Registration Dossier

Administrative data

Endpoint:
dissociation constant
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2011
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
1. SOFTWARE
ACD/Percepta QSAR for the pKa values, Log D Suite Program

2. MODEL
ACD/Log D Suite Program, Version 12, Advanced Chemistry Development, Toronto, Canada

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
1,3,5-triazine-2,4,6-trithione (= trithiocyanuric acid; CAS 638-16-4)
1,3,5-triazine-2,4,6-trithione, trisodium salt (CAS 17766-26-6)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Defined endpoint: pKa values (in dependence on the pH-value)
- Unambiguous algorithm: The QSAR (Quantitative Structure Activity Relationship) method calculates the pKa values and the log n-octanol/water partition coefficients (log POW) of organic chemicals in dependence of pH (=log D) using a molecule fragment contribution method.
- Defined domain of applicability: The model (ACD/LogD suite) uses a dataset of experimentally derived logKow values and considers the similarity of the test substance to the dataset. The applicability domain is defined based on the compounds of the trainings set by similarity index and consitency of the experimental values to the baseline model.


5. APPLICABILITY DOMAIN
The possible dissociation/(de)protonation processes and the associated pKa values and the concentration dependences of all neutral or ionic species, which are part of the system have been calculated. However, no detailed information on the specific applicability domain for calculation of pKa values is given in the report.

6. ADEQUACY OF THE RESULT
The program is commonly used to predict the octanol/water coefficient and is recommended in the REACh guidance document chapter R.6 and in the practical guide "How to use and report (Q)SARs" (2016). The calculations of the pKa values are considered to be valid and reliable for the organic acid and its sodium salts. Thus, the result is adequate for chemical safety assessment.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011
Title:
Dissociation constant
Author:
ACD
Year:
2011
Bibliographic source:
Calculated using Advanced Chemistry Developement (ACD/Labs), Software v.12, Toronto, Canada

Materials and methods

Test guidelineopen allclose all
Guideline:
other: REACh guidance document on QSAR R.6
Qualifier:
according to guideline
Guideline:
other: QSAR method used
Deviations:
no
Remarks:
see priciples of method
Principles of method if other than guideline:
estimated by using (Q)SAR program ACD/Log D suite, version 12, Advanced Chemistry Developement, Toronto, Canada
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
1,3,5-triazine-2,4,6-trithione (= trithiocyanuric acid; CAS 638-16-4)

Results and discussion

Dissociating properties:
yes
Dissociation constantopen allclose all
No.:
#1
pKa:
10.37
Temp.:
25 °C
No.:
#2
pKa:
8.9
Temp.:
25 °C
No.:
#3
pKa:
6.35
Temp.:
25 °C
No.:
#4
pKa:
0.2
Temp.:
25 °C
No.:
#5
pKa:
-1.25
Temp.:
25 °C
No.:
#6
pKa:
-3.3
Temp.:
25 °C

Any other information on results incl. tables

The ACD program clearly recommends the use of the results yielded for the keto form.

Applicant's summary and conclusion

Conclusions:
For the test substance six pKa values (three dissociation steps of 1,2,5-triazine-2,4,6-trithione in the pH range above 5 and three steps of protonating the amino groups in strong acid pH regions) were estimated with ACD/LogD Suite Program: 10.37, 8.9, 6.35, 0.2, -1.25 and -3.3.