Exo-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl propionate

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: read-across from a guideline study

Justification for type of information:

The adsorption / desorption potential of Isobornyl propionate is based on read-across from Cyclaprop. The documentation is presented in the Adsorption / Desorption Endpoint summary. The accompanying files are also attached there.

Reason / purpose for cross-reference:

read-across source

Key result

Type:

Koc

Value:

1 300 dimensionless

Type:

log Koc

Value:

3.11 dimensionless

Validity criteria fulfilled:

yes

Remarks:

Value is based on read across. Read across rationale is documented according to Annex XI criteria

Conclusions:

The Koc of Isobornyl propionate is 1300 (Log Koc is 3.11) based on read across from Cyclaprop, which was tested in an OECD TG 121.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 Oct 2011 to 22 Nov 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The information is used for read across to Isobornyl propionate.

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Alliance Separation Module 2695 (Waters, Milford, MA, USA)
- Type, material and dimension of analytical (guard) column: Hypersil BDS-CN, 150 mm  4.6 mm i.d., dp = 5 μm (Thermo Fisher Scientific, Waltham, MA, USA)
- Detection system: Dual λ Absorbance Detector 2487 (Waters)

MOBILE PHASES
- Type: 30/70 (v/v) methanol/water
- Experiments with additives carried out on separate columns: no
- pH: Neutral

DETERMINATION OF DEAD TIME
- Method: by means of homologous series

REFERENCE SUBSTANCES
- Identity: Acetanilide (CAS 103-84-4), Atrazine (CAS 191224-9), Monuron (CAS 150-68-5), 2,5-Dichloroaniline (95-82-9), Benzoic acid phenylester (CAS 93-99-2), Fenthion (CAS 55-38-9), Phenanthrene (CAS 85-01-8)

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k': k' = (tr - t0) / t0
- Determination of the log Koc value: by substituting its mean log k' in the calibration curve

Analytical monitoring:

no

Key result

Type:

Koc

Value:

1 300 dimensionless

Remarks on result:

other: Value for major compound

Key result

Type:

log Koc

Value:

3.11 dimensionless

Remarks on result:

other: Value for major compound

Type:

log Koc

Value:

1.86 dimensionless

Remarks on result:

other: Value for impurity I

Type:

log Koc

Value:

2.18 dimensionless

Remarks on result:

other: Value for impurity II

Type:

log Koc

Value:

2.99 dimensionless

Remarks on result:

other: Value for impurity III

Details on results (HPLC method):

- Retention times of reference substances used for calibration:
Acetanilide: 2.7 minutes
Atrazine: 3.9 minutes
Monuron: 3.7 minutes
2,5-Dicholoaniline: 4.4 minutes
Benzoic acid phenylester: 7.7 minutes
Fenthion: 15.4 minutes
Phennthrene: 14.7 minutes
- Details of fitted regression line (log k' vs. log Koc): log k' = 0.479 x log Koc - 1.00 (r=0.95, N=14)
- Graph of regression line attached: yes
- Average retention data for test substance: 8.227 minutes

K_ocof the test substance

Substance	tr,1 (min)	tr,2 (min)	mean tr(n=2)	log Koc	Koc	Area %
Formamide (to)   Acetanilide Atrazine Monuron 2,5-Dichloroaniline Benzoic acid phenylester Fenthion Phenanthrene   Impurity I Impurity II Impurity III Major compound	2.012   2.701 3.865 3.660 4.402 7.686 15.431 14.671   3.581 4.245 7.447 8.228	2.014   2.700 3.864 3.658 4.401 7.680 15.424 14.675   3.580 4.244 7.447 8.226	2.013                   3.581 4.245 7.447 8.227	1.26 1.81 1.99 2.55 2.87 3.31 4.09   1.86 2.18 2.99 3.11	7.3 x 10^1 1.5 x 10^2 9.8 x 10^2 1.3 x 10^3	0.39 0.83 8.2 91

HPLC chromatograms and the regression line are included as illustrations below.

Validity criteria fulfilled:

not applicable

Conclusions:

The log Koc of the major compound of the test substance is 3.11 (Koc 1300) at neutral pH. The log Koc's for impurities I, II and III were found to be 1.86, 2.18 and 2.99 respectively.

Executive summary:

The adsorption coefficient of the substance was investigated according to OECD guideline 121 using the HPLC method under GLP. The log Koc of the major compound was found to be 3.11 (Koc 1300) at neutral pH. The log Koc's for impurities I, II and III were found to be 1.86, 2.18 and 2.99 respectively.

Description of key information

The Koc is 1300 (log Kow is 3.11) based on read across from Cyclaprop, tested according to OECD TG 121.

Key value for chemical safety assessment

Koc at 20 °C:

1 300

Additional information

The information from Cyclaprop is presented first, followed by the read across rationale.

Cyclaprop

Cyclaprop was tested according to OECD TG 121 under GLP and resulted in a Koc of 1300 (log Koc 3.11)

Adsorption/Desorption (Koc)of Isobornyl propionate (CAS #2756-56-1) based on read-across from Cyclaprop (CAS # 68912-13-0)

 

Introduction and hypothesis for the analogue approach

Isobornyl propionate has an exo-1,7,7-Trimethylbicyclo[2.2.1]heptane-2-ol (Isobornyl alcohol) backbone to which a propionic ester group is attached. For this substance there are no experimental adsorption/desorption data available. According to REACH Annex XI 1.5, information can be generated by other means, i.e. applying alternative methods such as QSARs, grouping and read-across. For assessing the Koc the information of Cyclaprop is used for read across.

Hypothesis: Isobornyl propionate has the same Koc as Cyclaprop.

Available information:For Cyclaprop the log Koc was determined to be 3.11 (Koc of 1300) using the HPLC method (OECD TG 121).

Target chemical and source chemical(s)

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

Purity / Impurities

Isobornyl propionate is a mono-constituent >=88%, with impurities similar to the parent substance and < 10%.

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 Isobornyl propionate the substance Cyclaprop was used as an analogue because this substance is similar to Isobornyl propionate and it has experimental Koc information.

Structural similarities and differences:Isobornyl propionate and Cyclaprop both have a similar cyclohexyl bridged hydrocarbon backbone and a propionic ester as a functional group. The minor difference is that Isobornyl propionate has a single bridged ring with on the bridge two methyl groups, while Cyclaprop has these carbons in a pentyl ring attached to the hexylring. The double bond in the pentyl fragments is making the structure slightly more planar but not affecting the Koc.

Koc, Kow and conversion: The log Kow is predictive for Koc. Isobornyl propionate has a similar log Kow as Cyclaprop but the former has a slightly higher measured log Kow: 5 versus 4.4, respectively. This is not expected to influence the Koc to a significant extent in the present case. The Koc calculations of EpiSuite (Kow and MCI method) indicate only a slightly higher value for Isobornyl propionate compared to Cyclaprop: 808 and 509, respectively, using the MCI method. These Kocs are lower than the measured ones. For support another substance Verdox (Cas no.20298-69-5)has a log Kow of 4.75, an experimental Koc of 1300 (ECHA dissemination site) and a KocWin prediction using MCIof 440. The Koc value selected for Isobornyl propionate is in line with experimental derived values of close analogues and the Koc is slightly higher than the predicted value.

Uncertainty of the prediction: There is no remaining uncertaintyother than discussed above.

Data matrix

The relevant information on physicochemical properties and environmental characteristics are presented in the data matrix below.

Conclusions for fate and risk assessment

For Isobornyl propionate no experimental Koc information is available. For an analogue such information is available and this can be used for read across. When using read across the result should be applicable for classification and labelling and risk assessment as well as presented with reliable and adequate documentation. This documentation is presented in the current document. Cyclaprop has a Koc of 1300 and this information can be used for read across to Isobornyl propionate.

Final conclusion: Isobornyl propionate has a Koc of 1300 (log Kow 3.11).

 

Data matrix supporting the Koc of Isobornyl propionate using read across from Cyclaprop

Common names	Isobornyl propionate	Cyclaprop
Source/target	Target	Source
Chemical structures
CAS no.	2756-56-1	68912-13-0
EINECS	220-410-5	272-805-7
Empirical formula	C13H22O2	C13H18O2
Molecular weight	210.32	206.28
Phys-chem properties	IFF measured	IFF measured
Physical state	Liquid	Liquid
Water solubility (mg/l)	19.8	5
Log Kow (measured)	5.0 (IFF measured)	4.3 (Simonich in EpiSuite)
Environmental fate
Adsorption/desorption (Log Koc)	1300 (3.11) (Read across)	(1300) 3.11 (OECD TG 121)