Benzen
Chú thích

↑  Critics pointed out a problem with Kekulé's original (1865) structure for benzene: Whenever benzene underwent substitution at the ortho position, two distinguishable isomers should have resulted, depending on whether a double bond or a single bond existed between the carbon atoms to which the substituents were attached; however, no such isomers were observed. In 1872, Kekulé suggested that benzene had two complementary structures and that these forms rapidly interconverted, so that if there were a double bond between any pair of carbon atoms at one instant, that double bond would become a single bond at the next instant (and vice versa). To provide a mechanism for the conversion process, Kekulé proposed that the valency of an atom is determined by the frequency with which it collided with its neighbors in a molecule. As the carbon atoms in the benzene ring collided with each other, each carbon atom would collide twice with one neighbor during a given interval and then twice with its other neighbor during the next interval. Thus, a double bond would exist with one neighbor during the first interval and with the other neighbor during the next interval. Therefore, between the carbon atoms of benzene there were no fixed (i.e., constant) and distinct single or double bonds; instead, the bonds between the carbon atoms were identical. See pages 86–89 of Auguste Kekulé (1872) "Ueber einige Condensationsprodukte des Aldehyds" (On some condensation products of aldehydes), Liebig's Annalen der Chemie und Pharmacie, 162(1): 77–124, 309–320. From p. 89: "Das einfachste Mittel aller Stöße eines Kohlenstoffatoms ergiebt sich aus der Summe der Stöße der beiden ersten Zeiteinheiten, die sich dann periodisch wiederholen. ... man sieht daher, daß jedes Kohlenstoffatom mit den beiden anderen, ... daß diese Verschiedenheit nur eine scheinbare, aber keine wirkliche ist." (The simplest average of all the collisions of a carbon atom [in benzene] comes from the sum of the collisions during the first two units of time, which then periodically repeat. ... thus one sees that each carbon atom collides equally often with the two others against which it bumps, [and] thus stands in exactly the same relation with its two neighbors. The usual structural formula for benzene expresses, of course, only the collisions that occur during one unit of time, thus during one phase, and so one is led to the view [that] doubly substituted derivatives [of benzene] must be different at positions 1,2 and 1,6 [of the benzene ring]. If the idea [that was] just presented — or a similar one — can be regarded as correct, then [it] follows therefrom that this difference [between the bonds at positions 1,2 and 1,6] is only an apparent [one], not a real [one].)
↑  “Benzene trên www.eco-usa.net”. Bản gốc lưu trữ ngày 12 tháng 5 năm 2008. Truy cập ngày 15 tháng 6 năm 2008.
↑  The word "benzoin" is derived from the Arabic expression "luban jawi", or "frankincense of Java". Morris, Edwin T. (1984). Fragrance: The Story of Perfume from Cleopatra to Chanel. Charles Scribner's Sons. tr. 101. ISBN 978-0684181950.
1 2  Rocke, A. J. (1985). “Hypothesis and Experiment in the Early Development of Kekule's Benzene Theory”. Annals of Science. 42 (4): 355–81. doi:10.1080/00033798500200411. ISSN 0003-3790.
↑  Faraday, M. (1825). “On new compounds of carbon and hydrogen, and on certain other products obtained during the decomposition of oil by heat”. Philosophical Transactions of the Royal Society. 115: 440–466. doi:10.1098/rstl.1825.0022. JSTOR 107752. On pages 443–450, Faraday discusses "bicarburet of hydrogen" (benzene). On pages 449–450, he shows that benzene's empirical formula is C6H6, although he doesn't realize it because he (like most chemists at that time) used the wrong atomic mass for carbon (6 instead of 12).
↑  Kaiser, R. (1968). “Bicarburet of Hydrogen. Reappraisal of the Discovery of Benzene in 1825 with the Analytical Methods of 1968”. Angewandte Chemie International Edition in English. 7 (5): 345–350. doi:10.1002/anie.196803451.
↑  Mitscherlich, E. (1834). “Über das Benzol und die Säuren der Oel- und Talgarten” [On benzol and oily and fatty types of acids]. Annalen der Pharmacie. 9 (1): 39–48. doi:10.1002/jlac.18340090103. In a footnote on page 43, Liebig, the journal's editor, suggested changing Mitscherlich's original name for benzene (namely, "benzin") to "benzol", because the suffix "-in" suggested that it was an alkaloid (e.g., Chinin (quinine)), which benzene isn't, whereas the suffix "-ol" suggested that it was oily, which benzene is. Thus on page 44, Mitscherlich states: "Da diese Flüssigkeit aus der Benzoësäure gewonnen wird, und wahrscheinlich mit den Benzoylverbindungen im Zusammenhang steht, so gibt man ihr am besten den Namen Benzol, da der Name Benzoïn schon für die mit dem Bittermandelöl isomerische Verbindung von Liebig und Wöhler gewählt worden ist." (Since this liquid [benzene] is obtained from benzoic acid and probably is related to benzoyl compounds, the best name for it is "benzol", since the name "benzoïn" has already been chosen, by Liebig and Wöhler, for the compound that's isomeric with the oil of bitter almonds [benzaldehyde].)
↑  Laurent, Auguste (1836) "Sur la chlorophénise et les acides chlorophénisique et chlorophénèsique," Annales de Chemie et de Physique, vol. 63, pp. 27–45, see p. 44: "Je donne le nom de phène au radical fondamental des acides précédens (φαινω, j'éclaire), puisque la benzine se trouve dans le gaz de l'éclairage." (I give the name of "phène" (φαινω, I illuminate) to the fundamental radical of the preceding acids, because benzene is found in illuminating gas.)
↑  Hofmann, A. W. (1845) "Ueber eine sichere Reaction auf Benzol" (On a reliable test for benzene), Annalen der Chemie und Pharmacie, vol. 55, pp. 200–205; on pp. 204–205, Hofmann found benzene in coal tar oil.
↑  Mansfield Charles Blachford (1849). “Untersuchung des Steinkohlentheers”. Annalen der Chemie und Pharmacie. 69 (2): 162–180. doi:10.1002/jlac.18490690203.
↑  Charles Mansfield filed for (ngày 11 tháng 11 năm 1847) and received (May 1848) a patent (no. 11,960) for the fractional distillation of coal tar.
↑  Hoffman, Augustus W. (1856). “On insolinic acid”. Proceedings of the Royal Society. 8: 1–3. doi:10.1098/rspl.1856.0002. The existence and mode of formation of insolinic acid prove that to the series of monobasic aromatic acids, Cn2Hn2-8O4, the lowest known term of which is benzoic acid, .... [Note: The empirical formulas of organic compounds that appear in Hofmann's article (p. 3) are based upon an atomic mass of carbon of 6 (instead of 12) and an atomic mass of oxygen of 8 (instead of 16).]
↑  Infrared Space Observatory's Discovery of C4H2, C6H2, and Benzene in CRL 618
↑  Claus, Adolph K.L. (1867) "Theoretische Betrachtungen und deren Anwendungen zur Systematik der organischen Chemie" (Theoretical considerations and their applications to the classification scheme of organic chemistry), Berichte über die Verhandlungen der Naturforschenden Gesellschaft zu Freiburg im Breisgau (Reports of the Proceedings of the Scientific Society of Freiburg in Breisgau), 4: 116-381. In the section Aromatischen Verbindungen (aromatic compounds), pp. 315-347, Claus presents Kekulé's hypothetical structure for benzene (p. 317), presents objections to it, presents an alternative geometry (p. 320), and concludes that his alternative is correct (p.326). See also figures on p. 354 or p. 379.
↑  Dewar James (1867). “On the oxidation of phenyl alcohol, and a mechanical arrangement adapted to illustrate structure in the non-saturated hydrocarbons”. Proceedings of the Royal Society of Edinburgh. 6: 82–86. doi:10.1017/S0370164600045387.
↑  Ladenburg Albert (1869). “Bemerkungen zur aromatischen Theorie” [Observations on the aromatic theory]. Berichte der Deutschen Chemischen Gesellschaft. 2: 140–142. doi:10.1002/cber.18690020171.
↑  Armstrong Henry E (1887). “An explanation of the laws which govern substitution in the case of benzenoid compounds”. Journal of the Chemical Society. 51: 258–268 [264]. doi:10.1039/ct8875100258.
↑  Thiele, Johannes (1899) "Zur Kenntnis der ungesättigten Verbindungen" (On our knowledge of unsaturated compounds), Justus Liebig's Annalen der Chemie306: 87–142; see: "VIII. Die aromatischen Verbindungen. Das Benzol." (VIII. The aromatic compounds. Benzene.), pp. 125–129. See further: Thiele (1901) "Zur Kenntnis der ungesättigen Verbindungen," Justus Liebig's Annalen der Chemie, 319: 129–143.
↑  In his 1890 paper, Armstrong represented benzene nuclei within polycyclic benzenoids by placing inside the benzene nuclei a letter "C", an abbreviation of the word "centric". Centric affinities (i.e., bonds) acted within a designated cycle of carbon atoms. From p. 102: " ... benzene, according to this view, may be represented by a double ring, in fact." See:
↑  Loschmidt, J. (1861). Chemische Studien (bằng tiếng Đức). Vienna, Austria-Hungary: Carl Gerold's Sohn. tr. 30, 65.
↑  Kekulé, F. A. (1865). “Sur la constitution des substances aromatiques”. Bulletin de la Société Chimique de Paris. 3: 98–110. On p. 100, Kekulé suggests that the carbon atoms of benzene could form a "chaîne fermée" (a closed chain, a loop).
↑  Kekulé, F. A. (1866). “Untersuchungen über aromatische Verbindungen (Investigations of aromatic compounds)”. Liebigs Annalen der Chemie und Pharmacie. 137 (2): 129–36. doi:10.1002/jlac.18661370202.
↑  Rocke, A. J. (2010). Image and Reality: Kekule, Kopp, and the Scientific Imagination. University of Chicago Press. tr. 186–227. ISBN 978-0226723358..
↑  Read, John (1995). From alchemy to chemistry. New York: Dover Publications. tr. 179–180. ISBN 9780486286907.
↑  English translation Wilcox, David H.; Greenbaum, Frederick R. (1965). “Kekule's benzene ring theory: A subject for lighthearted banter”. Journal of Chemical Education. 42 (5): 266–67. Bibcode:1965JChEd..42..266W. doi:10.1021/ed042p266.
↑  Kekulé, F. A. (1890). “Benzolfest: Rede”. Berichte der Deutschen Chemischen Gesellschaft. 23: 1302–11. doi:10.1002/cber.189002301204.
↑  Benfey O. T. (1958). “August Kekulé and the Birth of the Structural Theory of Organic Chemistry in 1858”. Journal of Chemical Education. 35 (1): 21–23. Bibcode:1958JChEd..35...21B. doi:10.1021/ed035p21.
↑  Gillis Jean (1966). “Auguste Kekulé et son oeuvre, réalisée à Gand de 1858 à 1867”. Mémoires de la Classe des Sciences - Académie Royale des Sciences, des Lettres et des Beaux-arts de Belgique. 37 (1): 1–40.
↑  Lonsdale, K. (1929). “The Structure of the Benzene Ring in Hexamethylbenzene”. Proceedings of the Royal Society. 123A (792): 494–515. Bibcode:1929RSPSA.123..494L. doi:10.1098/rspa.1929.0081.
↑  Lonsdale, K. (1931). “An X-Ray Analysis of the Structure of Hexachlorobenzene, Using the Fourier Method”. Proceedings of the Royal Society. 133A (822): 536–553. Bibcode:1931RSPSA.133..536L. doi:10.1098/rspa.1931.0166.
↑  See:
↑  Graebe (1869) "Ueber die Constitution des Naphthalins" (On the structure of naphthalene), Annalen der Chemie und Pharmacie, 149: 20–28; see especially p. 26.
↑  Victor Meyer (1870) "Untersuchungen über die Constitution der zweifach-substituirten Benzole" (Investigations into the structure of di-substituted benzenes), Annalen der Chemie und Pharmacie, 156: 265–301; see especially pp. 299–300.
↑  Williams, P.R.D.; Knutsen, J.S.; Atkinson, C.; Madl, A.K.; Paustenbach, D.J. (2007). “Airborne Concentrations of Benzene Associated with the Historical Use of Some Formulations of Liquid Wrench”. Journal of Occupational and Environmental Hygiene. 4 (8): 547–561. doi:10.1080/15459620701446642. PMID 17558801.
↑  “Ullmann's Encyclopedia of Industrial Chemistry”. Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. 2005. doi:10.1002/14356007.a03_475. ISBN 978-3527306732.
↑  Astral Chemistry (11 tháng 3 năm 2017), Reppe Chemistry: Synthesis of benzene from acetylene, truy cập ngày 20 tháng 5 năm 2024
Điều[liên kết hỏng] chỉnh năm 1872 của Kekulé về lý thuyết năm 1865 của ông, minh họa sự thay đổi nhanh chóng của liên kết đôi
Các[liên kết hỏng] cấu trúc benzen lịch sử (từ trái sang phải) của Claus (1867), Dewar (1867), Ladenburg (1869), Armstrong (1887), Thiele (1899)  và Kekulé (1865). Dewar benzen và prismane là khác biệt có cấu trúc của Dewar và Ladenburg. Cấu trúc của Thiele và Kekulé được sử dụng đến ngày nay.
Cấu trúc phân tử benzene
Phản ứng thế trong nhân thơm
Điều chế C6H6 bằng acid benzoic. Chú thích : 1 : Bình đựng hỗn hợp C6H5COOH và NaOH. 2 : Ống sinh hàn. 3 : Bình thu C6H6. 4 : Nguồn nhiệt. 5: Hỗn hơp sau phản ứng. 6 : C6H6 không tinh khiết