Registration Dossier
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EC number: 211-522-5 | CAS number: 657-84-1
Henry's Law constant
Administrative data
Link to relevant study record(s)
Description of key information
The HYDROTOPES Category comprises the following 6 substances:
STS - Sodium toluene 4-sulphonate (CAS 657-84-1, EC 211-522-5)
SXS - Sodium (xylenes and 4-ethylbenzene) sulphonate (EC 701-037-1)
NH4XS - Ammonium (xylenes and 4-ethylbenzene) sulphonate (EC 943-024-5)
SCS - Sodium p-cumenesulphonate (CAS 15763-76-5, EC 239-854-6)
KCS - Potassium p-cumenesulphonate (CAS 164524-02-1, EC 629-764-9)
NH4CS - Ammonium p-cumenesulphonate (CAS 680972-33-2, EC 811-484-5)
In addition CaXS (Calcium Xylenesulphonate, CAS 28088-63-3, EC 248-829-9) was evaluated for complete the assessment despite it is not registered under REACH.
No experimental data are existing for the substances of the category. The Henry's law constant has been estimated with HENRYWIN v3.20, Bond method and the results are reported below:
STS, CAS: 657-84-1; 2.83 e-004 Pa-m3/mole, episuite v. 4.1
SXS, CAS: 1300-72-7; 3.12 e-004 Pa-m3/mole, episuite v. 4.1
NH4XS, CAS: 26447-10-9; not estimated
SCS, CAS: 15763-76-5; 4.98 e-004 Pa-m3/mole, episuite v. 4.1
KCS, CAS: 164524-02-1; not estimated
NH4CS, CAS: 37475-88-0; not estimated
The value of STS has been selected as representative of the category for the Chemical safety assessment
Key value for chemical safety assessment
- Henry's law constant (H) (in Pa m³/mol):
- 0
- at the temperature of:
- 25 °C
Additional information
Henry's Law Constant characterizes the equilibrium of dilute concentrations of volatile, soluble substances between the gas and liquid phases. The aromatic sulphonic hydrotopes are not volatile and therefore a Henry's Law Constant is not feasible or relevant. An indicative value to complete the Chemical safety assessment has been calculated with EPIWIN 4.1. The value 0.000283 has been reported as key value for safety assessment, as conservative case.
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