Tetra(sodium/potassium)-7-[(E)-{2-acetamido-4-[(E)-(4-{[4-chlor-6-({2-[(4-fluor-6-{[4-(vinylsulfonyl)phenyl]amino}-1,3,5-triazin-2-yl)amino]propyl}amino)-1,3,5-triazin-2-yl]amino}-5-sulfonato-1-naphthyl)diazenyl]-5-methoxyphenyl}diazenyl]-1,3,6-naphthalintrisulfonate

Dissociation constant

Link to relevant study record(s)

Reference

Endpoint:

dissociation constant

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Study period:

Study completion date - 28 June 2006.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Qualifier:

no guideline required

Principles of method if other than guideline:

Estimation using Taft and Hammett Correlation equation

GLP compliance:

no

Specific details on test material used for the study:

Identity: FAT 40827/A
Batch: T2 5572 BOP 01/06
Purity: determined in this study
Appearance: black sticky powder
Expiration date: 28.02.2011
Storage: at room temperature

Dissociating properties:

yes

No.:

#1

pKa:

-6.7

Remarks on result:

other: ArSO3H, completely dissociated in aqueous solution.

No.:

#2

pKa:

ca. 1.65 - ca. 1.85

Remarks on result:

other: Diamino substituted chlorotriazine/fluorotriazine, neutral form in the environmental relevant pH range

No.:

#3

pKa:

> 22

Remarks on result:

other: Amide, no relevance for the environmental behaviour

The overall behaviour of FAT 40827/A in aqueous solutions will be dominated by the strongly arene acidic sulfonic acid groups (ArSO3H). Therefore, the molecule will be negatively charged and is present in its anionic form over the whole environmentally relevant pH range from approximatively pH = 4 to 9.

Conclusions:

The overall behaviour of FAT40827/A in aqueous solutions will be dominated by the strongly arene acidic sulfonic acid groups (ArSO3H). Therefore, the molecule will be negatively charged and is present in its anionic form over the whole environmentally relevant pH range from approximately pH = 4 to 9.

Executive summary:

The purpose of this study was to estimate the dissociation constants (pKa values) of FAT 40827/A.

The dissociation of a chemical in water is of importance in assessing its impact upon the environment. It governs the form of the test item, which in turn determines its behaviour and transport. It may affect the adsorption of the chemical on soils and uptake into biological cells.

The overall behaviour of FAT 40827/A in aqueous solutions will be dominated by the strongly arene acidic sulfonic acid groups (ArSO3H). Therefore, the molecule will be negatively charged and is present in its anionic form over the whole environmentally relevant pH range from approximately pH = 4 to 9.

Description of key information

The overall behaviour of FAT 40827/A in aqueous solutions will be dominated by the strongly arene acidic sulfonic acid groups (ArSO3H, pKa = -6.7). Therefore, the molecule will be negatively charged and is present in its anionic form over the whole environmentally relevant pH range from approximately pH = 4 to 9.

Key value for chemical safety assessment

pKa at 20°C:

-6.7