Use of methylene azelaic acid as a corrosion inhibitor

摘要

The use of methylene azelaic acid having the formula CH2=C-[(CH2)3-COOH]2 or an alkali metal salt thereof in glycol and water based automotive antifreeze formulations is described. Unlike natural dicarboxylic acids such as sebacic acid, methylene azelaic acid does not form a precipitate and drop out of solution, rendering the antifreeze unprotected against corrosion. The methylene azelaic acid component should be present in an amount of from 1.5 to 4.5 wt. % based on the glycol component.