Paraformaldehyde(synonyms such as polyformaldehyde or polyoxymethylene) is a white solid formed by the combination of formaldehyde and water. It is similar in its chemical compound to formaldehyde and exhibits the typical characteristics of similar polymers with long-chain polyoxymethylene glycols, namely the ability to turn to liquid when exposed to heat and solidify upon cooling or being frozen to a hard, glass-like material. When it is heated with sodium hydroxide, or lye, in a water solution, it depolymerizes or “dissolves” as it reacts to the water molecules.
This compound is classified as an aldehyde, meaning that it contains a carbonyl group. In the case of this particular substance, the carbon atom is bonded to two hydrogen atoms. It is readily absorbed via the respiratory system, but is quickly metabolized to formate and excreted through the lungs or kidneys. Aldehydes typically give off a strong odor, as evidenced by the distinct aroma of many familiar botanicals, such as cinnamon and vanilla. Aldehyde-based solutions are also well-known as biological fixatives capable of inhibiting cellular degradation due to the breakdown of enzymes and bacterial replication. That’s why formaldehyde and its derivatives, including paraformaldehyde, are used to preserve tissue samples.
Paraformaldehyde can be synthesized from formaldehyde solutions. In its naturally occurring state, formaldehyde is a water-soluble gas that forms methylene hydrate when hydrated. Methylene hydrate can then be polymerized, which yields the compound as a white precipitate. However, the addition of methanol is necessary to stabilize the polymerization process.
Because of being a condensed form of formalin, or aqueous formaldehyde, it possesses the same characteristics. In fact, it can be substituted in place of aqueous formaldehyde to produce the resinous binding material needed to make particleboard and plywood when combined with melamine, phenol, or other reactive agents. In addition, there are some advantages to doing so. For one thing, it produces a greater yield of raw product. For another, its use reduces the need to remove water from the reactive agent before processing by up to 20 times.
Paraformaldehyde(CAS:30525-89-4) is usually found in a wide variety of consumer goods, including vitamins, personal care products, and household cleaning products. In addition, this compound useful as a fungicide and pesticide. It is also used in the manufacture of fertilizers, fluorescent lights, and certain chemicals used in photography and printing.
What shoule be noted is that there is evidence to indicate that the chemcial is hazardous to human health. Studies have shown that repeated exposure, even in small amounts, may produce nasal squamous cell carcinomas. It is also corrosive to skin and mucous membranes. Therefore, caution should be exercised when handling this substance.