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EC number: 936-023-6 | CAS number: 950782-86-2
- 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
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: GLP-Guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 830.7370 (Dissociation constants in water)
- Deviations:
- no
- Principles of method if other than guideline:
- Spectrophotometric Method
- GLP compliance:
- yes (incl. QA statement)
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 3.56
- Temp.:
- 22 °C
- Remarks on result:
- other: SD=0.02; T=22 °C +/- 5 °C
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: GLP-Guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 830.7370 (Dissociation constants in water)
- Deviations:
- no
- Principles of method if other than guideline:
- Spectrophotometric Method
- GLP compliance:
- yes (incl. QA statement)
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 3.51
- Temp.:
- 22 °C
- Remarks on result:
- other: SD=0.05; T=22 °C +/- 5 °C
Referenceopen allclose all
Experiment A was discarded due to the fact that the data of only 4 pH values were within the
range between 10 and 90 % ionization. According to the OECD guideline 112 a number of at least 5
valid data points are required.
Experiment B
Experiment
|
Volume and concentration of added NaOH
|
Volume and concentration of added HCl
|
Resulted pH value
|
Absorption
|
pKa
|
B1 |
- |
- |
6.09 |
0.013 |
4.91 |
B2 |
0.1 ml - 0.01 mol/L |
- |
6.34 |
0.015 |
5.70 |
B3 |
1.0 ml - 0.1 mol/L |
- |
11.00 |
0.014 |
10.154 |
B4(dm) |
1.0 ml - 1.0 mol/L |
- |
12.02 |
0.012 |
2 |
B5 |
- |
0.1 ml - 0.01 mol/L |
5.92 |
0.011 |
³ |
B6 |
- |
0.3 ml - 0.1 mol/L |
3.59 |
0.019 |
3.48 |
B7 |
- |
0.4 ml - 0.1 mol/L |
3.45 |
0.022 |
3.67 |
B8 |
- |
0.5 ml - 0.1 mol/L |
3.36 |
0.023 |
3.70 |
B9 |
- |
0.6 ml - 0.1 mol/L |
3.28 |
0.023 |
3.61 |
B10 |
- |
0.8 ml - 0.1 mol/L |
3.15 |
0.023 |
3.49 |
B11 |
- |
1.0 ml - 0.1 mol/L |
3.05 |
0.024 |
3.53 |
B12 |
- |
2.0 ml - 0.1 mol/L |
2.74 |
0.025 |
3.38 |
B13 |
- |
2.0 ml - 1.0 mol/L |
1.78 |
0.026 |
2.63 |
B14(di) |
- |
10.0 ml - 1.0 mol/L |
1.11 |
0.028 |
1 |
|
|
|
|
Mean
|
3.81 ± 0.87
|
1dissociated form2undissociated form3no evaluation possible4outlier
The pKa value for each determination was calculated as the average of the individual values for which the dissociated proportion was between 10% and 90%. Data points for which the dissociated proportion was outside this range were not used to calculate the final result.
To calculate the percentage of the ionized test item and the usable pH range the following equations were used:
pH range = pKamean± log 9
pH range = 3.81 ± 0.95 = pH 2.86 to pH 4.76
Applying this pH range (i.e. experiments B6 to B11) the mean pKa-value is resulting in
pKa = 3.58 (SD = 0.10)
Applying this pKa value again for the definition of the pH range the experiments B6 to B12 are selected for the calculation of the final result:
pH range = 3.58 ± 0.95 → pH = 2.63 to pH = 4.53
This is resulting in the final value pKa = 3.55 (SD = 0.12)
Experiment C
Experiment
|
Volume and concentration of added NaOH
|
Volume and concentration of added HCl
|
Resulted pH value
|
Absorption
|
pKa
|
C1 |
- |
- |
5.81 |
0.012 |
4.66 |
C2 |
0.1 ml - 0.01 mol/L |
- |
6.32 |
0.012 |
5.17 |
C3 |
1.0 ml - 0.1 mol/L |
- |
10.99 |
0.011 |
³ |
C4(dm) |
1.0 ml -1.0 mol/L |
- |
12.02 |
0.011 |
² |
C5 |
- |
0.1 ml - 0.01 mol/L |
5.82 |
0.012 |
4.67 |
C6 |
- |
0.3 ml - 0.1 mol/L |
3.68 |
0.019 |
3.74 |
C7 |
- |
0.4 ml - 0.1 mol/L |
3.48 |
0.020 |
3.66 |
C8 |
- |
0.5 ml - 0.1 mol/L |
3.37 |
0.021 |
3.67 |
C9 |
- |
0.6 ml - 0.1 mol/L |
3.27 |
0.020 |
3.45 |
C10 |
- |
0.8 ml - 0.1 mol/L |
3.15 |
0.021 |
3.45 |
C11 |
- |
1.0 ml - 0.1 mol/L |
3.04 |
0.022 |
3.48 |
C12 |
- |
2.0 ml - 0.1 mol/L |
2.74 |
0.023 |
3.34 |
C13 |
- |
2.0 ml -1.0 mol/L |
1.78 |
0.025 |
2.93 |
C14(di) |
- |
10.0 ml -1.0 mol/L |
1.11 |
0.026 |
1 |
|
|
|
|
Mean
|
3.84±0.69
|
1dissociated form2undissociated form3no evaluation possible4outlier
The pKa value for each determination was calculated as the average of the individual values for which the dissociated proportion was between 10% and 90%. Data points for which the dissociated proportion was outside this range were not used to calculate the final result.
To calculate the percentage of the ionized test item and the usable pH range the following equations were used:
pH range = pKamean± log 9
pH range = 3.84 ± 0.95 = pH 2.89 to pH 4.79
Applying this pH range (i.e. experiments C6 to C11) the mean pKa-value is resulting in
pKa = 3.57 (SD = 0.13)
Applying this pKa value again for the definition of the pH range the experiments C6 to C12 are selected for the calculation of the final result:
pH range = 3.57 ± 0.95 → pH = 2.62 to pH = 4.52
This is resulting in the final value pKa = 3.54(SD = 0.15)
Experiment C
Experiment
|
Volume and concentration of added NaOH
|
Volume and concentration of added HCl
|
Resulted pH value
|
Absorption
|
pKa
|
D1 |
- |
- |
5.54 |
0.009 |
³ |
D2 |
0.1 ml - 0.01 mol/L |
- |
5.66 |
0.009 |
³ |
D3 |
1.0 ml - 0.1 mol/L |
- |
11.00 |
0.009 |
² |
D4(dm) |
1.0 ml -1.0 mol/L |
- |
12.04 |
0.010 |
³ |
D5 |
- |
0.1 ml - 0.01 mol/L |
5.53 |
0.009 |
³ |
D6 |
- |
0.3 ml - 0.1 mol/L |
3.64 |
0.017 |
3.49 |
D7 |
- |
0.4 ml - 0.1 mol/L |
3.48 |
0.019 |
3.53 |
D8 |
- |
0.5 ml - 0.1 mol/L |
3.39 |
0.020 |
3.54 |
D9 |
- |
0.6 ml - 0.1 mol/L |
3.29 |
0.022 |
3.67 |
D10 |
- |
0.8 ml - 0.1 mol/L |
3.16 |
0.023 |
3.67 |
D11 |
- |
1.0 ml - 0.1 mol/L |
3.07 |
0.024 |
3.74 |
D12 |
- |
2.0 ml - 0.1 mol/L |
2.75 |
0.024 |
3.42 |
D13 |
- |
2.0 ml -1.0 mol/L |
1.78 |
0.026 |
2.98 |
D14(di) |
- |
10.0 ml -1.0 mol/L |
1.12 |
0.027 |
1 |
|
|
|
|
Mean
|
3.51±0.24
|
1dissociated form2undissociated form3no evaluation possible4outlier
The pKa value for each determination was calculated as the average of the individual values for which the dissociated proportion was between 10% and 90%. Data points for which the dissociated proportion was outside this range were not used to calculate the final result.
To calculate the percentage of the ionized test item and the usable pH range the following equations were used:
pH range = pKamean± log 9
pH range = 3.51 ± 0.95 = pH 2.56 to pH 4.46
Applying this pH range (i.e. experiments D6 to D12) the mean pKa-value is resulting in
pKa = 3.58 (SD = 0.12)
Three individual experiments were carried out measuring the pH dependency of the UV /spectra of the test item at room temperature (22°C ± 5°C).
Experiment A
Experiment
|
Volume and concentration of added NaOH
|
Volume and concentration of added HCl
|
Resulted pH value
|
Absorption
|
pKa
|
A1 |
- |
- |
6.18 |
0.0201 |
3 |
A2 |
0.1 mL - 0.01 mol/L |
- |
6.61 |
0.0207 |
3 |
A3 |
1.0 mL - 0.1 mol/L |
- |
10.81 |
0.0224 |
3 |
A4(dm) |
1.0 mL - 1.0 mol/L |
- |
11.85 |
0.0229 |
2 |
A5 |
- |
0.1 mL - 0.01 mol/L |
5.89 |
0.0292 |
5.21 |
A6 |
- |
0.3 mL - 0.1 mol/L |
3.52 |
0.0400 |
3.46 |
A7 |
- |
0.4 mL - 0.1 mol/L |
3.42 |
0.0441 |
3.55 |
A8 |
- |
0.5 mL - 0.1 mol/L |
3.32 |
0.0448 |
3.49 |
A9 |
- |
0.6 mL - 0.1 mol/L |
3.25 |
0.0482 |
3.59 |
A10 |
- |
0.8 mL - 0.1 mol/L |
3.11 |
0.0483 |
3.46 |
A11 |
- |
1.0 mL - 0.1 mol/L |
3.02 |
0.0491 |
3.41 |
A12 |
- |
2.0 mL - 0.1 mol/L |
2.71 |
0.0537 |
3.42 |
A13 |
- |
2.0 mL - 1.0 mol/L |
1.72 |
0.0595 |
3.98 |
A14(di) |
- |
10.0 mL - 1.0 mol/L |
1.06 |
0.0597 |
1 |
|
|
|
|
Mean
|
3.73±0.58
|
1dissociated form 2undissociated form 3no evaluation possible
To calculate the percentage of the ionized test item and the usable pH range the following equations were used:
pH range = pKamean± log 9
pH range = 3.73 ± 0.95→pH 2.78 to pH 4.68
Applying this pH range (i.e. experiments A6 to A11) the mean pKa-value is resulting in
pKa = 3.49 (SD = 0.07)
Applying this pKa value again for the definition of the pH range the experiments A6 to A12 are selected for the calculation of the final result:
pH range = 3.49 ± 0.95 → pH = 2.54 to pH = 4.44
This is resulting in the final value pKa = 3.48(SD = 0.07)
Experiment B
Experiment
|
Volume and concentration of added NaOH
|
Volume and concentration of added HCl
|
Resulted pH value
|
Absorption
|
pKa
|
B1 |
- |
- |
6.27 |
0.0209 |
3 |
B2 |
0.1 ml - 0.01 mol/L |
- |
6.65 |
0.0239 |
5.08 |
B3 |
1.0 ml - 0.1 mol/L |
- |
10.79 |
0.0344 |
10.484 |
B4(dm) |
1.0 ml - 1.0 mol/L |
- |
11.86 |
0.0230 |
2 |
B5 |
- |
0.1 ml - 0.01 mol/L |
6.20 |
0.0285 |
5.48 |
B6 |
- |
0.3 ml - 0.1 mol/L |
3.55 |
0.0403 |
3.55 |
B7 |
- |
0.4 ml - 0.1 mol/L |
3.42 |
0.0440 |
3.61 |
B8 |
- |
0.5 ml - 0.1 mol/L |
3.31 |
0.0442 |
3.51 |
B9 |
- |
0.6 ml - 0.1 mol/L |
3.24 |
0.0465 |
3.57 |
B10 |
- |
0.8 ml - 0.1 mol/L |
3.10 |
0.0480 |
3.52 |
B11 |
- |
1.0 ml - 0.1 mol/L |
3.00 |
0.0514 |
3.67 |
B12 |
- |
2.0 ml - 0.1 mol/L |
2.72 |
0.0527 |
3.51 |
B13 |
- |
2.0 ml - 1.0 mol/L |
1.74 |
0.0579 |
3 |
B14(di) |
- |
10.0 ml - 1.0 mol/L |
1.06 |
0.0575 |
1 |
|
|
|
|
Mean
|
3.94 ± 0.76
|
1dissociated form2undissociated form3no evaluation possible4outlier
The pKa value for each determination was calculated as the average of the individual values for which the dissociated proportion was between 10% and 90%. Data points for which the dissociated proportion was outside this range were not used to calculate the final result.
To calculate the percentage of the ionized test item and the usable pH range the following equations were used:
pH range = pKamean± log 9
pH range = 3.94 ± 0.95 = pH 2.99 to pH 4.89
Applying this pH range (i.e. experiments B6 to B11) the mean pKa-value is resulting in
pKa = 3.57 (SD = 0.06)
Applying this pKa value again for the definition of the pH range the experiments B6 to B12 are selected for the calculation of the final result:
pH range = 3.57 ± 0.95 → pH = 2.62 to pH = 4.52
This is resulting in the final value pKa = 3.56(SD = 0.06)
Experiment C
Experiment
|
Volume and concentration of added NaOH
|
Volume and concentration of added HCl
|
Resulted pH value
|
Absorption
|
pKa
|
C1 |
- |
- |
6.22 |
0.0323 |
5.77 |
C2 |
0.1 ml - 0.01 mol/L |
- |
6.72 |
0.0255 |
5.59 |
C3 |
1.0 ml - 0.1 mol/L |
- |
10.79 |
0.0238 |
9.104 |
C4(dm) |
1.0 ml -1.0 mol/L |
- |
11.83 |
0.0231 |
2 |
C5 |
- |
0.1 ml - 0.01 mol/L |
5.92 |
0.0210 |
3 |
C6 |
- |
0.3 ml - 0.1 mol/L |
3.56 |
0.0385 |
3.46 |
C7 |
- |
0.4 ml - 0.1 mol/L |
3.43 |
0.0407 |
3.43 |
C8 |
- |
0.5 ml - 0.1 mol/L |
3.32 |
0.0445 |
3.52 |
C9 |
- |
0.6 ml - 0.1 mol/L |
3.24 |
0.0458 |
3.51 |
C10 |
- |
0.8 ml - 0.1 mol/L |
3.09 |
0.0483 |
3.50 |
C11 |
- |
1.0 ml - 0.1 mol/L |
3.01 |
0.0492 |
3.48 |
C12 |
- |
2.0 ml - 0.1 mol/L |
2.71 |
0.0530 |
3.48 |
C13 |
- |
2.0 ml -1.0 mol/L |
1.73 |
0.0573 |
3.36 |
C14(di) |
- |
10.0 ml -1.0 mol/L |
1.06 |
0.0581 |
1 |
|
|
|
|
Mean
|
3.91±0.94
|
1dissociated form2undissociated form3no evaluation possible4outlier
The pKa value for each determination was calculated as the average of the individual values for which the dissociated proportion was between 10% and 90%. Data points for which the dissociated proportion was outside this range were not used to calculate the final result.
To calculate the percentage of the ionized test item and the usable pH range the following equations were used:
pH range = pKamean± log 9
pH range = 3.91 ± 0.95 = pH 2.96 to pH 4.86
Applying this pH range (i.e. experiments C6 to C11) the mean pKa-value is resulting in
pKa = 3.48 (SD = 0.03)
Applying this pKa value again for the definition of the pH range the experiments C6 to C12 are selected for the calculation of the final result:
pH range = 3.48 ± 0.95 → pH = 2.53 to pH = 4.43
This is resulting in the final value pKa = 3.48(SD = 0.03)
Description of key information
pKa= 3.51-3.56 at 22 °C +/- 5 °C
(OECD 112, Spectrophotometric Method)
Key value for chemical safety assessment
Additional information
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.