Reaction mass of 2-methyl-6-methylideneoct-7-en-2-yl acetate and 2-(4-methylcyclohex-3-en-1-yl)propan-2-yl acetate and 1-methyl-4-(propan-2-ylidene)cyclohexyl acetate

Endpoint summary

Description of key information

For Pseudo Linalyl Acetate the following results were derived:

Species	Guideline / Method	Result	Remarks
Daphnia magna	OECD TG 202, GLP	48-h EC50: 6.3 mg/L	Key study, Rel. 2. Value derived from read-across to Myrcenyl acetate (CAS# 1118 -39 -4)
Green algae (P. subcapitata)	OECD TG 201, GLP	72-h ErC50: 19.0 mg/L 72-h ErC10: 1.7 mg/L 72 -h NOEC: 1.1 mg/L	Key study, Rel. 2. Values derived from read-across to Myrcenyl acetate (CAS# 1118 -39 -4)

Additional information

The aquatic toxicity is assessed based on read-across from Myrcenyl acetate to Pseudo Linalyl Acetate. The executive summary of the Myrcenyl acetate 'mono' are presented in the respective Endpoint summaries. The read across rationale is presented below.

Aquatic toxicity of Pseudo linalyl acetate based on read across from data available for Myrcenyl acetate ‘mono’ (CAS# 1118-39-4).

 

Introduction and hypothesis for the analogue approach

Pseudo linalyl acetate has one major, two minor constituents and a number of impurities. Myrcenyl acetate ‘mono’ with 25-35% is the main constituent. Alpha and Gamma Terpinlyl acetate are the minor ones, each between 10-20%. For Pseudo linalyl acetate there are no experimental aquatic toxicity data available.In accordance with Article 13 of REACH, lacking information can be generated by other than experimental testing, i.e. applying alternative methods such as QSARs, grouping and read-across.For assessing the aquatic toxicity of Pseudo linalyl acetate, the analogue approach is selected because for its main constituent, Myrcenyl acetate ‘mono’, experimental data is available which can be used for read across.

Hypothesis:The aquatic toxicity of Myrcenyl acetate ‘mono’ is considered to be representative for all constituents of Pseudo linalyl acetate.

Available information:ForMyrcenyl acetate ‘mono’ analgae test was performed according to OECD TG 201 (Rel. 1). In this study, algae were exposed to test concentrations of 1, 3.2, 10, 32 and 100% v/v saturated solution. The 72-h ErC50 and ErC10 values were determined at 19 and 1.7 mg/L, respectively, based on geometric mean measured concentrations. With the same substance aDaphnia toxicity test was performed (OECD TG 202, Rel. 1). In this semi-static study, Daphnia were exposed to test concentrations of 6.25, 12.5, 25, 50 and 100% v/v saturated solution. The 48-h EC50 was determined at 6.3 mg/L, based on mean measured concentrations of freshly prepared media, because the concentrations remained stable during the test.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical(s) are shown in the data matrix, including physico-chemical properties and available environmentalfateinformation.

Purity / Impurities

Pseudo linalyl acetate’s key constituents are covered by Myrcenyl acetate ‘mono’. All impurities (< 10%) are not expected to impact the assessment because these have similar structures. In Appendix 1 all components are presented.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection: For Pseudo linalyl acetate Myrcenyl acetate ‘mono’ was selected as the key analogue because it is the major constituent and expected to represent the substance as a whole.

Structural similarities and differences: The chemical structures of the Pseudo linalyl acetate key constituents all have a hydrocarbon backbone with one or more (non)conjugated double bonds, to which an acetate is attached. The difference is that Myrcenyl acetate ‘mono’ has a conjugated double bond and has a straight branched chain while the Terpinyl acetates are cyclic. The conjugated double bond is expected to be more electrophilic and therefore more reactive, but the experimental data show very similar results.

Bioavailability: Theconstituents of Pseudo linalyl acetate, including its key constituent Myrcenyl acetate ‘mono’ have similar log Kows around 4.4 and therefore will show similar bioavailability.

Reactivity: The constituents of Pseudo linalyl acetate are all esters and therefore fall into the same reactivity class. The aquatic toxicity of Myrcenyl acetate ‘mono’ is very similar to Terpinyl acetate alpha (see data matrix). The alcohol impurities, when present, are neutral organics and therefore have a lower reactivity.

Uncertainty of the prediction: There are no other remaining uncertainties than already discussed above. Conversion is not considered necessary in view of the similarities in molecular weight and log Kow of the constituents.

Data matrix

The relevant information on physico-chemical properties and ecotoxicological characteristics are presented in the data matrix below.

Conclusions for hazard and risk assessment

ForPseudo linalyl acetateno experimental aquatic toxicity information is available. Read-across is performed to data available Myrcenyl acetate ‘mono’, the main constituent of Pseudo linalyl acetate. The EC50 for Daphnia and algae is 6.3 and 1.7 mg/l, respectively and the EC10 for algae is 1.7 mg/l. These values can be used for Pseudo linalyl acetate directly.

Final conclusion on hazard and risk assessment:Pseudo linalyl acetate has EC50 for Daphnia and algae are 6.3 and 1.7, respectively. The EC10 is 1.7 mg/l.

 

Data matrixfor the read across to Pseudo linalyl acetate from Myrcenyl acetate ‘mono’ for acute oral toxicitywith supporting information from Alpha-Terpinyl acetate

Common name	Pseudo linalyl acetate	Myrcenyl acetate ‘mono’	Alpha-Terpinyl acetate	Gamma-Terpinyl acetate
	Target	Source (Major constituent)	Supporting source (Minor constituent	Minor constituent
Structure
CAS #	--	1118-39-4	80-26-2	10235-63-9
EC #	--	214-262-0	201-265-7	233-564-3
Reach registration	2018	2018	Registered	Not found
Empirical formula	n.a.	C12H20O2	C12H20O2	C12H20O2
SMILES	n.a.	CC(=O)OC(C)(C)CCCC(=C)C=C	O=C(OC(C(CCC(=C1)C)C1)(C)C)C	O=C(OC(CCC(=C(C)C)C1)(C1)C)C
Molecular weight	n.a.	196	196	196
Physico-chemical data
Log Kow	4.4 (selected as key)	4.4 (exp.)	4.3	4.5
Ecotoxicity
Daphnia 48-h EC50 in mg/l	6.3 mg/L (Read-across)	6.3 mg/L (OECD TG 202)	> 10 (OECD TG 202)	6.3 mg/L (Read-across)
Aquatic algae in mg/l 72-h ErC50 72-h ErC10	19.0 1.7 (Read across)	19.0 1.7  (OECD TG 201)	6.9 2.7 (OECD TG 201)	19.0 1.7 (Read across)

 

Appendix 1: Constituents and possible impurities of Pseudo linalyl acetate

CAS#	Type of constituent	Type and Name
		Esters linear and alicyclic
1118-39-4	Major	2-methyl-6-methylideneoct-7-en-2-yl acetate (Myrcenyl acetate ‘mono’)
7643-61-0	Impurity	(5Z)-2,6-dimethylocta-5,7-dien-2-yl acetate
7643-62-1	Impurity	(5Z)-2,6-dimethylocta-5,7-dien-2-yl acetate
105-87-3 *	Impurity	(2E)-3,7-dimethylocta-2,6-dien-1-yl acetate (Geranyl acetate)
80-26-2 *	Minor	2-(4-methylcyclohex-3-en-1-yl)propan-2-yl acetate (Alpha-Terpinyl acetate)
150461-96-4	Impurity	1-(3,3-dimethylcyclohex-1-en-1-yl)ethyl acetate
150461-97-5	Impurity	1-(5,5-dimethylcyclohex-1-en-1-yl)ethyl acetate
10235-63-9	Minor	1-methyl-4-(propan-2-ylidene) cyclohexyl acetate (Gamma-Terpinyl acetate)
20777-47-3	Impurity	cis-1-methyl-4-(prop-1-en-2-yl)cyclohexyl acetate (Beta-terpinyl acetate)
97890-05-6	Impurity	(2Z)-2-(3,3-dimethylcyclohexylidene)ethyl acetate
76-49-3	Impurity	(1R,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-ylrel-acetate (Bornyl acetate)
210648-12-7	Impurity	3,3,5-trimethylcyclohept-4-en-1-yl acetate
		Alcohol linear and alicyclic
543-39-5	Impurity	2-methyl-6-methylideneoct-7-en-2-ol (Myrcenol)
98-55-5 *	Impurity	2-(4-methylcyclohex-3-en-1-yl)propan-2-ol (Alpha-Terpineol)
586-81-2	Impurity	1-methyl-4-(propan-2-ylidene)cyclohexanol (Gamma-terpineol)