2-Oxetanone

Toxicity

Based on experimental trials, it has been determined that propiolactone is a human carcinogen. The results have shown the generation of tumors in several tissues and from different administration routes.

Description

Beta-propiolactone is a colorless liquid with a strong, slightly sweet odor. It may occur naturally, but no clear documentation of its occurrence in nature was found, and it must be synthesized for commercial purposes. Beta-propiolactone is unstable at room temperature but stable when stored at 5
C in glass containers.
Its tendency to be unstable and react with other molecules in the vicinity is responsible for both its toxicity and its usefulness. Significant commercial production of beta-propiolactone took place during the late 1950s through the mid-1970s, when it was widely used in chemical synthesis in reactions with other molecules to produce new chemicals. All lactones are characterized by a ring structure consisting of two or more carbon atoms – as can be seen from its structure, beta-propiolactone has three in its ring – and a single oxygen, coupled with an adjacent ketone. The fewer the carbons in the ring, the more ‘strained’ is the ring structure and the more unstable and reactive its characteristics. When the ring bonds break, the betapropiolactone molecules attach to other nearby molecules.

Chemical properties

β-Propiolactone is a colorless liquid which slowly hydrolyzes to hydracrylic acid and must be cooled to remain stable. It reacts with alcohols, acid chlorides, ammonia, and water to yield β-substituted propionic acid derivatives. The most important characteristic of the substance is its ability to polymerize. This highly exothermic process occurs simply by warming, although it is also catalyzed by both acid and base.

Physical properties

β-Propiolactone is a colorless, highly reactive liquid,thatis solublein water, alcohol, acetone, and chloroform (solubilityinwaterat 25℃, 37 vol %).

The Uses of 2-Oxetanone

Reacts with bacteriphage DNA causing inactivation, repair and recombination

The Uses of 2-Oxetanone

As late as 1974, b-propiolactone was used in the United States in the preparation of acrylic acid and acrylate esters. Today, its principal significance is as a reactive intermediate in organic syntheses; a small amount is treated with ammonia to provide balanine. b-Propiolactone was also used as a disinfectant. It appeared to be an attractive replacement for formaldehyde due to its 25-fold greater disinfecting power, but it has since been abandoned because of its carcinogenic properties.

The Uses of 2-Oxetanone

Versatile intermediate in organic synthesis.

Indications

Propiolactone was used for vaccines, tissue grafts, surgical instruments, and enzymes, as a sterilant of blood plasma, water, milk and nutrient broth as a vapor-phase disinfectant in enclosed spaces. Its sporicidal action is used against vegetative bacteria, pathologic fungi, and viruses. It is no longer used in medical procedures or in food.

Background

Propiolactone is a lactone compound with a four-membered ring. It is a colorless liquid with a pungent slightly sweet odor. Propiolactone is a disinfectant used for the sterilization of blood plasma, vaccines, tissue grafts, surgical instruments, and enzymes. It has been used against bacteria, fungi, and virus. It is currently FDA approved for its use as an indirect additive used in food contact substances. Propiolactone was first commercially available in the United States in 1958.

Definition

ChEBI: Beta-propiolactone is a propan-3-olide. It is functionally related to a 3-hydroxypropionic acid. It derives from a hydride of an oxetane.

Preparation

β-Propiolactone is synthesized by passing equimolar amounts of ketene and formaldehyde into either acetone or b-propiolactone itself. The reaction is carried out at low temperature (<20℃) with a yield of ca. 90 %. Both aluminum chloride and zinc chloride have been employed as catalysts, and the use of methyl borate has also been suggested.

brand name

Betaprone (Forest).

General Description

A colorless liquid with a slightly sweetish, pungent odor. Used as an intermediate in organic synthesis; disinfectant, sterilant for blood plasma, tissue grafts, vaccines, enzymes and surgical instruments.

Air & Water Reactions

Slow reaction with water to form beta- hydroxypropionic acid.

Reactivity Profile

2-Oxetanone is an ester. Esters react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides. 2-Oxetanone may be incompatible with alkalis.

Hazard

Strong skin and upper respiratory tract irri- tant, skin cancer. Possible carcinogen. Worker expo- sure should be minimized.

Health Hazard

The toxicity potential of 2-Oxetanone via inhalation or ingestion is high; may cause death or permanent injury after very short exposures to small quantities. It is a carcinogen.

Fire Hazard

Containers may explode. When heated to decomposition, 2-Oxetanone emits acrid smoke and fumes. Stable when stored at 41F. Avoid storing in areas of exposure to the direct rays of the sun and in areas of high fire hazard. Tends to polymerize on storage. Avoid elevated temperatures.

Pharmacokinetics

When employed under conditions of maximum effectiveness, propiolactone is approximately 25 more active as a vapor phase disinfectant than formaldehyde, 4000 times more active than ethylene oxide and 50000 times more active than methyl bromide. It has been shown to be mutagenic by inducing cell transformation, chromosomal aberrations and chromatoid exchange. Propiolactone has been shown to be mutagenic in both somatic and germ cells.

Safety Profile

Confirmed carcinogen with experimental carcinogenic, neoplastigenic, and tumorigenic data. Poison by inhalation. Moderately toxic by intraperitoneal route. An initiator. Human mutation data reported. When heated to decomposition it emits acrid smoke and irritating fumes.

Potential Exposure

β-Propiolactone is used as a chemical intermediate in synthesis of acrylic acid and esters, acrylate plastics; as a vapor sterilizing agent; phase disinfectant; and a viricidal agent.

Carcinogenicity

β-Propiolactone is reasonably anticipated to be a human carcinogenbased on sufficient evidence of carcinogenicity from studies in experimental animals.

Environmental Fate

Chemical/Physical. Slowly hydrolyzes to hydracrylic acid (Windholz et al., 1983). In a reactor heated to 250 °C and a pressure of 12 mmHg, β-propiolactone decomposed to give equal amounts of ethylene and carbon dioxide (James and Wellington, 1969).

Metabolism

Propiolactone is completely hydrolyzed after 3 hours of being in an aqueous solution and this time can be even faster in the presence of cellular debris and cell culture media. When in water, the lactone ring opens at the alkyl and acyl bonds. The degradation products of propiolactone are not toxic.

Shipping

UN3382 Toxic by inhalation liquid, n.o.s. with an LC 50 ≤1000 mL/m 3 and saturated vapor concentration ≥10 LC 50 , Hazard class: 6.1; Labels: 6.1 Technical Name Required, Inhalation Hazard Zone B. UN2810 Toxic liquids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Purification Methods

Fractionally distil the lactone from sodium under reduced pressure. It gives an acidic solution in H2O. It irritates the skin and is a possib

Toxicity evaluation

It is soluble in water (370 g l1 at 25°C) and miscible in other common organic solvents including acetone, chloroform, diethyl ether, and ethanol (Log Kow 0.462). Hydrolysis occurs in water where the half-life in aqueous media at 25°C is approximately 3.5 h. If released to soil, relatively rapid hydrolysis can be expected to occur in the presence of moisture. Significant evaporation may occur from dry surfaces. With a vapor pressure of 3.4 mm Hg at 25°C, it can also vaporize into the air as temperature rises. If released to the atmosphere, beta-propiolactone is expected to exist in the gas phase, where it may be relatively more persistent in the absence of moisture than it is in aqueous media. The half-life for the reaction with photochemically produced hydroxyl radicals was estimated to be a relatively slow rate of 45 days in the atmosphere.

Incompatibilities

Reacts with water, causing decomposi- tion and forming 3-hydroxypropionic acid (CAS: 503-66- 3), an irritant. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explo- sions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Incompatible with acet- ates, halogens, thiocyanates, thiosulfates, strong oxidizers; strong bases. Forms explosive mixture with air above 75℃. May polymerize upon storage or due to warming. Stable if kept under refrigeration @ 5 to 10 ℃/40 to 50 ℃.

Waste Disposal

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