Glycerides, C16-18 mono-

Endpoint summary

Additional information

Justification for grouping of substances and read-across

The Glycerides category covers aliphatic (fatty) acid esters of glycerol. The category contains both well-defined and UVCB substances with aliphatic acid carbon chain lengths of C2 (acetate) and C7-C22, which are mostly linear saturated and even numbered. Some of the substances in the category contain unsaturated fatty acids (e.g. oleic acid in 2,3-dihydroxypropyl oleate, CAS 111-03-5 or general fatty acids C16-22 (even) unsaturated in Glycerides, C14-18 and C16-22-unsatd., mono- and di-, CAS 91744-43-7). Some category members contain branched fatty acids. Branching is mostly methyl groups (e.g. isooctadecanoic acid, monoester with glycerol, CAS 66085-00-5 or 1,2,3-propanetriyl triisooctadecanoate, CAS 26942-95-0). In one category member the branching cannot be located precisely (Glycerides, C16-18 and C18-unsatd., branched and linear mono-, di- and tri, ELINCS 460-300-6). Hydroxylated fatty acids are present in three substances (Castor oil, CAS 8001-79-4; castor oil hydrogenated, CAS 8001-78-3 and 2,3-dihydroxypropyl 12-hydroxyoctadecanoate, CAS 6284-43-1). Hydroxylation occurs on C12 of stearic acid in all these substances. Acetylated chains are present in the last part of the category, comprising fatty acids from C8 to C18 (even) and also C18 unsaturated, additionally a C18 acetylated fatty acid is present with the acetic acid located in C12 position (e.g. Glycerides, castor oil mono-, hydrogenated acetates / 12-acetoxy-octadecanoic acid, 2,3-diacetoxy, CAS 736150-63-3). All glycerides build mono-, di- and tri-esters in variable proportions.

Fatty acid esters are generally produced by chemical reaction of an alcohol (e.g. glycerol) with an organic acid (e.g. acetic, stearic or oleic acid) in the presence of an acid catalyst (Radzi et al., 2005). The esterification reaction is started by the transfer of a proton from the acid catalyst to the acid to form an alkyloxonium ion. The carboxylic acid is protonated on its carbonyl oxygen followed by a nucleophilic addition of a molecule of the alcohol to the carbonyl carbon of the acid. An intermediate product is formed. This intermediate product loses a water molecule and proton to give an ester (Liu et al., 2006; Lilja et al., 2005; Gubicza et al., 2000; Zhao, 2000). Mono-, di- and tri-esters are the final products of esterification with glycerol.

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, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006, whereby substances may be considered as a category provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity, the substances listed below are allocated to the category of Glycerides.

Glycerides category members include

 

CAS	EC name	Molecular weight (range in case of UVCBs)	Fatty acids chain length	Degree of esterification	Molecular formula
26402-26-6 (b)	Octanoic acid, monoester with glycerol	218.29	C8	Mono	C11H22O4
142-18-7 (a)	2,3-dihydroxypropyl laurate	274.40	C12	Mono	C15H30O4
25496-72-4	Oleic acid, monoester with glycerol	356.54	C18:1	Mono	C21H40O4
111-03-5	2,3-dihydroxypropyl oleate	356.54	C18:1	Mono	C21H40O4
66085-00-5	Isooctadecanoic acid, monoester with glycerol	358.55	C18iso	Mono	C21H42O4
6284-43-1	2,3-dihydroxypropyl 12-hydroxyoctadecanoate	374.56	C18OH	Mono	C21H42O5
620-67-7	Propane-1,2,3-triyl trisheptanoate	428.60	C7	Tri	C24H44O6
538-23-8	Glycerol trioctanoate	470.68	C8	Tri	C27H50O6
538-24-9	Glycerol trilaurate	639.00	C12	Tri	C39H74O6
122-32-7	1,2,3-propanetriyl trioleate	885.43	C18:1	Tri	C57H104O6
555-43-1	Glycerol tristearate	891.48	C18	Tri	C57H110O6
26942-95-0	1,2,3-propanetriyl triisooctadecanoate	891.48	C18iso	Tri	C57H110O6
91052-47-0	Glycerides, C16-18 mono-	330.51 - 358.56	C16, C18	Mono	C19H38O4; C21H42O4
91744-09-1	Glycerides, C16-18 and C18-unsatd. mono-	330.51 - 358.56	C16, C18; C18uns.	Mono	C19H38O4; C21H42O4; C21H40O4
85536-07-8	Glycerides, C8-10 mono- and di-	218.29 - 400.60	C8, C10	Mono and di	C11H22O4; C13H26O4; C19H36O5; C23H44O5
91052-49-2	Glycerides, C12-18 mono- and di-	274.40 - 625.04	C12, C14, C16, C18	Mono and di	C15H30O4; C21H42O4; C27H52O5; C39H76O5
67701-33-1	Glycerides, C14-18 mono- and di-	302.45 - 625.02	C14, C16, C18	Mono and di	C17H34O4; C21H42O4; C31H60O5; C39H76O5
67784-87-6	Glycerides, palm-oil mono- and di-, hydrogenated	302.45 - 625.02	C14, C16, C18	Mono and di	C17H34O4; C21H42O4; C31H60O5; C39H76O5
91845-19-1	Glycerides, C16-18 and C18-hydroxy mono- and di-	330.51 - 657.02	C16, C18 C18OH	Mono and di	C19H38O4; C21H42O4; C35H68O5; C39H76O5; C21H42O5; C39H76O7
97358-80-0	Isooctadecanoic acid, mono- and diesters with glycerol	358.57 - 625.02	C18iso	Mono and di	C21H42O4; C39H76O5
91744-13-7	Glycerides, C14-18 and C16-22-unsatd. mono- and di-	302.45 - 733.20	C14, C16, C18, C16, C18 and C22uns.	Mono and di	C17H34O4; C21H42O4; C19H36O4; C25H48O4; C31H60O5; C39H76O5; C35H64O5; C47H88O5
31566-31-1	stearic acid, monoester with glycerol	330.51 - 325.03	C16, C18	Mono and di	C19H38O4; C21H42O4; C35H68O5, C39H76O5
85251-77-0	Glycerides, C16-18 mono- and di-	330.51 - 625.03	C16, C18	Mono and di	C19H38O4; C21H42O4; C35H68O5; C39H76O5
91744-32-0	Glycerides, C8-10 mono-, di- and tri-	218.29 - 554.84	C8, C10	Mono, di and tri	C11H22O4; C13H26O4; C19H36O5; C23H44O5; C27H50O6; C33H62O6
91052-28-7	Glycerides, C14-18 and C16-18-unsatd. mono-, di- and tri-	302.46 - 885.46	C14, C16, C18, C16:1, C18:1, C18:2, C18:3	Mono, di and tri	C17H34O4; C21H42O4; C19H36O4; C21H40O4; C31H60O5; C39H76O5; C35H64O5; C39H72O5; C45H86O6; C57H110O6; C51H92O6; C57H104O6
91052-54-9	Glycerides, C16-18 mono-, di- and tri-	330.50 - 891.48	C16, C18	Mono, di and tri	C19H38O4; C21H42O4; C35H68O5; C39H76O5; C51H98O6; C57H110O6
91744-20-6	Glycerides, C16-18 and C18-unsatd. mono-, di and tri-	330.51 - 891.50	C16, C18, C18uns.	Mono, di and tri	C19H38O4; C35H68O5; C51H98O6; C21H40O4; C39H72O5; C57H104O6
no CAS	ELINCS 460-300-6: Glycerides, C16-C18 and C18-unsaturated, branched and linear mono-, di- and tri-	330.51 - 891.50	C16, C18, C18uns., branched and linear	Mono, di and tri	C19H38O4; C35H68O5; C51H98O6; C21H40O4; C39H72O5; C57H104O6
97722-02-6	Glycerides, tall-oil mono-, di-, and tri-	356.54 - 885.43	C16, C18, C20, C18uns.	Mono, di and tri	C21H40O4; C39H72O5; C57H104O6
77538-19-3	Docosanoic acid, ester with 1,2,3-propanetriol	414.66 - 1059.80	C22	Mono, di and tri	C25H50O4; C47H92O5; C69H134O6
91744-28-4	Glycerides, C12-18 di- and tri-	456.70 - 891.50	C12, C14, C16, C18	Di and tri	C27H52O5; C39H76O5; C39H74O6; C57H110O6
68606-18-8	Glycerides, mixed coco, decanoyl and octanoyl	470.69 - 807.32	C8, C10, C12, C14, C16	Di and tri	C27H50O6; C33H62O6; C39H74O6; C45H86O6; C51H98O6
65381-09-1	Decanoic acid, ester with 1,2,3-propanetriol octanoate	470.69 - 554.85	C8, C10	Tri	C27H50O6; C33H62O6
73398-61-5	Glycerides, mixed decanoyl and octanoyl	470.69 - 554.85	C8, C10	Tri	C27H50O6; C33H62O6
85536-06-7	Glycerides, C8-18	470.68 - 891.48	C8, C10, C12, C14, C16, C18	Tri	C27H50O6; C57H110O6
67701-26-2	Glycerides, C12-18	639.01 - 891.48	C12, C14, C16, C18	Tri	C39H74O6; C57H110O6
67701-30-8	Glycerides, C16-18 and C18-unsatd.	807.32 - 891.48	C16, C18; C18uns.	Tri	C21H40O4; C39H72O5; C57H104O6
8001-79-4	Castor oil	933.43	C18:1(OH)	Tri	C57H104O9
8001-78-3	Castor oil, hydrogenated	939.48	C18OH	Tri	C57H110O9
97593-30-1	Glycerides, C8-21 and C8-21-unsatd. mono- and di-, acetates	330.42 - 442.63	C2; C10	Tri (FA mono, diacetate)	C17H30O6; C25H46O6
97593-30-1	Glycerides, C8-21 and C8-21-unsatd. mono- and di-, acetates	358.47 - 498.74	C2; C12	Tri (FA mono, diacetate)	C19H34O6; C29H54O6
93572-32-8	Glycerides, palm-oil mono-, hydrogenated, acetates	372.54 - 400.59	C2; C16	Tri (FA mono, diacetate)	C21H40O5; C23H44O5
91052-13-0	Glycerides, C8-18 and C18-unsatd. mono- and di-, acetates	302.36 - 442.63	C2; C8, C10, C12, C14, C16, C18, C18uns.	Mono, di and tri	C15H26O6; C19H34O6; C21H38O6; C25H46O6
736150-63-3	Glycerides, castor-oil-mono, hydrogenated, acetates (main component: 12-acetoxy-octadecanoic acid (2,3-diacetoxy)propyl ester [CAS 330198-91-9])	500.67	C2; C18Ac	Tri (FA mono, diacetate)	C27H48O8
no CAS (c, d)	Short-, medium- and long-chain triglycerides (SCT, MCT, LCT)	-	C2-C18 (even numbered), C18uns.	Tri	-
no CAS (c, d)	mixture of mono-, di-, and triglycerides of lauric acid	274.40 - 639.00	C12	Mono, di and tri	C15H30O4; C27H52O5; C39H74O6
no CAS (c, d)	Modified triglyceride. Main components: 1,3-dioleoyl 2-palmitoyl triacylglycerol and 1,2-dipalmitoyl 3-oleoyl triacylglycerol	833.36 - 859.39	C16, C18, C18uns.	Tri	C53H100O6; C55H102O6
56-81-5 (c)	Glycerol	92.09	--	--	C3H8O3
111-14-8 (c)	Heptanoic acid	130.18	C7	--	C7H14O2
112-85-6 (c)	Docosanoic acid	340.58	C22	--	C22H44O2

(a) Category members subject to the REACh Phase-in registration deadline of 31 May 2013 are indicated in bold font.

(b) Substances that are either already registered under REACh or not subject to the REACh Phase-in registration deadline of 31 May 2013 are indicated in normal font.

(c) Surrogate substances are either chemicals forming part of a related category of structurally similar fatty acid esters or precursors/breakdown products of category members (i.e. alcohol and fatty acid moieties). Available data on these substances are used for assessment of (eco )toxicological properties by read-across on the same basis of structural similarity and/or mechanistic reasoning as described below for the present category.

For all category members registered under REACh a full data set for each endpoint is provided. For substances not subject to the current REACh Phase-in registration, lack of data for a given endpoint is indicated by "--".

(d) Assessment of toxicological properties is conducted also taking into account available data on mixtures of synthetic and/or naturally occurring glycerides (e.g. vegetable oils), which cannot be identified by a (single) CAS/EC number. The test materials short-, medium- and long-chain triglycerides (SCT, MCT, LCT) and their combinations (e.g. MLCT, SALATRIM – a SLCT) comprise triesters of glycerol with fatty acid chain lengths of C2 and C4 (short-chain), C8 and C10 (medium-chain) and C18 saturated/unsaturated (long-chain). The substance “mixture of mono-, di-, and triglycerides of lauric acid” comprises mono-, di and triesters of glycerol with dodecanoic acid (C12). The substance “Modified triglyceride” contains main components: 1,3-dioleoyl 2-palmitoyl triacylglycerol and 1,2-dipalmitoyl 3-oleoyl triacylglycerol, comprising triesters of glycerol with hexadecanoic (C16) and (9Z)-Octadec-9-enoic acid (C18:1). Available data on identity and composition of the individual test material for a given study is provided in the technical dossier.

 

Grouping of substances into this category is based on:

(1) common functional groups: all members of the Glycerides category are esters of a tri-functional alcohol (glycerol) with one or more carboxylic (fatty) acid(s) chain(s). The alcohol moiety (glycerol) is common to all category members. The fatty acid moiety comprises carbon chain lengths of C2 (acetate) and from C7-C22 (uneven/even-numbered) and includes mainly linear saturated alkyl chains, but also unsaturated, branched, hydroxylated and acetylated chains bound to the alcohol, resulting in mono-, di-, and tri-esters; and

(2) common precursors and the likelihood of common breakdown products via biological processes, which result in structurally similar chemicals: all members of the Glycerides category result from esterification of glycerol with the respective fatty acid(s). Esterification is, in principle, a reversible reaction (hydrolysis). Thus, the glycerol and fatty acid moieties are simultaneously precursors and breakdown products of Glycerides. For the purpose of grouping of substances, enzymatic hydrolysis in the gastrointestinal tract and/or liver is identified as the biological process, by which the breakdown of Glycerides result in structurally similar chemicals. Furthermore, hydrolysis represents the first chemical step in the absorption, distribution, metabolism and excretion pathways anticipated to be similarly followed by all Glycerides (CIR, 1984, 2004, 2007; Elder, 1990, 1982, 1986; FDA, 1975; Johnson, 2001; Lehninger, 1998; NTP, 1994; Stryer, 1996; WHO, 1967, 1974, 1975, 1979, 2001). Hydrolysis is catalysed by a class of enzymes known as lipases, a subgroup of carboxylesterases. In general, Glycerides are enzymatically hydrolysed in the small intestine to glycerol and corresponding carboxylic acid(s), and in the case of di- and triglycerides also to monoglycerides (with the ester bond at the sn-2 position). Following hydrolysis, glycerol is readily absorbed through the gastrointestinal tract and can be re-esterified to form endogenous glycerides or be metabolised to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate, which can be incorporated in the standard metabolic pathways of glycolysis and gluconeogenesis. Being a polar molecule, glycerol can also be readily excreted in the urine. Fatty acids are likewise readily absorbed by the intestinal mucosa and distribute systemically. Fatty acids are a source of energy. They are either re-esterified into triacylglycerols and stored in adipose tissue, or enzymatically degraded for energy primarily via β-oxidation. Alternative oxidation pathways (alpha- and omega-oxidation) are available and are relevant for degradation of branched fatty acids. Unsaturated fatty acids require additional isomerization prior to enter the β-oxidation cycle. Acetate, resulting from hydrolysis of acetylated Glycerides, is readily absorbed and feeds naturally into physiological pathways of the body and can be utilized in oxidative metabolism or in anabolic syntheses; and

(3) constant pattern in the changing of the potency of the properties across the category:the available data show similarities and trends within the category in regard to physicochemical, environmental fate, ecotoxicological and toxicological properties. For those individual endpoints showing a trend, the pattern in the changing of potency is clearly and expectedly related to the length of the fatty acid chains and the degree of substitution of glycerol (mono-, di- or triester).

a) Physicochemical properties:

The physico-chemical properties of the category members are similar or follow a regular pattern over the category. The patterns observed depend on the fatty acid chain length and the degree of esterification (mono-, di- or triester).

The molecular weight of the category members (glycerol esters) ranges from 218.29 to 1059.80 g/mol. The physical state is related to the chain length of the fatty acid moiety, the degree of saturation and the number of ester bonds. Thus, monoesters of short- and long-chain fatty acids (C8-C12) as well as unsaturated (C18:1) fatty acids and C18OH are solids, whereas monoesters of branched fatty acids (C18iso) are liquids. Triesters of shorter-chain fatty acids (C8-12) as well as unsaturated (C18:1) and branched longer-chain acids (C18iso) are liquids. The physical state of mixtures of mono-, di- and tri-esters depends on the amount of different esters. Mono-, di- and tristers of shorter-chain fatty acids are liquid (C8-12), mono-, di- and tristers of longer-chain fatty acids are solids (C14-18, C18OH and also C18iso). The turning point of this property seems to be fatty acids C12. In addition, mono- and diesters with a certain amount of unsaturated acids are liquids. Following the described pattern the UVCB triesters of shorter-chain fatty acids (C8-14) and unsaturated fatty acids (C18:1 and C18:1OH) are liquids. For the glycerides with acetic acid (mainly monoester of fatty acids and diester of acetic acid) the turning point seems to be the fatty acid chain length C14/C16. Below this point the substances are liquid, above this point category members are solid.

Also the boiling points are following a pattern: Increasing molecular weight results in increasing boiling temperatures. For a molecular weight of below 300 g/mol the boiling point is around 170 °C (C12 monoester), between a molecular weight of 350 to 480 g/mol the boiling point is between 230-300 °C. Above 300 g/moles the decomposition of the substances is probable. Also the acetate esters have boiling points >300 °C. According to Blake et al. (J. Chem. Eng. Data, 1961, 6, 87-98), esters of long chain acids with β‑hydrogen atoms in the alcohol moiety (i.e. alcohols with C3, e.g. propanol) decompose in the range between 262 and 283 °C. Since for longer chains the boiling temperature is higher, esters of fatty acids esterified with alcohols ≥ C3 and having a molecular weight exceeding 300 amu have a boiling point >300 °C and decompose before boiling.

All category members are non-volatile with a vapour pressure <0.01 Pa at temperature of 20 °C, mainly based on (Q)SAR calculation.

The n-octanol/water partition coefficient increases with increasing chain length and increasing degree of esterification (e.g. C8 monoester: 1.71; C7 triester: 8.86; C22 triester >15). A positive correlation with the overall number of CH2 units is observed.

The water solubility decreases accordingly with increasing chain length or increasing overall number of CH2 units (20-60 mg/L for C8 monoester to <0.05 mg/L for C7 triester; <4 mg/L for C18:1 monoester to <0.05 mg/L for C18iso monoester). The cut-off value for water solubility below 1 mg/L seems to be the C16 to C18 monoester. Fo higher degree of esterification (di and triesters) other limits are applicable: a C12 diester at least has a water solubility of below 1 mg/L, the C7 triester has a solubility well below 1 mg/L. The water solubility depends on the method used for testing and for analysis of test item. Testing by GC-MS is more selective than testing by TOC/DOC method, GC-MS results are therefore lower than results obtained by TOC. Nevertheless a correlation between increasing molecular weight and decreasing water solubility can be found.

b) Environmental fate and ecotoxicological properties:

The members of the Glycerides category are readily biodegradable and show low bioaccumulation potential in biota. Hydrolysis is not a relevant degradation pathway for these substances, due to their ready biodegradability and estimated half-lives in water > 250 days at pH 7 and 25 days at pH 8 (HYDROWIN v2.00). The majority of the Glycerides category members have log Koc values > 3, indicating potential for adsorption to solid organic particles. Therefore, the main compartments for environmental distribution of these substances are expected to be soil and sediment, with the exception of 2,3-dihydroxypropyl laurate (CAS 142-18-7), for which a log Koc < 3 is reported. Therefore, this substance will be most likely available in the water phase. Nevertheless, all substances are readily biodegradable, indicating that persistency in the environment is not expected. The volatilization potential of the Glycerides category members is negligible, based on vapour pressure values ranging from < 0.0001 Pa to < 5 Pa at 20°C. Nevertheless, if released into the atmosphere, these substances are expected to be rapidly photodegraded in view of their estimated half-lives in air, ranging from 1.5 to 20.7 hours (AOPWIN 1.92 program). Based on the above information, accumulation in air, subsequent transportation through the atmosphere and deposition into other environmental compartments is not anticipated. Regarding aquatic toxicity, acute and chronic values obtained in tests conducted on fish, invertebrates, algae and microorganisms showed no adverse effects in the range of the water solubility of the substances (or the highest attainable solubility in aqueous medium), with the exception of Glycerides, palm-oil mono-, hydrogenated, acetates (CAS 93572-32-8). Even though it cannot be excluded that for this substance the observed effects are due to physical interference with undissolved test material (particulate material observed in test solutions), the NOEC value of the algae test is < 1 mg/L (0.565 mg/L) and within the water solubility range of the substance (1.3-7.4 mg/L). Therefore, a conservative approach is applied and the substance classified as environmental hazard Chronic category 3, according to Regulation (EC) No. 1272/2008. Based on the available data, no toxicity to aquatic microorganisms, sediment and terrestrial organisms is to be expected for the substances of the Glycerides category.

c) Toxicological properties:

The available data shows that the category of Glycerides is characterised by a lack of change of the potency of toxicological properties. No human health hazard is identified. Thus, all available studies consistently show that Glycerides are not acutely toxic via the oral, dermal and inhalation routes. The available animal and human studies indicate that Glycerides are not skin or eye irritating and not skin sensitising. All available in vitro and in vivo genetic toxicity studies are negative for the induction gene mutations in bacteria and mammalian cells and of chromosome aberrations or micronuclei in mammalian cells. No adverse effects were observed up to, including and even well above the limit dose of 1000 mg/kg bw/day in the available short- and long-term toxicity studies via the oral route. Likewise, no reproductive toxicity effects were observed in any of the available studies.

 

The available data allows for an accurate hazard and risk assessment of the category and the category concept is applied for the assessment of environmental fate, environmental and human health hazards. Thus where applicable, environmental and human health effects are predicted from adequate and reliable data for source substance(s) within the group by interpolation to the target substances in the group (read-across approach) applying the group concept in accordance with Annex XI, Item 1.5, of Regulation (EC) No 1907/2006. In particular, for each specific endpoint the source substance(s) structurally closest to the target substance is/are chosen for read-across, with due regard to the requirements of adequacy and reliability of the available data. Structural similarities and similarities in properties and/or activities of the source and target substance are the basis of read-across.

A detailed justification for the grouping of chemicals and read-across is provided in the technical dossier (see IUCLID Section 13).

The Environmental Fate parameters of the Glycerides category are presented in the table below.

CAS	Phototransformation in air [DT50, 24 h day]	Hydrolysis [DT50, pH 7]	Biodegradation: screening tests	BCF / BAF [L/kg]	Adsorption / Desorption [log Koc]
142-18-7 (a)	(Q)SAR: 13.1 h	(Q)SAR: >1 yr	RA: 91744-28-4	(Q)SAR: 10.8/10.8 (Arnot-Gobas)	(Q)SAR: 1.5-2.0
6284-43-1	(Q)SAR: 8.2 h	(Q)SAR: >1 yr	RA: CAS 8001-78-3	(Q)SAR: 12.4/12.4 (Arnot-Gobas)	(Q)SAR: 2.8-3.2
620-67-7	(Q)SAR: 14.7 h	(Q)SAR: > 200 d	Experimental result: readily biodegradable	(Q)SAR: 1.01/1.01 (Arnot-Gobas)	(Q)SAR: 5.6-5.7
122-32-7	(Q)SAR: 1.5-1.7 h	(Q)SAR: >1 yr	Experimental result: readily biodegradable	(Q)SAR: 0.89/0.89 (Arnot-Gobas)	(Q)SAR: 13.7-14.2
555-43-1	(Q)SAR: 5.3 h	(Q)SAR: >1 yr	RA: CAS 8001-78-3	Experimental result: BCF (fish) < 10 (Q)SAR: 0.89/0.89 (Arnot-Gobas)	(Q)SAR: 14.0-14.2
91052-47-0	(Q)SAR: 4 - 11 h	Q)SAR: >1 yr	RA CAS 67701-33-1	Q)SAR:34.81 - 38.13/34.81 -38.34	(Q)SAR: 4 - 11 h
91744-09-1	(Q)SAR: 4 - 11 h	Q)SAR: >1 yr	RA CAS 97722-02-6	Q)SAR:34.81 – 56.78/34.81 - 57.01	(Q)SAR: 4 - 11 h
85536-07-8	(Q)SAR: 12.4-16.2 h	(Q)SAR: >1 yr	Experimental result: readily biodegradable	(Q)SAR: 1.7-12.3/1.7-12.3 (Arnot-Gobas)	(Q)SAR: 0.4-3.8
91052-49-2	(Q)SAR: 7.2-13.1 h	(Q)SAR: >1 yr	RA: CAS 91744-28-4	(Q)SAR: 0.9-38.1/0.9-38.3 (Arnot-Gobas)	(Q)SAR: 1.5-7.9
67701-33-1	(Q)SAR: 6.7-13.3 h	(Q)SAR: >1 yr	Experimental result: readily biodegradable:	(Q)SAR: 0.9-38.1/0.9-38.3 Arnot-Gobas)	(Q)SAR: 2.0-7.9
67784-87-6	Q)SAR: 6.7-13.3 h	(Q)SAR: >1 yr	RA: CAS 67701-33-1	Q)SAR: 0.9-38.1/0.9-38.3 Arnot-Gobas)	(Q)SAR: 2.0-7.9
97358-80-0	(Q)SAR: 7.2-10.2 h	(Q)SAR: >1 yr	RA: CAS 8001-78-3	(Q)SAR:0.9-36.7/0.9-36.6 (Arnot-Gobas)	(Q)SAR: 2.9-8.6
31566-31-1	(Q)SAR: 6.8 - 11 h	Q)SAR: >1 yr	RA CAS 67701-33-1	(Q)SAR:0.89-34.81/0.9-38.13 (Arnot-Gobas)	(Q)SAR: 2-7.9
85251-77-0	(Q)SAR: 6.8 - 11 h	Q)SAR: >1 yr	RA CAS 67701-33-1	Q)SAR:0.89-34.81/0.9-38.13 (Arnot-Gobas)	(Q)SAR: 3.7 – 4.8
91052-28-7	(Q)SAR: 1.5-13.4 h	(Q)SAR: >1 yr	RA: CAS 122-32-7	(Q)SAR: 0.9-56.7/0.9-57.1 (Arnot-Gobas)	(Q)SAR: 2.0-14.1
91052-54-9	(Q)SAR: 5.3-10.9 h	(Q)SAR: >1 yr	RA: CAS 67701-33-1 RA: CAS 77538-19-3	(Q)SAR: 0.9-38.1/0.9-38.3 (Arnot-Gobas)	(Q)SAR: 2.5-14.2
91744-20-6	(Q)SAR: 2.2 – 10.2 h	Q)SAR: >1 yr	Experimental result: readily biodegradable	(Q)SAR: 0.89-56.78/0.89-57.07	(Q)SAR: 3 – 16.6
97722-02-6	(Q)SAR: 1.5 - 4 h	Q)SAR: >1 yr	Experimental result: readily biodegradable	(Q)SAR: 0.89-56.78/0.89-57.07	(Q)SAR: 3 - 14.2
77538-19-3	(Q)SAR: 4.3-8.8 h	(Q)SAR: >1 yr	Experimental result: readily biodegradable	Q)SAR: 0.89-3.9/0.89-6 (Arnot-Gobas)	(Q)SAR: 4.1-17.3
91744-28-4	(Q)SAR: 5.3-9.6	(Q)SAR: >1 yr	Experimental result: readily biodegradable	(Q)SAR: 0.89-1.2/0.89-1.3 (Arnot-Gobas)	(Q)SAR: 4.8-14.2
68606-18-8	(Q)SAR: 5.9-12.7 h	(Q)SAR: > 200 d	RA: CAS 620-67-7 RA: CAS 122-32-7	(Q)SAR: 0.89-0.99/0.89-1 (Arnot-Gobas)	(Q)SAR: 6.4-12.6
65381-09-1	--	--	Experimental result: readily biodegradable	--	--
73398-61-5	(Q)SAR: 9.9 – 12.7 h	Q)SAR: >250 d	Experimental result: readily biodegradable	(Q)SAR: 0.89-1/0.89-1 (Arnot-Gobas)	(Q)SAR: 6.4-7.9
85536-06-7	(Q)SAR: 5.3-12.7 h	(Q)SAR: >1 yr	RA: CAS 8001-78-3	(Q)SAR: 0.89-38.1/0.89-38.3 (Arnot-Gobas)	(Q)SAR: 6.4-14.2
67701-26-2	(Q)SAR: 5.3-8.1 h	Q)SAR: >1 yr	RA: CAS 97722-02-6	(Q)SAR: 0.89/0.89 (Arnot-Gobas)	(Q)SAR: 9.2-14.2
67701-30-8	--	--	Experimental result: readily biodegradable	--	--
8001-78-3 (b)	(Q)SAR: 3.96	Q)SAR: >1 yr	Experimental result: readily biodegradable	(Q)SAR: 0.89/0.89 (Arnot-Gobas)	(Q)SAR: 10.9-12.7
97593-30-1 (C10)	(Q)SAR: 13.4-20.7 h	(Q)SAR: > 190 d	RA:CAS 97593-30-1 (C12)	(Q)SAR: 1.38-12.6/1.38-12.6 (Arnot-Gobas)	(Q)SAR: 3.2-5.8
97593-30-1 (C12)	Q)SAR: 11.2-17.9 h	(Q)SAR: > 190 d	Experimental result: readily biodegradable	(Q)SAR: 0.91-12.3/0.91-12.3 (Arnot-Gobas)	(Q)SAR: 3.7-4.2
93572-32-8	(Q)SAR: 11.9-13.1 h	(Q)SAR: > 200 d	Experimental result: readily biodegradable	(Q)SAR: 7.4-12.3/7.4-12.3 (Arnot-Gobas)	(Q)SAR: 3.2-4.4

(a) Category members subject to the REACh Phase-in registration deadline of 31 May 2013 are indicated in bold font.

(b) Substances that are either already registered under REACh or not subject to the REACh Phase-in registration deadline of 31 May 2013 are indicated in normal font.

For all category members registered under REACh a full data set for each endpoint is provided. For substances not subject to the current REACh Phase-in registration, lack of data for a given endpoint is indicated by "--".

 

The results of several biodegradation screening studies confirmed that all Glyceride category members are readily biodegradable according to OECD criteria (biodegradation ranges between 64% and 92% after 28 days). Due to their ready biodegradability, hydrolysis is not expected to be a relevant degradation pathway for these substances. The QSAR calculations performed with the HYDROWIN v2.00 program resulted in estimated half-lives in water ranging from 250 days to 10.2 years (at pH 7) and 25 days to 1 year (at pH 8). These results indicate that indeed hydrolysis is not expected to be a relevant process for the Glyceride category members in the environment.

The water solubility decreases at increasing fatty acid C-chain length and at increasing degree of esterification. A correlation between increasing molecular weight and decreasing water solubility is observed. Eight substances have water solubility values above 1 mg/L. Glycerides, C8-21 and C8-21 unsatd., mono- and diacetates (C10 and C12) (CAS 97593-30-1) and Glycerides palm-oil mono-, hydrogenated, acetates (CAS 93572-32-8) have water solubility values ranging from 1.3 mg/L up to 21.9 mg/L. The other five substances having a relatively higher solubility have a high content of medium fatty acid C-chain lengths (C8, C10, C12 and C14). The water solubility values of these substances, 2,3-dihydroxypropyl laurate (CAS 142-18-7), Glycerides, C8-10 mono- and di- (CAS 85536-07-8), Glycerides, C12-18 mono- and di- (CAS 91052-49-2), Glycerides, C12-18 di- and tri- (CAS 91744-28-4) and Glycerides C8-18 (CAS 85536-06-7), range from 2 mg/L up to 46 mg/L. The rest of the Glycerides category members are insoluble in water, with water solubility values ranging from < 1 mg/L to < 0.05 mg/L.

The adsorption potential of the Glyceride category members also increases with C-chain length and degree of esterification. QSAR estimations of log Koc values for these substances were performed with the KOCWIN 2.00 program. 2,3-dihydroxypropyl laurate (CAS 142-18-7) has the lowest log Koc values within the category, ranging from 1.5 to 2.1. Based on these results, the substance is not expected to show high adsorption potential to solid particles in the environment. For all other substances, high adsorption potential cannot be excluded, since log Koc values are above 3. QSAR estimations for multiconstituent/UVCB substances were performed on representative components. Therefore, the evaluation of their adsorption potential was made taking into account the content of each representative fatty acid and the degree of esterification. For substances with fatty acid representatives both below and above 3, high adsorption potential is expected for the larger constituents.

The volatilization potential of the Glycerides category members is negligible, based on vapour pressure values ranging from < 0.0001 Pa to < 5 Pa at 20°C. Nevertheless, if released into the atmosphere, these substances are expected to be rapidly photodegraded in view of their estimated half-lives in air, ranging from 1.5 to 20.7 hours (AOPWIN 1.92 program). Based on the above information, accumulation in air, subsequent transportation through the atmosphere and deposition into other environmental compartments is not anticipated.

Considering the expected high adsorption and low volatilization potential of the majority of the members of the Glycerides category, if released into the environment, sediment and soil are expected to be the target compartments for these substances. On the other hand, 2,3-dihydroxypropyl laurate (CAS 142-18-7) is expected to be also found in the water phase due to its low adsorption potential. Nevertheless, due to their readily biodegradable nature, all substances are expected to be rapidly and ultimately degraded in all environmental compartments and persistency is unlikely.

Due to the rapid environmental biodegradation and metabolization via enzymatic hydrolysis of the Glycerides category members, a relevant uptake and bioaccumulation in aquatic organisms is not expected. Enzymatic breakdown will initially lead to the free fatty acid and glycerol. From literature it is well known, that these hydrolysis products will be metabolised and excreted in fish effectively (Tocher, 2003). This is supported by calculated BCF values ranging from 0.89-57.1 L/kg within the category (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic). Experimental data on glycerol tristearate (CAS No. 555-43-1, category member) showed a BCF value in fish < 10 (Freitag, 1985). Please refer to IUCLID Section 5.3.1 for a detailed overview on bioaccumulation of the Glycerides category members.

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within the CSR.