 The reaction was discovered by the two Italian chemists Angelo Angeli and Enrico Rimini (1874–1917), and was published in 1896.The reaction is used in a chemical test for the detection of aldehydes in combination with ferric chloride.In this test a few drops of aldehyde containing specimen is dissolved in ethanol, the sulfonamide is added together with some sodium hydroxide solution and then the solution is acidified to Congo red.