Friedrich Wöhler
<<THIS ARTICLE DOES NOT CITE ANY SOURCES.>>
<<IT IS IMPORTANT TO MENTION HIS INFLUENCE ON THE THEORY OF VITALISM, IN THE INTRODUCTION AS WELL AS IN THE MAIN TEXT.>>
| Friedrich Wöhler |
|---|
 German chemist
|
| Born |
| July 31, 1800 Eschersheim, Frankfurt am Main, Germany |
| Died |
| September 23, 1882 Göttingen, Germany |
Friedrich Wöhler (July 31, 1800 - September 23, 1882) was a German chemist, who ushered in a new age of organic chemistry when he demonstrated that urea, a chemical produced in the bodies on animals and humans, could be manufactured in the laboratory. This discovery overthrew the then-current theory of vitalism, which held that the chemistry of living things was governed by a different set of laws from that of inorganic chemicstry.
Early days
Friedrich Wohler was born in Eschersheim near Frankfurt am Main. At an early age, he showed an interest in scientific subjects, the study of which he pursued on an informal basis through a retired physician named Buch who had taken up an interest in physics and chemistry. At the age of 14, Wohler began attending the Frakfort gymnasium, but did not particularly distinguish himself at the time. He often neglected his formal studies to pursue his interest in chemistry and mineralogy, and this had the unintended side-effect of bringing him in contact with a number of high-profile mineral collectors such as Johann Wolfgang von Goethe, who was perhaps better known for his literary accomplishments than his scientific pursuits. During these early years, Wohler took a great interest in the isolation of elements, and wrote a paper in which he demonstrated its presence in what was called Bohemian sulfuric acid. He also successfully isolated potassium and and cadmium, his sister acting as an assistant in his experiments. Wohler was also an avid hobbyist, his interests ranging from mathematics to fine art and the collection of Roman antiquities.
During this period, Wohler, with the help of his mentor, investigated the properties of cyanogen compounds. He also isolated selenium, and published several papers on his research with the help of Buch.
At the age of 19, Wohler began formal studies in medicine at the University of Marburg. After a year, he transferred to the University of Heidelberg to study under Leopold Gmelin, who held the chair of medicine and chemistry. Wohler graduated from Heidelberg in 1823, earning the title of doctor of medicine, surgery and obstetrics. Recognizing Wohler's proficiency in chemistry, Gmelin encouraged him to persue his primary interest, and arranged for him to study under Jöns Jakob Berzelius, who was among the most famous chemists of Europe at the time. Spending a year in Stockholm, he traveled with Berzelius for two months. He then planned to settle down to an assitant professorship at the University of Heidelberg. Through the intervention of the renowned scientists Leopold Buch, Poggendorff and Mitscherlich, however, Wohler was appointed to a position at the Trade School in Berlin, where he had a laboratory at his disposal. It was there that he began to perform some of his most important research.
Aluminum and beryllium
aluminum is a major constituent of the bulk of minerals that constitute the earth's crust. Humphrey Davy was the first to have attempted to isolate aluminum in 1808 through electrolysis, He made other attempts, but could only produce an amalgam of aluminum with other metals. Hans Christian Oersted is credited with a similar feat in 1825, using an amalgam of mercury and potassium to reduce the aluminum in amonium chloride. Wohler used pure potassium heated with ammonium chloride, and was able to produce aluminum in a purer form. He refined the process, and in 1845 was able produce samples of metal in quantities sufficient to determine its characteristics. <<<McKetta, John J., and William A. Cunningham. 1976. Encyclopedia of chemical processing and design. New York: M. Dekker. ISBN 0824724518 62-63>>>
Also in 1828, Wohler purified Beryllium in the form of a dark metallic poweder by heating Beryllium chloride with potassium metal. A dark powder was formed that was insoluble in water and that took on a metallic luster. This feat was also accomplished around the same time by the French chemist Antoine Alexandre Bussy. <<<Adair, Rick. 2007. Beryllium. Understanding the elements of the periodic table. New York: Rosen Pub. Group. ISBN 1404210032. 9.>>>
Synthesis of urea
In 1928, Wohler noticed a white crystalline substance that formed when he heated ammonium cyanate. He identified the crystals as urea, a substance found in the urine of animals and humans. It had the same chemical constitution as ammonium cyanate, but exhibited different properties. The synthesis of urea is considered a landmark in chemistry.
In announcing his finding to Berzelius, he wrote: "I must tell you that I can prepare urea without requiring the kidney of an animal, either man or dog." Before Wohler's synthesis of urea, it was generally believed that organic substances (i.e., protoplasm) could only be formed under the influence of the "vital force" in the bodies of animals and plants. Wöhler proved by the artificial preparation of urea from inorganic materials that this view was false. Urea synthesis was integral for biochemistry because it showed that a compound known to be produced only by biological organisms could be produced in a laboratory, under controlled conditions, from "inanimate" matter. This synthesis of organic matter disproved the common theory (vitalism) about the vis vitalis, a transcendent "life force" needed for producing organic compounds. By showing that ammonium cyanate can become urea by an internal arrangement of its atoms, without gaining or losing in weight, Wöhler furnished one of the first and best examples of isomerism, demolishing the old view that equality of composition could not coexist in two bodies with differences in their respective physical and chemical properties.
Isomers
Wohler, during his stay in Stockholm, had produced a compound called silver cyanate, for which he worked out a chemical formula. Another scientist, Justus Liebig, also in his early career, produced silver fulminate while working with his mentor, Gay-Lussac. The two compounds had different properties but were identical in chemical composition. Liebig first challenged Wohler, believing that his results must be faulty. But the two later met in Frankfort, and Liebig finally accepted Wohler's results. Berzelius offered a solution to the surprising finding by proposing that two different substances could have the same chemical composition if the arrangement of their atoms differed. He called such compounds isomers.
Wohler, recognizing the scope of the work that lay before him, suggested to Liebig that the two collaborate in the research of organic compounds. In 1830, Wöhler published, jointly with Justus von Liebig, the results of a research on cyanic acid and cyanuric acid and on urea. Berzelius, in his report to the Royal Swedish Academy of Sciences, called it the most important of all researches in physics, chemistry, and mineralogy published in that year. The results were quite unexpected, and furnished additional evidence in favour of isomerism.
In 1831 Wohler accepted a position at the Higher Polytechnic School]] at Kassel. He continued working with Liebig.
In 1834, Wöhler and Liebig published an investigation of the oil of bitter almonds, or benzaldehyde. They proved by their experiments that a group of carbon, hydrogen, and oxygen atoms called the benzoyl radical can behave like an element, take the place of an element, and can be exchanged for elements in organic chemical compounds. Thus the foundation was laid of the doctrine of compound radicals, a doctrine which had a profound influence on the development of chemistry. Among the compounds that they found contained the benzoyl radical were ethyl benzoate, benzoic acid, and benzoyl chloride.
In 1836, Wohler was appointed to the chair of chemistry at the University of Gottingen, winning the position over his friend and collaborator, Liebig.
1854, Henri Sainte Claire Deville manufactured Aluminum using sodium, but Wohler had used potassium metal.
1832
Wöhler was also a co-discoverer of beryllium and silicon, as well as the synthesis of calcium carbide, among others. To him also is due the isolation of the elements yttrium, beryllium, and titanium, the observation that "silicium" (silicon) can be obtained in crystals, and that some meteoric stones contain organic matter. He analyzed a number of meteorites, and for many years wrote the digest on the literature of meteorites in the Jahresbericht der Chemie; he possessed the best private collection of meteoric stones and irons existing. Wöhler and Sainte Claire Deville discovered the crystalline form of boron, and Wöhler and Buff the hydrogen compounds of silicon (the silanes) and a lower oxide of the same element.
Final days and legacy
Wöhler's discoveries had great influence on the theory of chemistry. The journals of every year from 1820 to 1881 contain contributions from him. It was remarked that "for two or three of his researches he deserves the highest honor a scientific man can obtain, but the sum of his work is absolutely overwhelming. Had he never lived, the aspect of chemistry would be very different from that it is now." <<WHERE IS THIS QUOTE TAKEN FROM? WE NEED A SOURCE AND WHO SAID IT.>>
While sojourning at Cassel, Wöhler made, among other chemical discoveries, one for obtaining the metal nickel in a state of purity, and with two friends he founded a factory there for the preparation of the metal. One of Wohler's students, August Wilhelm Hoffman, described him, as "...unimpassioned, meeting even the most malignant provocation with an immovable equanimity, disarming the bitterest opponent by the sobriety of his speech, a firm enemy to strife and contention..." 35 Hunter, Graeme K. 2000. Vital forces: the discovery of the molecular basis of life. San Diego: Academic Press. ISBN 012361810X
Works
- Lehrbuch der Chemie, Dresden, 1825, 4 vols.
- Grundriss der Anorganischen Chemie, Berlin, 1830
- Grundriss der Organischen Chemie, Berlin, 1840
- Praktische Übungen in der Chemischen Analyse, Berlin, 1854
See also
- Urea
- Vitalism
ReferencesISBN links support NWE through referral fees
<<We need at least 3 reliable references here, properly formatted.>> Knight, David M. 1998. The development of chemistry, 1789-1914. London: Routledge/Thoemmes Press. ISBN 0415179122 278-284
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