Isopropyl 2-methylbutyrate

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

Study report date: 29th November 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE; EPISUITE

2. MODEL (incl. version number); EPIWEB v4.11

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: CCC(C)C(=O)OC(C)C
MOL FOR: C8 H16 O2
MOL WT: 144.22
Log Kow (octanol-water): 3.30

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL

Episuite is a software program developed by the EPA and is recognised internationally as the accepted QSAR software.

5. APPLICABILITY DOMAIN

No data

6. ADEQUACY OF THE RESULT
Results from EPISUITE are appropriate in the absence of other data on physicochemical characteristics. The decomposition rate constant of IMB in air following reaction with hydroxyl radicals was calculated to be 5.6617x 10-12cm3 molecule-1sec-1. Assuming that the 12 hour daytime hydroxyl radical concentration is 1.5 x 106molecules. cm-3, the half-life was calculated to be 1.889 days (12 hour day).

Qualifier:

no guideline available

Principles of method if other than guideline:

- Principle of test: EPISUITE
- Short description of test conditions: as per program
- Parameters analysed / observed: V4.11

GLP compliance:

no

Key result

DT50:

1.899 d

Test condition:

Assuming that the 12 hour daytime hydroxyl radical concentration is 1.5E06 molecules. cm-3

Key result

Reaction with:

OH radicals

Rate constant:

0 cm³ molecule-1 s-1

Conclusions:

The decomposition rate constant of IMB in air following reaction with hydroxyl radicals was calculated to be 5.6617x 10-12cm3 molecule-1sec-1. Assuming that the 12 hour daytime hydroxyl radical concentration is 1.5 x 106molecules. cm-3, the half-life was calculated to be 1.889 days (12 hour day).

Executive summary:

The decomposition rate constant of Isopropyl 2-Methylbutanoate (IMB) in air occurring through reaction with hydroxyl radicals was estimated according to the method of Atkinson using the Atmospheric Oxidation Program (AOPWIN version 1.92, US EPA). This method estimates the rate constant for the atmospheric gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals and between ozone and olefinic/acetylenic compounds (Fabienne Ericher 2017).

 

The decomposition rate constant of IMB in air following reaction with hydroxyl radicals was calculated to be 5.6617x 10-12cm3 molecule-1sec-1. Assuming that the 12 hour daytime hydroxyl radical concentration is 1.5 x 106molecules. cm-3, the half-life was calculated to be 1.889 days (12 hour day).

Description of key information

Assuming that the 12 hour daytime hydroxyl radical concentration is 1.5E+06 molecules. cm-3, the half-life was calculated to be 1.889 days (12 hour day).

Key value for chemical safety assessment

Half-life in air:

1.889 d

Additional information

The decomposition rate constant of Isopropyl 2-Methylbutanoate (IMB) in air occurring through reaction with hydroxyl radicals was estimated according to the method of Atkinson using the Atmospheric Oxidation Program (AOPWIN version 1.92, US EPA). This method estimates the rate constant for the atmospheric gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals and between ozone and olefinic/acetylenic compounds (Fabienne Ericher 2017).

 

The decomposition rate constant of IMB in air following reaction with hydroxyl radicals was calculated to be 5.6617x 10-12cm3 molecule-1sec-1. Assuming that the 12 hour daytime hydroxyl radical concentration is 1.5 x 106molecules. cm-3, the half-life was calculated to be 1.889 days (12 hour day).

                                               

The calculation of the decomposition rate constant of IMB in air following reaction with ozone was not carried out as this calculation is only applicable to olefins and acetylenes.