Reaction mass of 3,7-dimethyloct-7-en-1-yl 3-methylbut-2-enoate and 3,7-dimethyloctyl 3-methyl-2-butenoate and citronellyl 3-methylcrotonate

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

05 December, 2019

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source

Qualifier:

no guideline required

Guideline:

other: QSAR : AOP Program (v1.92) module of EPISuite (v4.11)

Version / remarks:

AOP Program (v1.92) module of EPISuite (v4.11)

Principles of method if other than guideline:

QSAR Evaluation :
Description taken from Introduction section of AOPWIN Help Module in EPISuite (v4.11) :
https://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-interface
The Atmospheric Oxidation Program for Microsoft Windows (AOPWIN) estimates the rate constant for the atmospheric, gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals. It also estimates the rate constant for the gas-phase reaction between ozone and olefinic/acetylenic compounds. The rate constants estimated by the pro-gram are then used to calculate atmospheric half-lives for organic compounds based upon average atmospheric concentrations of hydroxyl radicals and ozone.
The estimation methods used by AOPWIN are based upon the structure-activity relationship (SAR) methods developed by Dr. Roger Atkinson and co-workers (Atkinson, 1985, 1986, 1987, 1991; Atkinson and Carter, 1984; Biermann et al, 1985; Kwok et al, 1992, Kwok and Atkinson, 1995; Kwok et al, 1996). AOPWIN incorporates updated fragment and reaction values as cited in Kwok and Atkinson (1995). In addition, Syracuse Research Corporation has derived some additional fragment and reaction values from new experimental data.
A journal article that discusses the Atmospheric Oxidation Program has been published (Meylan and Howard, 1993).
AOPWIN requires only a chemical structure to make these predictions. Structures are entered into AOPWIN by SMILES (Simplified Molecular Input Line Entry System) notations.
Hydroxyl Radical Reaction Half-Life Estimation :
Since a chemical in the troposphere is usually at a very low concentration and a steady-state concentration of OH radicals is produced by sunlight, the hydroxyl radical concentration can be treated as a constant so the reaction can be considered a pseudo first-order reaction.
The half-life in the troposphere, t½ = 0.693/kOH[OH]
where kOH is the hydroxyl radical rate constant in units of cm3/molecule-sec and [OH] is the hydroxyl radical concentration in units of molecules (or radicals) per cm3. Thus, to calculate the half-life in the troposphere, one needs the estimated or measured rate constant of the chemical as well as some average OH radical concentration. In a U.S. EPA review by Leifer (no date), the author concluded that the diurnally and annually averaged 12-h daylight hy-droxyl radical concentration of 1.5 × 106 molecules (radicals)/cm3 should be used as the de-fault in the AOPWIN program based upon data from Atkinson et al. (1990). More recent reviews (Atkinson and Arey, 2003) have suggested 2.0 × 106 molecules (radicals)/cm3 12-hour daylight hydroxyl radical concentration.
Twelve hour daylight OH radical concentrations are reasonable for fast reacting chemicals but for chemicals that react more slowly (> a few days) 24 hours averages might be more appro-priate. Atkinson (1985) suggested seasonally and diurnally 24 hour averaged hydroxyl radical concentrations at 298 K of:
5 × 105 molecules/cm3 in the northern hemisphere and
6 × 105 molecules/cm3 in the southern hemisphere
The AOPWIN program allows the user to select 12 or 24 hour time frames and any average hydroxyl radical concentrations, but the default is originally set at 1.5 × 106 molecules (radi-cals)/cm3 per 12-h of daylight

GLP compliance:

no

Specific details on test material used for the study:

SINODOR CQ :
Main Isomer IUPAC Name : 3,7-dimethyloct-6-en-1-yl 3-methylbut-2-enoate
SMILES ANNOTATION : CC(C)=CCCC(C)CCOC(=O)C=C(C)C

Estimation method (if used):

QSAR : AOP Program (v1.92) module of EPISuite (v4.11).

Key result

DT50:

0.084 d

Test condition:

Interaction with atmospheric Hydroxyl radicals. Based on 12 hours of daylight per day.

DT50:

0.023 d

Test condition:

Interaction with atmospheric Ozone.

Reaction with:

OH radicals

Rate constant:

0 cm³ molecule-1 s-1

Remarks on result:

other: Interaction with atmospheric Hydroxyl radicals. Based on 12 hours of daylight per day

Reaction with:

ozone

Rate constant:

0 cm³ molecule-1 s-1

Remarks on result:

other: Interaction with atmospheric Ozone.

AOP Program (v1.92) Results:

===========================

SMILES : CC(C)=CCCC(C)CCOC(=O)C=C(C)C

CHEM  : SINODOR CQ (Main Peak)

MOL FOR: C15 H26 O2

MOL WT : 238.37

------------------- SUMMARY (AOP v1.92): HYDROXYL RADICALS (25 deg C) --------

Hydrogen Abstraction      =  9.4593 E-12 cm3/molecule-sec

Reaction with N, S and -OH =  0.0000 E-12 cm3/molecule-sec

Addition to Triple Bonds  =  0.0000 E-12 cm3/molecule-sec

Addition to Olefinic Bonds = 117.3150 E-12 cm3/molecule-sec

Addition to Aromatic Rings =  0.0000 E-12 cm3/molecule-sec

Addition to Fused Rings   =  0.0000 E-12 cm3/molecule-sec

 

OVERALL OH Rate Constant = 126.7743 E-12 cm3/molecule-sec

HALF-LIFE =    0.084 Days (12-hr day; 1.5E6 OH/cm3)

HALF-LIFE =    1.012 Hrs

------------------- SUMMARY (AOP v1.91): OZONE REACTION (25 deg C) -----------

OVERALL OZONE Rate Constant =   50.393749 E-17 cm3/molecule-sec

HALF-LIFE =     0.023 Days (at 7E11 mol/cm3)

HALF-LIFE =    32.747 Min

 

Experimental Database: NO Structure Matches

Fraction sorbed to airborne particulates (phi):

0.000413 (Junge-Pankow, Mackay avg)

0.000159 (Koa method)

Note: the sorbed fraction may be resistant to atmospheric oxidation

Conclusions:

According to the AOPWIN (v1.92) Module of EPISuite (v4.11), SINODOR CQ is predicted to undergo rapid atmospheric degradation via interactions with both Hydroxy radicals and Ozone :

Hydroxy Radicals :
OVERALL OH Rate Constant = 126.7743 E-12 cm3/molecule-sec
HALF-LIFE = 0.084 Days (12-hr day; 1.5E6 OH/cm3)
HALF-LIFE = 1.012 Hrs

Ozone :
OVERALL OZONE Rate Constant = 50.393749 E-17 cm3/molecule-sec
HALF-LIFE = 0.023 Days (at 7E11 mol/cm3)
HALF-LIFE = 32.747 Min

According to this output, SINODOR CQ is unlikely to undergo long-range transport events.

Description of key information

According to the AOPWIN (v1.92) Module of EPISuite (v4.11), SINODOR CQ is predicted to undergo rapid atmospheric degradation via interactions with both Hydroxy radicals and Ozone :

Hydroxy Radicals :

OVERALL OH Rate Constant = 126.7743 E-12 cm3/molecule-sec

HALF-LIFE =    0.084 Days (12-hr day; 1.5E6 OH/cm3)

HALF-LIFE =    1.012 Hrs

Ozone :

OVERALL OZONE Rate Constant =   50.393749 E-17 cm3/molecule-sec

HALF-LIFE =     0.023 Days (at 7E11 mol/cm3)

HALF-LIFE =    32.747 Min

According to this output, SINODOR CQ is unlikely to undergo long-range transport events.

Key value for chemical safety assessment

Half-life in air:

0.084 d

Degradation rate constant with OH radicals:

0 cm³ molecule-1 s-1

Additional information

According to the AOPWIN (v1.92) Module of EPISuite (v4.11), SINODOR CQ is predicted to undergo rapid atmospheric degradation via interactions with both Hydroxy radicals and Ozone :

Hydroxy Radicals :

OVERALL OH Rate Constant = 126.7743 E-12 cm3/molecule-sec

HALF-LIFE =    0.084 Days (12-hr day; 1.5E6 OH/cm3)

HALF-LIFE =    1.012 Hrs

Ozone :

OVERALL OZONE Rate Constant =   50.393749 E-17 cm3/molecule-sec

HALF-LIFE =     0.023 Days (at 7E11 mol/cm3)

HALF-LIFE =    32.747 Min

According to this output, SINODOR CQ is unlikely to undergo long-range transport events