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EC number: 403-530-4 | CAS number: 129423-54-7 PV-ECHTGELB HGR
- 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

Dissociation constant
Administrative data
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Remarks:
- according to OECD 112
Data source
Reference
- Title:
- Unnamed
- Year:
- 2 021
- Report date:
- 2021
Materials and methods
Test guidelineopen allclose all
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Qualifier:
- according to guideline
- Guideline:
- other: Regulation (EC) 2017/735, A.25.
- GLP compliance:
- no
Test material
- Test material form:
- solid: nanoform
Constituent 1
Results and discussion
- Dissociating properties:
- yes
Dissociation constant
- pKa:
- 9
- Temp.:
- 20 °C
- Remarks on result:
- other: mean of 23 measurements
Any other information on results incl. tables
Table 3: Results of the 3 main tests
quantities between 0.1 and 0.5 mL of 0.01 mol/L sodium hydroxide solution were added respectively to the samples of the stock solutions
1) unionized form dm
2) ionized form di
main test I: pka = 9.00, standard deviation 0.35
main test II: pka = 9.00, standard deviation 0.41
main test III: pka = 8.89, standard deviation 0.42
| Main test I | Main test II | Main test III | ||||||
Experiment | pH value | Absorption | pKa | pH value | Absorption | pKa | pH value | Absorption | pKa |
I-1(dm) | 5.7 | 1.1570 | 1) | 5.7 | 1.1519 | 1) | 5.4 | 1.1381 | 1) |
I-2 (di) | 10.5 | 0.9796 | 2) | 10.5 | 0.9742 | 2) | 10.5 | 0.9647 | 2) |
I-3 | 8.6 | 1.0921 | 8.82 | 7.6 | 1.1178 | 8.18 | 7.3 | 1.1170 | 8.18 |
I-4 | 9.3 | 1.0525 | 9.13 | 8.6 | 1.0728 | 8.73 | 7.9 | 1.0977 | 8.43 |
I-5 | 9.5 | 1.0522 | 9.29 | 9.2 | 1.0567 | 9.18 | 8.2 | 1.0933 | 8.67 |
I-6 | 9.5 | 1.0444 | 9.27 | 9.5 | 1.0257 | 9.11 | 8.7 | 1.0725 | 8.93 |
I-7 | 8.0 | 1.1151 | 8.51 | 9.7 | 1.0264 | 9.28 | 9.4 | 1.0292 | 9.21 |
I-8 | 9.6 | 1.0350 | 9.29 | 9.9 | 1.0115 | 9.29 | 9.7 | 1.0115 | 9.22 |
I-9 | 9.9 | 1.0103 | 9.19 | 10.0 | 1.0020 | 9.23 | 9.9 | 0.9914 | 9.15 |
I-10 | 7.9 | 1.1227 | 8.47 |
| - | - | 9.3 | 1.0490 | 9.31 |
|
|
| 9.00 |
|
| 9.00 |
|
| 8.89 |
Applicant's summary and conclusion
- Executive summary:
The dissociation constant of C.I. Pigment Yellow 191 (nanoform) was determined according to OECD 112 and regulation (EC) 2017/735.
Based on the results of a preliminary test (low water solubility) the spectrophometric method was chosen to investigate the dissociation behaviour of the test item. Three main tests, 7 to 8 measurements respectively, where performed. Small quantities of 0.01 mol/L sodium hydroxide solution were added to samples prepared from stock solutions. The absorption spectra were recorded at 393 nm. The pka values were calculated using the determined pH values and measured absorptions of the unionised form, the ionised form and the test solutions at several intermediate pH values.
The mean pka value was 9.0
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