メチルジフルオロホスフィンオキシド

1.3314 g/cu cm at 20 °C

1.33 @25 °C

98 °C

98 °C @760 [mm Hg]

36.0 [mmHg]

36 mm Hg at 77 °F /25 °C/

This compound is a precursor to the chemical weapons sarin and soman and is expected to react similarly to both of those compounds. See the chemical datasheets for sarin and soman for more information.

Liquid with a pungent acrid odor; [HSDB]

Organization for the Prohibition of Chemical Weapons; Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and Their Destruction. Available from http://www.opcw.org as of November 12, 2008. The Chemical Weapons Convention (CWC) is an international treaty which bans the development, production, stockpiling, and transfer or use of chemical weapons. The Convention mandates the destruction and prohibition of chemical weapons and related facilities and provides for restrictions on international trade in toxic chemicals and precursors.

DF

CUM 100g

CUM 100g

Chemical Weapons/Chemical Weapons Precursors chemical material that, if stolen or diverted, can be converted into weapons using simple chemistry, equipment, or techniques.

Principles and methods for destructoin of chemical weapons: ... "Destruction of chemical weapons" means a process by which chemicals are converted in an essentially irreversible way to a form unsuitable for production of chemical weapons, and in which an irreversible manner renders munitions and other devices unusable as such. ... Each ... /nation/ shall determine how it shall destroy chemical weapons, except that the following processes may not be used: dumping in any body of water, land burial or open pit burning. It shall destroy chemical weapons only at specifically designated and appropriately designed and equipped facilities. ... Each /nation/ shall ensure that its chemical weapons destruction facilitiesare constructed and operatedin a manner to ensure the destruction of the chemical weapons; and that the destruction process can be verified under the provisions of the Convention.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

0.53 [mg/m3]

5.9 [mg/m3]

35 [mg/m3]

DOE Protective Action Criteria (PAC): Temporary Emergency Exposure Limits (TEELs) for Methylphosphonyl difluoride: TEEL-0: 0.75 mg/cu m; PAC-1: 2.5 mg/cu m; PAC-2: 20 mg/cu m; PAC-3: 100 mg/cu m (TEEL-0: The threshold concentration below which most people will experience no adverse health effects; PAC-1: The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing other than mild transient adverse health effects or perceiving a clearly defined objectionable odor; PAC-2: The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair their abilities to take protective action; PAC-3: The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing life-threatening health effects).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that methylphosphonyl difluoride is expected to have very high mobility in soil(SRC). Volatilization of methylphosphonyl difluoride from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.2X10-5 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Methylphosphonyl difluoride is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 36 mm Hg at 25 °C(4). Biodegradation data for methylphosphonyl difluoride were not available(SRC, 2008).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that methylphosphonyl difluoride is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 2.2X10-5 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 1.8 days and 16 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 3.2(SRC), from an estimated log Kow of -0.75(2) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data for methylphosphonyl difluoride were not available(SRC, 2008).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methylphosphonyl difluoride, which has a vapor pressure of 36 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methylphosphonyl difluoride is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 240 days(SRC), calculated from its rate constant of 1.4X10-13 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Methylphosphonyl difluoride does not contain chromophores that absorb at wavelengths >290 nm(4) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of methylphosphonyl difluoride can be estimated to be 1(SRC). According to a classification scheme(2), this estimated Koc value suggests that methylphosphonyl difluoride is expected to have very high mobility in soil.

An estimated BCF of 3.2 was calculated for methylphosphonyl difluoride(SRC), using an estimated log Kow of -0.75(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for methylphosphonyl difluoride is estimated as 2.2X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that methylphosphonyl difluoride is expected to volatilize from water surfaces(2). Methylphosphonyl difluoride's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Methylphosphonyl difluoride is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 36 mm Hg at 25 °C(3).

/LABORATORY ANIMALS: Acute Exposure/ This paper reports the toxicity and environmental impact of neutralents produced from the hydrolysis of binary chemical agent precursor chemicals DF (methylphosphonic difluoride) and QL (2-[bis(1-methylethyl)amino]ethyl ethyl methylphosphonite). Following a literature review of the neutralent mixtures and constituents, basic toxicity tests were conducted to fill data gaps, including acute oral and dermal median lethal dose assays ... . For methylphosphonic acid (MPA), a major constituent of DF neutralent, the acute oral LD(50) in the Sprague-Dawley rat was measured at 1888 mg/kg ...

/GENOTOXICITY/ For methylphosphonic acid (MPA), a major constituent of DF neutralent, ... the Ames test using typical tester strains of Salmonella typhimurium and Escherichia coli was negative.

/OTHER TOXICITY INFORMATION/ Methylphosphonic difluoride (difluoro) and its hydrolysis products, methylphosphonofluoridate (MF) and fluoride, were examined for cholinesterase-inhibiting ability in rats and guinea pigs by both inhalation and intraperitoneal exposure routes. In vivo inhibition was compared to in vitro inhibition. In the whole animal, MF was the active chemical, but in vitro under special conditions, difluoro was more potent than MF and fluoride. Rat and guinea pig blood cholinesterase were equally sensitive to inhibition by MF, but only the guinea pig displayed cholinergic signs leading to death from MF toxicity. Data imply that MF is responsible for the cholinesterase inhibition resulting from exposure to DF vapor. MF may be the first example of a moderately strong acid shown to inhibit cholinesterase and cause death from cholinergic effects.

The rate constant for the vapor-phase reaction of methylphosphonyl difluoride with photochemically-produced hydroxyl radicals has been estimated as 1.4X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 236 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Hydrolysis rate constants were determined to be dependent on pH in sodium hydroxide solutions. Rate constants of 1.12 h-1, 0.90 h-1, and 0.76 h-1 were determined at 23 °C in solutions with sodium hydroxide concns of 0.10 mol/cu dm, 0.15 mol/cu dm, and 0.20 mol/cu dm, respectively. These rate constants correspond to half-lives of 37.2 mins, 46 mins, and 55 mins, respectively(2). Methylphosphonyl difluoride does not contain chromophores that absorb at wavelengths >290 nm(3) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Methylphosphonyl difluoride's production and use in the synthesis of various 'G' series nerve agents and as a component in the binary nerve agent GB2. If released to air, a vapor pressure of 36 mm Hg at 25 °C indicates methylphosphonyl difluoride will exist solely as a vapor in the atmosphere. Vapor-phase methylphosphonyl difluoride 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 236 days. Methylphosphonyl difluoride does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, methylphosphonyl difluoride is expected to have very high mobility based upon an estimated Koc of 1. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 2.2X10-5 atm-cu m/mole. Methylphosphonyl difluoride may volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation data for methylphosphonyl difluoride were not available. If released into water, methylphosphonyl difluoride is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 1.8 days and 16 days, respectively. An estimated BCF of 3.2 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis of methylphosphonyl difluoride in solution with sodium hydroxide was determined to be pH dependent with half-lives ranging from 37.2 to 54.7 mins. Occupational exposure to methylphosphonyl difluoride may occur through dermal contact with this compound at workplaces where methylphosphonyl difluoride is produced or used. (SRC)

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Nerve Agents/

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Aggressive airway control may be needed. Watch for signs of respiratory insufficiency and assist ventilations it necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . /Nerve Agents/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Initial ventilation may be difficult. Airway resistance may be high (50 to 70 cm H2O) because of secretions and bronchoconstriction. Frequent suctioning may be necessary. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Administer atropine. Correct hypoxia before administration ... . In severely poisoned patients, administer pralidoxime chloride (2-PAM). ... Treat seizures with adequate atropinization, correction of hypoxia, and diazepam (Valium) or lorazepam as necessary ... . In mass casualty events the use of auto-injector atropine and 2-PAM is advised. These auto-injectors are know as the Mark I ket. An auto-injector diazepam is also available ... . Administer homatropine drops for miosis and eye pain ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Nerve Agents/

LD50 Rat iv 13.7 mg/kg /from table/

LD50 Mouse iv 114 mg/kg /from table/

LD50 Dog iv 25.8 mg/kg /from table/

LD50 Monkey iv 26.9 mg/kg /from table/

DF

CUM 100g

CUM 100g

Chemical Weapons/Chemical Weapons Precursors chemical material that, if stolen or diverted, can be converted into weapons using simple chemistry, equipment, or techniques.

Rats were exposed by both inhalation and noninhalation routes to carbon-14-labeled methylphosphonic difluoride (difluoro) or its hydrolysis products. Exposed rats were serially killed and dissected so that the movement of the radiolabel could be traced over 7 days. Hydrolysis products cleared rapidly after noninhalation administration (t 1/2 <24 hr). The deposition of inhaled difluoro was mainly in the maxillo- and ethmoturbinates, and clearance was mainly by mucociliary clearance and swallowing. Constants were calculated for relating doses of difluoro to various respiratory tract tissues as a function of total deposited vapor. These constants indicate that the maxilloturbinates in the anterior of the nose receive more than four times the dose of difluoro than do the ethmoturbinates, whereas the trachea and lung receive much lower doses than do the nasal tissues. The derived constants may be applicable for calculating doses to respiratory tract tissues for other inhaled vapors that do not saturate the mucus (e.g, irreversibly react with water).

Used to make 'G' series nerve agents (i.e. sarin and soman) and as a component of GB2 (binary nerve agent); [HSDB]

Synthesis of various 'G' series nerve agents and as a component in the binary nerve agent GB2.

Precursor to sarin and soman

Phosphonic difluoride, P-methyl-: ACTIVE

/The Chemical Weapons Convention (CWC) is an international treaty which bans the development, production, stockpiling, and transfer or use of chemical weapons. The Convention mandates the destruction and prohibition of chemical weapons and related facilities and provides for restrictions on international trade in toxic chemicals and precursors./ The Convention's monitoring and verification measures involve submission of declarations regarding ... /Schedule 1, 2, and 3 chemicals/ and inspections by the Organization for the Prohibition of Chemical Weapons of the facilities where these chemicals are produced. ... Schedule 1 lists chemicals considered to pose a high risk to the object and purpose of the Convention by virtue of their high potential for use in activities prohibited by the CWC. These chemicals have little or no use for peaceful purposes in commercial or industrial trade. ... Schedule 1 also lists precursor chemicals that may be used in the final single technological stage of production of any of the toxic chemicals listed in the schedule (2). Methylphosphonyl difluoride is listed in the CWC Annex on Chemicals under Schedule 1 (1).

The U.S. Army Non-Stockpile Chemical Materiel Project's Binary Destruction Facility, Pine Bluff Arsenal, Ark., reached a substantial milestone when workers destroyed the last of the United States' inventory of the binary chemical precursor DF April 6. The binary chemical DF, methylphosphonic difluoride, was designed to mix with another non-lethal chemical in flight to a target to form the nerve agent sarin. A 1989 agreement with the former USSR ended the binary program in 1991, leaving the DF in secure storage until destruction. The BDF crew began destroying DF in December 2005.