crème de la crème

Jai Ganesh · 2026-02-22 18:00:01

2439) Cyril N. Hinshelwood

Gist:

Work

During chemical reactions, atoms and molecules regroup and form new constellations. When molecules formed during a reaction readily react with molecules present from the beginning, a chain reaction can occur. Explosions and fire are examples of chain reactions. During the 1930s Cyril Hinshelwood analyzed conditions and sequences of events involved in chain reactions from a theoretical standpoint. Among other things, he found that the theoretical results corresponded with observations of the reaction between hydrogen and oxygen.

Summary

Sir Cyril Norman Hinshelwood (born June 19, 1897, London, Eng.—died Oct. 9, 1967, London) was a British chemist who worked on reaction rates and reaction mechanisms, particularly that of the combination of hydrogen and oxygen to form water, one of the most fundamental combining reactions in chemistry. For this work he shared the 1956 Nobel Prize for Chemistry with the Soviet scientist Nikolay Semyonov.

Hinshelwood obtained his doctorate at the University of Oxford in 1924 and became professor of chemistry there in 1937. After retiring from Oxford in 1964 he became a senior research fellow at Imperial College, London.

About 1930 Hinshelwood began investigating the complex reaction in which hydrogen and oxygen atoms combine to form water. He showed that the products of this reaction help to spread the reaction further in what is essentially a chain reaction.

He next sought to explore molecular kinetics within the bacterial cell. Upon observing the biological responses of bacteria to changes in environment, he concluded that more or less permanent changes in a cell’s resistance to a drug could be induced. This finding was important in regard to bacterial resistance to antibiotic and other chemotherapeutic agents. Hinshelwood was knighted in 1948. His publications include The Kinetics of Chemical Change in Gaseous Systems (1926) and The Chemical Kinetics of the Bacterial Cell (1946).

Details

Sir Cyril Norman Hinshelwood (19 June 1897 – 9 October 1967) was a British physical chemist and expert in chemical kinetics. His work in reaction mechanisms earned the 1956 Nobel Prize in chemistry.

Education

Born in London, his parents were Norman Macmillan Hinshelwood, a chartered accountant, and Ethel Frances née Smith. He was educated first in Canada, returning in 1905 on the death of his father to a small flat in Chelsea where he lived for the rest of his life. He then studied at Westminster City School and Balliol College, Oxford.

Career

During the First World War, Hinshelwood was a chemist in an explosives factory. He was a tutor at Trinity College, Oxford, from 1921 to 1937 and was Dr Lee's Professor of Chemistry at the University of Oxford from 1937. He served on several advisory councils on scientific matters to the British Government.

His early studies of molecular kinetics led to the publication of Thermodynamics for Students of Chemistry and The Kinetics of Chemical Change in 1926. With Harold Warris Thompson he studied the explosive reaction of hydrogen and oxygen and described the phenomenon of chain reaction. His subsequent work on chemical changes in the bacterial cell proved to be of great importance in later research work on antibiotics and therapeutic agents, and his book, The Chemical Kinetics of the Bacterial Cell was published in 1946, followed by Growth, Function and Regulation in Bacterial Cells in 1966. In 1951 he published The Structure of Physical Chemistry. It was republished as an Oxford Classic Texts in the Physical Sciences by Oxford University Press in 2005.

The Langmuir-Hinshelwood process in heterogeneous catalysis, in which the adsorption of the reactants on the surface is the rate-limiting step, is named after him. He was a senior research fellow at Imperial College London from 1964 to 1967.

Awards and honours

In addition to being named the second Dr. Lee's Professor of Chemistry at Oxford, Hinshelwood was elected Fellow of the Royal Society (FRS) in 1929, serving as president from 1955 to 1960. He was knighted in 1948 and appointed to the Order of Merit in 1960. With Nikolay Semenov of the USSR, Hinshelwood was jointly awarded the Nobel Prize in Chemistry in 1956 for his researches into the mechanism of chemical reactions. He was also an elected member of the American Academy of Arts and Sciences, the United States National Academy of Sciences, and the American Philosophical Society.

Hinshelwood was president of the Chemical Society, the Royal Society, the Classical Association, and the Faraday Society, and received numerous awards and honorary degrees. He was elected on 1 January 1960 to honorary membership of the Manchester Literary and Philosophical Society who awarded him its Dalton medal in 1966.

Personal life

Hinshelwood never married. He was fluent in seven classical and modern languages and his main hobbies were painting, collecting Chinese pottery, and foreign literature. As an artist, Hinshelwood painted scenes in Oxford, as well as portraits of Oxford University people including Harold Hartley, his doctoral supervisor, and Herbert Blakiston, the President of Trinity College. The portrait of Hartley is now owned by the Royal Society, and that of Blakiston is owned by Trinity College, as are a number of Hinshelwood's other paintings.

He died, at home, on 9 October 1967. In 1968, his Nobel Prize medal was sold by his estate to a collector, who then sold it in 1976 for $15,000. In 2017, his Nobel Prize medal was sold at auction for $128,000.

Jai Ganesh · Yesterday 17:37:59

2440) Nikolay Semyonov

Gist:

Work

During chemical reactions, atoms and molecules regroup and form new constellations. When molecules formed during a reaction readily react with molecules present from the beginning, a chain reaction can occur. Explosions and fire are examples of chain reactions. During the 1930s Nikolay Semyonov analyzed conditions and sequences of events involved in chain reactions from a theoretical and mathematical standpoint. Among other things, he found that the theoretical results corresponded with observations of the reactions between phosphorus and oxygen and between hydrogen and oxygen.

Work

During chemical reactions, atoms and molecules regroup and form new constellations. When molecules formed during a reaction readily react with molecules present from the beginning, a chain reaction can occur. Explosions and fire are examples of chain reactions. During the 1930s Nikolay Semyonov analyzed conditions and sequences of events involved in chain reactions from a theoretical and mathematical standpoint. Among other things, he found that the theoretical results corresponded with observations of the reactions between phosphorus and oxygen and between hydrogen and oxygen.

Summary

Nikolay Nikolayevich Semyonov (born April 15 [April 3, Old Style], 1896, Saratov, Russia—died Sept. 25, 1986, Moscow, U.S.S.R.) was a Soviet physical chemist who shared the 1956 Nobel Prize for Chemistry with Sir Cyril Hinshelwood for research in chemical kinetics. He was the second Soviet citizen (after the émigré writer Ivan Bunin) to receive a Nobel Prize.

Semyonov was educated in St. Petersburg, graduating from the city’s university in 1917, the year of the Russian Revolution, and taught for a time at the University of Tomsk in western Siberia. Associated with the Leningrad A.F. Ioffe Physicotechnical Institute from 1920 to 1931, he became a professor at the Leningrad (St. Petersburg) Polytechnic Institute in 1928. He was director of the Institute of Chemical Physics at the Academy of Sciences of the U.S.S.R. after 1931 and became a professor at Moscow State University in 1944.

Like Hinshelwood, Semyonov conducted research on the mechanism of chemical chain reactions and their significance in relation to explosions. Semyonov was the first to show that chain reactions are the norm in chemical transformations of matter. He published the influential book O nekotorykh problemakh khimicheskoy kinetiki i reaktsionnoy sposobnosti (1954; Some Problems in Chemical Kinetics and Reactivity).

Details

Nikolay Nikolayevich Semyono , sometimes Semenov, Semionov or Semenoff (15 April [O.S. 3 April] 1896 – 25 September 1986) was a Soviet physicist and chemist. Semyonov was awarded the 1956 Nobel Prize in Chemistry for his work on the mechanism of chemical transformation.

Life and career

Semyonov was born in Saratov, the son of Yelena Dmitrieva and Nikolai Aleksandrovich Semyonov. He graduated from the department of physics of Petrograd University (1913–1917), where he was a student of Abram Fyodorovich Ioffe. In 1918, he moved to Samara, where he was enlisted into Kolchak's White Army during Russian Civil War.

Semyonov published his first research paper in 1916 and became a lecturer at the University of Tomsk in western Siberia.

After graduating from Saint Petersburg State University, he worked as an assistant and lecturer at the Tomsk and Tomsk University Institute of Technology, where he published his first research paper in 1916. He returned to western Siberia, Petrograd and took charge of the electron phenomena laboratory of the Petrograd Physico-Technical Institute in 1920. He also became the vice-director of the institute. In 1921, he married philologist Maria Boreishe-Liverovsky (student of Zhirmunsky). She died two years later. On September 15, 1924, Nikolay married Maria's niece, Natalia Nikolayevna Burtseva. They had two children, son Yuri and daughter Lyudmila.

During that difficult time, Semyonov, together with Pyotr Kapitsa, discovered a way to measure the magnetic field of an atomic nucleus (1922). Later the experimental setup was improved by Otto Stern and Walther Gerlach and became known as Stern–Gerlach experiment.

In 1925, Semyonov, together with Yakov Frenkel, studied kinetics of condensation and adsorption of vapors. In 1927, he studied ionisation in gases and published an important book, Chemistry of the Electron. In 1928, he, together with Vladimir Fock, created a theory of thermal disruptive discharge of dielectrics.

In 1927, Semyonov studied the ionization of gases, the chemistry of the electron. In 1928, he created the theory of the broken discharge of dielectrics with Vladimir Fock.

He lectured at the Petrograd Polytechnical Institute and was appointed Professor in 1928. In 1931, he organized the Institute of Physical Chemistry of the USSR Academy of Sciences (which moved to Chernogolovka in 1943) and became its first director. In 1932, he became a full member of the Soviet Academy of Sciences.

The ideas of Semyonov have been applied in the science of reaction and production of polymerization reactions. His ideas are also applied in catalysis studies in biological systems.

Semyonov married Natalya Nikolayevna Semyonov and together they both have a son and a daughter. Semyonov died on September 25, 1986, in Moscow, and was buried at the Novodevichy Cemetery.

Significant works

Semyonov's outstanding work on the mechanism of chemical transformation includes an exhaustive analysis of the application of the chain theory to varied reactions (1934–1954) and, more significantly, to combustion processes. He proposed a theory of degenerate branching, which led to a better understanding of the phenomena associated with the induction periods of oxidation processes. He spent most of his career focusing and developing the field of chemical chain reactions.

Semyonov wrote two important books outlining his work. Chemical Kinetics and Chain Reactions was published in 1934, with an English edition in 1935. It was the first book in the U.S.S.R. to develop a detailed theory of unbranched and branched chain reactions in chemistry. Some Problems of Chemical Kinetics and Reactivity, first published in 1954, was revised in 1958; there are also English, American, German, and Chinese editions. He is the only Soviet/Russian Chemistry Nobel Laureate, who received the Nobel Prize in Chemistry (together with Sir Cyril N. Hinshelwood) for his work in 1956.

Semyonov had long been a supporter of the Communist Party and the Soviet Union. After the Bulletin of the Atomic Scientists accused the Soviet Union of heavy scientific censorship in 1953, he coauthored the Soviet response which denied all accusations. He is also noted as being the most famous signatory to a 1971 public letter from Soviet scientists to United States president Richard Nixon, on displeasure in the murder trial of Angela Davis.

Semyonov trained Russian organometallic chemist Alexander Shilov, who discovered platinum catalyzed C-H activation.

Math Is Fun Forum

#1876 2026-02-22 18:00:01

Re: crème de la crème

#1877 Yesterday 17:37:59

Re: crème de la crème

Board footer