Description

Sulfurous Acid CAS NO 7782-99-2 is a crucial intermediate and reducing agent, primarily existing in aqueous solution. Its commercial value lies in its powerful reducing and bleaching properties, making it essential for water treatment and various industrial synthesis processes. This chemical is indispensable for manufacturers in the pulp & paper, textile, and chemical processing industries who require a reliable and effective source of sulfur dioxide in solution.

Application

• Water Treatment: Acts as a reducing agent for dechlorination and an oxygen scavenger in boiler feed water and wastewater systems.
• Pulp & Paper Industry: Used in the bleaching process of wood pulp and paper to achieve high brightness.
• Textile Processing: Employed as a bleaching agent for wool, silk, and other delicate textiles.
• Chemical Synthesis: Serves as a key intermediate and reducing agent in the production of various chemicals, including pharmaceuticals, dyes, and other sulfur-containing compounds.
• Food & Beverage: Used as a preservative and disinfectant (E220) in winemaking, dried fruit processing, and other applications where microbial control is needed.
• Disinfectant & Fumigant: Applied for sterilizing equipment and fumigating storage facilities in food and agricultural contexts.

Basic Information

Product Name	Sulfurous Acid
CAS No.	7782-99-2
Molecular Formula	H2SO3
Molecular Weight	82.07 g/mol
Synonyms	Sulfurous Acid; Sulfur Dioxide Solution; Sulphurous Acid; Dihydrogen Sulfite; Sulfurous Acid (aqueous); SO2 Solution; Sulfur Dioxide (aqueous); E220
EINECS	231-973-1

Quality Control

Our Sulfurous Acid is manufactured under strict quality management protocols. We provide material that meets technical and food-grade specifications where applicable, with a focus on consistent assay and impurity profile. Certificates of Analysis (COA) detailing key parameters such as assay (as SO2), specific gravity, and heavy metal content are available for every batch upon request.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, well-ventilated area away from heat sources and incompatible materials such as strong bases, oxidizing agents, and metals. Due to its nature as a strong acid and its tendency to be easily oxidized, containers should be kept sealed to minimize exposure to air and moisture. Recommended storage temperature is between 15°C and 25°C.

Specification

Item	Specification
Appearance	Colorless to pale yellow liquid
Assay (as SO2)	≥ 6.0 % w/w
Specific Gravity (20°C)	1.03 - 1.05
Identification	Conforms (IR / Chemical)
Heavy Metals (as Pb)	≤ 10 ppm
Arsenic (As)	≤ 3 ppm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.