Sodium pyrosulfate (Na₂S₂O₇) is an inorganic compound that usually exists in colorless or white solid form. It is produced by the dehydration of sodium sulfate (Na₂SO₄) at high temperatures. Sodium pyrosulfate has strong hygroscopicity and can quickly absorb moisture in the air to form hydrate Na₂S₂O₇·5H₂O.

Sodium pyrosulfate is a strong oxidizing agent, which exhibits stronger oxidizing properties in acidic solutions. It is capable of reacting with many substances, especially in organic synthesis, and it is often used as a dehydrating agent and oxidizing agent.

1. Dehydrating agent: sodium pyrosulfate is often used as a dehydrating agent in organic synthesis, especially in the dehydration reaction of alcohol, which can promote the dehydration of alcohol molecules to form ethers.

2. Oxidizing agent: It is also a strong oxidizing agent that can be used in organic synthesis to oxidize certain compounds, such as oxidizing aromatic compounds to phenols.

3. Bleach: In the paper industry, sodium pyrosulfate can be used as a bleaching agent for pulp to help improve the whiteness of the paper.

4. Purifying agent: In the textile industry, it is used for the bleaching and purification of cotton, as well as in the manufacture of dyes and pigments.

5. Metal refining and refining: In the metallurgical industry, sodium pyrosulfate can be used as a flux to help remove impurities from metals and improve the purity of metals.

6. Detergents: In petroleum processing, sodium pyrosulfate is used to remove organic sulfur compounds from crude oil and reduce the sulfur content in the refining process.

7. Water treatment: Sodium pyrosulfate can be used in the water treatment process to help remove organic matter and microorganisms from the water and purify the water.

8. Chemical analysis: In chemical analysis, sodium pyrosulfate can be used as a reagent for some specific chemical reactions.

9. Pharmaceutical industry: In pharmaceutical processes, sodium pyrosulfate may be used in specific chemical reactions in the synthesis process, such as oxidation or dehydration reactions.