reaction mass of isomers of: C7-9-alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption

Remarks:

other: QSAR assessment of adsorption/desorption potential

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

27 January 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Substance is a hydrocarbon based UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is characterized using quantitative structure property relationships for representative hydrocarbon structures that comprise the potential structures available for exposure. Calculations have been conducted using the US EPA EPIWIN KOCWIN V2.0 model, which is considered to be an appropriate tool for substances of this type. The full report is attached below under "Additional Background Information".

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Please refer to the full report attached below under "Additional Background Information".

GLP compliance:

no

Type of method:

other: QSAR

Media:

other: Not applicable

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

406-040-9

EC Name:

-

Cas Number:

125643-61-0

Molecular formula:

C17 H25 O3 R, Where R = (C7 H15) or (C8 H17) or (C9 H19)

IUPAC Name:

C7-9-(branched)-alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate

Details on test material:

Not applicable.

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Study design

Test temperature:

Not applicable

HPLC method

Details on study design: HPLC method:

Not applicable

Batch equilibrium or other method

Analytical monitoring:

not required

Details on sampling:

Not applicable

Details on matrix:

Not applicable

Details on test conditions:

Not applicable

Computational methods:

Not applicable

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

log Koc

Value:

>= 5.3 - <= 6.3

Remarks on result:

other: Calculated using KOWWIN v2.0

Adsorption coefficient 2

Type:

Koc

Value:

>= 210 000 - 1 900 000

Remarks on result:

other: Calculated using KOWWIN v2.0

Results: HPLC method

Details on results (HPLC method):

Not applicable

Results: Batch equilibrium or other method

Adsorption and desorption constants:

Not applicable

Recovery of test material:

Not applicable

Concentration of test substance at end of adsorption equilibration period:

Not applicable

Concentration of test substance at end of desorption equilibration period:

Not applicable

Details on results (Batch equilibrium method):

Not applicable

Statistics:

Not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The substance is a UVCB molecule, comprising of the main phenyl structure and variable ester groups of C7 - C9 branched and linear alkyls. The proposed water solubility of the substance is very low (<0.03 mg/l at RTP). Experimental results have also demonstrated that the material forms emulsions in water when tested at higher concentrations. As such, it is proposed that conducting an assessment of adsorption/desorption using an experimental study is not appropriate given the known properties of the substance in water. These difficulties were also observed during assessment of the partition coefficient value for the substance, resulting in a calculation method being applied.
It was therefore deemed appropriate to assess the potential Adsorption / Desorption nature using a QSAR methodology, rather than an experimental test. Following review of QSAR programmes, KOCWIN™ (V2.0) was selected for use in assessing the substance. On the basis of the calculated results using KOCWIN v2.0, the following values are proposed in support of the registration dossier:

Log Koc – Range of 5.3 to 6.3

Koc (L/Kg) – Range of 2.1E+05 to 1.9E+06

This is indicative of the potential for high adsorption to soil / sludge, which is expected given the low water solubility. Further assessment of this endpoint is not required at the level of registration currently being applied, hence any further review would be conducted at the next level of registration.

Executive summary:

The substance is a UVCB molecule, comprising of the main phenyl structure and variable ester groups of C7 - C9 branched and linear alkyls.The proposed water solubility of the substance is very low (<0.03 mg/l at RTP). Experimental results have also demonstrated that the material forms emulsions in water when tested at higher concentrations. As such, it is proposed that conducting an assessment of adsorption/desorption using an experimental study is not appropriate given the known properties of the substance in water. These difficulties were also observed during assessment of the partition coefficient value for the substance, resulting in a calculation method being applied. 

It was therefore deemed appropriate to assess the potentialAdsorption / Desorption nature using a QSAR methodology, rather than an experimental test. Following review of QSAR programmes,  KOCWIN™ (V2.0) was selected for use in assessing the substance. On the basis of the calculated results using KOCWIN v2.0, the following values are proposed in support of the registration dossier:

 

Log Koc – Range of 5.3 to 6.3

 

Koc (L/Kg) – Range of 2.1E+05 to 1.9E+06

 

This is indicative of the potential for high adsorption to soil / sludge, which is expected given the low water solubility. Further assessment of this endpoint is not required at the level of registration currently being applied, hence any further review would be conducted at the next level of registration.