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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Magnesium methanolate hydrolyse very fast into methanol and magnesium hydroxide. The determination of the adsorption/desorption coefficient is technically not feasible with magnesium methanolate and the endpoint is waived.

The half life of magnesium methanolate was determined to be T1/2 < 1 min (Hydrolysis as a Function of pH). In all experiments the hydrolysis of magnesium methanolate in buffer solutions (pH4, pH7, pH9) takes place immediately. Hydrolysis rates of >= 90% within 1 minute reaction time are observed.

Hydrolysis product methanol:

Adsorption on soil is not to be expected due to the high water solubility (> 1000g/l) of the hydrolysis product methanol as well as its low octanol-water partition coefficient (-0.77). Lokke (1984) studied the adsorption of methanol onto three different soil types at 6 deg C. Adsorption coefficients of between 0.13 and 0.61 were measured for all soil types and at all concentrations. A Koc of 1 was calculated by BASF (2004). These coefficients indicate that methanol has a low adsorptive capacity on soils.

Hydrolysis product magnesium hydroxide:

Magnesium hydroxide has a low potential to adsorb to soil based on the derived Kd value of 1.65.

Key value for chemical safety assessment

Koc at 20 °C:
0.13

Additional information

The Koc 0.13 of the hydrolysis product methanol is used for the chemical safety report