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Environmental fate & pathways

Phototransformation in air

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Reference
Endpoint:
phototransformation in air
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Half-life in air estimated using the EPIsuite QSAR
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Guideline:
other:
Principles of method if other than guideline:
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 program are then used to calculate atmospheric half-lives for organic compounds based upon average atmospheric concentrations of hydroxyl radicals and ozone.
GLP compliance:
no
Reaction with:
OH radicals
Rate constant:
cm³ molecule-1 s-1

Tetramine DiC18

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

Hydrogen Abstraction = 134.7350 E-12 cm3/molecule-sec

**Reaction with N, S and -OH = 192.0000 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

OVERALL OH Rate Constant = 326.7350 E-12 cm3/molecule-sec

HALF-LIFE = 0.049 Days (24-hr day; 0.5E6 OH/cm3)

HALF-LIFE = 1.178 Hrs

........................ ** Designates Estimation(s) Using ASSUMED Value(s)

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

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

(ONLY Olefins and Acetylenes are Estimated)

Tetramine diC16

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

Hydrogen Abstraction = 129.0828 E-12 cm3/molecule-sec

**Reaction with N, S and -OH = 192.0000 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

OVERALL OH Rate Constant = 321.0828 E-12 cm3/molecule-sec

HALF-LIFE = 0.050 Days (24-hr day; 0.5E6 OH/cm3)

HALF-LIFE = 1.199 Hrs

........................ ** Designates Estimation(s) Using ASSUMED Value(s)

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

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

(ONLY Olefins and Acetylenes are Estimated)

Experimental Database: NO Structure Matches

Conclusions:
In the atmosphere tetramine di C16-18 are likely to be degraded by reaction with hydroxyl radicals. The half-life in air is calculated using the EPIsuite QSAR using the advised 500000 OH-radicals/cm3
Executive summary:

In the atmosphere tetramine di C16 -18 is likely to be degraded by reaction with hydroxyl radicals. Degradation rates for some components were calculated with the Atmospheric Oxidation Programme based on structure activity relationships developed by Atkinson (1987). With a concentration of 500,000 OH-radicals/cm3, degradation half-lives of 1.2 h were calculated. Because there are no important releases into the atmosphere and volatilisation is expected to be negligible, this removal mechanism is thought to be of low relevance.

Description of key information

In the atmosphere tetramine di-C16-18 is likely to be degraded by reaction with hydroxyl radicals. Degradation rates for some components were calculated with the Atmospheric Oxidation Programme based on structure activity relationships developed by Atkinson (1987). With a concentration of 500,000 OH-radicals/cm3, degradation half-lives of 1.7 h and 1.24 h for resp triamine C18 and tetramines C18, and 2.1 and  1.4 h for the cis- and trans-isomer of the triamines 9-octadecenyl , respectively, were calculated. For the exposure calculations, a mean value for the tri- and tetraamines of 1.9 h is used. Because there are no important releases into the atmosphere and volatilisation is expected to be negligible, this removal mechanism is thought to be of low relevance.

Key value for chemical safety assessment

Half-life in air:
1.9 h

Additional information

Because there are no important releases into the atmosphere and volatilisation is expected to be negligible, this removal mechanism is thought to be of low relevance.