520-10-5

Basic information

• Product Name: ARSENAZO I
• Synonyms: ARSENAZO;ARSENAZO 1;ARSENAZO I;2-(O-ARSONOPHENYLAZO)-1,8-DIHYDROXYNAPHTHALENEDISULFONIC ACID, SODIUM SALT;2-(1,8-DIHYDROXY-3,6-DISULFO-2-NAPHTHYLAZO)BENZENEARSONIC ACID TRISODIUM SALT;2-(1,8-DIHYDROXY-3,6-DISULFO-2-NAPHTHYLAZO)PHENYLARSONIC ACID DISODIUM SALT;2-(2-ARSONOPHENYLAZO)CHROMOTROPIC ACID DISODIUM SALT;O-(1,8-DIHYDROXY-3,6-DISULFO-2-NAPHTHYLAZO)BENZENEARSONIC ACID SODIUM SALT
• CAS NO: 520-10-5
• Molecular Formula: C₁₆H₁₃AsN₂O₁₁S₂
• Molecular Weight: 614.28
• EINECS: 222-600-3
• Mol File: 520-10-5.mol
• Article Data: 0

Chemical Properties

• Melting Point: ≥300 °C(lit.)
• Boiling Point: °Cat760mmHg
• Flash Point: °C
• Appearance: /
• Density: g/cm³
• Solubility: methanol: 1 mg/mL, clear, red
• PKA: -0.71±0.40(Predicted)
• CAS DataBase Reference: ARSENAZO I(CAS DataBase Reference)
• NIST Chemistry Reference: ARSENAZO I(520-10-5)
• EPA Substance Registry System: ARSENAZO I(520-10-5)

Safety Data

• Hazard Codes: T,N
• Statements: 23/25-50/53
• Safety Statements: 20/21-28-45-60-61
• RIDADR: UN 3465 6.1/PG 3
• WGK Germany: 3
• HazardClass: 6.1(b)
• PackingGroup: III
• Hazardous Substances Data: 520-10-5(Hazardous Substances Data)

Usage

Uses

The reagent reacts with many metal ions, such as uranium(IV), thorium(IV), zirconium(IV), scandium(III), lanthanum(III), cerium(III), aluminium(III), beryllium( III), titanium(III), niobium(lll), tantalum(III), vanadium(IV), tin(IV), bismuth( III), gallium(III), copper(III), palladium(II), magnesium(II) and calcium(II) to give coloured complexes. It has been used for the photometric determination of the majority of the above-listed metal ions. Though the reagent reacts with such a variety of metal ions, the complex formation reaction may be made selective for individual metal ions by appropriate choice of the reaction conditions, primarily of the pH of the solution. For instance, thorium can be determined with Arsenazo I in the presence of almost all rare earth metals, and similarly zirconium and thorium in the presence of uranium, etc. The stabilities of the metal complexes of Arsenazo I are lower than those of the corresponding complexes of EDTA. It can also therefore be used advantageously as indicator in complexometric determination of some metals (e.g. plutonium, thorium). The analytical sensitivity of the formation of Arsenazo I complexes is comparatively high (0.05-0.1 γ/ml). However, the importance of the reagent is decreasing in analytical practice, in parallel with an increase in significance of the related reagent, Arsenazo III, which gives more stable complexes with higher absorbances, and which is therefore of greater analytical sensitivity.

InChI:InChI=1/C16H13AsN2O11S2/c20-12-7-9(31(25,26)27)5-8-6-13(32(28,29)30)15(16(21)14(8)12)19-18-11-4-2-1-3-10(11)17(22,23)24/h1-7,20-21H,(H2,22,23,24)(H,25,26,27)(H,28,29,30)/b19-18+

Synthetic route

copper(II) choride dihydrate + 3-(2-arsono-phenylazo)-4,5-dihydroxy-naphthalene-2,7-disulfonic acid (520-10-5) → [Cu2(O3AsC6H4NNC10H3(OH)2(SO3)2)]

Conditions	Yield
With hydrogenchloride; sodium hydroxide; potassium chloride In water at 25.degdee.C, ionic strength of 1.0 mol*dm**-3 (KCl), pH values in range 3.221-11.045; not isolated, monitored by UV at 340-700 nm;