30525-89-4

White solid

ChEBI: Paraformaldehyde is a macromolecule composed of repeating methyleneoxy units arising from polymerisation of formaldehyde.

For disinfecting sickrooms, clothing, linen, and sickroom utensils. Active ingredient of contraceptive creams. Also used as fumigant; in dentistry; in manufacture of synthetic resins and artificial horn or ivory.

Paraformaldehyde(30525-89-4) appears as a white solid with a light pungent odor. A linear polymer of formaldehyde of formula HO(CH2-O)xH where x averages about 30. Soluble in water when x is less than 12; higher polymers are not immediately soluble. Slow dissolution in water proceeds by means of hydrolysis to give fragments of lower x. Flammable, although may take some effort to ignite. Flash point 158 °F. Used in fungicides, bactericides, and in the manufacture of adhesives. A hazard to the environment. Immediate steps should be taken to limit spread to the environment.

Flammable. Forms aqueous solution of formaldehyde, often quite slowly.

Paraformaldehyde may react violently with strong oxidizing agents (hydrogen peroxide, performic acid, perchloric acid in the presence of aniline, potassium permanganate, nitromethane). May react with bases (sodium hydroxide, potassium hydroxide, ammonia), and with nitrogen dioxide (explosive reaction around 180°C). Reacts with hydrochloric acid to form highly toxic bis(chloromethyl) ether. Polymerization reaction with phenol may develop sudden destructive pressure [Bretherick, 5th ed., 1995, p.168]. May generate flammable and/or toxic gases in combination with azo, diazo compounds, dithiocarbamates, nitrides, and strong reducing agents. Generates toxic formaldehyde gas when heated. Can react with air to give first peroxo acids, and ultimately formic acid. These reactions are activated by light, catalyzed by salts of transition metals, and are autocatalytic (catalyzed by the products of the reaction). Incompatible with liquid oxygen.

Vapor or dust irritates eyes, mucous membranes, and skin; may cause dermatitis. Ingestion of solid or of a solution in water irritates mouth, throat, and stomach and may cause death.

Behavior in Fire: Changes to formaldehyde gas, which is highly flammable.

Paraformaldehyde is used in polyacetal resin manufacture; as a food additive; and as an odorless fuel.

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 30 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. Medical observation is recommended for 24－48 hours after breathing overexposure, as pulmonary edema may be

UN2213 Paraformaldehyde, Hazard Class: 4.1; Labels: 4.1-Flammable solid.

Paraformaldehyde dust forms an explosive mixture with air. Decomposes on contact with oxidizers, strong acids; acid fumes; and bases; with elevated temperatures, forming formaldehyde. May explode when heated. May explode on impact if peroxide contamination develops. Mixtures with hydrogen peroxide or liquid oxygen are explosives sensitive to heat, shock, or contact with lead.

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.

Paraformaldehyde is the smallest solid form of liquid formaldehyde, formed by the polymerization of formaldehyde with a typical degree of polymerization of 8-100 units. As paraformaldehyde is basically a condensed form of formaldehyde, it possesses the common characteristics with a wide range of applications.
Paraformaldehyde does not need to be dissolved in water in order to take part in a chemical reaction.
Use of paraformaldehyde is convenient and safe. It avoids pollution arising from the disposal of the distillate obtained in the thermosetting resin production which is contaminated with organic matter.
Paraformaldehyde made with very low acid content in a chemical resistant environment can prevent the formation of acidic by-products.

Paraformaldehyde is used as a agricultural chemical, fungicide, bactericide, and wood preservative. Paraformaldehyde is the polymerized form of formaldehyde, used in root canal sealers that provide antimicrobial activity. 4% Paraformaldehyde tissue fixation solution is widely used in the detection of tissue, tissue slice, cell and other biological sample fixation solutions such as immunohistochemistry (IHC), immunofluorescence (IF), immunocytochemistry (IC), flow cytometry (FACS).

Paraformaldehyde [30525-89-4] was first produced in 1859. This polymer, at first mistakenly called dioxymethylene and trioxymethylene, consists of a mixture of poly(oxymethylene) glycols HO-(CH2O)n-H with n=8-100. The formaldehyde content varies between 90 and 99 % depending on the degree of polymerization n (the remainder is bound or free water). It is an industrially important linear polyoxymethylene.
Paraformaldehyde is prepared industrially in continuously operated plants by concentrating aqueous formaldehyde solutions under vacuum conditions. At first, colloidal, waxy gels are obtained, which later become brittle. The use of a fractionating column through which gases were passed dates from about 1925.
Paraformaldehyde is currently produced in several steps which are carried out at low pressure and various temperatures. Highly reactive formaldehyde is produced under vacuum conditions starting with solutions that contain 50-100 ppm of formic acid and also 1-15 ppm of metal formates where the metals have an atomic number of 23-30 (e.g., Mn, Co, and Cu). The solutions are processed in thin-layer evaporators and spray dryers.