Нитрозодисульфонат калия

Description

Potassium nitrosodisulfonate, known as Fremy's salt, is the dipotassium salt of nitrosodisulfonic (peroxylamine disulfonic) acid. This is a stable free radical: the ON(SO3)2(2-) anion carries an unpaired electron on the nitrogen atom, stabilized by two sulfo groups. In solid form, the product exists as a yellow-orange dimer; when dissolved in water, it transforms into a monomeric radical, which is why the solutions are colored purple. Other designations: nitroxide, disulfo, dipotassium salt; potassium nitrosyl disulfonate; potassium peroxylamine disulfonate; potassium nitroxide disulfonate; K2(SO3)2NO; additional registration numbers 8067-43-4, 13859-98-8, 14772-12-4, 36604-13-4.

Identification

• CAS No: 14293-70-0
• Chemical formula: H2NO7S2 2K
• EU number: 238-219-0
• RTECS number: QZ1300000

Basic Attributes

• Molecular weight: 268.33
• Exact weight: 267.839020
• PSA: 134.40000
• Storage conditions: −20 °C

Purpose and mechanism

The product works as a one-electron oxidizer with a radical mechanism. The Teuber reaction - the oxidation of phenols, naphthols and anilines to the corresponding quinones - occurs specifically on Fremy salts. The same reagent oxidizes benzyl alcohols to aldehydes and ketones, amino acids to α-keto acids, as well as indoles and amines. The second direction is EPR metrology: a long-lived radical with a known concentration serves as a standard for the quantitative determination of radicals using the electron paramagnetic resonance method.

Scope of application

• oxidation of phenols and naphthols to quinones in fine organic synthesis
• preparation of quinones from anilines
• oxidation of benzyl alcohols, indoles, amines, amino acids
• standard for quantitative EPR spectroscopy

Safety Information

• Hazard statements: H260, H302+H312+H332
• Precautions: P223, P231+P232, P280, P370+P378, P422
• Hazard category: 4.3 - substances that emit flammable gases upon contact with water
• Transport codes: UN 2813, 4.3/page 1; packaging level II
• Tags: Xn, F
• Hazard class code: 14-20/21/22-14/15
• Safety instructions: 36
• WGK Germany: 3

Storage and handling

The reagent is stored at −20 °C: at room temperature the radical gradually decomposes. Contact with water and air moisture is excluded - according to class 4.3 this leads to the release of flammable gases, hence the requirements P223, P231+P232 and P422. Wear protective clothing (S36) and avoid inhalation and skin contact: product is harmful if swallowed, in contact with skin and if inhaled. In case of fire, use dry extinguishing agents (P370+P378), do not use water. Class WGK 3 means a high danger for water bodies, therefore flushing into the sewer is unacceptable.