Butyryl chloride

Ecotoxicological Summary

Conclusion on classification

The parent compound butyryl chloride (CAS 141-75-3) rapidly hydrolyses in contact with water and forms butyric acid (CAS 107-92-6) and HCl (CAS 7647-01-0). Due to the rapid hydrolysis of the parent compound butyryl chloride (CAS 141-75-3), the assessment will mainly be based on the results for the parent compound, the hydrolysis product butyric acid (CAS 107-92-6) and the structurally similar substance isobutyric acid (CAS 79-31-2). Data from HCl have not been taken into consideration as observed effects are caused by a pH-shift in the test medium.

Results are availabe for fish (butyryl chloride, 96h LC50 = 299 mg/L (not neutralized), 96h LC50 > 464 mg/L (neutralized)), invertebrates (isobutyric acid, EC50 = 51.25 mg/L), algae (isobutyric acid, 72h ErC50 = 53.9 mg/L, 72h ErC10 = 33.7 mg/L) and microorganisms (butyric acid, 40h EC50 = 329 mg/L; isobutyric acid, 17h EC10 = 39 mg/L).

 

Therefore, the conclusion on classification will be based on the information available for butyryl chloride (CAS 141-75-3) its hydrolysis product butyric acid (CAS 107-92-6) and the structurally similar substance isobutyric acid (CAS 79-31-2).

 

Official classification regarding environmental hazards:

Aquatic compartment

In accordance with Regulation (EC) 1272/2008 Annex VI Table 3.1 and Table 3.2, the substances butyryl chloride (CAS 141-75-3) and its hydrolysis product butyric acid (CAS 107-92-6) are not officially classified.

 

Self-classification

Following CLP (GHS-EU), butyryl chloride is not to be classified as acutely or chronically hazardous to the aquatic environment.

Rationale:

According to the criteria outlined in Table 4.1.0 (a) (Comission Regulation (EU) No 286/2011 amending Regulation (EC) No 1272/2008), the substance is not to be classified as acutely hazardous to the aquatic environment, since the lowest acute effect value is > 1 mg/L (Daphnia, 48h EC50 = 51.3 mg/L, isobutyric acid).

Chronic data are only available for algae; therefore, classification is based on the available chronic data (algae) and on acute toxicity data for the trophic level not covered by chronic data (fish and daphnia).

 

Chronic toxicity data:

Chronic data are available for algae (ErC10 = 33.7 mg/L, isobutyric acid). The available data indicate that the substance does not present a long-term hazard according to the categories outlined in Table 4.1.0(b) (i) (Commission Regulation (EU) No 286/2011 amending Regulation (EC) No 1272/2008).

 

Acute toxicity data:

The lowest acute effect value (EC50) is 51.3 mg/L (daphnia), for the structurally similar substance isobutyric acid (CAS 79-31-2), which is rapidly degradable. Additionally, the log Kow of either butyryl chloride, its hydrolysis product butyric acid and the structurally similar substance isobutyric acid is < 4. According to the criteria outlined in Table 4.1.0(b) (iii) (Commission Regulation (EU) No 286/2011 amending Regulation (EC) No 1272/2008), butyryl chloride is not to be classified as chronically hazardous to the environment.

 

Atmospheric compartment

The test substance is not listed in Annex 1 of Regulation (EC) 2037/2000 on substances that deplete the ozone layer.

The test substance does not belong to the green house gases listed in P Forster, PV Pamaswamy et al. Changes in Atmospheric Constituents and Radiative Forcing. In: Climate Change 2007: The Physical Basis. Contribution of Working Goup 1 to the Fourth Assessment Report of the Intergovernmental Panel on climate Change.

 

Conclusion

Based on the available data, parent compound along with its hydrolysis product are not to be classified as acutely or chronically hazardous to the aquatic environment.