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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:
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
Key result
Reaction with:
OH radicals
Rate constant:
0 cm³ molecule-1 s-1
Remarks on result:
other: AOP v1.92 QSAR
Transformation products:
not measured

SMILES : CCCCCCCCCCCCCCCCN(C)CCCN(C)(C)(H)

CHEM   : Diamine methylated (C16)

MOL FOR: C22 H49 N2

MOL WT : 341.65

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

Hydrogen Abstraction       =  56.9453 E-12 cm3/molecule-sec

**Reaction with N, S and -OH =  66.0000 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 = 122.9453 E-12 cm3/molecule-sec

  HALF-LIFE =     0.261 Days (12-hr day; 0.5E6 OH/cm3)

  HALF-LIFE =     3.132 Hrs

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

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

           

SMILES : CCCCCCCCCCCCCCCCCCN(C)CCCN(C)(C)(H)

CHEM   : Diamine methylated

MOL FOR: C24 H53 N2

MOL WT : 369.70

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

Hydrogen Abstraction       =  59.7714 E-12 cm3/molecule-sec

**Reaction with N, S and -OH =  66.0000 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 = 125.7714 E-12 cm3/molecule-sec

  HALF-LIFE =     0.255 Days (12-hr day; 0.5E6 OH/cm3)

  HALF-LIFE =     3.062 Hrs

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

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

SMILES : CCCCCCCCC=CCCCCCCCCN(C)CCCN(C)(C)(H)

CHEM   : Diamine methylated

MOL FOR: C24 H51 N2

MOL WT : 367.69

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

Hydrogen Abstraction       =  56.4168 E-12 cm3/molecule-sec

**Reaction with N, S and -OH =  66.0000 E-12 cm3/molecule-sec

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

Addition to Olefinic Bonds =  56.4000 E-12 cm3/molecule-sec [Cis-isomer]

Addition to Olefinic Bonds =  64.0000 E-12 cm3/molecule-sec [Trans-isomer]

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 = 178.8168 E-12 cm3/molecule-sec [Cis-isomer]

  OVERALL OH Rate Constant = 186.4168 E-12 cm3/molecule-sec [Trans-isomer]

  HALF-LIFE =    2.153 Hrs (12-hr day; 0.5E6 OH/cm3) [Cis-isomer]

  HALF-LIFE =    2.066 Hrs (12-hr day; 0.5E6 OH/cm3) [Trans-isomer]

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

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

  OVERALL OZONE Rate Constant =  13.000000 E-17 cm3/molecule-sec [Cis-]

  OVERALL OZONE Rate Constant =  20.000000 E-17 cm3/molecule-sec [Trans-]

  HALF-LIFE =  2.116 Hrs (at 7E11 mol/cm3) [Cis-isomer]

  HALF-LIFE =  1.375 Hrs (at 7E11 mol/cm3) [Trans-isomer]

NOTE: Reaction with Nitrate Radicals May Be Important!

Experimental Database:  NO Structure Matches

Conclusions:
In the atmosphere diamine methylated is 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 Diamine methylated 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 2 h were calculated for the C18 unsaturated diamine methylated and 3 h were calculated for the saturated C16 and 18 diamine methylated. 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 diamine methylated 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 2.0 h and 2.1 h for resp cis- and trans-isomer of C18 unsaturated and 3.13 and 3.06 h for respectively C16 and C18 diamine methylated were calculated. For the exposure calculations, the worst case of 3.1 h can be 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:
3.1 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.