Registration Dossier
Registration Dossier
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EC number: 918-594-3 | CAS number: 7723-14-0
pH
Administrative data
- Endpoint:
- pH
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Study period:
- 2010
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- The study was performed and peer-reviewed by experienced researchers on the filed of properties of phosphorus on a sample of pure red phosphorus. The study results are very reliable and helpful for long term investigation even so ist is not performed under GLP compliance and can not be used as key study due to formal restriction of the TCC
Cross-reference
- Reason / purpose for cross-reference:
- reference to same study
Data source
Reference
- Reference Type:
- other company data
- Title:
- Unnamed
- Year:
- 2 010
Materials and methods
- Principles of method if other than guideline:
- 10g of red phosphorus was suspended in 1L water (containing some salts) stirred with magnetic stirrer at temperatures of 37°C in a 2L three-neck flask with a condenser, open on the top. 20mL samples were filtered with a 0.45µm filter and the total phosphorus content of the filtrate was quantitavely determined after oxidative pulping. After each sample preparation the pH value of the suspension was measured and adjusted to pH 7 with caustic soda.
- GLP compliance:
- no
Test material
- Reference substance name:
- Phosphorus
- EC Number:
- 231-768-7
- EC Name:
- Phosphorus
- Cas Number:
- 7723-14-0
- IUPAC Name:
- phosphine
- Details on test material:
- This material is a sample of red phosphorus from the production of the applicant without stabilizer, representative for all corresponding commercial grades of red phosphorus powder.
- Name of test material: P-red, untreated (Fra 23/07)
- Substance type: Powder
- Physical state: Solid
- Stability under test conditions: not applicable
- Storage condition of test material: storage under nitrogen atmosphere
- Internal sample name: Red Phosphorus, untreated
- Production date: 25.04.2007
- Analytical purity: 99,5 %(w/W)
- Lot/batch No.: Fra 23/07
- Watercontent: 0,09 %(w/W)
- Impurities : < 1 % and not relevant for endpoint
(Details on impurities see in the AZ in IUCLID chapter 1.4)
- Mass median diameter d50 ca. 22µm (Details see IUCLID chapter 4.5)
- Percentil d10 ca. 3µm (Details see IUCLID chapter 4.5)
- Percentil d90 ca. 75µm (Details see IUCLID chapter 4.5)
In respect to the solubility the particle size distribution might be relevant. Details are given in IUCLID chapter 4.5
Constituent 1
Results and discussion
pH valueopen allclose all
- pH value:
- ca. 3
- Temp.:
- 37 °C
- Concentration:
- ca. 10 g/L
- Remarks on result:
- other: nominal suspended red phosphorus after 24days
- pH value:
- ca. 3
- Temp.:
- 37 °C
- Concentration:
- ca. 500 mg/L
- Remarks on result:
- other: dissolved phosphorus components after 14 days
- pH value:
- ca. 3
- Temp.:
- 37 °C
- Concentration:
- ca. 900 mg/L
- Remarks on result:
- other: dissolved phosphorus components after 40 days
Applicant's summary and conclusion
- Conclusions:
- Suspending red phosphorus in water leads to an immediately release of water-soluble phosphorus impurities (oxyacids on the surface) and a slow continuous dissolving by further disproportionation into phosphorus components and traces of hydrogen according to the qualitative description below.
Px + H2O + O2 ---> H3PO4 + H3PO3 + H3PO2 + H2 + PH3
These dissolved oxyacids reduce the pH value of the suspension. The pH drift is s function of the rate of hydrolysis which depends from different parameter as described in the IUCLID chapter 5.1.2..
Suspending 10g red phosphorus in 1 L water leads after 14 day to a pH value of about 3. - Executive summary:
Suspending red phosphorus in water leads to an immediately release of water-soluble phosphorus impurities (oxyacids on the surface) and a slow continuous dissolving by further disproportionation into phosphorus components and traces of hydrogen according to the qualitative description below.
Px + H2O + O2 ---> H3PO4 + H3PO3 + H3PO2 + H2 + PH3
These dissolved oxyacids reduce the pH value of the suspension. The speed of the pH drift is a function of the rate of hydrolysis, which is described in detail in the IUCLID chapter 5.1.2. It depends from different parameter and becomes smaller with lower pH values. This results in a slowing down of the rate of hydrolysis and pH drift.
Suspending 10g red phosphorus in 1 L water leads after 14 day to a pH value of about 3.
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