Edward Frankland
Sir Edward Frankland ( born January 18, 1825 Churchtown in Lancaster; † August 9, 1899 in Golaa, Gudbrandsdalen, Norway ) was an English chemist. Frankland synthesized organometallic compounds and introduced the concept of saturation capacity in organic chemistry. The saturation capacity was the intellectual forerunner of the valence.
Life and work
Frankland was after visiting the Lancaster Royal Grammar School ( Gymnasium) for six years, an assistant pharmacist in his hometown. In 1845 he went to London and studied at the Museum of Practical Geology chemistry at Lyon Playfair. Frankland met on Hermann Kolbe, made friends with him and later followed him to Marburg to do research in the laboratory of Robert Bunsen. In Marburg Frankland acquired in 1849 and the doctoral degree with his dissertation Concerning the isolation of ethyl radicales. His wife, Sophie, nee Fick (1821-1874), whom he married in 1851, he got to know in Marburg.
In 1851 Frankland was appointed Professor in Chemistry at Owen's College in Manchester. In 1858 he became head of the chemical department at St Bartholomew's Hospital in London. 1863 Frankland successor of Michael Faraday at the Royal Institution of Great Britain, and in 1865 the successor of August Wilhelm von Hofmann at the Royal College of Chemistry. It was later renamed the Royal College of Chemistry in Normal School of Science. In 1868 Frankland was appointed a royal commission to investigate the water pollution and considerations for water treatment. In 1873 his wife died. In 1885 he resigned his professorship and retired to his country seat The Yews in Reigate, Surrey back.
He was a member of the X- Club.
Frankland died during a holiday stay.
Scientific work
As Frankland began his work, no structural formulas were known, fundamental discoveries for the representation of chemical compounds and functional groups were still unknown.
Kolbe and Frankland first wanted to confirm the free radical theory of Jöns Jacob Berzelius. The development of the free radical theory was the pairing theory.
Pelouze had received in 1834 by the heating of basic ethyl sulfate with potassium cyanide a compound which he described as Cyanwasserstoffether ( Propylnitril ). From alkali, the connection was hardly affected. A year later the methylnitrile (acetonitrile ) was obtained by heating dimethyl sulfate and potassium cyanide by Jean Baptiste Dumas and Peligot. In 1844 Hermann Fehling had received a substance from ammonium by dry distillation, which he called benzonitrile.
According to Kolbe and Frankland, the oxalic acid ( carboxyl group) paired with a phenyl benzoic acid with a methyl radical to acetic acid, with an ethyl radical to propionic acid. The two researchers claimed in 1847 a nitrile group situation would be quite similar to the oxalic acid ( carboxyl group). Kolbe and Frankland was followed by the presentation of Pelouze. You got a very clean acetonitrile. Also Propylnitril they received in a very pure form. The two compounds, they were converted into the acetic acid and propionic acid by heating in alkaline solution.
At the same time also Dumas developed a good process for the preparation of acetonitrile by heating with phosphorus pentoxide ammonium acetate.
Frankland introduced in 1848, together with Hermann Kolbe the first synthetic heterocycle from propionitrile and elemental potassium, which Kyanäthin (or modern 4-amino- 2 ,6 -diethyl -5- methylpyrimidin ), the structure at that time has not yet been elucidated.
After consideration of Bunsen for the isolation of pure methyl radical Frankland and Kolbe trickled the acetonitrile on some potassium. The resulting unknown gas was investigated by the method of Bunsen. However, instead of the expected methyl radical was a gas having the same chemical composition as the methyl radical - but with twice the molecular weight, it was ethane. By the simultaneous action of chlorine gas on the emerging gas, they received a chlorine-containing gas ( methyl chloride), that could not be isolated, such as ethyl chloride in an ice bath.
In this phase, the development of the atomic weight of carbon in organic matter has been misinterpreted. In the chemical formulas therefore appeared two carbon atoms of formic acid, methanol and acetic acid for four carbon atoms. So far, only the ethyl chloride was known that was then still regarded as methylene chloride. Therefore, Kolbe and Frankland suggested the resulting product wrong.
Charles Gerhardt suspected that during the reaction of acetonitrile potassium ethyl not be formed, but the methyl chloride.
While Kolbe now went to Brunswick to customize the manual for Chemistry, Frankland stayed with Bunsen in Marburg. Frankland put forth the ethyl iodide to isolate the radical ethyl. Similar to the study of acetonitrile to potassium, Frankland hoped to break with an active metal, the ethyl iodide in the radical. It melted the ethyl iodide with zinc in a glass tube and heated to the glass tube. He received a gas that actually had a chemical composition of an ethyl radical.
The experiment was repeated with methyl iodide, and zinc. In this case, a gas was that the chemical composition of a methyl radical ( actually ethane ) had. The crystalline residue in the tube was checked by Frankland. With a glass of water was methane gas. The crystalline residue was distilled by Frankland, but he received a compound which he described as zinc methyl ( dimethyl ). Even with Zinkethyl ( diethyl zinc ) resulted Frankland from the distillation.
While Frankland believed at this time to the isolation of the pure methyl and ethyl radicals, was represented by Laurent and Gerhardt the view that the formulas would be ( instead of the methyl radical of ethane, butane instead of ethyl radical ) doubled. August Wilhelm von Hofmann was able to support this claim because of the boiling points.
The Zinkethyl played an essential role in the molecular theory by Stanislao Cannizzaro.
In 1852, Frankland also said of the pairing theory going on. He developed the theory of the saturation capacity of the chemical elements. The elements zinc, tin, arsenic, phosphorus, nitrogen, antimony, mercury, were examined by it with respect to the binding ability to oxygen and ethyl radicals. Frankland showed that nitrogen, phosphorus and arsenic can bind to both five and three equivalents. The saturation capacity was the intellectual forerunner for the atomicity and the subsequent valence.
After 1851 Frankland took over scientific work in the public interest. The technique of heating and light gas industry was examined by him. It made recommendations for the fabrication and purification methods of illuminating gas. In 1854 he examined the light intensity of a burner developed by him, in 1862, the light intensity and the composition of illuminating gas were investigated by him. From 1865 onwards, he gave suggestions for improvements in the situation of waste water in industrial and residential area as well as the supply of homes with fresh drinking water. He led by both chemical and bacteriological water analysis and improved research methods. From 1875 he wrote annual reports on the situation of drinking water in the living area and the contamination of rivers.
In addition to these technical tasks in the public interest he took with his colleague Francis Baldwin Duppa time for chemical research. Duppa and Frankland prepared from zinc alkyls produces the Bortrialkylverbindungen ( triethyl ), which passed the admission of air into mixed Boralkylester.
Ethyl acetate translated Frankland and Duppa order with sodium and ethyl iodide to ethyl butyrate or their dialkylated derivative. They also received acetoacetic ester.
In 1859 he took part in an expedition John Tyndall's part of the Mont Blanc. He investigated how does a candle flame when changing the air pressure, but noted that the burn rate remained unaffected by the air pressure. However, he found that on the top of the light of the candle was very weak.
Frankland was one of the discoverers of helium. He introduced in 1868 in the solar spectrum, a yellow line fixed that belonged to no known hitherto fabric and has been declared with a hypothetical element, the then-unknown helium.
Awards
In 1853 he was elected as a member ( "Fellow" ) to 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 1894, the Copleymedaille. The Chemical Society elected him in 1871, the Institute of Chemistry at its founding president. In 1897 Sir Edward Frankland was appointed Knight Commander ( KCB, Knight Commander band).
Writings
- Concerning the isolation of Aethyls. Inaugural Dissertation that will be filed with the permission of the philosophical faculty of Marburg for obtaining the Doctor dignity Edward Frankland from Lancaster. Marburg, 1849. Pressure of George [ sic] Westermann, Braunschweig. [45 pages].