Ester reaction products of 1,4-Benzenedicarboxylic acid with C11-14 iso-alcohols, C13-rich

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:

key study

Study period:

2010 calculated

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The reliability rating was 2 because the data were calculated

Qualifier:

according to guideline

Guideline:

other: computer model

Principles of method if other than guideline:

Calculated values using AOPWIN version 1.92, a subroutine of the computer program EPI Suite v4.0 (US EPA 2009).
Indirect photodegradation or atmospheric oxidation potential is based on the structure activity relationship methods developed by R. Atkinson under the following conditions:
Temperature: 25 degree C
Sensitizer: OH- radical
Concentration of sensitizer: 1.5 E+6 OH- radicals/cm3

GLP compliance:

no

Light source:

sunlight

DT50:

3.7 h

Test condition:

Estimated value

Transformation products:

not specified

see below

Validity criteria fulfilled:

yes

Conclusions:

Rate constant: 34.695 E-12 cm3/molecule-sec
Degradation: 50% after 3.70 hr (or 0.308 day)

Executive summary:

Indirect photochemical degradation of the test material as mediated by OH-attack is estimated to have a half-life of 0.308 days or 3.7 hrs based on a 12 hour sunlight day, a rate of 34.695E-12 cm3/molecule*sec, and an average OH- concentration of 1.5E6 OH-/cm3. A 12-hour day half-life value normalizes degradation to a standard day light period during which hydroxyl radicals needed for photolysis are generated in the atmosphere. Although the test substance has the potential to degrade rapidly by OH-attack, multimedia Level III distribution modeling indicates the test substance is predicted to partition negligibly (0.133%) to the air compartment because it has a low vapor pressure (4.2 x e-4 Pa). Although the test substance has a relatively short atmospheric oxidation half-life (3.70 hours), this process is unlikely to contribute significantly to the loss of test susbtance from the environment.

Description of key information

Indirect photochemical degradation of the test material as mediated by OH-attack is estimated to have a half-life of 0.308 days or 3.7 hrs based on a 12-hour sunlight day, a rate of 34.695E-12 cm3/molecule*sec, and an average OH- concentration of 1.5E6 OH-/cm3. A 12-hour day half-life value normalizes degradation to a standard day light period during which hydroxyl radicals needed for photolysis are generated in the atmosphere. Although the test substance has the potential to degrade rapidly by OH-attack, multimedia Level III distribution modeling indicates the test substance is predicted to partition negligibly (0.133%) to the air compartment because it has a low vapor pressure (4.2 x e-4 Pa). Although the test substance has a relatively short atmospheric oxidation half-life (3.70 hours), this process is unlikely to contribute significantly to the loss of test substance from the environment.

Rate constant: 34.695 E-12 cm3/molecule-sec

Degradation: 50% after 3.70 hr (or 0.308 day)

Key value for chemical safety assessment

Half-life in air:

3.7 h

Degradation rate constant with OH radicals:

0 cm³ molecule-1 s-1