Phosphonic acid, dimethyl ester

Fire Extinguishing Agents Not to Be Used: Water may be ineffective.

Use foam, alcohol-resistant foam, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water. NO direct contact with water. Combat fire from a sheltered position.

Fresh air, rest. Refer for medical attention.

First rinse with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Refer for medical attention .

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

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.

Personal protection: chemical protection suit and filter respirator for acid gases and vapours adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Cover the spilled material with inert absorbent. Collect leaking and spilled liquid in sealable containers as far as possible.

TERRESTRIAL FATE: Adsorption to soil, volatilization from moist soil surfaces, and biodegradation are not expected to be important fate processes due to the hydrolysis of dimethyl hydrogen phosphite(SRC). Hydrolysis occurs under both acidic and basic conditions(1). Final hydrolysis products include methanol and phosphorous acid or its salts(1). In neutral water, dimethyl hydrogen phosphite was reported to hydrolyze completely within 144 hours; the half-life is in the range of 50 to 70 hours(2). Hydrolysis half-lives of 10 days at 25 °C and 19 days at 20 °C have also been reported for dimethyl hydrogen phosphite(3). Basic conditions speed the hydrolysis(4). Dimethyl hydrogen phosphite may leach, possibly reaching groundwater where it will hydrolyze completely(SRC). Dimethyl hydrogen phosphite is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.5 mm Hg(1).

AQUATIC FATE: Hydrolysis occurs under both acidic and basic conditions(1). Final hydrolysis products include methanol and phosphorous acid or its salts(1). In neutral water dimethyl hydrogen phosphite was reported to hydrolyze completely within 144 hours; the half-life is in the range of 50 to 70 hours(2). Hydrolysis half-lives of 10 days at 25 °C and 19 days at 20 °C have also been reported for dimethyl hydrogen phosphite(3). Basic conditions speed the hydrolysis(4). Adsorption to suspended solids and sediment, volatilization from water surfaces, bioconcentration, and biodegradation are not expected to be important fate processes due to the rapid hydrolysis of dimethyl hydrogen phosphite(SRC). The ethyl homologue of dimethyl hydrogen phosphite has been reported to photolyze in water(5) indicating that dimethyl hydrogen phosphite may also photolyze(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dimethyl hydrogen phosphite, which has a vapor pressure of 1.5 mm Hg at 20 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase dimethyl hydrogen phosphite 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 3.2 days(SRC), calculated from its rate constant of 5.08X10-12 cu cm/molecule-sec at 25 °C(3). Dimethyl hydrogen phosphite does not absorb at wavelengths >290 nm(4) and therefore is not expected to be susceptible to direct photolysis by sunlight(5).

Cough. Nausea. Sore throat.

MAY BE ABSORBED! Redness. Pain.

Redness. Pain.

Diarrhoea. Nausea. Vomiting.

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical. [http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=868-85-9]

The mutagenicity of dimethyl hydrogen phosphite was evaluated in Salmonella tester strains TA98, TA100, TA1535, TA1537 and TA1538 (Ames Test), and in Saccharomyces cerevisiae strain D4, both in the presence and absence of added metabolic activation by Aroclor-induced rat liver S9 fraction. Based on preliminary toxicity determinations, dimethyl hydrogen phosphite, diluted in DMSO, was tested at concentrations up to 5ul/plate using the plate incorporation technique. Dimethyl hydrogen phosphite did not cause a positive response in any tester strain with or without metabolic activation.

The mutagenicity of dimethyl hydrogen phosphite was evaluated in Salmonella tester strains TA98, TA100, TA1535, TA1537 and TA1538 (Ames Test), both in the presence and absence of added metabolic activation by Aroclor-induced rat liver S9 fraction. Based on preliminary toxicity determinations, dimethyl hydrogen phosphite, diluted in DMSO, was tested at concentrations up to 15ul/plate using the preincubation method. Dimethyl hydrogen phosphite did not cause a positive response in any tester strain with or without metabolic activation.

The ability of dimethyl hydrogen phosphite to induce specific locus mutations at the TK locus of cultured L5178Y mouse lymphoma cells (Mouse Lymphoma Mutagenicity Assay) was evaluated in the presence and absence of Aroclor-induced rat liver S9 metabolic activation. Based on preliminary toxicity determinations, nonactivated cultures were treated with 1.3, 1.0, 0.75, 0.56, 0.42, 0.32, 0.24, 0.18 and 0.13ul/ml, producing a range of 13 - 107% total growth. S9 activated cultures treated with 1.8, 1.3, 1.0, 0.75, 0.56, 0.42, 0.32, 0.24, 0.18 and 0.13ul/ml produced a range of 8 - 61% total growth. The nonactivated culture at highest dose level produced a mutant frequency which was two fold of the solvent control (DMSO). Activated cultures at the four highest concentrations produced mutant frequencies significantly greater than the solvent control, and a dose-response relationship was observed.

The mutagenic potential of dimethyl hydrogen phosphite was evaluated in the germ cells of Drosophila melanogaster males employing the following: somatic reversion of white-ivory test, Y chromosome loss test, Dominant lethal test and Bithorax test, sex-linked lethal test and timing of crosses test. Male flies were exposed to 0.07ml of test article delivered as an aerosol in an 25ml flask, after 5 minutes of exposure flies experienced a 20% mortality with about 20% of the survivors being sterile. Dimethyl hydrogen phosphite did cause a significant increase in the mutant frequencies in male Drosophila germ cells employing the dominant lethal and sex-linked lethal assays. All other tests were negative.

The effect of dimethyl hydrogen phosphite (DMHP) was evaluated in the bacterial DNA repair assay using E. coli tester strains WP2uvrA+recA+ and WP100uvrA-recA- and Salmonella tester strains TA1978uvrB+ and TA1538uvrB-, both with and without metabolic activation by Aroclor-induced rat liver S9 fraction. (strains designated with a "+" are repair proficient and strains designated with a "-" are repair deficient). DMHP was tested at a concentrations of 0, 0.3, 3.0, 30.0 or 50.0 ug/plate. DMHP caused significant preferential killing of the repair deficient strain WP100, at 30.0 mg/plate with activation and at 50.0 ug/plate without activation (survival indices = , 0.01 and 0.38, respectively). DMHP caused significant preferential killing of the repair deficient strain TA1538, at 30.0 and 50.0 mg/plate without activation (survival indices = < 0.01). A clear dose-response was not observed in any of the tests. DMHP did not cause significant preferential killing of the repair deficient strain TA1538 with activation.

AEROBIC: Dimethyl hydrogen phosphite, present at 100 mg/L, reached 48% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L and the Japanese MITI test(1). However, biodegradation is not expected to be an important fate process(SRC) due to the hydrolysis of dimethyl hydrogen phosphite(2-5).

Dimethyl hydrogen phosphite

Group 2B: Possibly carcinogenic to humans

Volume 48: (1990) Some Flame Retardants and Textile Chemicals, and Exposures in the Textile Manufacturing Industry

2024 online

2023

Dimethyl hydrogen phosphite

Used to make insecticides and herbicides; [ChemIDplus] Used as a lubricant additive, an adhesive, a flame retardant for fabrics, a stabilizer in oil and plaster, and as a steel corrosion inhibitor in combination with pyrocatechol; [HSDB] Used to make water treatment chemicals, flame retardants, and pharmaceuticals; [eChemPortal: SIDSUNEP]

Steel Producing [Category: Industry]

Lubricant additives; intermediate; adhesive

Dimethyl hydrogen phosphite is used as a flame retardant on Nylon 6 fibers and, in combination with guanidine and formaldehyde, to impart flame and crease resistance to cotton textiles. The compound is also used to increase fire resistance to cellulosic textiles, acrolein-grafted polyamide fibers and gamma-irradiated polyethylene. It is used as a lubricant additive, as a chemical intermediate in the production of organophosphorous pesticides and as an adhesive. Dimethyl hydrogen phosphite has also been used as a stabilizer in oil and plaster and, in combination with pyrocatechol, as a corrosion inhibitor on steel.

Feedstock for chemical synthesis.

Scheduled 3B precursor to DMMP.

2023: 1,000,000 - <5,000,000 lb

This chemical is listed as a High Production Volume (HPV) (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

(1972) PROBABLY GREATER THAN 4.54X10+5 GRAMS

(1975) PROBABLY GREATER THAN 4.5X10+5 GRAMS

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#4072]

Dimethyl hydrogen phosphite is manufactured by the reaction of phosphorous trichloride with methanol or with sodium methoxide.

Reaction of phosphorus trichloride and methanol or sodium methoxide

Synthesis: Phosphorous trichloride and methanol. Catalyst: Methyl chloride.

All Other Basic Organic Chemical Manufacturing

Phosphonic acid, dimethyl ester: ACTIVE

Dimethyl hydrogen phosphite is a Scheduled 3B precursor.