Catechol was first isolated in 1839 by Edgar Hugo Emil Reinsch (1809–1884) by distilling it from the solid tannic preparation catechin, which is the residuum of catechu, the boiled or concentrated juice of "Mimosa catechu" ("Acacia catechu"). Upon heating catechin above its decomposition point, a substance that Reinsch first named "Brenz-Katechusäure" (burned catechu acid) sublimated as a white efflorescence. This was a thermal decomposition product of the flavanols in catechin. In 1841, both Wackenroder and Zwenger independently rediscovered catechol; in reporting on their findings, "Philosophical Magazine" coined the name "pyrocatechin". By 1852, Erdmann realized that catechol was benzene with two oxygen atoms added to it; in 1867, August Kekulé realized that catechol was a diol of benzene, so by 1868, catechol was listed as "pyrocatechol". In 1879, the "Journal of the Chemical Society" recommended that catechol be called "catechol", and in the following year, it was listed as such.