Пиросульфат аммония

Description

Ammonium pyrosulfate is an ammonium salt of pyrosulfuric (disulfuric) acid, CAS 10031-68-2, formula H8N2O7S2. English name Ammonium pyrosulfate. Belongs to the class of inorganic acidic oxidizing salts based on condensed sulfuric acids.

Basic Attributes

• CAS No.: 10031-68-2
• Chemical formula: H8N2O7S2
• Molecular weight: 212.191
• Exact weight: 211.97700
• DSSTox ID: DTXSID30474790
• PSA Specifications: 142
• XLogP3: 1.4180

Properties and class of substance

Acid ammonium salt of disulfuric (pyrosulfuric) acid H2S2O7 - a condensation product of two molecules of sulfuric acid with the elimination of water. Exhibits strong oxidizing properties characteristic of peroxydisulfates and related condensed sulfuric acids. The PSA value of 142 indicates a large number of polar oxygen atoms in the molecule, providing high oxidative activity and solubility in water.

Scope of application

A strong oxidizing agent used in organic synthesis reactions, in particular in the production of sulfonic acids, important intermediates in the production of medicinal substances, agrochemicals and dyes. Promotes the conversion of alcohols into aldehydes and ketones. In polymer chemistry, it acts as a radical initiator of the polymerization of alkenes in the production of polystyrene and polyacrylamide. In the production of printed circuit boards it is used as an etching reagent that effectively oxidizes the surface of metals. In the cosmetic industry it is used as a component of hair lighteners. In laboratory practice, it serves as a reagent for the determination of reducing agents in analytical procedures and as a catalyst for a number of catalytic organic reactions.

Mechanism of oxidative action

Like other pyrosulfates, the substance decomposes when heated to release sulfur trioxide (SO3), an active oxidizing and sulfonating agent, which explains its use as a flux and oxidizing agent in analytical chemistry in the decomposition of sparingly soluble metal oxides by fusion.

Precautions

Direct data on toxicity, UN transport codes and GHS labeling are not provided in the primary source. As a strong oxidizer, the substance is incompatible with reducing agents, flammable and organic materials - contact may cause fire. When working with dry powder, it is necessary to avoid the formation of dust, use respiratory and eye protection, and avoid contact with moisture until intended use.

Storage and transportation

Store in a dry, cool, well-ventilated area, in sealed containers, away from reducing agents, organic substances, flammable materials and moisture. The substance is hygroscopic and upon contact with water hydrolyzes to form ammonium sulfate and sulfuric acid, which is accompanied by the release of heat.

Place in the series of persulfates and pyrosulfates

Ammonium pyrosulfate is related to ammonium persulfate, but is produced by condensation of sulfuric acid rather than by the peroxide route, and therefore is not a peroxide oxidizer in the strict sense - its oxidizing power is realized through the release of SO3 when heated, and not through the generation of radicals at room temperature. This makes it a more convenient reagent for “dry” fusion in analytical practice, where persulfates are used less frequently.