Methylphosphonic acid

96.02

96.02

1739372

237-027-4

329W4YM10Z

119358

DTXSID5047748

White solid

2931900090

67.34000

-2.02

White to off-white Crystalline Powder

1.5±0.1 g/cm3

108.5 °C

265.2±23.0 °C at 760 mmHg

114.2±22.6 °C

1.431

soluble in water and alcohol.H2O: soluble 2.88 g in 30 mL, clear, colorless

-20°C

pKa1= 2.12; pKa2= 7.29

II

8

UN 3261 8/PG 2

3

22-34-39/23/24/25-23/24/25-11

26-36/37/39-45-36/37-16-7

C,T,F

Stable. Incompatible with strong oxidizing agents, strong bases.

P280-P305 + P351 + P338-P310

H302-H314

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

WHO; Diseases Caused by Phosphorus and Its Toxic Compounds; Early Detection of Occupational Diseases pg 53-62 (1986). Review of diseases and health related effects resulting from exposure to phosphorus or phosphorus cmpd. /Phosphorus or phosphorus cmpd/

|Danger|H302 (50.63%): Harmful if swallowed [Warning Acute toxicity, oral]|P260, P264, P270, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P405, and P501|Aggregated GHS information provided by 79 companies from 6 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Respiratory protection (supplied-air respirator with full facepiece or self-contained breathing apparatus) should be available where these compounds are manufactured or used and should be worn in case of emergency and overexposure. /Phosphorus compounds/

The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 11.0 ug/l in industrial polluted waste water in the Federal Republic of Germany(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 2.4 ug/l in drainage water from an industrial waste deposit near Davamyran (Sweden) on March 26, 1980 and treated waste water from an industrial waste deposit in Kansas City (USA)(1).

Methylphosphonic acid may be released to the environment during its production and use as a chemical warfare simulant(1). Methylphosphonic acid is a degradation product of the nerve agents sarin (GB), soman(2), and VX(3). It is also a degradation product of the two pesticides, O,O-bis(2,4,5-trichlorophenyl)methylphosphonate(4) and mecarphon (no longer being produced)(2) and O-ethyl S-2 diisopropyl-aminoethylmethyl-phosphonothioate(1). Methylphosphonic acid is a degradation product of the flame retardants dimethyl methyl phosphonate, Fyrol 58 and Antiblaze 19(5). Another source of methyl phosphonic acid in the environment may be methylphospholane dichloride(5). Therefore, methyl phosphonic acid may be released to the environment in waste streams during the production and use of these compounds(1,5).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that methyl phosphonic acid is expected to have very high mobility in soil(SRC). In soils with high metal content, methyl phosphonic acid may adsorb to metal oxide surfaces(3,4). Methyl phosphonic acid is expected to exist in the dissociated form in the environment based on its pKa of 2.12(5). Dissociated methyl phosphonic acid will not volatilize from moist or dry soils(SRC). Some microorganisms and bacterial cells have been shown to cleave the C-P bond producing methane gas(6-8); however, this occurs only when the C-P compound is the sole phosphorus source. Most soil environments are not characterized by a lack of phosphorus(7); therefore, biodegradation in soil may not be an important removal process(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from an estimation method(2), indicates that methylphosphonic acid is not expected to adsorb to suspended solids and sediment(SRC). A pKa of 2.12(3) indicates methyl phosphonic acid will exist almost entirely in the dissociated form at pH values of 5 to 9. Therefore volatilization from water surfaces is not expected to be an important fate process(SRC). The half-life for the OH radical reaction with methyl phosphonic acid in water can be estimated to be approximately 18 years based on an experimental rate constant of 1.2X10+8 /Mole/sec(4) and an average OH concn of 1X10-17(5). According to a classification scheme(6), an estimated BCF of 3(SRC), from an estimated log Kow of -0.70(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is low. Biodegradation in water to methane gas may be an important removal process if methyl phosphonic acid is the sole phosphorus source especially in marine water where there is a low phosphorus content(9).|ATMOSPHERIC FATE: A pKa of 2.12(1) indicates methyl phosphonic acid will exist almost entirely in the dissociated form in the ambient environment. Since dissociated compounds are not volatile, methyl phosphonic acid will only exist in the particulate phase in the atmosphere. Particulate phase methyl phosphonic acid will be removed from the atmosphere by wet and dry deposition(SRC). Based on its high water solubility, 2.0X10+4 mg/l(2), wet deposition will be an important atmospheric removal process(SRC).

The resistance of methyl phosphonic acid to hydrolysis, photolysis, and thermal decomposition has been thoroughly substantiated in the literature(1-5). Methyl phosphonic acid in the ionized form can be oxidized to phosphoric acid when treated with ozone in an aqueous medium(6-7). The half-life for the OH radical reaction with methyl phosphonic acid in water can be estimated to be approximately 18 years based on an experimental rate constant of 1.2X10+8 /Mole/sec(8) and an average OH concn of 1X10-17(9). Oxidation of methyl phosphonic acid in basic solution has been shown to occur by a photochemically initiated reaction(10). Methylphosphonic acid is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(11) nor to directly photolyze due to the lack of absorption in the environmental UV spectrum(>290 nm).

An estimated BCF of 3 was calculated for methyl phosphonic acid(SRC), using an estimated log Kow of -0.70(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. Furthermore, methyl phosphonic acid will be highly dissociated under environmental conditions (pH 5-9) based on its pKa values (pKa1 of 2.12 and pKa2 of 7.29(4)) and methyl phosphonic acid in the dissociated form will not bioconcentrate in aquatic organisms(SRC).

The adsorption of methylphosphonic acid onto solid silt particles in a river sample was negligible(1). Based on a classification scheme(2), an estimated Koc value of 1(SRC), determined from a structure estimation method(3), indicates that methyl phosphonic acid is expected to have very high mobility in soil(SRC). In soils with high metal content, methyl phosphonic acid may adsorb to metal oxide surfaces(4,5). Methyl phosphonic acid is expected to exist in the dissociated form in the environment based on its pKa1 of 2.12 and pKa2 of 7.29(6). Dissociated methyl phosphonic acid is expected to be highly mobile in soil environments(SRC).

A pKa of 2.12(1) indicates methyl phosphonic acid will exist almost entirely in the dissociated form at pH values of 5 to 9. Therefore volatilization from water surfaces is not expected to be an important fate process(SRC).

SURFACE WATER: Compounds containing the phosphorus-methyl linkage expressed as methyl phosphonic acid were quantitatively reported at concn ranging from 0.35-1.23 ug/l in samples taken from the river Rhine, Netherlands and at concn of 0.21 and 0.25 ug/l in two samples from the river Muese, Netherlands in the period of August, 1975 to April, 1978(1). The analytical method first hydrolyzed the sample so that all compounds containing the P-CH3 bond would be converted to methyl phosphonic acid and then the methyl phosphonic acid was esterifed to trimethyl methylphosphonate for analytical detection(1). In the same study, concn of P-CH3 bond expressed as methyl phosphonic acid were reported at concn of 0.25 ug/l and 0.5 ug/l in Maarsseveen Lake and Viagtwedde Lake, respectively(1).|SURFACE WATER: The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.09 ug/l in water from the river Meuse (Dinant, Belgium) in April, 1980(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.39 ug/l in industrially polluted water from the river Schelde (Helchin, Belgium) in April, 1980 and 0.17 ug/l in water from the river Renkajoki (Renko, Finland) sampled on April 22, 1980(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.11 ug/l in water from the River Bow (Canada), sampled 60 km from the glacier source on May 13, 1980(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.31 ug/l in industrial polluted water from the river South Saskatchewan, sampled at 450 km from the source and 250 km from Calgary (Canada) on May 21, 1980(1).|SURFACE WATER: The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.45 ug/l in surface water in the Federal Republic of Germany. The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.29 ug/l in industrially polluted surface water from the river Tervajoki sampled at Janankala (Finland) on May 5, 1980(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.18 ug/l in water from the Lake of Maarseveen (The Netherlands) on August 4, 1980. The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to range from 0.21-2.65 ug/l in industrial polluted water from the river Rhine, sampled at Bergambacnt (The Netherlands) in the period of 1979-1980(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.02 ug/l in water from the lake Gittsjon (Sweden) beneath the ice on April 11, 1980(1). The concn of P-CH3 bond expressed as methyl phosphonic acid was reported to be 0.30 ug/l in water from the river Ume (Gimonas, Sweden) on April 21, 1980(1).

Occupational exposure to methylphosphonic acid may occur through inhalation and dermal contact with this compound at workplaces(SRC) where methylphosphonic acid is produced or used as a chemical warfare simulant(1).

For the verification of the use of chemical warfare agents (CWA), sarin, soman and VX, a simple rapid and accurate method which allows us to simultaneously determine their degradation products, isopropyl methylphosphonic acid (IPMPA), pinacolyl methylphosphonic acid (PMPA), ethyl methylphosphonic acid (EMPA) and methylphosphonic acid (MPA), in human serum, was explored by indirect photometric detection ion chromatography (IPD-IC) which employs an anion-exchange column. IC analysis was performed after sample preparation with an Ag+-form cation-exchange resin cartridge, and the four methylphosphonic acids could be separated well. The proposed conditions are as follows: eluent, 0.5 mM phthalic acid-0.1 mM Tris (hydroxymethyl) aminomethane-5% acetonitrile; flow-rate, 1.0 ml/min; temperature, 50 degrees C; UV detector, 266 nm. All four methylphosphonic acids were eluted within 30 min with hardly any disturbance by impurities in the serum. Linear calibration curves were obtained for methylphosphonic acid, ethyl methylphosphonic acid and isopropyl methylphosphonic acid in the concentration range from 50 ng/ml to 1 ug/ml and for pinacolyl methylphosphonic acid from 100 ng/ml to 1 ug/ml. The relative standard deviation for the methylphosphonic acids ranged from 3.8 to 6.9% at 500 ng/ml and the detection limits were 40 ng/ml for methylphosphonic acid, ethyl methylphosphonic acid and isopropyl methylphosphonic acid and 80 ng/ml for pinacolyl methylphosphonic acid. The method would be suitable for analysis of human serum samples.

aluminum methylphosphonate

Methyl phosphonic acid is a degradation product of the nerve agents sarin, soman, and VX.

Environmental transformation -> Pesticide transformation products (metabolite, successor)

Methylphosphonic acid is a known environmental transformation product of Glufosinate ammonium.