Reaction mass of decyl acrylate and octyl acrylate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

According to chapter R.7a of the ECHA Guidance on information requirements and chemical safety assessment (version 2.0, November 2014), as the test substance is manufactured at more than 10 and less than 100 tons a year and as the test substance is not a surfactant, the Koc should be calculated as a first step. In addition, the two major components of the test substance fall in the applicability domain of the QSAR as described below, with molecular weight values of 184.28 and 212.34:

Training Set Molecular Weights:
Minimum MW: 32.04
Maximum MW: 665.02
Average MW: 224.4

Validation Molecular Weights:
Minimum MW: 73.14
Maximum MW: 504.12
Average MW: 277.8

Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that log Koc estimates are less accurate for compounds outside the MW range of the training set compounds, and/or that have more instances of a given fragment than the maximum for all training set compounds. It is also possible that a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient or correction factor was developed. These points should be taken into consideration when interpreting model results.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The Koc values were determined by using a QSAR (KOCWIN v2.00 EPI SUITE 2000 U.S. Environmental Protection Agency) recommended by ECHA.

Key result

Type:

log Koc

Value:

2.591 dimensionless

Remarks on result:

other: Octyl acrylate (CAS 2499-59-4)

Key result

Type:

log Koc

Value:

3.112 dimensionless

Remarks on result:

other: Decyl acrylate (CAS 2156-96-9)

Validity criteria fulfilled:

not applicable

Conclusions:

Octyl acrylate (CAS 2499-59-4):
log Koc = 2.5912 (estimated from MCI)
log Koc = 3.5311 (estimated from measured log Kow = 4.83)

Decyl acrylate (CAS 2156-96-9):
log Koc = 3.1125 (estimated from MCI)
log Koc = 4.1174 (estimated from measured log Kow = 5.89)

Executive summary:

The adsorption/desorption coefficients of the two major components of Reaction mass of decyl acrylate and octyl acrylate (EC Number 911 -295 -9), which are Octyl Acrylate (CAS Number 2499 -59 -4) and Decyl Acrylate (CAS Number 2156 -96 -9) were estimated using the recommended QSAR model KOCWIN v2.00 from the MCI method and measured log Kow values (OECD Test Guideline 117, HPLC Method).

The estimated values were:

Octyl acrylate (CAS 2499 -59-4):

log Koc = 2.5912 (estimated from MCI)

log Koc = 3.5311 (estimated from measured log Kow = 4.83)

Decyl acrylate (CAS 2156-96-9):

log Koc = 3.1125 (estimated from MCI)

log Koc = 4.1174 (estimated from measured log Kow = 5.89)

Description of key information

The adsorption/desorption coefficients of the two major components of Reaction mass of decyl acrylate and octyl acrylate (EC Number 911-295-9), which are Octyl Acrylate (CAS Number 2499-59-4) and Decyl Acrylate (CAS Number 2156-96-9) were estimated using the recommended QSAR model KOCWIN v2.00 from the MCI method and measured log Kow values (OECD Test Guideline 117, HPLC Method).

The estimated values were:

Octyl acrylate (CAS 2499-59-4):

log Koc = 2.59 (estimated from MCI)

log Koc = 3.53 (estimated from measured log Kow = 4.83)

Decyl acrylate (CAS 2156-96-9):

log Koc = 3.11 (estimated from MCI)

log Koc = 4.12 (estimated from measured log Kow = 5.89)

According to the EPI SUITE documentation (U.S. Environmental Protection Agency, 2000), the MCI method is "somewhat more accurate than the log Kow methodology, although both methods yield good results." The documentation reports values of r², standard deviation and average deviation of 0.916, 0.330 and 0.263 for the MCI method, respectively, versus 0.86, 0.429 and 0.321 for the Log Kow methodology. The training datasets include a total of 516 compounds for the estimation of these correlations. For these reasons, the MCI method is preferred by the registrant as a more accurate predictor of Koc values.

 

Among the two components, the highest log value of adsorption/desorption calculated via the MCI method (3.11) was used for chemical safety assessment (CSA). This value is considered as a worst-case value, as an increase of the adsorption/desorption coefficient leads to a significant increase of Predicted Environmental Concentration in sediments and soil.

Key value for chemical safety assessment

Koc at 20 °C:

1 296

Additional information

[LogKoc: 3.11]