ptasasulfonihappo

p-toluenesulfonic acid (PTSA), also known as p-toluenesulfonic acid monohydrate or p-TsOH, is an organic sulfonic acid widely used as a strong, non-volatile acid catalyst in organic synthesis. Its formula is C7H8O3S, and it appears as a white crystalline solid (anhydrous) or as a monohydrate. In organic media it behaves as a strong Brønsted acid, offering a convenient alternative to mineral acids.

Commercial PTSA is prepared by sulfonation of toluene followed by isolation of the para isomer and subsequent neutralization; the para isomer is favored due to directing effects. It is available as anhydrous material or a monohydrate; both forms dissolve in polar organic solvents and water.

Applications include catalysis of esterifications, acetalizations, amidations, and glycosylations in organic synthesis. PTSA is favored when a strong, soluble acid is needed in non-aqueous media. It is also used to generate tosyl esters from alcohols via reaction with tosyl chloride (TsCl) to form tosylates, enabling subsequent substitution reactions.

Safety: PTSA is corrosive and irritant to skin, eyes, and mucous membranes; handle with gloves in a well-ventilated area; store in a dry place away from oxidizers. Refer to the material safety data sheet for detailed information.