Trichloronitromethane

Description

Chloropicrin is a colorless to faint-yellow oily liquid with an intensely irritating and sharp odor with characteristics of tear gas. Some common trade names of products containing chloropicrin include Dolochlor, Aquinite, Nemax, Pic-Chlor, Timberfume, Profume A, Tri-Clor, and Microlysin. It has a molecular weight of 164.38, water solubility of 2000 mg l
1 at 25°C, and melting and boiling points of
64 and 112°C, respectively. Chloropicrin is nonflammable and has a vapor density of 5.7 compared to the vapor density of one assigned to air. Heating above 234 F results in explosive decomposition of chloropicrin, leading to the release of toxic gases, including nitrogen oxides, phosgene, nitrosyl chloride, chlorine, and carbon monoxide. Chloropicrin is a widely used fungicide that is primarily used for preplant soil fumigation. Chloropicrin is used to fumigate stored grain and to treat soil against fungi, insects, and nematodes either as a stand-alone treatment or in combination with other fumigants like methyl bromide and sulfuryl fluoride for enhanced potency. Chloropicrin is also used to prevent internal decay of wood poles and timber caused by fungi and insects.

Description

Chloropicrin, or trichloronitromethane, is a dense, pale yellow liquid that decomposes when heated to ≥112 oC. Its property as a lachrymator prompted Germany to use it as a tear gas against the Allied forces during World War I—one of the first uses of a chemical weapon.
In 1848, Scottish chemist J. Stenhouse prepared chloropicrin by treating picric acid with sodium hypochlorite. Nitro groups were the only parts of the picric acid molecule to be used in chloropicrin, but the “picrin” name stuck. Today, chloropicrin is manufactured by the reaction between nitromethane and sodium hypochlorite.
Chloropicrin has long been used as an agricultural soil fumigant because it is effective against a broad spectrum of fungi, nematodes, and insects. In 2008, the US Environmental Protection Agency reapproved it for this use, but restricted its scope and required strict protections for farm workers. Additional restrictions have been applied since then. In early 2015, the California Department of Pesticide Regulation added even more stringent regulations on chloropicrin to protect workers and residents who live near fields where it is used

Chemical properties

oily colourless liquid

Chemical properties

Chloropicrin is a highly reactive, colorless, oily liquid with a sharp, penetrating odor that causes tears.

Physical properties

Colorless to pale yellow, oily liquid with a sharp, penetrating odor. Odor threshold concentration is 0.78 ppm (quoted, Amoore and Hautala, 1983).

The Uses of Trichloronitromethane

Chloropicrin (PS), nitrotrichloromethane, trichloronitromethane, nitrochloroform, is a slightly oily, colorless, pale to transparent liquid that is nearly stable. It is nonflammable, with a boiling point of approximately 235°F (112°C) and slight water solubility. The vapor density is 5.7, which is heavier than air.

The Uses of Trichloronitromethane

Nitrochloroform is a potentially toxic disinfection byproducts generated at water treatment plants in USA.

The Uses of Trichloronitromethane

Disinfecting cereals and grains; in synthesis, especially in manufacture of methyl violet; fumigant; soil insecticide; war gas.

The Uses of Trichloronitromethane

Disinfecting cereals and grains; fumigant and soil insecticide; fungicide; rat exterminator

The Uses of Trichloronitromethane

Chloropicrin is an insecticide which is used as a fumigant of stored grain and to control soil nematodes and other pests. It is also used to protect timber against internal decay.

Definition

ChEBI: A C-nitro compound that is nitromethane in which all three hydrogens are replaced by chlorines. It is a severe irritant, and can cause immediate, severe inflammation of the eyes, nose and throat, and significant injuries to the upper and lower respiratory tract. Formerly stockpiled as a chemical warfare agent, it has been widely used in the US as a soil fumigant, particularly for strawberry crops. It is not approved for use within the European Union.

General Description

Chloropicrin mixture is a variable colored liquid usually colorless to yellow. Chloropicrin is noncombustible and the flammability of the mixture will depend on the other component of the mixture. Chloropicrin vapors are heavier than air and Trichloronitromethane is toxic by inhalation.

Air & Water Reactions

Slowly decomposes in water.

Reactivity Profile

CHLOROPICRIN is a powerful irritant affecting all body surfaces, more toxic then chlorine. Trichloronitromethane can be shocked into detonation. When heated to decomposition, Trichloronitromethane emits highly toxic fumes of chlorine gas and nitrogen oxides [Sax, 9th ed., 1996, p. 821]. Trichloronitromethane produces a violent reaction with aniline [Jackson, K. E., Chem. Rev., 1934, 14, p. 269] or strong bases in the presence of alcohols (alkoxides) [Ramsey, B. G., et al., J. Am. Chem. Soc., 1966, 88, p. 3059].

Hazard

Very toxic by ingestion and inhalation; strong eye irritant; pulmonary edema. Questionable carcinogen.

Health Hazard

Chloropicrin is a strong lachrymator (tear gas) and is severely irritating to eyes, skin and mucosal membranes of the respiratory and gastrointestinal tracts, causing nausea, vomiting, difficulty breathing and respiratory tract inflammation. Because of its high volatility, the main route of human exposure to chloropicrin is inhalation. Damage to the respiratory tract can lead to pulmonary edema and death. Chloropicrin can be absorbed systemically through inhalation, ingestion and the skin. It is severely irritating to the lungs, eyes and skin, causing potentially fatal tissue damage and edema at higher levels. In the atmosphere, it is rapidly degraded and does not deplete the ozone layer.

Agricultural Uses

Soil fumigant, Nematicide: Not approved for use in EU countries. A U.S. EPA restricted Use Pesticide (RUP) as telone. Chloropicrin is used in the manufacture of the dye-stuff methyl violet and in other organic syntheses. It has been used as a chemical warfare gas. It is used as a preplant soil fumigant in seed beds and transplant nurseries for control of verticillium wilt, nematodes, weed seeds and insects. In grain elevators, it is used to control insects and rodents. The top four uses in California are on strawberries, tomatoes, bell peppers, and outdoor nursery plants.

Trade name

BROM-O-GAS®[C]; BROZONE®[C]; CHLOR-O-PIC®; DOWFUME®; FUM-A-CIDE® 15[C]; KLOP®; LARVACIDE®[C]; LARVACIDE 100®; METAPICRIN®; NAMFUME®[C]; NEMAX®; OG25®; PESTMASTER® FUMIGANT 1[C]; PICFUME®; PIC-CHLOR® 16; PICRIDE®; PROFUME A®; PS®; TELONE®; TELONE® C[C]; TERR-O-CIDE® 15[C]; TERR-O-GAS®; TIMBERFUME II®; TRI-CLOR®[C]; TRI-CON®; TRI-FORM®; TRIFUME®[C];

Safety Profile

Poison by ingestion, intravenous, and intraperitoneal routes. Moderately toxic by inhalation. Humansystemic effects by inhalation: lachrymation, conjunctiva irritation, and pulmonary changes. Mutation data reported. A powerful irritant that affects all body surfaces. It causes lachrymation, vomiting, bronchitis, pulmonary edema, irritation to gastrointestinal and respiratory tracts. Questionable carcinogen with experimental tumorigenic data. An addrtional toxic effect is its reaction with SH-groups in hemoglobin, thus interfering with oxygen transport. Photochemical transformation of chloropicrin into phosgene (carboxp chloride, COCl2) has been reported. A concentration of 1 ppm causes a smarting pain in the eyes and therefore in itself constitutes a good warning of exposure. Inhalation causes vomiting, probably due to swallowing saliva in which small amounts of chloropicrin have dssolved. Its primary lethal effect is to produce lung injury and it is a difficult gas to protect oneself against because it is chemically inert and does not react with the usual chemicals used in gas masks. Four ppm is sufficient to render a worker unfit for action and 20 ppm, when breathed from 1 to 2 minutes, causes definite bronchal or pulmonary lesions. Industrially it is used as a warning agent in commercial fumigants. It is more toxic than chlorine but less so than phosgene. Above a critical volume it can be shocked into detonation. Mixtures with 3 bromopropyne are shockand heat-sensitive -explosives. Violent reaction with aniline + heat, alcoholic sodum hydroxide, sodium methoxide, and propargyl bromide. When heated to decomposition it emits very toxic fumes of Cland NOx. Used for insect and rodent control in grain elevators and bins and as a soil fumigant and fungcide. See also NITRO COMPOUNDS.

Potential Exposure

Chloropicrin is an important insecticide and is used in the manufacture of the dye-stuff methyl violet and in other organic syntheses. It is used as a fumigant insecticide. It is a riot control and tear agent and has been used as a military poison gas. Some forms of tear gas also contain chloropicrin. Since tank trucks, tank cars, and tank vessels carry this throughout the world in large quantities, it is a potential problem.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Medical observation is recommended for 24-48 h afterbreathing overexposure, as pulmonary edema may bedelayed. As first aid for pulmonary edema, a doctor orauthorized paramedic may consider administering a corticosteroid spray.

Carcinogenicity

Chloropicrin was genotoxic in bacterial test systems.

Environmental Fate

Biological. Four Pseudomonas sp., including Pseudomonas putida (ATCC culture 29607) isolated from soil, degraded chloropicrin by sequential reductive dechlorination. The proposed degradative pathway is chloropicrin → nitrodichloromethane → nitrochloromethane → nitromethane + small amounts of carbon dioxide. In addition, a highly water soluble substance tentatively identified as a peptide was produced by a nonenzymatic mechanism (Castro et al., 1983).
Photolytic. Photodegrades under simulated atmospheric conditions to phosgene and nitrosyl chloride. Photolysis of nitrosyl chloride yields chlorine and nitrous oxide (Moilanen et al., 1978; Woodrow et al., 1983). When aqueous solution of chloropicrin (10^-3 M) is exposed to artificial UV light (λ <300 nm), protons, carbon dioxide, hydrochloric and nitric acids are formed (Castro and Belser, 1981).
Chemical/Physical. Releases very toxic fumes of chlorides and nitrogen oxides when heated to decomposition (Sax and Lewis, 1987). Reacts with alcoholic sodium sulfite solutions and ammonia to give methanetrisulfonic acid and guanidine, respectively (Sittig, 1985).

Metabolic pathway

Although chloropicrin is stable to hydrolytic degradation, it degrades rapidly and extensively in soil and under photolytic conditions. The primary degradation and metabolic pathway in the environment and animal systems involves step-wise dechlorination reactions, followed by fragmentation and mineralisation to yield low molecular weight components and carbon dioxide as terminal residues.

storage

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Color Code—White: Corrosiveor Contact Hazard; Store separately in a corrosion-resistantlocation. Prior to working with chloropicrin you should betrained on its proper handling and storage. Before enteringconfined space where chloropicrin may be present, check tomake sure that an explosive concentration does not exist.Chloropicrin must be stored to avoid contact with strongoxidizers, such as chlorine or chlorine dioxide, since violentreactions occur. Store in tightly closed containers in a cool,well-ventilated area away from heat. High temperatures orsevere shock may cause an explosion, particularly with containers having capacities of greater than 30 gallons. Wherepossible, automatically pump liquid from drums or otherstorage containers to process containers. Sources of ignition, such as smoking and open flames, are prohibitedwhere this chemical is used, handled, or stored in a mannerthat could create a potential fire or explosion hazard.

Shipping

UN1580 Chloropicrin, Hazard Class: 6.1; Labels: 6.1-Poison Inhalation Hazard, Inhalation Hazard Zone B.

Purification Methods

Dry with MgSO4 and fractionally distil. [Beilstein 1 IV 106.] EXTREMELY NEUROTOXIC, u s e appropriate precautions.

Degradation

Chloropicrin is stable to hydrolytic degradation. No degradation was observed at 85 °C after 40 hours. When exposed to UV light, the compound was degraded rapidly at pH 7 at 25 °C with a DT₅₀ of 31 hours. Carbon dioxide, bicarbonate, chloride, nitrate and nitrite were recovered as terminal products (Jeffers and Wolfe, 1996; Wilhelm et al., 1996). Chloropicrin decomposed in air when exposed to simulated sunlight (DT₅₀ 20 days) to phosgene, CO₂, HCl, nitric oxide, nitrogen dioxide, dinitrogen tetroxide and chlorine.

Toxicity evaluation

The half-life of chloropicrin in sandy loam soil was 8–24 h and 4.5 days, with carbon dioxide being the terminal breakdown product. Chloropicrin can be produced during chlorination of drinking water in the presence of nitrated organic contaminants. If released to air, a vapor pressure of 23.8 mm Hg at 25°C indicates chloropicrin will exist solely as a vapor in the atmosphere. Vapor-phase chloropicrin will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 123 days. Chloropicrin absorbs UV light in the 280–390 nm range and therefore may be susceptible to direct photolysis. The photolysis products of chloropicrin are phosgene, nitric oxide, chlorine, nitrogen dioxide, and dinitrogen tetroxide. Chloropicrin dissipates from soil primarily via volatilization followed by chemical degradation and microbial decomposition. Under reducing conditions, chloropicrin is capable of undergoing reductive dechlorination. The calculated Henry’s Law constant is 2.51×10^-3 atm-m3 mol^-1 at 25°C. Chloropicrin does not move rapidly in aquatic environment, since it is only slightly water soluble. Field volatility data suggest that substantial portions of applied chloropicrin are emitted from soil. Chloropicrin is susceptible to rapid degradation in soil both under aerobic and anaerobic conditions.

Incompatibilities

Chloropicrin decomposes explosively when heated above 112C. It can be dangerously self-reactive; and, may explode when heated under confinement or if shocked. Chloropicrin is stable except when it’s heated to a high temperature; it explosively breaks down, releasing other poison gases including nitrogen oxides, nitrosyl chloride, chlorine, phosgene, and carbon monoxide. Liquid chloropicrin (PS) is unstable with high temperatures or severe shock, particularly when involving containers of greater than 30 gal capacity. Chloropicrin reacts violently with aniline, sodium methoxide, and propargyl bromide; 2-bromopropyne and strong oxidizers. Violent reaction with reducing agents; aniline (especially in presence of heat), alcoholic sodium hydroxide. Quickly elevated temperatures, shock, contact with alkali metals or alkaline earth may cause explosions. It is a strong acid and will react violently with bases and alkali materials. Liquid attacks some plastics, rubber, and coatings. Chloropicrin reacts with iron, zinc, light metals including aluminum, magnesium, and alloys containing these metals. It reacts, sometimes violently, with some types of rubbers and plastics, as well as some chemicals including common sulfuric acid; and bases. Contact with metals may evolve explosive hydrogen gas.

Waste Disposal

Incineration (816C, 0.5 seconds minimum for primary combustion; 1204C, 1.0 second for secondary combustion) after mixing with other fuel. The formation of elemental chlorine may be prevented by injection of steam or using methane as a fuel in the process. Chloropicrin reacts readily with alcoholic sodium sulfite solutions to produce methanetrisulfonic acid (which is relatively nonvolatile and less harmful). This reaction has been recommended for treating spills and cleaning equipment. Although not specifically suggested as a decontamination procedure, the rapid reaction of chloropicrin with ammonia to produce guanidine (LD50 5 500 mg/kg) could be used for detoxification. The Chemical Manufacturers’ Association has suggested two procedures for disposal of Chloropicrin: (1) Pour or sift over soda ash. Mix and wash slowly into large tank. Neutralize and pass to sewer with excess water. (2) Absorb on vermiculite. Mix and shovel into paper boxes. Drop into incinerator with afterburner and scrubber. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.