Letnii, Aleksandr

Born Dec. 13 (25), 1848, in St. Petersburg; died May 3 (15), 1883, in Tbilisi. Russian chemical technologist.

Letnii graduated from the St. Petersburg Institute of Technology in 1871. He then worked there as a laboratory technician and later as an assistant (until 1879). In 1875 he discovered that the bottom products of heavy petroleum undergo partial decomposition to lighter products (for example, gasoline, kerosene, gases) at temperatures above 300°C. This discovery constituted the basis of the development of the cracking process. In 1877, Letnii first isolated aromatic hydrocarbons from petroleum (benzene, toluene, xylene, anthracene) and established important regularities involved in the pyrolysis of petroleum. After 1879 special plants for the production of some petroleum products were constructed under the direction of and in accordance with the designs of Letnii.