2-Aminobenzenearsonic acid CAS 2045-00-3 98% white to off-white crystalline powder organoarsenic reagent / chromogenic agent and synthesis intermediat

1. Product Overview

2-Aminobenzenearsonic acid, also known as o-Arsanilic acid or ortho-arsanilic acid (CAS 2045-00-3, molecular formula C₆H₈AsNO₃, MW 217.05), is an organoarsenic aromatic derivative featuring both an amino group (ortho to the arsonic acid substituent) and an arsonic acid group (–AsO(OH)₂). It appears as white to off-white or pale yellow crystalline needles/powder. This compound is historically known as “Atoxyl” (though atoxyl more strictly refers to the sodium salt of p-arsanilic acid). It is primarily used as a chromogenic reagent in analytical chemistry for the spectrophotometric determination of metal ions (especially scandium, titanium, thorium, vanadium in the presence of salicylaldehyde), as a precursor for synthesizing azo dyes such as Arsenazo III, and as a research-grade intermediate in organic synthesis, pharmaceutical R&D, and materials science. The product is supplied at ≥98% purity (HPLC/Assay), suitable for laboratory reagent, analytical standard, and custom synthesis applications. Note: this is a toxic organoarsenic compound; handle under strict safety controls and only for authorized research/industrial use.

2. Key Features and Advantages

• Dual functional groups (ortho‑NH₂ and –AsO(OH)₂) enable versatile chelation with metal ions and facile diazotization for azo dye synthesis.

• High solubility in water, dilute acids, and alkaline solutions, making it ideal for aqueous colorimetric and spectrophotometric assays.

• Serves as a direct precursor to Arsenazo III and other arsenazo chromophores widely used in trace metal analysis.

• Consistent crystallinity and ≥98% assay ensure reproducible performance in quantitative metal‑ion determinations.

• Stable under dry, cool, dark storage; compatible with standard organic synthesis workflows (diazotization, electrophilic substitution, ligand design).

• Available in reagent grade (≥98%) and customizable purity/particle size for specialized applications.

3. Main Applications

• Analytical chemistry / chromogenic reagent: used with salicylaldehyde for colorimetric/spectrophotometric determination of Sc, Ti, Th, V; precursor to Arsenazo III for rare‑earth and actinide detection.

• Dye and pigment manufacturing: via diazotization coupled to form azo dyes and arsenazo‑based colorants for analytical indicators.

• Organic synthesis intermediate: building block for organoarsenic ligands, chelating agents, and heterocyclic frameworks in materials research.

• Pharmaceutical and agrochemical R&D: historical arsanilic acid scaffold studied for antimicrobial/antiprotozoal activity; used in early‑stage drug discovery and veterinary product development (restricted, research‑only).

• Metal‑ion binding studies: employed in designing chelating ligands for selective extraction, separation, and sensing of transition/heavy metals.

4. Technical Specifications

5. Storage and Handling

Store in a cool, dry, well‑ventilated area at 2–8 °C in a tightly sealed container, protected from light and moisture. This material is hygroscopic; keep container closed when not in use to prevent water absorption and decomposition. For long‑term storage (>12 months), keep at 2–8 °C under desiccant. Avoid contact with strong oxidizers, strong acids (beyond normal dissolution), and reducing agents. Handle in a certified fume hood with appropriate PPE: nitrile gloves, lab coat, safety goggles, and if dust/aerosol possible, use N95/P100 respirator. Minimize dust generation during weighing; wash hands thoroughly after handling. Do NOT eat, drink, or smoke in handling areas. Decontaminate work surfaces with appropriate arsenic‑binding reagents (e.g., hypochlorite bleach solution for organoarsenic breakdown) before disposal. Dispose of as hazardous toxic waste per local regulations for organoarsenic compounds.

6. Safety Overview

Classified under GHS as Danger (GHS06 Toxic, GHS09 Environmental Hazard). Hazard statements: H301+H331 (Toxic if swallowed/inhalation of dust), H410 (Very toxic to aquatic life with long‑lasting effects). Precautionary statements: P261 (Do not breathe dust), P264 (Wash thoroughly after handling), P270 (Do not eat/drink/smoke when using), P271 (Use only outdoors or in well‑ventilated area), P273 (Avoid release to environment), P280 (Wear protective gloves/protective clothing/eye protection), P301+P310 (IF SWALLOWED: Immediately call poison center/doctor; rinse mouth), P304+P340 (IF INHALED: Remove person to fresh air and keep comfortable for breathing), P391 (Collect spillage), P405 (Store locked up), P501 (Dispose of contents/container in accordance with local/regional/national regulations for toxic arsenic compounds). This substance is a toxic organoarsenic compound; not for human or veterinary therapeutic use except under authorized research protocols. WGK Germany: 3. Transport: UN2811, Hazard Class 6.1, Packing Group III (toxic solids, organic, n.o.s.). Consult full SDS before use; keep antidote information and poison control contact readily available.