Sodium Benzoate

About This Product

Sodium benzoate, C7H5NaO2 with CAS number 532-32-1, is supplied as a white granular powder, freely soluble in water and giving a mildly alkaline solution. Its industrial role is corrosion inhibition. Benzoate anions adsorb onto a steel surface and support the formation of a passive oxide film, stopping the anodic dissolution that drives rusting. Because it works at low concentration, is water-soluble, and is far less toxic than the chromates and nitrites it replaced, it became a standard inhibitor in engine coolants, hydraulic fluids, cutting fluids and boiler condensate systems. It is also used in vapour phase inhibitor papers and films for packaging steel components in transit, where it volatilises slowly and deposits on the metal. One formulation constraint is well documented: benzoate inhibits ferrous metals well but is far less effective on aluminium and can accelerate attack on soldered joints, so mixed-metal systems require a blended inhibitor package rather than benzoate alone. It is used in engine coolants and antifreeze, hydraulic and cutting fluids, vapour phase corrosion inhibitors, boiler condensate treatment and in industrial preservation. Bio Green Chem supplies sodium benzoate to specification on assay, loss on drying, acidity, chlorinated compounds, iron and heavy metals.