beginning in 1866, haarmann studied at the mining academy clausthal later he changed to the university of göttingen. he joined august wilhelm von hofmann 1869 at the university of berlin. he received his phd in göttingen 1872. together with ferdinand tiemann, both working with hoffmann, haarmann founded 1875 haarmann's vanillinfabrik, producing vanillin from coniferin. the reimer-tiemann reaction discovered by karl reimer opened an alternative path to vanillin and reimer joined the company which was renamed to haarmann & raimer.