A process that can be used for sulfonating, sulfating, or sulfamating an organic compound is disclosed. The process can comprise, consist essentially of, or consist of, contacting the organic compound with sulfur trioxide under a condition sufficient to effect the sulfonation, sulfation, or sulfamation of the organic compound. The organic compound can be an aromatic compound, alcohol, carbohydrate, amine, amide, protein, or combinations of two or more thereof. The sulfur trioxide can be present in a complex comprising an inorganic support such as zeolite, silicalite, silica, titanosilicate, borosilicate, clay, aluminophosphate, and combinations of two or more thereof.