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EC number: 810-161-6 | CAS number: 1229654-66-3
- 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
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 8 to 11 November 2013
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 830.7370 (Dissociation constants in water)
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- Hess, Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 9.1
- Temp.:
- 23 °C
Reference
The following tables report the results of the experiments using the three stock solutions. The pH value, absorption (at 312 nm) and calculated pKa are reported for each solution obtained after the addition of different aliquots of hydrochloric acid or sodium hydroxide, as well as for the stock solutions.
[1] undissociated form (dM)
[2] dissociated form (dI)
[3] pH out of the range between the pH values associated with dM and dI
[4] no evaluation possible (absorption greater than dI)
[5] no evaluation possible (absorption less than dM)
Results using stock solution A
Exp. |
Volume and concentration of added HCl |
Volume and concentration of added NaOH |
Resulted pH value |
Absorption [ 312 nm ] |
pKa |
A1 (dM) |
- |
- |
5.73 |
0.018 |
[1] |
A2 |
10 mL – 1.0 mol/L |
- |
1.05 |
0.019 |
(3.04) [3] |
A3 |
- |
1 mL – 1.0 mol/L |
12.10 |
0.144 |
[4] |
A4 |
- |
2 mL – 0.01 mol/L |
10.42 |
0.132 |
[4] |
A5 (dI) |
- |
1 mL – 0.01 mol/L |
9.97 |
0.117 |
[2] |
A6 |
- |
9 mL – 0.001 mol/L |
9.79 |
0.112 |
8.52 |
A7 |
- |
7.5 mL – 0.001 mol/L |
9.65 |
0.099 |
9.00 |
A8 |
- |
6 mL – 0.001 mol/L |
9.44 |
0.082 |
9.18 |
A9 |
- |
5.5 mL – 0.001 mol/L |
9.31 |
0.072 |
9.23 |
A10 |
- |
5 mL – 0.001 mol/L |
9.15 |
0.066 |
9.18 |
A11 |
- |
4.5 mL – 0.001 mol/L |
9.04 |
0.061 |
9.15 |
A12 |
- |
4 mL – 0.001 mol/L |
8.82 |
0.043 |
9.29 |
A13 |
- |
3.5 mL – 0.001 mol/L |
8.47 |
0.026 |
9.53 |
A14 |
- |
3 mL – 0.001 mol/L |
7.98 |
0.022 |
9.36 |
|
Mean of A6 - A14 |
9.16 ± 0.28 |
Results using stock solution B
Exp. |
Volume and concentration of added HCl |
Volume and concentration of added NaOH |
Resulted pH value |
Absorption [ 312 nm ] |
pKa |
B1 (dM) |
- |
- |
5.80 |
0.018 |
[1] |
B2 |
10 mL – 1.0 mol/L |
- |
1.05 |
0.019 |
(3.05) [3] |
B3 |
- |
1 mL – 1.0 mol/L |
12.12 |
0.142 |
[4] |
B4 |
- |
2 mL – 0.01 mol/L |
10.41 |
0.134 |
[4] |
B5 (dI) |
- |
1 mL – 0.01 mol/L |
9.99 |
0.118 |
[2] |
B6 |
- |
9 mL – 0.001 mol/L |
9.89 |
0.114 |
8.51 |
B7 |
- |
7.5 mL – 0.001 mol/L |
9.74 |
0.103 |
8.99 |
B8 |
- |
6 mL – 0.001 mol/L |
9.48 |
0.088 |
9.11 |
B9 |
- |
5.5 mL – 0.001 mol/L |
9.38 |
0.077 |
9.22 |
B10 |
- |
5 mL – 0.001 mol/L |
9.27 |
0.071 |
9.22 |
B11 |
- |
4.5 mL – 0.001 mol/L |
9.00 |
0.062 |
9.10 |
B12 |
- |
4 mL – 0.001 mol/L |
8.96 |
0.053 |
9.23 |
B13 |
- |
3.5 mL – 0.001 mol/L |
8.47 |
0.043 |
8.95 |
B14 |
- |
3 mL – 0.001 mol/L |
7.95 |
0.027 |
8.95 |
|
Mean of B6 - B14 |
9.03 ± 0.23 |
Results using stock solution B
Exp. |
Volume and concentration of added HCl |
Volume and concentration of added NaOH |
Resulted pH value |
Absorption [ 312 nm ] |
pKa |
C1 (dM) |
- |
- |
5.89 |
0.019 |
[1] |
C2 |
10 mL – 1.0 mol/L |
- |
1.05 |
0.018 |
[5] |
C3 |
- |
1 mL – 1.0 mol/L |
12.09 |
0.144 |
[4] |
C4 |
- |
2 mL – 0.01 mol/L |
10.36 |
0.133 |
[4] |
C5 (dI) |
- |
1 mL – 0.01 mol/L |
9.88 |
0.110 |
[2] |
C6 |
- |
9 mL – 0.001 mol/L |
9.70 |
0.101 |
8.74 |
C7 |
- |
7.5 mL – 0.001 mol/L |
9.35 |
0.084 |
8.95 |
C8 |
- |
6 mL – 0.001 mol/L |
9.17 |
0.070 |
9.06 |
C9 |
- |
5.5 mL – 0.001 mol/L |
9.02 |
0.054 |
9.22 |
C10 |
- |
5 mL – 0.001 mol/L |
8.78 |
0.048 |
9.11 |
C11 |
- |
4.5 mL – 0.001 mol/L |
8.45 |
0.028 |
9.41 |
C12 |
- |
4 mL – 0.001 mol/L |
7.76 |
0.026 |
8.84 |
C13 |
- |
3.5 mL – 0.001 mol/L |
7.24 |
0.020 |
9.19 |
C14 |
- |
3 mL – 0.001 mol/L |
7.10 |
0.020 |
9.05 |
|
Mean of C6 - C14 |
9.07 ± 0.20 |
The pKa value for each determination was calculated as the average of individual values for which the dissociated portion laid between 10% and 90%. Data points for which the dissociated portion was outside this range were not used to calculate the final result.
To calculate the percentage of the dissociated test item and the usable pH range the following equations were used:
pH range = pKa(mean) ± log 9
The following table report the resulting pH range values, the solutions having a pH within this range (therefore considered for the mean pKa calculation), and the mean pKa.
Experiment |
pH range |
Solutions considered |
pKa (mean) |
A |
8.21 to 10.11 |
A6 to A13 |
9.13 (SD = 0.29) |
B |
8.08 to 9.98 |
B6 to B13 |
9.04 (SD = 0.24) |
C |
8.12 to 10.02 |
C6 to C11 |
9.08 (SD = 0.23) |
For all three cases, a re-calculation of the applicable pH range using this final pKa value resulted in the selection of the same solutions previously considered (A6-A13, B6-B13 and C6-C11, respectively).
Finale results
The dissociation constant in water of the test substance, calculated as the mean of the three experiments performed, resulted as pKa = 9.1 at 23 °C
Description of key information
The dissociation constant in water of the test substance resulted as pKa = 9.1 at 23 °C (OECD Guideline 112)
Key value for chemical safety assessment
Additional information
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