Carboxylic acids, di-, C4-6

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Reason / purpose for cross-reference:

read-across: supporting information

Principles of method if other than guideline:

Calculated with AOP Program v1.92 of EPI-Suite Software.

GLP compliance:

no

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
PHYSICO-CHEMICAL PROPERTIES
- Vapour pressure: 0.097 hPa at 18.5°C (Kirk-Othmer)
- Henry's Law constant: 9,656e-9 hPa m³/mol 25°C (Currenta, 2009)
- log Pow: 0.093 at pH 3.3 (BASF-Study, 1988)
- pKa: 4.34-5.44 at 18°C; 4.43-5.42 at 20°C; 4.43 at 25°C (Beilstein, 2003)

Estimation method (if used):

PHOTOCHEMICAL REACTION WITH OH RADICALS
- sensitiser for indirect photolysis: OH radicals
- Concentration of OH radicals: 0.5 E6 OH/cm³, 24 h/d

% Degr.:

50

Sampling time:

2.9 d

Transformation products:

not measured

A 24-hour day and an OH radical concentration of 0.5 E06 OH/cm³ are assumed for the calculation.

Overall OH rate constant (for indirect photolysis): 5.5893E-12 cm³/(molecule*sec)

Validity criteria fulfilled:

yes

Conclusions:

In the atmosphere, a half-life of 2.9 days for adipic acid is estimated.

Executive summary:

In the atmosphere, a half-life of 2.9 days for adipic acid is estimated due to the reaction with photochemically produced hydroxyl radicals, considering a OH concentration of 500,000 radicals/cm³ as a 24h-average.

Description of key information

In the atmosphere, a half-life of 2.9 days for the constitutent adipic acid is estimated due to the reaction with photochemically produced hydroxyl radicals, considering a OH concentration of 500,000 radicals/cm³ as a 24h-average (Currenta, 2009).

Key value for chemical safety assessment

Half-life in air:

2.9 d

Additional information

For the mixture no data on phototransformation in air are available. Adipic acid is applied for read-across approach. Adipic acid is one of the constituents of the dicarboxylic acid mixture. All constituents are homologues linear alkyl dicarboxylic acids with a chain length of four to six carbon atom. The mixture is composed of three discrete carboxylic acids. Due to the structural relationship, adipic acid is a good representative for the dicarboxylic acid mixture. Adipic acid is well assessed on behalf of the ICCA/OECD HPV-program.