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EC number: 293-917-2
CAS number: 91648-55-4
The category consists of alkyl sulfates with a predominantly linear
alkyl chain length of C8-C20. Most chemicals of this category are not
defined substances, but mixtures of homologues with different alkyl
chain lengths (UVCBs). The most important common structural feature of
the category members is the presence of a predominantly linear aliphatic
hydrocarbon chain with a polar sulfate group, neutralized with a counter
ion (i.e., Na+, K+, NH4+, ethanolamine or monoisopropanolamine cation).
The hydrophobic hydrocarbon chain (with a length between C8 and C20) and
the polar sulfate group confer surfactant properties and enable the
commercial use of these substances as anionic surfactants. Common
physical and biological pathways result in structurally similar
breakdown products, and are, together with the surfactant properties,
responsible for similar environmental behavior and essentially identical
hazard profiles with regard to human health. The counter ion will not
influence chemical reactivity and classification for the purpose of this
assessment is not expected to be affected by the difference in counter
ion (ref. OECD SIDS 2007, HERA Report 2002, Koennecker et al. 2011).
In aqueous environments the salts will dissociate, so that the counter
ions will not fundamentally alter pathways of tissue disposition,
metabolism, excretion, or target organs of toxicity. Accordingly no
major differences were found in most of the endpoints between the
compounds with different counter ions (ref. OECD SIDS 2007, HERA Report
2002, Koennecker et al. 2011). Moreover, several of the counter-ions
have also been assessed in the OECD HPV Program and/or according to
REACH Regulation (EC) No 1907/2006: ethanolamine (CAS 141-43-5)
triethanolamine (CAS 102-71-6), monoisopropanolamine (CAS 78-96-6), the
ammonia category (CAS 7664-41-7; 1336-21-6; 7783-18-8; 12593-60-1) and
ammonium salts, like ammonium sulfate (CAS 7783-20-2), chloride (CAS
12125-02-9) and bicarbonate (CAS 1066-33-7).
In accordance with Article 13 (1) of Regulation (EC) No 1907/2006,
"information on intrinsic properties of substances may be generated by
means other than tests, provided that the conditions set out in Annex XI
are met. In particular for environmental fate and eco-toxicity,
information shall be generated whenever possible including the use of
information from structurally related substances. In this particular
case the similarity of the alkyl sulfates category members is justified,
in accordance with the specifications listed in Regulation (EC) No.
1907/2006 Annex XI, 1.5 Grouping of substances and read-across, is based
on the scope of overlapping of composition, similar molecular structure,
physico-chemical properties, toxicological, ecotoxicological profiles
and supported by various QSAR methods.
Physico-chemical properties relevant for environmental fate of alkyl
Physico-chemical characteristics of the substances in the category are
similar, or follow regular patterns. The most important parameter
influencing PC-properties is the varying length of the alkyl chain.
- Vapour pressure - as ionic substances, category members are
characterized by low vapour pressures.
- Partition coefficient - as surfactants concentrate at
hydrophilic/hydrophobic boundaries and do not equilibrate between
phases, Pow is not a good descriptor of surfactant hydrophobicity and
only of a limited predictive value for the partitioning of these
compounds in the environment. Nevertheless, experimental Pow values have
been obtained, usually as quotients of solubilities in octanol and in
water. Partition coefficients are low but they increase with the alkyl
- Water solubility - the solubility in water of the category members is
in the range of 1-1000 g/L. Particular values decrease with the alkyl
Environmental fate and pathways of alkyl sulfates:
- All members of the alkyl sulfates category are well soluble in water.
- The substance is readily biodegradable. The same result was
demonstrated in numerous studies for the whole category of alkyl
- Abiotic degradation like hydrolysis is not a relevant for
environmental pathway due to the chemical structure of the substances.
- All the substances in this category are essentially non-volatile,
which implies that atmospheric photodegradation is irrelevant.
- Due to the low to moderate log Koc-values, it can be predicted that
the sorption to sludge, sediments and soils will be relatively low.
- The members of alkyl sulfates category are unlikely to persist in the
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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