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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

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) 

The susbtances in the Hydrotropes category does not have any oxydizing properties based on oxygen balance calculation and based on the availbale test on SXS.

The oxygen balance is calculated using the formula: 

                     2 ( x ) + (y / 2)  + M – (z)

OB = -1600 * __________________________



X = number of atoms of carbon

Y = number of atoms of hydrogen

Z = number of atoms of oxygen

M = number of atoms of metal (metallic oxide produced).

The Oxygen balance of Hydrotropes substances are:

STS (C7H7O3SNa, MW = 194.18 Da): OB = -119,47

SXS (Former EC 215-090-9, C8H9O3SNa, MW = 208.21 Da): OB =  -134,48

NH4XS (Former EC 247-710-9, C8H10O3S.H3N, MW = 203.26 Da): OB = -161,37

SCS (C9H12O3SNa, MW = 223.24 Da): OB = -150,51

KCS (C9H12O3SK, MW = 223.24 Da): OB = -140,97

NH4CS (C9H15O3NS, MW = 217 Da): OB = -165,90

A negative oxygen balance is an indication that substance contains less oxygen than is needed; therefore it is not expected that substance may, generally by yielding oxygen, cause, or contribute to the combustion of other materials. Based on the oxygen balance values, no oxidizing properties are expected for Hydrotropes substances.

Key value for chemical safety assessment

Oxidising properties:

Additional information

Justification for classification or non-classification