Science

Formaldehyde is a naturally occurring colourless substance composed of hydrogen, carbon and oxygen. It is a colourless gas at room temperature but can quickly convert into other forms. Commercial formaldehyde is sold in liquid form as formalin.

Naturally occurring formaldehyde is found all around us; it is present in low levels within our body, it is in a wide variety of fruits, vegetables, meats and beverages, as well as trees.

However, formaldehyde does not accumulate in the environment or within our bodies. In the atmosphere it is quickly broken down by photo-oxidation (sunlight), and within our bodies it is broken down through metabolic processes.

How is it made?

There are two ways in which to produce formaldehyde, the metal oxide process and the silver process, both require different types of catalysts.

One of the most frequently used processes is the metal oxide process from Formox which is explained in the flow-diagram below.

Process description

A catalyst is used to create a reaction between methanol and oxygen at high temperature to create formaldehyde and water. The reaction between methanol and oxygen generates heat which is used to produce steam.

CH₃OH + ½ O₂ → H₂CO + H₂O +heat.

The gas mix (air, formaldehyde and steam) is then cooled down and sent to an absorber where the formaldehyde is absorbed by water.

Depending on the end use, the aqueous formaldehyde is either transported via trucks to other manufacturing sites or mixed with other substances onsite for use in one of its many of different applications.