2-phosphonobutane-1,2,4-tricarboxylic acid is(pbtc) a member of phosphonate family, and used as corrosion and scale inhibitor in cooling water systems. phosphonocarboxylates as a member of organophosphorus compounds have c-p and p-o bonds in their structures. pbtc is mainly used as carbonate scale inhibitor (caco3), sulphate scale inhibitor (caso4), corrosion inhibitor of low alloyed steel, eff...