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EC number: 500-148-0
CAS number: 61788-89-4
The Dimerised Fatty Acids and its Derivatives category covers C16 - C18
unsaturated fatty acids derived monomers, dimers and trimers, as well as
their hydrogenated products in different proportions and in accordance
with their corresponding production and purification processes. They are
all prepared by the dimerisation of C16 - C18 unsaturated fatty acids.
As UVCB substances derived from natural sources, members of this
category are chemically similar as they are all essentially a complex
mixture of C16 - C18 unsaturated and saturated, branched and linear
fatty acids, their monomers, dimers and trimers with varying structural
geometric isomers. All substances in the category have an overlap in
regard to their composition. With reference to information of existing
categories, the category of Dimerised Fatty Acids and Its Derivatives is
based on similar physicochemical and toxicological properties and 2
sub-categories are further defined on the basis of their environmental
fate and toxicity. The first sub-category covers three monomeric
(by-)products of the dimerization process (readily biodegradable
substances). The second sub-category covers the predominately oligomers
(dimeric and trimeric products) of dimerization based on their lack of
ready biodegradability and other environmental fate properties.
Sub-category 1: predominantly monomers
Fatty acids, C16-18 and C18-unsaturated, branched and linear
Hydrogenated monomer acid
Octadecanoic acid, branched and linear
Sub category 2: predominantly oligomers (dimers, trimers)
Fatty acids, C16-C18 and C18-unsaturated, dimerized
Fatty acids, C18-unsaturated, dimers
Fatty acids, C18-unsaturated, dimers, hydrogenated
Fatty acids, C18-unsaturated, trimers
Derived from the same starting substance, all substances in this
category have a homologous composition of fatty acids with a C16 - C18
carbon chain in diverse forms, that is susceptible to oxidation through
metabolic processes. In view of the results of various QSAR analyses,
the toxic hazard of these substances mainly depends on the number of
carbons, on the chain “structure”, such as branching, unsaturation,
grade of cyclics and aggregation, as well as on their position in the
whole molecular structure. In contrast, the number of the functional
group “carboxylic acids” has no significant influence on the tox- and
Sub-category 2: predominantly oligomers (dimers, trimers)
Aquatic toxicity Sub-Category 2: Dimerised Fatty Acids and its
derivatives, predominantly oligomers (dimer, trimers)
Aquatic toxicity: All available aquatic toxicity studies within this
category showed that Dimerised Fatty Acids, predominantly oligomers are
not harmful to aquatic organisms.
Short term tests with freshwater and marine species of three trophic
levels (fish: Danio rerio and Cyprinus carpio), Daphnia
magna, algae (Pseudokirchnerella subcapitata)) are available
for Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4). All
organisms did not show any effects up to the limit of water solubility
(<0.12 mg/L, detection limit) of the tested substance. Finally it can be
seen from the toxicity test with a water accommodated fraction of Fatty
acids, C18-unsaturated, dimers (CAS
No. 61788-89-4) with Pseudomonas putida bacteria that no effects
up to 10000 mg/L (nominal) were observed.
These short-term toxicity results are supported by long-term toxicity
data within the category, and in particular for Fatty acids, C18
-unsaturated, dimers, hydrogenated (CAS No. 68743-41-5). In a long term
test with fish (Danio rerio) no effects were observed within the
water solubility of the substance. Both Fatty acids, C18-unsaturated,
dimers (CAS No. 61788-89-4) and Fatty acids, C18-unsaturated, dimers,
hydrogenated (CAS No. 68783-41-5) are derived from Fatty acids, C16-18
and C18-unsaturated, dimerised (CAS No 71808-39-4), the crude dimer. The
only difference between the two “dimer acids” is the degree of
saturation or hydrogenation. Data from the MITI-database (MOE, 2003;
MOE, 2008) indicate for C16/C18 fatty acids a slightly higher toxicity
of unsaturated forms than the saturated forms, however this MITI data
also shows that the length of the chain is correlated to the level of
toxicity. For dimerised C18 chains resulting in 36 carbon molecules,
i.e. a duplication of C atoms, this is directly reflected by the very
low water solubilities (both < 0.52 mg/L). As the C16-and C18 fatty
acids are in general more water soluble than dimerised fatty acids it is
not expected that effects will occur up to the limit of water solubility
regardless of the level of saturation and thus read across for to the
C36 saturated form to the unsaturated form is fully valid.
Since all members of the sub-category 2 (predominantly oligomers) are
insoluble (< 0.52 mg/L, limit of detection) and taking into account that
all tests carried out with freshwater and marine species of three
trophic levels (fish, Daphnia, algae) for substances within the
category did not show any effects within the water solubility of the
tested substances, neither in short- nor in long-term tests, the
category members of Dimerised Fatty Acids and Its Derivatives and
therefore also Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4)
can be regarded as not harmful for aquatic organisms.
Ministry of the Environment, Government of Japan (2003). Daphnia
magna, reproduction test by oleic acid. Food Research Laboratories.
Report No. 14053. 2003-03-31.
Ministry of the Environment, Government of Japan (2008). Daphnia,
reproduction toxicity test for palmitic acid. Mitsubishi Chemical Safety
Institute Ltd.,Laboratory. Report No. A050381. 2008-02-14.
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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