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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
other: secondary source
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Studies reviewed in EU RAR
Qualifier:
no guideline followed
Version / remarks:
The EU RAR (2004) reviews several studies which investigated the abiotic aquatic degradation of acrylonitrile.
Principles of method if other than guideline:
Abiotic degredation
GLP compliance:
not specified
Radiolabelling:
not specified
Analytical monitoring:
not specified
Details on sampling:
No information available
Buffers:
No information available
Estimation method (if used):
No information available
Details on test conditions:
See below
Number of replicates:
No information available
Statistical methods:
No information available
Preliminary study:
No information available
Test performance:
No information available
Transformation products:
not specified
Details on hydrolysis and appearance of transformation product(s):
Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported to occur in distilled water over the pH range 4-10 (Going et al., 1978).
Remarks on result:
other: Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported in distilled water over the pH range 4-10 (Going et al., 1978)
Other kinetic parameters:
No information available
Details on results:
Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported to occur in distilled water over the pH range 4-10.
99.0% wet air oxidation of acrylonitrile after 1 hour at 275°C and pressures of 70-140 kg/cm³.

Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported to occur in distilled water over the pH range 4-10 (Going et al., 1978). Knoevenagel and Himmelreich (1975) reported photo-oxidation of acrylonitrile in the presence of water to occur under experimental conditions, approximately 25% degradation being reported in a 24-hour period. It appears that elevated temperatures were used in this study, and the results may be of little relevance for normal environmental conditions. The authors suggest that this process of abiotic aquatic degradation will occur in surface waters, in the layers accessible by light. Randall (1980) reported 99.0% wet air oxidation of acrylonitrile after 1 hour at 275°C and pressures of 70-140 kg/cm³. Going et al. (1978) also demonstrated decomposition of acrylonitrile over a period of 23 days at a concentration of 10 mg/l in Mississipi River water at different pHs. Concentrations of acrylonitrile in river water at unadjusted pH fell linearly to undetectable levels by day 6, decomposition was slower at pH 4.0 and pH 10.0, although levels at pH 10 were also below the limits of detection by day 23. The degradation seen in this study may be due to a combination of biodegradation and volatilisation of acrylonitrile from the test medium rather than abiotic degradation.

EU RAR (2004)

Validity criteria fulfilled:
not applicable
Conclusions:
Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported to occur in distilled water over the pH range 4-10
Executive summary:

Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported to occur in distilled water over the pH range 4-10 (Going et al., 1978). Knoevenagel and Himmelreich (1975) reported photo-oxidation of acrylonitrile in the presence of water to occur under experimental conditions, approximately 25% degradation being reported in a 24-hour period. It appears that elevated temperatures were used in this study, and the results may be of little relevance for normal environmental conditions. The authors suggest that this process of abiotic aquatic degradation will occur in surface waters, in the layers accessible by light. Randall (1980) reported 99.0% wet air oxidation of acrylonitrile after 1 hour at 275°C and pressures of 70-140 kg/cm³. Going et al. (1978) also demonstrated decomposition of acrylonitrile over a period of 23 days at a concentration of 10 mg/l in Mississipi River water at different pHs. Concentrations of acrylonitrile in river water at unadjusted pH fell linearly to undetectable levels by day 6, decomposition was slower at pH 4.0 and pH 10.0, although levels at pH 10 were also below the limits of detection by day 23. The degradation seen in this study may be due to a combination of biodegradation and volatilisation of acrylonitrile from the test medium rather than abiotic degradation.

EU RAR (2004)

Description of key information

Acrylonitrile is relatively hydrolytically stable.

Key value for chemical safety assessment

Additional information

Acrylonitrile is relatively hydrolytically stable, with no hydrolysis reported to occur in distilled water over the pH range 4-10 (EU RAR, 2004). Photo-oxidation of acrylonitrile in the presence of water is reported to occur under experimental conditions, with approximately 25% degradation being reported in a 24-hour period at elevated temperature (EU RAR, 2004). However the relevance of the experimental conditions to normal environmental conditions is questioned.