METHYLARSONIC ACID

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.

The Uses of METHYLARSONIC ACID

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 350
400 ppm as calcium oxide @ pH 5 11.3)