Composition information of fuming sulfuric acid products:

Fuming sulfuric acid is a product produced during the production of sulfuric acid. It is unstable in nature and reacts with water to form sulfuric acid. Fuming sulfuric acid can be seen as sulfuric acid with a concentration exceeding 100%, which volatilizes SO3 in the air and forms an acid mist to produce smoke (just like more than 68% of nitric acid is called fuming nitric acid due to the acid mist). The content of oleum is usually calculated based on its sulfur trioxide content, for example, 20% oleum indicates that 20% of its mass is sulfur trioxide. In H2SO4 · xSO3, when x=1, it is pyrosulfuric acid. Generally, the mass fraction containing SO3 includes 20%, 40%, 60%, 66%, etc. If converted to sulfuric acid concentration, H2SO4 in oleum can exceed 100%. Some people believe that pyrosulfuric acid (H2S2O7) is mainly present in oleum. Has strong oxidation and water absorption properties, dehydration and corrosiveness. Used for synthesizing dyes and drugs. Nicotinic acid is often used for sulfonation reactions, not only because of its high concentration, but also because it contains a large amount of electrophilic reagent sulfur trioxide. In addition, it is commonly used as a water absorbent and dehydrating agent.

The composition of substances in fuming sulfuric acid is complex. In addition to sulfuric acid and sulfur trioxide, there are also various sulfuric acid polymers such as pyrosulfuric acid (H2S2O7), dimeric sulfuric acid (H4S2O8), trimeric sulfuric acid (H6S3O12), and H4S3O15, H2S3O10, (H2SO4) 20

Fuming sulfuric acid