Formaldehyde

Polyacetal resins are widely used in the production of plastics. Formaldehyde is also used extensively as an intermediate in the manufacture of industrial chemicals, such as 1,4-butanediol, 4,4'-methylenediphenyl diisocyanate, penta-erythritol, and hexamethylenetetramine. Formaldehyde is used directly in aqueous solution (known as formalin) as a disinfectant and preservative in many applications.

Formaldehyde is used predominantly as a chemical intermediate. It also has minor uses in agriculture, as an analytical reagent, in concrete and plaster additives, cosmetics, disinfectants, fumigants, photography, and wood preservation. One of the most common uses of formaldehyde in the U.S is manufacturing urea-formaldehyde resins, used in particleboard products.

The silver catalyst process is conducted in one of two ways: (i) partial oxidation and dehydrogenation with air in the presence of silver crystals, steam and excess methanol at 680-720 °C and at atmospheric pressure (also called the BASF process, methanol conversion, 97-98%), and (ii) partial oxidation and dehydrogenation with air in the presence of crystalline silver or silver gauze, steam and excess methanol at 600-650 °C (primary conversion of methanol, 77-87%), the conversion is completed by distilling the product and recycling the unreacted methanol. Carbon monoxide, carbon dioxide, methyl formate and formic acid are by-products. In the metal oxide (Formox) process, methanol is oxidized with excess air in the presence of a modified iron-molybdenum-vanadium oxide catalyst at 250-400 °C and atmospheric pressure (methanol conversion, 98-99%). By-products are carbon monoxide, dimethyl ether and small amounts of carbon dioxide and formic acid.