Toluenesulfonic acid

Toluenesulfonic acid (also known as tosylic acid) is an organic compound with the formula CH3C6H4SO3H. It is a white solid that is soluble in water, alcohols, and other polar solvents. Toluenesulfonic acid is one of the most commonly used acid catalysts in organic synthesis.

Chemical Structure and Properties

Toluenesulfonic acid consists of a toluene ring substituted with a sulfonic acid group. The presence of the sulfonic acid group makes the compound strongly acidic. It is more acidic than typical carboxylic acids.

Synthesis

Toluenesulfonic acid is produced by the sulfonation of toluene. This process involves the reaction of toluene with sulfuric acid and oleum at controlled temperatures. The resulting product is then neutralized with water to yield toluenesulfonic acid.

Applications

Toluenesulfonic acid is widely used in organic synthesis as an acid catalyst. It is particularly useful in reactions that require a strong acid but cannot tolerate the presence of moisture. Examples of such reactions include esterification, acetalization, and Friedel-Crafts alkylation.

Toluenesulfonic acid is also used in the production of pharmaceuticals, dyes, and resins. In addition, it is used as a laboratory reagent.

Safety

Toluenesulfonic acid is a strong acid and can cause burns if it comes into contact with skin or eyes. It should be handled with care, using appropriate personal protective equipment.

See Also

• Sulfonic acid
• Toluene
• Acid catalyst