Description
Salts of methanearsonic acid,CH3AsO(OH)2, especially the iron ammonium salt, Neoasozin, used as a fungicide in rice growing and the sodium, ammonium, and diethanolam monium salts used as herbicides in cotton growing.
Chemical Properties
Plates from EtOH or Me2CO.Sol in H
2O and EtOH.
Chemical Properties
White crystalline solid.
Uses
Methylarsonic acid is used as herbicide.
Definition
ChEBI: Methylarsonic acid is a member of arsonic acids, a one-carbon compound and an organoarsonic acid. It is a conjugate acid of a methylarsonate(1-).
Hazard
Moderately toxic by ingestion.
Potential Exposure
Methanearsonic acid is an organoarsenic herbicide.
Shipping
UN3465 Organoarsenic compound, solid, n.o.s.,
Hazard Class: 6.1; Labels: 6.1-Poisonous materials,
Technical Name Required.
Purification Methods
Recrystallise this herbicide from Me2CO or absolute EtOH (white plates; its solubility is 28g/100mL EtOH). [Quick & Adams J Am Chem Soc 44 809 1922, Beilstein 4 H 613, 4 I 577, 4 II 996, 4 III 1822, 4 IV 3682.]
Incompatibilities
A strong acid. Incompatible with
caustics, ammonia, amines, amides, organic anhydrides,
isocyanates, vinyl acetate, alkylene oxides, epichlorohydrin.
May not be compatible with nitrates. Moisture may cause
hydrolysis or other forms of decomposition. Attacks metals
in the presence of moisture
Waste Disposal
Do not discharge into drains
or sewers. Dispose of waste material as hazardous waste
using a licensed disposal contractor to an approved landfill.
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. If allowed,
Incineration with effluent gas scrubbing is recommended.
Containers must be disposed of properly by following package label directions or by contacting your local or federal
environmental control agency, or by contacting your
regional EPA office. Chemical Treatability of Arsenic—
(1) Concentration Process: Chemical Precipitation;
Chemical Classification: Metal; Scale of Study: Pilot Scale;
Type of Wastewater Used: Domestic Wastewater1Pure
Compound; Results of Study: 5 ppm @ 4 gpm @ pH 5 7.0.
Iron system—90% reduction; low lime system—80%
reduction; high lime system—76% reduction; (3 coagulant
systems were used; Iron system used 45 ppm as Fe of
Fe2(SO4)3 @ pH 5 6.0. Low lime system used 20 ppm
Fe of Fe2(SO4)3 and 260 ppm of CaO @ pH 5 10.0. High
line system used 600 ppm of CaO @ pH 5 11.5.
Chemical coagulation was followed by multimedia filtration); (2) Concentration Process: Chemical Precipitation;
Chemical Classification: Metal; Scale of Study: Full Scale Continuous Flow; Type of Wastewater Used: Domestic
Wastewater; Results of Study: Effluent character (ppb):
2.5, 56% reduction with lime; 3.3, 24% reduction with
lime; (lime dose of 350400 ppm as calcium oxide @
pH 5 11.3)
