COASOL 290 PLUS

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP accepted calculation method

Principles of method if other than guideline:

EPI Suite AOP Program (v1.92)

GLP compliance:

no

% Degr.:

50

Sampling time:

1.4 d

SMILES : O=C(OCCCC)CCCCC(=O)OCCCC

CHEM  : Hexanedioic acid, dibutyl ester

MOL FOR: C14 H26 O4

MOL WT : 258.36

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

Hydrogen Abstraction      = 12.6729 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 =  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 = 12.6729 E-12 cm3/molecule-sec

  HALF-LIFE =    1.266 Days (24-hr day; 0.5E6 OH/cm3)

  HALF-LIFE =   30.384 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

SMILES : O=C(OCCCC)CCCC(=O)OCCCC

CHEM  : PENTANEDIOIC ACID, DIBUTYL ESTER

MOL FOR: C13 H24 O4

MOL WT : 244.33

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

Hydrogen Abstraction      = 11.2598 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 =  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 = 11.2598 E-12 cm3/molecule-sec

  HALF-LIFE =    1.425 Days (24-hr day; 0.5E6 OH/cm3)

  HALF-LIFE =   34.197 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

Hydroxyl Radical Reaction Rate

The accuracy of the estimation methods used by the Atmospheric Oxidation Program can be examined by comparing a list of more than 640 experimentally determined hydroxyl radical rate constants to the program's estimated rate constants. 

 

The statistical accuracy is as follows :

 

AOPWIN

correlation coefficient (r^2)           0.963

standard deviation (sd)                 0.218

absolute mean error (me)             0.127

 

 

Over 90 percent of the estimated rate constants for the 647 different chemicals are within a factor of two of the experiment value. 

Over 95 percent of the estimates are within a factor of three of experimental. 

 

This can be compared to the PCFAP program (Fate of Atmospheric Pollutants) of the U.S. EPA GEMS software which estimates the same rate constants as AOPWIN. For 617 compounds (PCFAP can not estimate or produces program errors for the remaining experimental values), PCFAP is within a factor of two for about 49 percent of the experimental values and within a factor of 3 for about 65 percent! PCFAP is particularly inaccurate for many compounds containing nitrogen, sulfur or phosphorus. 

Conclusions:

Indirect photolysis rate constants range from 12.7 E-12 to 11.3 E-12 cm³/(molecule*sec). 50% degradation after 1.3 to 1.4 days.

Description of key information

The half-life for the test compound in the atmosphere based on reaction with hydroxyl radicals was estimated using the Atmospheric Oxidation Program in EPI Suite.

Key value for chemical safety assessment

Half-life in air:

1.4 d

Additional information

The estimated half-life for the test compound in air based on reaction with hydroxyl radicals is 1.4 days.