Synthesis and Characterization of Benzilate Esters as Aqueous Corrosion Inhibitors for Mild Steel and 2024, 6061, and 7075 Aluminum Alloys

In this investigation, synthesis and characterization of environmentally friendly metallo-organic corrosion inhibitors for protection of mild steel and certain aluminum alloys are being sought to replace hexavalent chromium based corrosion inhibitors. For this reason, several corrosion inhibiting species such as benzilic acid and metal oxyanions were combined in a single compound with the general formula, (M)x(benzilicacid)y(M?aOb)z. First group of such compounds were synthesized in a similar study of the first author reported in another study with the title of “Synthesis and Characterization of Salts and Esters of Hydroxy Acids as Corrosion Inhibitors for Mild Steel and Aluminum Alloys” and this work aims to build on the success of those compounds since theoretically, there is no reason why benzilates cannot be good replacements for a-hydroxy acids such as gluconates. Additionally, benzilates are less soluble in general than hydroxyl acids, which could result in a corrosion inhibiting compound with an optimum window of solubility. Practical results have mostly proven the hypothesized advantages of benzilates correct and yielded that certain salts and esters of benzilates can be suitable corrosion inhibitors for certain metals and their alloys.