Registration Dossier
Registration Dossier
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EC number: 256-170-3 | CAS number: 44914-03-6
Endpoint summary
Administrative data
Description of key information
Additional information
The logarithm of the organic carbon-normalized adsorption coefficient to soil and sediment (log Koc) of 2-methylbutyl acrylate (2-MBA) was calculated from the experimental log Kow of 2.90 ± 0.07 using the applicable equation from European Chemicals Bureau: Technical Guidance Document, Part III.(1) The log Koc was calculated to be 2.45 ± 0.03, which indicates that 2-MBA has a moderate potential to partition to soils and sediment from the aqueous phase. For comparison purposes, butyl acrylate has an experimental log Kow of 2.38 and an experimental Koc of 40-148. Using the same Koc calculation above, butyl acrylate has an estimated Koc of 162. Based on this read-across information the calculated log Koc of 2-MBA is considered reliable.
The Henry’s Law constant (HLC) for 2-MBA was calculated from experimental water solubility and extrapolated vapor pressure data reported in the key studies for each endpoint. The resulting HLC is 96.3 Pa m³/mol (9.50E-04 atm m³/mol at 23 °C) and based on this value, the test substance is not expected to remain in aqueous solution in open systems.
The Henry’s Law constant of 96.3 Pa m³/mol for 2-MBA can be converted to a dimensionless log Kaw (air-water partition coefficient) of -1.41 at 23 °C. Given its log Kow (octanol-water partition coefficient) of 2.90, a log Koa (octanol-air partition coefficient) of 4.31 may be calculated for 2-MBA (where log Koa = log Kow – log Kaw), which is less than the value Koa >5 for which biomagnification is expected to occur in many mammals (as per Chapter R7.10.3.4, Other indications of bioaccumulation potential, of the Guidance on Data Requirements) (2) . Based on this value, 2-MBA is not anticipated to bioconcentrate in air-breathing organisms.
1. European Chemicals Bureau: Technical Guidance Document on Risk Assessment, Part III.
2. ECHA: Guidance on information requirements and chemical safety assessment, Chapter R.7c: Endpoint specific guidance.
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