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, beryllium and yttrium
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 and iron. Hans Christian Oersted was more successful, producing an impure form of the metal in 1825, using an amalgam of mercury and potassium to reduce the aluminum in aluminum chloride. Wohler tried but failed, to duplicate Oersted's method. He then used pure potassium heated with ammonium chloride, and was able to produce aluminum in a purer form. <<<McKetta, John J., and William A. Cunningham. 1976. Encyclopedia of chemical processing and design. New York: M. Dekker. 62-63 ISBN 0824724518 >>>
Also in 1828, Wohler produced 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.>>>
In the same year he isolated the element yttrium by synthesizing its chloride and heating it with potassium metal. <<<Turner, Edward. 1827. Elements of chemistry including the recent discoveries and doctrines of the science. Edinburgh: W. Tait. 302-303.>>>
Synthesis of urea
In 1928, Wohler noticed a white crystalline substance that formed when he used silver cyanate and a solution of ammonium chloride in an attempt to produce ammonium cyanate. Instead, he produced white crystals that he dentified 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. <<<Ihde, Aaron John. 1964. The development of modern chemistry. New York: Harper & Row. 164-165.>>>
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.
Researches with Liebig
In 1832, 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.
The two scientists embarked on another epic investigation in the 1830s into uric acid and its derivatives and metabolytes, publishing their results in 1837. Based on their research, they predicted the synthesis of sugar and morphine and other organic compounds. After this project, the two went their separate ways, Wohler back into inorganic chemistry, Liebig into the agricultural applications of chemistry. But they remained life-long friends, a feat that Liebig would be able to achieve with few other scientists because of his contentious nature.
Later work and collaboration
In 1845, Wohler, by refining his process of producing aluminum, was able produce samples of metal in quantities sufficient to determine its characteristics. Based on his process, Henri Sainte Claire Deville, in 1854, manufactured ingots of aluminum. Deville used sodium chloride and sodium metal, and although his process differed from Wohler's in some respects, he credited Wohler by placing his name on a medal struck in aluminum. Some of the more fantastic claims for the metal were debunked by Wohler.
During his years in Gottingen, Wohler's reputation both as a researcher and an educator began to grow. He was made a foreign member of the Royal Society of London in 1854, and a member of the Royal Academy of Berlin in 1855.
In the 1850s, Wöhler conducted research on silicon and its compounds, particularly its oxides. In researches with Deville, he showed that both boron and silicon exist, in their pure state,in three different forms, analogous to carbon's graphite, charcoal and diamond<<<Timbs, John. 1858. The Year-book of facts in science and art. London: Simpkin, Marshall, and Co. 184>>>. Based on a hunch that its chemical properties are similar to carbon, the two scientists were the first to crystallize boron by heating boric acid and aluminum. They found that the crystals of boron resemble diamond in hardness and brilliancy. <<<The Popular science review: a quarterly miscellany of entertaining and instructive articles on scientific subjects. 1861. London: Robert Hardwicke. 335-336>>>
Wohler observed 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.
Wohler also collaborated with Heinrich Buff in the discovery that boron burns in nitrogen.
In 1862, Wohler produced calcium carbide, from which he synthesized acetylene gas by the addition of water. The high temperature needed to produce calcium carbide made its commercial use for making acetylene prohibitive until the perfection of the electric furnace in the late 1800s.
Final days and legacy
In 1872, Wohler was awarded the Copley medal of the Royal Society of London. He continued to work for the last decade of his life, producing research papers, mentoring and teaching.
In 1872, Wohler was awarded the Copley medal of the Royal Society of London. He continued to work for the last decade of his life, producing research papers, mentoring and teaching. He died on October 9, 1882.
Wohler's greatest accomplishment was ushering in the age of organic chemistry with Liebig. In retrospect, not only did both of these chemists produce results that solidified the foundation of the subject, but they also were mentors to innumerable researchers who made an impact on the field.
On a personal level, Wohler demonstrated patience and magnanimity in his relationship with Liebig. Liebig on several occasions claimed credit for himself the work that was accomplished jointly by the two scientists. Liebig was argumentative and headstrong, but Wohler seems to have worked around these characteristics. 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
- Brock, W H. 1997. Justus von Liebig: The Chemical Gatekeeper. New York: Cambridge University Press.
- Weeks, Mary Elvira. 2003. The discovery of the elements. Whitefish, Mont.: Kessinger Pub. 165-171. ISBN 0766138720.
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