What is the Kharash Effect

Morris S. Kharasch

Morris Blessed Kharasch (born August 24, 1895 in Kremenez, Ukraine, † October 9, 1957 in Copenhagen) was an American chemist. He was Professor of Organic Chemistry at the University of Chicago.

Kharasch came to the USA with his family in 1908 and studied from 1913 at the University of Chicago with a bachelor's degree in 1917 and a doctorate in 1919 under Jean-Felix Piccard. He was from 1922 professor at the University of Maryland in Baltimore and from 1928 associate professor and from 1935 full professor at the University of Chicago, from 1957 as director of the Institute for Organic Chemistry.

Markovnikov's rule on propene with hydrogen bromide

He showed with research from 1930 that there are reactions under the influence of free radicals that violate the Markovnikov rule. He demonstrated this using the example of the reaction of 3-bromopropene with hydrogen bromide: in the absence of oxygen / peroxides, 1,2-dibromopropane was preferably formed according to the Markovnikov rule, with the presence of oxygen / peroxide, preferably 1, 3-dibromopropane, which is the rule injured (peroxide effect according to Kharasch).

He dealt with organic mercury compounds and synthesized thimerosal (merthilate), which he patented in 1928 (he passed the patent to Eli Lilly) and which was used as an additive in vaccines from 1931 because of its antibacterial effect. During World War II he worked in the US government's synthetic rubber program.

In 1936 he founded the Journal of Organic Chemistry. In 1946 he was elected to the National Academy of Sciences. In 1952 he received the Richard's Medal from the ACS and in 1949 the Scott Award from the Franklin Institute. The Kharasch-Sosnovsky reaction for acyloxylation is named after him. He later deals with Grignard reactions.

Herbert C. Brown was one of his students.

Fonts (selection)

  • with Otto Reinmuth: Grignard reaction in nonmetallic substances. Prentice-Hall 1954


  • Entry in Winfried Pötsch, Annelore Fischer, Wolfgang Müller: Lexicon of important chemists, Harri Deutsch 1989

Individual evidence

  1. ↑ Life data, publications and academic family tree of Morris S. Kharasch at academictree.org, accessed on February 15, 2018.