Edward Frankland

Edward Frankland, around 1870

Sir Edward Frankland (born January 18, 1825 in Churchtown near Lancaster , † August 9, 1899 in Golaa , Gudbrandsdalen , Norway ) was an English chemist . Frankland synthesized organometallic compounds and introduced the concept of saturation capacity to organic chemistry . Saturation capacity was the conceptual precursor of valence .

Live and act

Frankland was a pharmacist's assistant in his hometown for six years after attending the Lancaster Royal Grammar School . In 1845 he went to London and studied chemistry in the Museum of Practical Geology near Lyon Playfair . Frankland met Hermann Kolbe there , made friends with him and later followed him to Marburg to do research in Robert Bunsen's laboratory . In Marburg Frankland was in 1849 with a dissertation Concerning the isolation of radicales ethyl doctorate . He met his wife Sophie, née Fick (1821–1874), whom he married in 1851, in Marburg; she was a sister of Adolf Fick .

In 1851 Frankland received the Chair of Chemistry at Owen's College , Manchester. In 1858 he became head of the chemistry department at St Bartholomew's Hospital in London. In 1863 Frankland succeeded Michael Faraday at the Royal Institution of Great Britain , and in 1865 succeeded August Wilhelm von Hofmann at the Royal College of Chemistry . Later, that was the Royal College of Chemistry in Normal School of Science renamed. In 1868 Frankland was appointed to a royal commission to investigate water pollution and consider water treatment. In 1873 his wife died. In 1885 he resigned his professorship and retired to his country estate The Yews in Reigate, Surrey.

He was a member of the X Club.

Frankland died while on vacation. His son Percy Faraday Frankland was also a chemistry professor.

Scientific work

When Frankland began his work, no structural formulas were known and fundamental discoveries for the representation of chemical compounds and functional groups were still unknown.

Kolbe and Frankland initially wanted to confirm the radical theory of Jöns Jacob Berzelius . The further development of the radical theory was the pairing theory.

In 1834, by heating basic ethyl sulfate with potassium cyanide, Pelouze obtained a compound that he called hydrogen cyanide ether (propyl nitrile). The compound was hardly attacked by alkali. A year later, from Jean Baptiste Dumas and Peligot, methyl nitrile ( acetonitrile ) was obtained by heating dimethyl sulfate and potassium cyanide . In 1844, after dry distillation , Hermann Fehling obtained a substance from ammonium benzoate that he called benzonitrile.

According to Kolbe and Frankland, oxalic acid ( carboxy group ) paired with a phenyl radical to form benzoic acid, with a methyl radical to form acetic acid, and with an ethyl radical to form propionic acid. The two researchers claimed in 1847 that a nitrile group behaved very similarly to oxalic acid (carboxy group). Kolbe and Frankland followed Pelouze's presentation. You received a very clean acetonitrile. They also received propyl nitrile in a very pure form. They were able to convert the two compounds into acetic and propionic acids by heating them in lye.

At the same time, Dumas also developed a good method for preparing acetonitrile by heating ammonium acetate with phosphorus pentoxide.

In 1848 Frankland, together with Hermann Kolbe, produced the first synthetic heterocycle made from propionitrile and elemental potassium , kyanethine (or modern 4-amino-2,6-diethyl-5-methylpyrimidine), the structure of which could not be clarified at the time.

After Bunsen considered the isolation of the pure methyl radical, Frankland and Kolbe added the acetonitrile to some potassium. The unknown gas produced was examined using the Bunsen method. Instead of the expected methyl radical, however, a gas was created with the same chemical composition as the methyl radical - but with twice the molar mass, it was ethane. The simultaneous action of chlorine gas on the resulting gas gave them a gas containing chlorine ( methyl chloride ), which, like ethyl chloride, could not be isolated in an ice bath.

At this stage of development, the atomic weight of carbon in organic matter was still misinterpreted. In the chemical formulas, therefore, there appeared two carbon atoms for formic acid, methanol and four carbon atoms for acetic acid. So far, only ethyl chloride was known, which at that time was still considered methyl chloride. Hence Kolbe and Frankland misinterpreted the resulting product.

Charles Gerhardt suspected that the reaction of acetonitrile with potassium did not produce ethyl chloride, but methyl chloride.

Also in 1848 Frankland also produced the first organotin compound, diethyltin diiodide , as a clear, colorless liquid, which he obtained by reacting ethyl iodide with elemental tin .

While Kolbe went to Braunschweig to prepare the handbook for chemistry , Frankland stayed with Bunsen in Marburg. Frankland made the ethyl iodide to isolate the radical ethyl. Similar to the investigation of acetonitrile for potassium, Frankland hoped to use an active metal to break down the ethyl iodide into the radical. He melted the ethyl iodide with zinc in a glass tube and heated the glass tube. He received a gas that actually had the chemical composition of an ethyl radical.

The experiment was repeated with methyl iodide and zinc. This produced a gas that had the chemical composition of a methyl radical (actually ethane ). The crystalline residue in the tube was checked by Frankland. Methane gas was created immediately with a little water. The crystalline residue was distilled by Frankland, thereby obtaining a compound which he called zinc methyl ( dimethyl zinc ). Frankland also carried out the distillation with zinc ethyl ( diethylzinc ).

While Frankland still believed in the isolation of the pure methyl and ethyl radicals at that time, Laurent and Gerhardt took the view that the formulas (instead of methyl radical ethane, instead of ethyl radical butane) had to be doubled. August Wilhelm von Hofmann was able to support this claim based on the boiling points.

Zinc ethyl played an essential role in Stanislao Cannizzaro's molecular theory .

In 1852 Frankland also renounced the pairing theory. He developed the theory of the saturation capacity of chemical elements. The elements zinc, tin, arsenic, phosphorus, nitrogen, antimony and mercury were examined by him with regard to their ability to bind to oxygen and ethyl radicals. Frankland was able to show that nitrogen, phosphorus and arsenic can bind five or three equivalents. The saturation capacity was the conceptual precursor for atomicity and later valence .

After 1851 Frankland took on scientific work in the public interest. The technology of the heating and lighting gas industry was examined by him. He gave recommendations for the manufacturing and cleaning methods of the luminous gas. In 1854 he examined the luminous intensity of a burner he had developed, and in 1862 he examined the luminous intensity and the composition of the luminous gas. From 1865 he made suggestions for improving the location of wastewater in industrial and residential areas as well as supplying households with fresh drinking water. He carried out both chemical and bacteriological water analyzes and improved the investigation methods. From 1875 he wrote annual reports on the situation of drinking water in living quarters and on the contamination of rivers.

In addition to these technical tasks in the public interest, he and his colleague Baldwin Francis Duppa found time for chemical research. Duppa and Frankland produced the boron trialkyl compounds (triethyl boron) from zinc alkyls, which converted into mixed boron alkyl esters when exposed to air.

Frankland and Duppa reacted ethyl acetate with sodium and ethyl iodide to give ethyl butyrate or its dialkylated derivative. They also received acetoacetic ester .

In 1859 he took part in an expedition by John Tyndall to Mont Blanc . He investigated how a candle flame behaves when the air pressure changes, but found that the burn rate remained unaffected by the air pressure. However, he found that on the summit the light from the candle became very dim.

Frankland was one of the discoverers of helium . In 1868 he found a yellow line in the solar spectrum that did not belong to any previously known substance and was explained with a hypothetical element, the then still unknown helium.

Awards

In 1853 he was elected a Fellow of the Royal Society , in 1887 and 1888 he was Vice President of the Royal Society. The Royal Society awarded him the Royal Medal in 1857 and the Copley Medal in 1894 . The Chemical Society elected him President in 1871, and the Institute of Chemistry when it was founded. In 1866 he became a corresponding member and in 1895 associé étranger of the Académie des sciences in Paris. In 1869 he was elected a foreign member of the Bavarian Academy of Sciences and in 1873 of the Göttingen Academy of Sciences . In 1875 he was accepted as a corresponding member of the Prussian Academy of Sciences and on December 3, 1876 in the Russian Academy of Sciences in St. Petersburg . In 1884 he became an Honorary Fellow of the Royal Society of Edinburgh .

In 1897 Edward Frankland was knighted as Knight Commander of the Order of the Bath (KCB).

Fonts

• About the isolation of ethyl. Inaugural dissertation, which Edward Frankland from Lancaster submitted with the approval of the Philosophical Faculty of Marburg in order to obtain the doctorate. Marburg, 1849. Printed by George [sic!] Westermann in Braunschweig. [45 pages].

literature

• Colin A. Russell : Edward Frankland. Chemistry, Controversy and Conspiracy in Victorian England. Cambridge University Press, 1996.
• Colin A. Russell: Lancastrian Chemist: The Early Years of Sir Edward Frankland . 1986
• Frankland, Sir Edward . In: Encyclopædia Britannica . 11th edition. tape 11 : Franciscans - Gibson . London 1910, p. 23 (English, full text [ Wikisource ]).
• Carl Graebe : History of Organic Chemistry . First volume. Published by Julius Springer, Berlin 1920, pp. 149 ff.
• Johannes Wislicenus : Sir Edward Frankland . In: Reports of the German Chemical Society , 33, 1901, p. 3847

Individual evidence

1. ↑ Short biography in German based on Colin A. Russells. P. 10
2. ↑ Liebigs Ann. Chem. 49 , 91 (1844).
3. ↑ Phil. Mag. 266 (1847).
4. ↑ Comptes rendus de l 'Acad. d. Sc. 25 , 442, 474, 656 (1847).
5. ↑ von Meyer, E. (1880), Ueber Kyanäthin and new bases resulting from it. Journal für Praktische Chemie, 22: 261-288, doi: 10.1002 / prac.18800220118 .
6. ↑ Comptes rendus des travaux de chimie par Laurent et Gerhardt 19 (1849).
7. ↑ Bernard Jousseaume: Organometallic synthesis and chemistry of tin and lead compounds. In: link.springer.com. Retrieved May 3, 2015 .  
8. ↑ Liebigs Ann. Chem. 71 , 171 (1849).
9. ↑ Liebigs Ann. Chem. 71 , 213 (1849).
10. ↑ Comptes rendus des travaux de chimie par Laurent et Gerhardt 233 (1850).
11. ↑ Liebigs Ann. Chem. 77 , 161 (1851).
12. ↑ Liebigs Ann. Chem. 85 , 329 (1853).
13. ↑ Liebigs Ann. Chem. 138 , 204, 328.
14. ↑ Philos. Trans. 156 , 37.
15. ^ List of members since 1666: Letter F. Académie des sciences, accessed on November 15, 2019 (French). 
16. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 84.
17. ^ Members of the previous academies. Sir Edward Frankland. Berlin-Brandenburg Academy of Sciences and Humanities , accessed on March 24, 2015 . 
18. ^ Foreign members of the Russian Academy of Sciences since 1724: Frankland, Edward. Russian Academy of Sciences, accessed November 15, 2019 (Russian). 
19. ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. Royal Society of Edinburgh, accessed December 6, 2019 .