Disodium methylarsonate

As(ONa), -I- CH,I — [CH,As(ONa)jI] CH,AsO(ONa), — CH,AsO(OH), unstable product losing sodium iodide to form disodium methylarsonate, which on acidification liberates methylarsonic acid. Note that this synthesis is limited to alkylarsonic acids, whereas the Bart synthesis (p. 312) is limited to aiy larsonic acids. 

Rice, Oryza sativum Disodium methylarsonate modest 75% decrease in yield at soil (silty loam) concentrations 1... 

Arsenic trioxide finds major use in the preparation of other compounds, notably those used in agricultural applications, The compounds monosodium methylarsonate. disodium methylarsonate, methane arsenic acid (cacodylic acid) are used for weed control, while arsenic acid, H3ASO4, is used as a desiccant for the defoliation of cotton crops, Other compounds once widely used in agriculture are calcium arsenate for control of boll weevils, lead arsenate as a pesticide for fruit crops, and sodium arsenite as a herbicide and for cattle and sheep dip. In some areas, arsenilic acid has been used as a feed additive for swine and poultry. Restrictions on these compounds vary from one country and region to the next. 

A potential hazard in the handling of methylated arsenical herbicides is generation of methylarsines when exposed to active metals. Contact of aluminum with a water solution of disodium methylarsonate is particularly hazardous because of the relatively high alkalinity of this arsenical, which makes it reactive with aluminum . ... 

Derivation Reaction of disodium methylarsonate with silver salts. 

Dimethylarsinic acid (cacodylic acid, 2) is prepared by the reduction of disodium methylarsonate with sulfur dioxid, followed by methylation. 

Disodium methylarsenate Disodium methylarsonate. See Disodium methanearsonate... 

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