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Environmental fate & pathways

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Dimethoxy(dimethyl)silane (CAS No. 1112-39-6) hydrolyses rapidly to dimethylsilanediol (DMSD) and methanol under environmental conditions (DT50 < 0.6 h at pH 7, pH 9 and 25 °C). Thus, the environmental fate assessment is based on the hydrolysis products dimethylsilanediol and methanol rather than the parent substance.

Both hydrolysis products exhibit a low potential for adsorption to soil, sediment or sludge. The volatilization from water is very low for DMSD (HLC = 1.65E-4 Pa m³/mole Pa m³/mole at 12 °C), whilst being higher for methanol (HLC = 0.3827 Pa m³/mole at 25 °C), owing to the high vapor pressure of the latter.

However it was shown that considerable quantities of DMSD are subject to volatilization from soil into the atmosphere (Lehmann and Miller, 1996; Xu and Miller, 2016) or subject to evapotranspiration in plant-covered soils (Xu and Miller, 2017).