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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

Parent compound butyryl chloride: No data available.
Hydrolysis product butyric acid: No data available, therefore the risk assessment is based on read-across to the structurally similar substance isobutyric acid.
Isobutyric acid: Acutely harmful to aquatic algae and cyanobacteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
53.9 mg/L
EC10 or NOEC for freshwater algae:
33.7 mg/L

Additional information

In aquatic systems, butyryl chloride (CAS 141-75-3) hydrolyses quickly and forms HCl (CAS 7647-01-0) and butyric acid (CAS 107-92-6) (for details see section 5.1.2).


Parent compound butyryl chloride and hydrolysis product butyric acid:

No data are available for butyryl chloride (CAS 141-75-3) and butyric acid (CAS 107-92-6). Therefore, the short-term toxicity to aquatic algae is assessed via read across to the structurally similar substance isobutyric acid (CAS 79-31-2).


Isobutyric acid (CAS 79-31-2): Isobutyric acid was tested on Desmodesmus subspicatus in a study following the German Industrial Standard DIN 38412, part 9 (similar to OECD 201). The 72 -h ErC10 and ErC50 were 33.7 and 53.9 mg/L, respectively (BASF, 1990, 2/0244/89).

The test concentrations were not analytically  monitored. However, it is assumed that the test item remained stable over the exposure period based on a high water solubility (618 g/L, OECD 105, OXEA, 2009), a low vapour pressure (2 hPa at 20 °C, OXEA, 2009) a low Henry's Law constant (0.098 Pa*m³/mol, HENRYWIN v3.20, BASF SE, 2022) and a low adsorption potential (log Kow = 1.1, OXEA, 2009; log Koc = 1.66 according to Franco&Trapp, BASF SE, 2022).



Based on the available data on isobutyric acid the parent compound and its hydrolysis product are assessed to be acutely harmful to aquatic algae and cyanobacteria.