Exo-1-methyl-4-(1-methylethyl)-7-oxabicyclo[2.2.1]heptan-2-ol

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

(Q)SAR

Adequacy of study:

key study

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:

Please refer to QMRF and QPRF in the section "Overall remarks" and "Executive summary", respectively.

Data source

Reference

Reference 1

Reference Type:

other: EPIWin calculation

Title:

Unnamed

Year:

2017

Report date:

2017

Reference 2

Reference Type:

other: Estimation software

Title:

Estimation Programs Interface Suite for Microsoft Windows, v4.11

Author:

US-EPA

Year:

2012

Bibliographic source:

United States Environmental Protection Agency, Washington, DC, USA

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

(1S,2S)-1-methyl-4-(propan-2-yl)-7-oxabicyclo[2.2.1]heptan-2-ol

Cas Number:

87172-89-2

IUPAC Name:

(1S,2S)-1-methyl-4-(propan-2-yl)-7-oxabicyclo[2.2.1]heptan-2-ol

Test material form:

solid

Results and discussion

Dissipation half-life of parent compound

Key result

DT50:

11.269 h

Test condition:

24-h day; 0.5E6 OH/cm³

Degradation rate constant

Key result

Reaction with:

OH radicals

Rate constant:

0 cm³ molecule-1 s-1

Any other information on results incl. tables

AOP Program (v1.92) Results:

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

SMILES : CC(C)C12CCC(O1)(C(C2)O)C

MOL FOR: C10 H18 O2

MOL WT : 170.25

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

Hydrogen Abstraction = 34.0284 E-12 cm3/molecule-sec

Reaction with N, S and -OH = 0.1400 E-12 cm3/molecule-sec

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

Addition to Olefinic Bonds = 0.0000 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

C:\Users\FEBINGS\Desktop\EPIWIN.doc

10

OVERALL OH Rate Constant = 34.1684 E-12 cm3/molecule-sec

HALF-LIFE = 0.470 Days (24-hr day; 0.5E6 OH/cm3)

HALF-LIFE = 11.269 Hrs

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

****** NO OZONE REACTION ESTIMATION ******

(ONLY Olefins and Acetylenes are Estimated)

Experimental Database: NO Structure Matches

Fraction sorbed to airborne particulates (phi):

0.000108 (Junge-Pankow, Mackay avg)

0.00251 (Koa method)

Note: the sorbed fraction may be resistant to atmospheric oxidation

Applicant's summary and conclusion

Executive summary:

QPRF:AOPWIN

 

1.	Substance	See “Test material identity”
2.	General information
2.1	Date of QPRF	See “Data Source (Reference)”
2.2	QPRF author and contact details	See “Data Source (Reference)”
3.	Prediction
3.1	Endpoint (OECD Principle 1)	Endpoint	Phototransformation in air
		Dependent variable	Hydroxyl reaction rate constant (cm^3/molecule*sec)
3.2		Model or submodel name	AOPWIN
		Model version	1.92
		Reference to QMRF	QMRF: Estimation of Atmospheric Degradation Using AOPWIN v1.92 (EPI Suite v4.11): Hydroxyl Radical Reaction
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number or SMILES
		Descriptor values	- Structure fragments
3.3	Algorithm (OECD Principle 2)	Domain (On-Line AOPWIN User’s Guide): As the complete training sets for AOPWIN's estimation methodology are not available, describing a precise estimation domain for this methodology is not possible. There is no information on the number of instances of fragments in the training dataset.
		If the substance is a member of one of the following chemical classes, the substance is probablywithinthe applicability domain of the model (based on information by other authors, e.g. Posthumus and Slooff, 2001): alkanes, haloalkanes, alkenes, haloalkenes, polyenes, terpenes, alkynes, aldehydes, ketones, alcohols, glycols, ethers, esters, epoxides, thiols, thioethers, aliphatic amines, hydrazines, nitrites, nitrates, nitriles, P-containing organics, aromatic compounds (alkylbenzenes, halobenzenes, phenols, PAHs, styrene, methoxybenzene, aniline, nitrobenzene, biphenyl, dibenzofurans, dibenzodioxins)		Fulfilled
		The substance isnotwithinthe applicability domain of the model if it is a perhalogenated alkanes.		Not Fulfilled
		Substance is a secondary, tertiary and heterocyclic amine. Estimated valueshighly uncertain.		Not Fulfilled
3.4	The uncertainty of the prediction (OECD principle 4)	- n = 667 - correlation coefficient r^2= 0.963 - standard deviation = 0.218 - absolute mean error = 0.127 - 90% of the estimated rate constants within a factor of two of the experimental data - 95% of the estimated rate constants within a factor of three of the experimental data
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Reaction rate constants for hydroxyl radicals are the summation of the following mechanisms: (1) Hydrogen abstraction (2) Reaction with specific nitrogen and sulphur fragments and reaction with hydroxyl (OH) fragments such as alcohols and phenols (3) Addition to triple bonds (4) Addition to olefinic bonds (5) Addition to aromatic rings (6) Addition to fused rings The model works according to the group contribution method which uses fragments and the corresponding reaction values to estimate the reaction rate constant of a given substance.

 

References

- R Posthumus and W Slooff (2001). Implementation of QSARs in ecotoxicological risk assessments. RIVM report 601516 003. Online: http://rivm.openrepository.com/rivm/bitstream/10029/9559/1/601516003.pdf

- US EPA (2012). On-Line AOPWIN User’s Guide.