the carbon chain.

Dear Dr. Brahim Hachlaf,

there are literally thousands of corrosion inhibitors. Consequently, the process of selecting a corrosion inhibitor is often overwhelming, particularly when one is assigned to select a corrosion inhibitor for the first time. Please remember that the corrosion inhibitors listed in patents are protected by patent laws, and using patented inhibitors without the inventor’s permission could result in costly litigation.

Results from corrosion inhibitor research (that is not patented or proprietary) could be published in suitable journals.

Corrosion inhibitors are generally used in open or closed systems and this difference plays a pivot role in their choice.

In closed systems you have to mantain them at a defined concentration and their possible toxicity towards the environment and their cost have a less impact.

In the case of an open system, the addition of the inhibitor could be continuous or, sometimes, limited in the starting phase of the plant and the inhibitor toxicity often becomes an essential feature and environmental-friendly compounds are generally used. This last methodology is also used in plants, pipes, etc. in the start-up phase of a plant with possible fluid recovery, if it is necessary.

The aim is to create a more protective and uniform passivation layer on the substrate material able to guarantee a long life time of the component in aggressive environment.

Best regards, Pierluigi Traverso

A very detailed response by Dear Dr. Traverso. It answered some of the questions I had regarding the usage of appropriate corrosion inhibitors.

Dear Brahim Hachlaf

That's a general question, However take a look at the following features:

The following are the features of excellent Corrosion Inhibitor(Buchweishaija, 2009; Gece, 2011; Kumar & Bashir, 2015; Fayomi et al., 2018):