1,3,5-trioxane

Chemical Properties

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.

Chemical Properties

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.

Uses

1,3,5-Trioxane is used in organic chemical processes such as aldol condensation of amides and syntheses of chloromethyl esters or other plastics.

Uses

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.

Definition

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.

General Description

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.

Air & Water Reactions

Highly flammable. Water soluble.

Reactivity Profile

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.

Health Hazard

ACUTE/CHRONIC HAZARDS: s-Trioxane is toxic and flammable. It can emit toxic fumes on contact with acid or acid fumes.

Fire Hazard

s-Trioxane is combustible.

Safety Profile

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.

Potential Exposure

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

Shipping

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

Purification Methods

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.]

Incompatibilities

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.

Waste Disposal

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.