Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-388-1 | CAS number: 7526-26-3
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Hydrolysis
Administrative data
Link to relevant study record(s)
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2012
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 111 (Hydrolysis as a Function of pH)
- Qualifier:
- according to guideline
- Guideline:
- EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- The Department of Health of the Government of the United Kingdom
- Specific details on test material used for the study:
- Details on properties of test surrogate or analogue material (migrated information):
No surrogate or analogue material was used. - Radiolabelling:
- no
- Analytical monitoring:
- yes
- Details on sampling:
- - Sampling intervals for the parent/transformation products: various times
- Others: determination of duplicate sample solutions - Buffers:
- Buffer solution (pH: 4)
- Composition of buffer and their concentrations: Citric acid (31 mM); Sodium chloride (22 mM); Sodium hydroxide (34 mM)
Buffer solution (pH: 7)
- Composition of buffer and their concentrations: Disodium hydrogen orthophosphate (anhydrous) (15 mM); Potassium dihydrogen orthophosphate (10 mM); Sodium chloride (10 mM)
Buffer solution (pH: 9)
- Composition of buffer and their concentrations: Disodium tetraborate (5 mM); Sodium chloride (10 mM)
These solutions were subjected to ultrasonication and degassing with nitrogen to minimise dissolved oxygen content. - Estimation method (if used):
- Not applicable.
- Details on test conditions:
- TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: glass flasks; water bath
- Lighting: solutions were shielded from light
- Methods to minimise dissolved oxygen content: ultrasonication and degassing with nitrogen
- no other details on test system are given
TEST MEDIUM
- Preparation of test medium: Sample solutions were prepared in stoppered glass flasks at a nominal concentration of 100 mg/L in the three buffer solutions. The concentration of each solution did not exceed the lesser of 0.01 mol/L or half the water solubility. The test solutions were split into individual vessels for each data point.
- Identity and concentration of co-solvent: 1 % co-solvent of methanol was used to aid solubility - Duration:
- 120 h
- pH:
- 4
- Initial conc. measured:
- >= 0.099 - <= 0.1 g/L
- Duration:
- 384 h
- pH:
- 7
- Initial conc. measured:
- >= 0.1 - <= 0.1 g/L
- Duration:
- 23.5 h
- pH:
- 9
- Initial conc. measured:
- >= 0.096 - <= 0.096 g/L
- Duration:
- 78 h
- pH:
- 7
- Initial conc. measured:
- >= 0.097 - <= 0.098 g/L
- Duration:
- 48 h
- pH:
- 7
- Initial conc. measured:
- >= 0.094 - <= 0.094 g/L
- Duration:
- 24 h
- pH:
- 9
- Initial conc. measured:
- >= 0.093 - <= 0.094 g/L
- Duration:
- 2.5 h
- pH:
- 9
- Initial conc. measured:
- >= 0.09 - <= 0.09 g/L
- Number of replicates:
- Duplicate sample solutions (A and B) were diluted by a factor of 2 using methanol (pH 4) or acidified methanol (pH 7 and pH 9).
- Positive controls:
- no
- Remarks:
- no information given
- Negative controls:
- yes
- Remarks:
- Matrix blanks have been prepared. Acidified methanol: reverse osmosis water (50:50 v/v) and methanol: reverse osmosis water (50:50 v/v).
- Statistical methods:
- No statistical methods are given.
- Preliminary study:
- pH 4 at 50 +/- 0.5°C
Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.
pH 7 at 50 +/- 0.5°C
The extent of hydrolysis after 384 hours indicated that a further test (Tier 2), conducted at 60 °C and 70 °C, was required to estimate the rate constant and half-life at 25 °C.
pH 9 at 50 +/- 0.5°C
The extent of hydrolysis after 6 hours indicated that a further test (Tier 2), conducted at 40 and 60 °C, was required to estimate the rate constant and half-life at 25 °C. - Test performance:
- Results from the preliminary test/Tier 1 showed it was necessary to undertake further testing at pH 7 and 9.
- Transformation products:
- not measured
- Details on hydrolysis and appearance of transformation product(s):
- Generally, hydrolysis products should be identified/confirmed using an analytical method like LC-MS or GC-MS. However, in this case, the test item was known to be the di-phenyl ester of methylphosphonic acid. Consequently, it is considered that one intermediate hydrolysis product will be the mono-phenyl ester of methylphosphonic acid, whereas the ultimate hydrolysis products will be phenol and methylphosphonic acid.
- pH:
- 4
- Temp.:
- 50 °C
- DT50:
- > 1 yr
- Type:
- (pseudo-)first order (= half-life)
- pH:
- 7
- Temp.:
- 25 °C
- Hydrolysis rate constant:
- ca. 0 h-1
- DT50:
- ca. 149 d
- Type:
- other: Arrhenius relationship
- pH:
- 9
- Temp.:
- 25 °C
- Hydrolysis rate constant:
- ca. 0.021 h-1
- DT50:
- ca. 33 h
- Type:
- other: Arrhenius relationship
- Other kinetic parameters:
- No other kinetic parameters are given.
- Details on results:
- TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes
PATHWAYS OF HYDROLYSIS
- Figures of chemical structures attached: No - Validity criteria fulfilled:
- yes
- Remarks:
- Basic criteria of the guideline are met.
- Conclusions:
- The study is regarded as a valid guideline study with certificated GLP compliance. At pH 4 the test substance can be regarded as stable at an ambient temperature of 25 °C (half-life greater than 1 year). At pH 7 and 9 further testing (Tier 2) was necessary. The higher the pH value (thus the more alkaline the environment), the lower the half-lives for diphenyl methylphosphonate.
- Executive summary:
In accordance with GLP compliance, an assessment of hydrolytic stability was carried out using a procedure designed to be compatible with Method C7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.
The test item is dissolved in an aqueous solution at a specific pH value and incubated in the dark and at a specific temperature, in a water bath thermostated at the specific temperature with a maximum deviation of ± 0.5 °C. The concentration of the test item is determined as a function of time, using a suitable analytical method. In the case of decreasing concentrations, the logarithms of the concentrations are plotted against time (log10 (ct)). If the plot is a straight line, the reaction is considered to be of (pseudo-) first order. The rate constant and the half-life time is then calculated using the slope. From data generated at differing temperatures for any single pH, an estimation of the rate constant and half-life at 25 °C is determined by the use of the Arrhenius relationship.
At pH 4 the test substance can be regarded as stable at an ambient temperature of 25 °C (half-life greater than 1 year). At pH 7 the estimated half-life at 25°C amounts 149 days with a hydrolysis rate constant of 1.94 E-4 h ^ -1. At pH 9 the estimated half-life at 25°C amounts 33 hours with a hydrolysis rate constant of 2.10 E-2 h ^ -1. Thus, the higher the pH value (thus the more alkaline the environment), the lower the half-lives for diphenyl methylphosphonate.
Reference
Preliminary test / Tier 1 - pH 4
The mean peak areas relating to the standard and sample solutions are shown in the following table:
Solution | Mean Peak Area |
Standard 50.2 mg/L | 1.169*E7 |
Standard 50.3 mg/L | 1.164*E7 |
Initial Sample A, pH 4 | 1.161*E7 |
Initial Sample B, pH 4 | 1.152*E7 |
Standard 50.1 mg/L | 1.146*E7 |
Standard 50.4 mg/L | 1.148*E7 |
48 Hour Sample A, pH 4 | 1.154*E7 |
48 Hour Sample B, pH 4 | 1.155*E7 |
Standard 50.3 mg/L | 1.170*E7 |
Standard 50.3 mg/L | 1.170*E7 |
120 Hour Sample A, pH 4 | 1.170*E7 |
120 Hour Sample B, pH4 | 1.129*E7 |
The test item concentrations for pH 4 at 50.0 °C +/- 0.5°C at the given time points are shown in the following tables:
Time (Hours) | Concentration (g/L) | % hydrolysis | ||
A | B | A | B | |
0 | 0.100 | 9.93*E-2 | - | - |
48 | 0.101 | 0.101 | -1.34 | -1.41 |
120 | 0.101 | 9.70*E-2 | -0.934 | 2.64 |
Result: Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.
Tier 2 - pH 7 and pH 9
The mean peak areas relating to the standard and sample solutions are shown in the following table:
Solution | Mean Peak Area |
Standard 50.2 mg/L | 1.205*E7 |
Standard 50.1 mg/L | 1.203*E7 |
Initial Sample A, pH 7, 60°C | 1.169*E7 |
Initial Sample B, pH 7, 60°C | 1.174*E7 |
Standard 50.2 mg/L | 1.226*E7 |
Standard 50.4 mg/L | 1.248*E7 |
24 Hour Sample A, pH 7, 60°C | 7.475*E6 |
24 Hour Sample B, pH 7, 60°C | 7.544*E6 |
30.5 Hour Sample A, pH 7, 60°C | 6.628*E6 |
30.5 Hour Sample B, pH 7, 60°C | 6.591*E6 |
Standard 50.5 mg/L | 1.197*E7 |
Standard 50.2 mg/L | 1.188*E7 |
48 Hour Sample A, pH 7, 60°C | 4.621*E6 |
48 Hour Sample B, pH 7, 60°C | 4.623*E6 |
54.5 Hour Sample A, pH 7, 60°C | 4.186*E6 |
54.5 Hour Sample B, pH 7, 60°C | 4.240*E6 |
Standard 50.2 mg/L | 1.361*E7 |
Standard 50.4 mg/L | 1.304*E7 |
72 Hour Sample A, pH 7, 60°C | 3.038*E6 |
72 Hour Sample B, pH 7, 60°C | 2.984*E6 |
78 Hour Sample A, pH 7, 60°C | 2.684*E6 |
78 Hour Sample B, pH 7, 60°C | 2.658*E6 |
Standard 50.2 mg/L | 1.226*E7 |
Standard 50.4 mg/L | 1.248*E7 |
Initial Sample A, pH 7, 70°C | 1.152*E7 |
Initial Sample B, pH 7, 70°C | 1.156*E7 |
2 Hour Sample A, pH 7, 70°C | 1.034*E7 |
2 Hour Sample B, pH 7, 70°C | 1.035*E7 |
Standard 50.2 mg/L | 1.243*E7 |
Standard 50.4 mg/L | 1.260*E7 |
4Hour Sample A, pH 7, 70°C | 9.445*E6 |
4 Hour Sample B, pH 7, 70°C | 9.379*E6 |
6 Hour Sample A, pH 7, 70°C | 8.611*E6 |
6 Hour Sample B, pH 7, 70°C | 8.637*E6 |
Standard 50.5 mg/L | 1.197*E7 |
Standard 50.2 mg/L | 1.188*E7 |
24Hour Sample A, pH 7, 70°C | 3.356*E6 |
24 Hour Sample B, pH 7, 70°C | 3.359*E6 |
30 Hour Sample A, pH 7, 70°C | 2.541*E6 |
30 Hour Sample B, pH 7, 70°C | 2.577*E6 |
Standard 50.2 mg/L | 1.361*E7 |
Standard 50.4 mg/L | 1.304*E7 |
48 Hour Sample A, pH 7, 70°C | 1.004*E6 |
48 Hour Sample B, pH 7, 70°C | 1.023*E6 |
Standard 50.3 mg/L | 1.226*E7 |
Standard 50.2 mg/L | 1.214*E7 |
Initial Sample A, pH 9, 40°C | 1.128*E7 |
Initial Sample B, pH 9, 40°C | 1.146*E7 |
1 Hour Sample A, pH 9, 40°C | 9.898*E6 |
1 Hour Sample B, pH 9, 40°C | 9.961*E6 |
2 Hour Sample A, pH 9, 40°C | 9.070*E6 |
2 Hour Sample B, pH 9, 40°C | 8.985*E6 |
3 Hour Sample A, pH 9, 40°C | 8.187*E6 |
3 Hour Sample B, pH 9, 40°C | 7.936*E6 |
4 Hour Sample A, pH 9, 40°C | 7.299*E6 |
4 Hour Sample B, pH 9, 40°C | 7.243*E6 |
6 Hour Sample A, pH 9, 40°C | 5.825*E6 |
6 Hour Sample B, pH 9,40°C | 5.857*E6 |
Standard 50.4 mg/L | 1.179*E7 |
Standard 50.3 mg/L | 1.194*E7 |
24 Hour Sample A, pH 9, 40°C | 8.113*E5 |
24 Hour Sample B, pH 9, 40°C | 7.987*E5 |
Standard 50.4 mg/L | 1.265*E7 |
Standard 50.3 mg/L | 1.263*E7 |
Initial Sample A, pH 9, 60°C | 1.131*E7 |
Initial Sample B, pH 9, 60°C | 1.131*E7 |
0.5 Hour Sample A, pH 9, 60°C | 7.436*E6 |
0.5 Hour Sample B, pH 9, 60°C | 7.511*E6 |
0.75 Hour Sample A, pH 9, 60°C | 5.963*E6 |
0.75 Hour Sample B, pH 9, 60°C | 6.080*E6 |
1 Hour Sample A, pH 9, 60°C | 4.847*E6 |
1 Hour Sample B, pH 9, 60°C | 4.779*E6 |
1.5 Hour Sample A, pH 9, 60°C | 3.370*E6 |
1.5 Hour Sample B, pH 9, 60°C | 3.343*E6 |
Standard 50.4 mg/L | 1.264*E7 |
Standard 50.3 mg/L | 1.264*E7 |
2 Hour Sample A, pH 9, 60°C | 2.354*E6 |
2 Hour Sample B, pH 9, 60°C | 2.314*E6 |
2.5 Hour Sample A, pH 9, 60°C | 1.486*E6 |
2.5 Hour Sample B, pH 9, 60°C | 1.496*E6 |
The test item concentrations for pH 7 at 60.0 °C +/- 0.5°C at the given time points are shown in the following tables:
Time (Hours) | Concentration (g/L) | Log10[concentration (g/L)] | % hydrolysis | |||
A | B | A | B | A | B | |
0 | 9.74*E-2 | 9.77*E-2 | -1.01 | -1.01 | - | - |
24 | 6.08*E-2 |
6.13*E-2 | -1.22 | -1.21 | 37.7 | 37.1 |
30.5 | 5.39*E-2 | 5.36*E-2 | -1.27 | -1.27 | 44.8 | 45.1 |
48 | 3.90*E-2 | 3.90*E-2 | -1.41 | -1.41 | 60.0 | 60.0 |
54.5 | 3.53*E-2 | 3.58*E-2 | -1.45 | -1.45 | 63.8 | 63.3 |
72 | 2.29*E-2 | 2.25*E-2 | -1.64 | -1.65 | 76.5 | 76.9 |
78 | 2.03*E-2 | 2.01*E-2 | -1.69 | -1.70 | 79.2 | 79.4 |
Result:
Slope = -8.73 * E-3
k(obs) = 2.01 * E-2 hour ^ -1 = 5.58 * E-6 second ^ -1
t(1/2) = 34.5 hours = 1.44 days
The test item concentrations for pH 7 at 70.0 °C +/- 0.5°C at the given time points are shown in the following tables:
Time (Hours) | Concentration (g/L) | Log10[concentration (g/L)] | % hydrolysis | |||
A | B | A | B | A | B | |
0 | 9.37*E-2 | 9.39*E-2 | -1.03 | -1.03 | - | - |
2 | 8.40*E-2 | 8.42*E-2 | -1.08 | -1.08 | 10.4 | 10.3 |
4 | 7.59*E-2 | 7.53*E-2 | -1.12 | -1.12 | 19.1 | 19.7 |
6 | 6.92*E-2 | 6.94*E-2 | -1.16 | -1.16 | 26.3 | 26.0 |
24 | 2.83*E-2 | 2.84*E-2 | -1.55 | -1.55 | 69.8 | 69.8 |
30 | 2.15*E-2 | 2.18*E-2 | -1.67 | -1.66 | 77.1 | 76.8 |
48 | 7.58*E-2 | 7.72*E-3 | -2.12 | -2.11 | 91.9 | 91.8 |
Result:
Slope = -2.23 * E-2
k(obs) = 5.13 * E-2 hour ^ -1 = 1.43 * E-5 second ^ -1
t(1/2) = 13.5 hours
The test item concentrations for pH 9 at 40.0 °C +/- 0.5°C at the given time points are shown in the following tables:
Time (Hours) | Concentration (g/L) | Log10[concentration (g/L)] | % hydrolysis | |||
A | B | A | B | A | B | |
0 | 9.29*E-2 | 9.44*E-2 | -1.03 | -1.03 | - | - |
1 | 8.15*E-2 | 8.21*E-2 | -1.09 | -1.09 | 12.9 | 12.4 |
2 | 7.47*E-2 | 7.40*E-2 | -1.13 | -1.13 | 20.2 | 21.0 |
3 | 6.74*E-2 | 6.54*E-2 | -1.17 | -1.19 | 28.0 | 30.2 |
4 | 6.01*E-2 | 5.97*E-2 | -1.22 | -1.22 | 35.8 | 36.3 |
6 | 4.80*E-2 | 4.82*E-2 | -1.32 | -1.32 | 48.8 | 48.5 |
24 | 6.89*E-3 | 6.78*E-3 | -2.16 | -2.17 | 92.6 | 92.8 |
Result:
Slope = -4.71 * E-2
k(obs) = 0.109 hour ^ -1 = 3.01 * E-5 second ^ -1
t(1/2) = 6.39 hours
The test item concentrations for pH 9 at 60.0 °C +/- 0.5°C at the given time points are shown in the following tables:
Time (Hours) | Concentration (g/L) | Log10[concentration (g/L)] | % hydrolysis | |||
A | B | A | B | A | B | |
0 | 9.00*E-2 | 9.01*E-2 | -1.05 | -1.05 | - | - |
0.5 | 5.92*E-2 | 5.98*E-2 | -1.23 | -1.22 | 34.3 | 33.6 |
0.75 | 4.75*E-2 | 4.84*E-2 | -1.32 | -1.32 | 47.3 | 46.2 |
1 | 3.86*E-2 | 3.81*E-2 | -1.41 | -1.42 | 57.1 | 57.7 |
1.5 | 2.68*E-2 | 2.66*E-2 | -1.57 | -1.58 | 70.2 | 70.4 |
2 | 1.87*E-2 | 1.84*E-2 | -1.73 | -1.74 | 79.2 | 79.5 |
2.5 | 1.18*E-2 | 1.19*E-2 | -1.93 | -1.92 | 86.9 | 86.8 |
Result:
Slope = -0.346
k(obs) = 0.798 hour ^ -1 = 2.22 * E-4 second ^ -1
t(1/2) = 0.869 hours
The Arrhenius plots were constructed using the data shown in the following tables:
pH 7 Arrhenius data
T(°C) | T(K) | 1/(T(K)) | k(obs) (h^-1) | Ln k(obs) |
50 | 332.15 | 3.095*E-3 | 5.09*E-3 | -5.280 |
60 | 333.15 | 3.002*E-3 | 2.01*E-2 | -3.907 |
70 | 343.15 | 2.914*E-3 | 5.13*E-2 | -2.970 |
From the graph of the above data, the rate constant and half-life at 25 °C have been estimated to be as follows:
k(obs) = 1.94 * E-4 hour ^ -1 = 5.38 * E-8 second ^ -1
t(1/2) = 3.58 * E3 hours = 149 days
pH 9 Arrhenius data
T(°C) | T(K) | 1/(T(K)) | k(obs) (h^-1) | Ln k(obs) |
40 | 313.15 | 3.193*E-3 | 0.109 | -2.221 |
50 | 332.15 | 3.095*E-3 | 0.334 | -1.095 |
60 | 333.15 | 3.002*E-3 | 0.798 | -0.226 |
From the graph of the above data, the rate constant and half-life at 25 °C have been estimated to be as follows:
k(obs) = 2.10 * E-2 hour ^ -1 = 5.84 * E-6 second ^ -1
t(1/2) = 33.0 hours = 1.38 days
Description of key information
Study report according to OECD Guideline 111 and EU Method C.7 considering the hydrolysis potential of diphenyl methylphosphonate. The half-lives will decrease with higher pH values.
Calculation with HYDROWIN v2.00 (EPIWIN software by US-EPA): detected hydrolysable substance class: Phosphorus ester. The half-lives will decrease with higher pH values.
Key value for chemical safety assessment
- Half-life for hydrolysis:
- 149 d
- at the temperature of:
- 25 °C
Additional information
The hydrolysis potential of the test substance is described by one study report (key study) as well as by an estimation with the computer program named HYDROWIN v2.00 (supporting study). In the following, available results are reported:
In accordance with GLP compliance, an assessment of hydrolytic stability was carried out using a procedure designed to be compatible with EU Method C.7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004. The test item is dissolved in an aqueous solution at a specific pH value and incubated in the dark and at a specific temperature, in a water bath thermostated at the specific temperature with a maximum deviation of ± 0.5 °C. The concentration of the test item is determined as a function of time, using a suitable analytical method. In the case of decreasing concentrations, the logarithms of the concentrations are plotted against time (log10 (ct)). If the plot is a straight line, the reaction is considered to be of (pseudo-) first order. The rate constant and the half-life time are then calculated using the slope. From data generated at differing temperatures for any single pH, an estimation of the rate constant and half-life at 25 °C is determined by the use of the Arrhenius relationship. At pH 4 the test substance can be regarded as stable at an ambient temperature of 25 °C (half-life greater than 1 year). At pH 7 the estimated half-life at 25 °C amounts 149 days with a hydrolysis rate constant of 1.94 E-4/h. At pH 9 the estimated half-life at 25 °C amounts 33 hours with a hydrolysis rate constant of 2.10 E-2/h. Thus, the higher the pH value (thus the more alkaline the environment), the lower the half-lives for diphenyl methylphosphonate. Besides, further information is given by the supporting study.
Considering the supporting study, the hydrolysis potential of the test substance was determined by the computer program HYDROWIN v2.00 (EPIWIN software) of US-EPA (Chemservice S.A., 2011). The program estimates the hydrolysis rate constants for specific organic classes and, furthermore, a chemical´s half-live under typical environmental conditions is also determined.Only hydrolysis properties of esters, carbamates, epoxides, halomethanes (containing 1-3 halogens), specific alkyl halides and phosphorous esters can be estimated, since these are specific organic classes, which are able to undergo hydrolysis. When present, various hydrolysable compound-types will be identified.The prediction for the test substance indicated that "phosphorous ester" was detected as hydrolysable substance class. The higher the pH value (thus the more alkaline the environment), the lower the half-lives for this type of chemicals. For example: the half-life at pH 4 will be around 378 years, at pH 8 it will be about 14 days and at pH 10 it is predicted as about 3.3 days.
In conclusion, both the key and the supporting study determine comparable results. The higher the pH value, the lower the half-lives of diphenyl methylphosphonate.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.