-α-sulfonate (CAS NO.: ), with other names as , potassium salt, could be produced through the following synthetic routes.

A 500-cc. three-necked flask fitted with a mechanical stirrer and a thermometer is half immersed in an oil bath mounted in a hood. In the flask are placed 120 g. of 19–22 per cent oleum and 1 g. of yellow mercuric oxide, the bath is warmed to 100°, and 100 g. (0.48 mole) of anthraquinone is added through a powder funnel attached by a piece of wide rubber tubing. The mixture is stirred vigorously and heated at 147–152° for forty-five to sixty minutes, after which the bath is removed and the flask is lowered from the stirrer and replaced by a 2-l. beaker containing 1 l. of hot water. While the water is being stirred, the hot acid solution is poured cautiously down the inner wall of the beaker; the mixture is then boiled for five minutes longer with stirring. After the unchanged anthraquinone (53–59 g.) is collected by suction on a 20-cm. Büchner funnel provided with a cotton filter cloth, it is washed with 200 cc. of hot water. The light brown filtrate, together with the wash water, is heated to 90°, and a solution of 32 g. of potassium chloride in 250 cc. of water is added. After cooling to room temperature, the potassium salt, which crystallizes in the form of pale yellow leaflets, is collected on a large Büchner funnel (filter paper) and washed with 200 cc. of cold water. The yield of product, dried at 100° in vacuo, is 57–55 g. (77–86 per cent of the theoretical amount based on the anthraquinone converted).