He then joined Kolbe, and his assistant, Ernst von Meyer, and started work on the oxidation of dialkyle sulfides.

After a year of voluntary military service, as a pharmacist, Beckmann began studying toxicology at the TU Braunschweig with Robert Otto, receiving his habilitation in 1882.

He returned to Leipzig and wanted to work as a lecturer with Kolbe, However, a "technical university's" habilitation was insufficient to qualify for this position.

Therefore, Beckmann again began studying, and was able to complete the necessary exams in Latin, Greek language, and history in 1883, and again work at Leipzig.

Beckmann used the methods of ebullioscopy (boiling-point elevation) and cryoscopy (freezing-point depression) to determine the molecular masses of several substances.

It was also during this time of work with Ostwald at Leipzig that Beckmann discovered that sodium and benzophenone react in dry ether to produce a blue solution, now known to be due to ketyl-radical formation.

It is speculated that this practice might have severely damaged his health, for by his retirement he was quite ill. Beckmann died in Berlin on July 12, 1923, and was buried at Dahlem.