| 词条 | Vladimir Markovnikov |
| 释义 |
|name = Vladimir Vasilyevich Markovnikov |image = VladimirMarkovnikov.jpg |caption = Late 19th-century photograph of Markovnikov. |birth_date = {{birth date|mf=yes|1838|12|22}} |birth_place = Knyaginino, Nizhny Novgorod Governorate, Russian Empire |death_date = {{death date and age|mf=yes|1904|2|11|1838|12|22}} |death_place = Saint Petersburg, Russian Empire |residence = |nationality = |alma_mater = University of Kazan |doctoral_advisor = Alexander Butlerov |doctoral_students = |known_for = |footnotes = |field = |work_institution = University of Kazan University of Saint Petersburg University of Odessa }} Vladimir Vasilyevich Markovnikov ({{lang-ru|Влади́мир Васи́льевич Марко́вников}}), also spelled as Markownikoff,[1] (December 22, 1838 – February 11, 1904), was a Russian chemist. Early life and educationMarkovnikov studied economics at the University of Kazan; during his studies, under the Russian cameral system, he also studied chemistry. CareerAfter a conflict with that university, Markovnikov was appointed professor at the University of Odessa in 1871 and, two years later, at the University of Moscow, where he stayed the rest of his career. WorkMarkovnikov is best known for Markovnikov's rule, elucidated in 1869 to describe addition reactions of H-X to alkenes. According to this rule, the nucleophilic X- adds to the carbon atom with fewer hydrogen atoms, while the proton adds to the carbon atom with more hydrogen atoms bonded to it. Thus, hydrogen chloride (HCl) adds to propene, CH3-CH=CH2 to produce 2-chloropropane CH3CHClCH3 rather than the isomeric 1-chloropropane CH3CH2CH2Cl.[2] The rule is useful in predicting the molecular structures of products of addition reactions. Why hydrogen bromide exhibited both Markovnikov as well as reversed-order, or anti-Markovnikov, addition, however, was not understood until Morris S. Kharasch offered an explanation in 1933. Hughes has discussed the reasons for Markovnikov's lack of recognition during his lifetime.[3] Although he published mostly in Russian which was not understood by most Western European chemists, the 1870 article in which he first stated his rule was written in German. However the rule was included in a 4-page addendum to a 26-page article on isomeric butyric acids, and based on very slight experimental evidence even by the standards of the time. Hughes concludes that the rule was an inspired guess, unjustified by the evidence of the time, but which turned out later to be correct (in most cases). Markovnikov also contributed to organic chemistry by finding carbon rings with more than six carbon atoms, a ring with four carbon atoms in 1879, and a ring with seven in 1889. Markovnikov also showed that butyric and isobutyric acids have the same chemical formula (C4H8O2) but different structures; i.e., they are isomers. References1. ^{{cite journal|last1=Zerong|first1=Wang|title=Markownikoff Rule and Anti-Markownikoff Rule|journal=Comprehensive Organic Name Reactions and Reagents|volume=411|pages=1833–1837|doi=10.1002/9780470638859.conrr411}} 2. ^{{cite journal | title=Ueber die Abhängigkeit der verschiedenen Vertretbarkeit des Radicalwasserstoffs in den isomeren Buttersäuren | author=Markownikoff, W. | journal=Annalen der Pharmacie | year=1870 | volume=153 | issue=1 | pages=228–259 | doi=10.1002/jlac.18701530204 | language=German}} 3. ^{{cite journal | doi = 10.1021/ed083p1152 | author = Hughes, Peter | title = Was Markovnikov's Rule an Inspired Guess? | journal = The Journal of Chemical Education | volume = 83 | issue = 8 | pages = 1152–1154 | year = 2006 |bibcode = 2006JChEd..83.1152H }} External links{{wikiquote}}
5 : 1838 births|1904 deaths|Imperial Russian chemists|Organic chemists|Russian inventors |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。