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Environmental fate & pathways

Hydrolysis

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Description of key information

The overall conclusion is that DMS is hydrolysed very rapidly in water and air (DT50 < 1 day).

Key value for chemical safety assessment

Additional information

According to the EU RAR:

Dimethyl sulphate hydrolyses in water. Reaction rate and type of hydrolysis products depend on pH and temperature. In neutral or acid medium methanol and sulphuric acid are formed, whereas under alkaline conditions the reaction products are methanol and monomethyl sulphate (room temperature) or methanol and sulphate (elevated temperature), respectively. Several estimates for the hydrolysis rate are reported in literature. The half-life at room temperature and pH 7 is about 24 hours; at room temperature and pH 10 it is about 86 seconds. Other observed degradation times are: >70 hours at 8°C, 14 hours at 23°C, and 70 min. at 40°C. In another study a half-life of 1.2 hours is reported for the hydrolysis of DMS under neutral conditions at 25°C. The EHC document (1985) mentions additional DT50 values of 4.5 h (temperature unknown) and 40 minutes (at 20°C), at neutral conditions.