Catalytic converters for emission control in motor vehicles are one of the most popular applications for metal catalysts. They convert the toxic emissions from combustion engines, mainly carbon monoxide, nitrogen oxides and unburned hydrocarbons, into harmless substances such as carbon dioxide, nitrogen and water.
While platinum, palladium and rhodium are effective catalysts, copper, iron, magnesium, calcium and strontium also play a part as activators in this field. With anions such as acetate or oxalate that readily break down, these metals are ideal for thermal deposition. Magnesium or lithium acetate or their citrates are suitable for use as vacancy forming agents in the production of ceramic catalysts.
Metal salts also find numerous uses as catalysts in the plastics industry. Hard foams such as polyisocyanurates are synthesized through the catalysis of polyurethanes using potassium acetate as a trimerization catalyst. Calcium, magnesium, zinc and manganese acetate are used as transesterification catalysts in the synthesis of various polyester fibres.
Yet another usage for catalysts in connection with transesterification is the synthesis of biodiesel from agriculturally produced oils and methanol.