Epoxy compounds usually have stronger nucleophilic ability, because the alkyl group on the oxygen atom makes the bond angle smaller, which makes the lone pair of electrons react more dissimilarly with the electron-deficient system. Compound: 2-Mercapto-5-methylbenzimidazole, is researched, Molecular C8H8N2S, CAS is 27231-36-3, about Benzimidazole-2-thione and benzoxazole-2-thione derivatives as corrosion inhibitors for aluminum in hydrochloric acid.Quality Control of 2-Mercapto-5-methylbenzimidazole.
The effect of benzimidazole-2-thione and benzoxazole-2-thione derivatives on the corrosion of aluminum in 0.1 M HCl has been investigated by using a potentiostatic polarization technique. Inhibition efficiencies followed the order benzimidazole-2-thione > 5-Me benzimidazole-2-thione > 5-chloro benzimidazole-2-thione, while that of benzoxazole-2-thione derivatives followed the order 5-methylbenzoxazole-2-thione > benzoxazole-2-thione > 5-chlorobenzoxazole-2-thione > 5-nitrobenzoxazole-2-thione. The inhibitor action of these heterocyclic compounds was mainly due to adsorption on the metal surfaces, which show parallelism with the calculated total neg. charge of each of the mols. Thermodn. parameters, such as free energy of adsorption and equilibrium constant were determined Activation energy, activation enthalpy and activation entropy were determined from the corrosion currents measured at different temperatures
Different reactions of this compound(2-Mercapto-5-methylbenzimidazole)Quality Control of 2-Mercapto-5-methylbenzimidazole require different conditions, so the reaction conditions are very important.
Reference:
Benzoxazole – Wikipedia,
Benzoxazole | C7H5NO – PubChem