Paraformaldehyde is a white crystalline solid.
Irritating odor. The term “trioxane” applies specifically to
this trimer (CH2O)3 but paraformaldehyde is applied both
to trioxane and other low polymers or oligomers of formaldehyde.
Trioxane is a most unusual chemical. It is an excellent solvent for many classes of materials. Concentrated aqueous solutions of trioxane have solvent properties which are not possessed by trioxane itself. Molten trioxane dissolves numerous organic compounds, such as naphthalene, urea, camphor, dichlorobenzene, etc. It is stable in alkaline or neutral solutions, yet it is depolymerized to formaldehyde by small amounts of strong acid or acid-forming materials, and the rate of depolymerization can be readily controlled.
1,3,5-Trioxane is used in organic chemical processes such as aldol condensation of amides and syntheses of chloromethyl esters or other plastics.
1,3,5-Trioxane is widely used as a source of anhydrous formaldehyde.
It can be used to synthesize:
- Polyoxymethylene and hyperbranched polyesters.
- Calixarenes such as calix[4]resorcinarene, calix[6]resorcinarene and para-tert-butylcalix[8] and [9]arene.
- Various natural products including ()-motuporin, (+)-sundiversifolide, (+)-lyconadin A and ()-lyconadin B.
Trioxymethylene is commercially produced primarily through the acid-catalysed trimerisation of formaldehyde, typically using concentrated aqueous solutions at elevated temperatures and pressures, with sulphuric acid, hydrochloric acid, or emerging acidic ionic liquids as catalysts. The cyclic trimer precipitates or is distilled from the reaction mixture, followed by purification via recrystallisation or vacuum distillation to yield the active substance.
ChEBI: A saturated organic heteromonocyclic parent that is cyclohexane in which the carbon atoms at positions 1, 3 and 5 are replaced by oxygen atoms.
Transparent crystals or white crystalline solid with a pleasant odor resembling the odor of chloroform. Melts at 62°C; boils at 115°C without polymerization. The cyclic trimer of formaldehyde.
Highly flammable. Water soluble.
s-Trioxane is stable under normal laboratory conditions but is unstable in the presence of acids, which initiate polymerization. Sublimes readily. May react with oxidizing matter . A stable polymeric product of formaldehyde that in the presence of strong aqueous acids will depolymerize (reforming the parent formaldehyde). Inert to strong alkalis. Readily converted in non aqueous solutions to the monomeric formaldehyde by small concentrations of acid---the rate of conversion is directly proportional to the concentration of the acid.
ACUTE/CHRONIC HAZARDS: s-Trioxane is toxic and flammable. It can emit toxic fumes on contact with acid or acid fumes.
s-Trioxane is combustible.
Mutation data reported.
Can evolve toxic formaldehyde fumes when
heated strongly or in contact with strong
acids or acid fumes. Flammable liquid when
exposed to heat, flame, or oxidzers. May
explode when heated. Explosive in the form
of vapor when exposed to heat or flame.
Explodes on impact, possibly due to
peroxide contamination. Mixtures with
hydrogen peroxide are explosives sensitive
to heat, shock, or contact with lead.
Mixtures with liquid oxygen are highly
explosive. Incompatible with oxidizing
materials. To fight fire, use foam, CO2, or
dry chemical. When heated to
decomposition it emits acrid smoke and
irritating fumes. See also
FORMALDEHYDE.
Paraformaldehyde is used in polyacetal
resin manufacture; as a food additive; and as an
odorless fuel.
UN2213 Paraformaldehyde, Hazard Class: 4.1;
Labels: 4.1-Flammable solid.
Crystallise 1,3,4-trioxane from sodium-dried diethyl ether or water, and dry it over CaCl2. It can also be purified by zone refining. [Beilstein 19 H 381, 19 II 392, 19 III/IV 4710, 19/9 V 103.]
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.
