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EC number: 204-464-7 | CAS number: 121-32-4
- 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
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- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
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- 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:
- from 22 DEC 2016 to 16 FEB 2017
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- 2015-07-28
- Dissociating properties:
- yes
- pKa:
- 7.51
- Remarks on result:
- other: Temperature is between 19.8°C and 21°C
- Conclusions:
- Under the conditions of the study, the pKa of the test material is equal to 7.51 between 19.8 °C and 21 °C.
- Executive summary:
The determination of the dissociation constant (pKa) of the test material was studied in compliance with OECD TG No. 112 using the titration method.
During this study, it was shown that the value of the water dissociation constant of 3-ethoxy-4-hydroxybenzaldehyde (ethylvanillin) [121-32-4] is equal to 7.51 between 19.8 °C and 21 °C.
- Endpoint:
- dissociation constant
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Result from ECHA recommended QSAR model.
- Justification for type of information:
- QSAR prediction
- Qualifier:
- no guideline required
- Principles of method if other than guideline:
- QSAR
- GLP compliance:
- no
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- -5.01
- Remarks on result:
- other: corresponds to ionisation of the aldehyde (calculated) / no data on T°C
- No.:
- #2
- pKa:
- 7.84
- Remarks on result:
- other: corresponds to ionisation of the OH (calculated) / no data on T°C
- Endpoint:
- dissociation constant
- Type of information:
- (Q)SAR
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- The value is not an experimental result, however the available elements justify the validity of the estimated value. The QSAR model SPARC was validated for compounds having one until 8 ionization sites and for all organic compounds except : covalent hydrates, tautomers, carbon acid reaction center where the perturbations for this group are very large and quaternary amines. Ethylvanillin is not part of this kind of compounds and has one possible ionization site implying that SPARC model is validated for this test item.
- Justification for type of information:
- QSAR prediction
- Principles of method if other than guideline:
- QSAR estimation
- GLP compliance:
- no
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 7.84
- Temp.:
- 25 °C
- Conclusions:
- The model has been run in November 2015 for this substance.
Ethylvanilline has a pka value of 7.84. - Executive summary:
The dissociation constant was predicted using a reliable QSAR model: SPARC (SPARC Automated Reasoning Calculator v5.1, March 2013). After confirmation that ethylvanillinfalls into the model applicability domain, it was shown that the test item has a pka value of 7.84.
Referenceopen allclose all
Minimal temperature during the test phase: 19.8 °C
Maximal temperature during the test phase: 21.0 °C
The values of the pH during the three titrations were between 6.17 and 10.53.
The pH curves show the equivalence point found during the titrations.
The tables summarise the results on the 10 most representative incremental additions before the equivalence point.
First determination
CNaOH(mol/L) |
0.00508 |
w NaOH(g) |
1.02402 |
Purity of NaOH(%) |
99.3 |
Molar mass(g/mol) |
40.0 |
Volume(mL) |
250 |
Dilution factor |
20 |
w test item(g) |
0.08309 |
VNaOH (mL) |
pH |
pKa |
Mean pKa |
SD |
RSD (%) |
5 |
7.08 |
7.55 |
7.51 |
0.022 |
0.30 |
6 |
7.18 |
7.54 |
|||
7 |
7.27 |
7.53 |
|||
8 |
7.35 |
7.51 |
|||
9 |
7.44 |
7.51 |
|||
10 |
7.52 |
7.50 |
|||
11 |
7.60 |
7.50 |
|||
12 |
7.69 |
7.49 |
|||
13 |
7.78 |
7.49 |
|||
14 |
7.87 |
7.48 |
Second determination
CNaOH(mol/L) |
0.00508 |
w NaOH(g) |
1.02402 |
Purity of NaOH(%) |
99.3 |
Molar mass(g/mol) |
40.0 |
Volume(mL) |
250 |
Dilution factor |
20 |
w test item(g) |
0.08112 |
VNaOH (mL) |
pH |
pKa |
Mean pKa |
SD |
RSD |
5 |
7.10 |
7.55 |
7.50 |
0.033 |
0.45 |
6 |
7.19 |
7.53 |
|||
7 |
7.28 |
7.52 |
|||
8 |
7.36 |
7.51 |
|||
9 |
7.44 |
7.49 |
|||
10 |
7.53 |
7.49 |
|||
11 |
7.61 |
7.48 |
|||
12 |
7.69 |
7.47 |
|||
13 |
7.78 |
7.46 |
|||
14 |
7.88 |
7.45 |
The mean average of the pKa for the three determinations was equal to 7.51.
The mean Relative Standard Deviation for the tree determinations was equal to 0.35%.
The results obtained during the three determinations were less than ± 0.1 log units.
No more data on results.
Predicted value (model result): see the attach illustration
Predicted value (comments): No comments
Input for prediction: SMILES
Table of results: pKa is function of pH:
pH |
Species 1 |
Species 2 |
0 |
1 |
0 |
1 |
1 |
0 |
2 |
1 |
0 |
3 |
1 |
0 |
4 |
1 |
0 |
4.8 |
0.999 |
0.001 |
5 |
0.999 |
0.001 |
5.2 |
0.999 |
0.001 |
5.4 |
0.998 |
0.002 |
5.6 |
0.996 |
0.004 |
5.8 |
0.994 |
0.006 |
6 |
0.991 |
0.009 |
6.2 |
0.986 |
0.014 |
6.4 |
0.977 |
0.023 |
6.6 |
0.965 |
0.035 |
6.8 |
0.945 |
0.055 |
7 |
0.916 |
0.084 |
7.2 |
0.873 |
0.127 |
7.4 |
0.812 |
0.188 |
7.6 |
0.732 |
0.268 |
7.8 |
0.632 |
0.368 |
8 |
0.52 |
0.48 |
8.2 |
0.406 |
0.594 |
8.4 |
0.302 |
0.698 |
8.6 |
0.214 |
0.786 |
8.8 |
0.147 |
0.853 |
9 |
0.098 |
0.902 |
9.2 |
0.064 |
0.936 |
9.4 |
0.041 |
0.959 |
9.6 |
0.027 |
0.973 |
9.8 |
0.017 |
0.983 |
10 |
0.011 |
0.989 |
10.2 |
0.007 |
0.993 |
10.4 |
0.004 |
0.996 |
10.6 |
0.003 |
0.997 |
10.8 |
0.002 |
0.998 |
11 |
0.001 |
0.999 |
12 |
0 |
1 |
13 |
0 |
1 |
14 |
0 |
1 |
Description of key information
Dissociation constant = 7.51 between 19.8°C and 21°C.
Key value for chemical safety assessment
- pKa at 20°C:
- 7.51
Additional information
One experimental GLP study (Défitraces, 2017), OECD 112 compliant, was available and was selected as key study. The dissociation constant value in this study is 7.51 between 19.8°C and 21°C. The study was with reliability 1 according to Klimisch scale.
Two other data issue from QSAR model were selected as supporting studies and were with reliability 2.
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