Synthesis of 1,8-Naphthyridines by the Ionic Liquid-Catalyzed Friedlander Reaction and Application in Corrosion Inhibition

Abstract

A several of basic ionic liquids (ILs) were synthesized as green solvents and catalysts for the preparation of 1,8-naphthyridyl derivatives via the Friedlander reaction. [Bmmim]­[Im] exhibited remarkable catalytic activity to achieve the synthetic targets, and the reaction conditions were optimized. The model product 2,3-diphenyl-1,8-naphthyridine (1,8-Nap), with carboxyethylthiosuccinic acid (CETSA) to form an IL corrosion inhibitor ([1,8-Nap]­[CETSA]), and its corrosion inhibition performance for Q235 steel in 1 M HCl were researched by weight loss measurements, and the results showed that the inhibition efficiency was 96.95% when the concentration of [1,8-Nap]­[CETSA] was 1 mM at 35 °C. The electrochemical test verified that [1,8-Nap]­[CETSA] acted as a mixed-type inhibitor but mainly exhibited cathodic behavior. The inhibitor adsorbed on the metal surface was further proved by surface topography analysis.

Enhanced Corrosion Resistance of Carbon Steel in Hydrochloric Acid Solution by Polyoxometalate-Estertin Derivatives

“…6 For instance, ionic liquids (ILs) have shown their outstanding performance in corrosion inhibition of steels in the acidic environment owing to many attractive characteristics such as high stability, high solubility, and low environmental hazards, although they suffer from the high production cost sometimes. 7,8 Moreover, plant extract corrosion inhibitors have been widely studied as green corrosion inhibitors owing to their high inhibition efficiency, chemical stability, and environmental friendliness. However, their application is limited by the difficulty of separation.…”

“…However, HCl solution is highly corrosive to metallic equipment, so a suitable corrosion inhibitor needs to be added in a chemical acidic cleaning process of equipment. , In the early stage, some simple oxysalts were used for metal corrosion inhibition, but they are mostly used in neutral media rather than acidic solution. , For organic corrosion inhibitors, they have more obvious advantages in acidic media . For instance, ionic liquids (ILs) have shown their outstanding performance in corrosion inhibition of steels in the acidic environment owing to many attractive characteristics such as high stability, high solubility, and low environmental hazards, although they suffer from the high production cost sometimes. , Moreover, plant extract corrosion inhibitors have been widely studied as green corrosion inhibitors owing to their high inhibition efficiency, chemical stability, and environmental friendliness. However, their application is limited by the difficulty of separation. − In recent years, intelligent corrosion inhibitors with pH responsivity, self-assembly, and self-healing properties have attracted more and more attention of scientists. − Despite the above achievements, the development of new sustainable, environmentally friendly, and highly efficient corrosion inhibitors in acidic media is still an important topic in metal protection.…”

Synthesis and biological evaluation of 1,2,4-Triazolo[4,3-a][1,8] naphthyridines under Microwave condition

“…6 The advantages of microwave-assisted organic synthesis which include faster reactions, higher yields, more selectivity for better final products. [7][8][9] Although there are a number of techniques for conducting microwave-induced reactions in solution with solvent free conditions, the most effective way to achieve consistent heating is with a homogenous mixture. [10][11] The synthetic utility of Chloramine-T (CAT) is significant, since it is a highly flexible oxidizing agent.…”