CAS RN: 60-51-5

Stability / Shelf Life

The biological activity remains practically unvaried for 2 yr under environmental conditions, provided stored in unopened and undamaged original containers, in shaded, cool, well-aired places. ... Crystals may form in formulations stored at < 32 deg F/0 deg C. Stable a minimum of 1 yr at < 25-30 deg C/77-86 deg F.
Stability increases at pH values between 4 to 7
... 50% loss occurs in 12 days at pH 9 ...
Dimethoate is thermally unstable and decomposes on heating after first being converted to the more toxic dithio-isomer. It is hydrolyzed more rapidly in alkaline medium: 50% hydrolysis @ 70 deg C @ pH 9 in 0.8 hr and 21 hr @ pH 2.
...Stable in aqueous solutions at pH 2-7, but hydrolyzes in alkaline media.
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