Registration Dossier

Administrative data

Endpoint:
dissociation constant
Study period:
08 January 2009 to 07 February 2009
Data waiving:
study technically not feasible
Justification for data waiving:
other:

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
no guideline available
Deviations:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Sponsor's identification : H-CB sodium salt
Description : blue solid
Purity : 94.8%
Lot number : MB-2
Date received : 04 December 2008
Storage conditions : room temperature in the dark

Results and discussion

Applicant's summary and conclusion

Conclusions:
Testing was not carried out according to Method 112 of the OECD Guidelines for Testing of Chemicals, 12 May 1981, due to the test material being a complex mixture. Different groups in varying numbers, are complexed to the main structure which would result in overlapping pKa’s. With the test material containing multiple sulphonic acid sodium salts, it will be ionised throughout the environmentally relevant pH range.
No computer-based estimates were available as the full structure could not be entered into the ACD/I-Lab Web Service (ACD/pKa 8.03) predictive software. However, using literature data sulphonic acid groups typically have low values, pKa = -1.8* for CH3SO3H. Pyridine has a pKa = 5.25*, of which more than one may occur in the structure, but this is likely to be lowered due to conjugation.
* McMurray; Organic Chemistry, 1992, 3rd edition
Executive summary:

Testing was not carried out according to Method 112 of the OECD Guidelines for Testing of Chemicals, 12 May 1981, due to the test material being a complex mixture. Different groups in varying numbers, are complexed to the main structure which would result in overlapping pKa’s. With the test material containing multiple sulphonic acid sodium salts, it will be ionised throughout the environmentally relevant pH range.