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Meerwein
Meerwein is a surname. People with the surname Meerwein include: * Carl Friedrich Meerwein, German engineer * Hans Meerwein, German chemist Meerwein may also refer to several chemical terms named after Hans Meerwein: * Meerwein arylation The Meerwein arylation is an organic reaction involving the addition of an aryl diazonium salt (ArN2X) to an electron-poor alkene usually supported by a metal salt. The reaction product is an alkylated arene compound. The reaction is named afte ... * Meerwein–Ponndorf–Verley reduction * Meerwein's salt * Wagner–Meerwein rearrangement {{surname, Meerwein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meerwein–Ponndorf–Verley Reduction
The Meerwein–Ponndorf–Verley (MPV) reduction in organic chemistry is the reduction of ketones and aldehydes to their corresponding alcohols utilizing aluminium alkoxide catalysis in the presence of a sacrificial alcohol. The advantages of the MPV reduction lie in its high chemoselectivity, and its use of a cheap environmentally friendly metal catalyst. The MPV reduction was independently discovered Albert Verley and the team of Hans Meerwein and Rudolf Schmidt in 1925. They found that a mixture of aluminium ethoxide and ethanol could reduce aldehydes to their alcohols. Ponndorf applied the reaction to ketones and upgraded the catalyst to aluminium isopropoxide in isopropanol. Mechanism The MPV reduction is believed to go through a catalytic cycle involving a six-member ring transition state as shown in Figure 2. Starting with the aluminium alkoxide 1, a carbonyl oxygen is coordinated to achieve the tetra coordinated aluminium intermediate 2. Between intermediates 2 and 3 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Meerwein
Hans Meerwein (May 20, 1879 in Hamburg, Germany – October 24, 1965 in Marburg, Germany) was a German chemist. Several reactions and reagents bear his name, most notably the Meerwein–Ponndorf–Verley reduction, the Wagner–Meerwein rearrangement, the Meerwein arylation reaction, and Meerwein's salt. Life and work His father was the architect, Wilhelm Emil Meerwein. He originally trained to be a chemistry technician or 'chemotechnician' at the Fresenius University of Applied Sciences (between 1898 and 1900) before studying for a chemistry degree at the University of Bonn. After finishing his PhD with Richard Anschütz he worked at the University of Berlin, before returning to Bonn where he became professor in 1914. From 1922 till 1928 he was professor for organic chemistry at the University of Königsberg. The last change in his academic career was to the University of Marburg. The war devastated the Institute and Meerwein was planning the rebuilding which was finished ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meerwein Arylation
The Meerwein arylation is an organic reaction involving the addition of an aryl diazonium salt (ArN2X) to an electron-poor alkene usually supported by a metal salt. The reaction product is an alkylated arene compound. The reaction is named after Hans Meerwein, one of its inventors who first published it in 1939. An electron-withdrawing group (EWG) on the alkene makes it electron deficient and although the reaction mechanism is unclear, involvement of an aryl radical is presumed after loss of nitrogen in the diazonium salt followed by a free radical addition. In the primary reaction product the intermediate alkyl radical is then captured by the diazonium counterion X which is usually a halogen or a tetrafluoroborate. In a subsequent step an elimination reaction liberates HX (for instance hydrochloric acid) and an aryl vinyl compound is formed. The reaction mechanism from the arene's view ranks as a radical-nucleophilic aromatic substitution. In a general scope a Meerwein ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Friedrich Meerwein
Carl Friedrich Meerwein (2 August 1737 – 6 December 1810) was a German civil engineer and aviation pioneer. Meerwein was born in Leiselheim. He built flying devices with moving wings. According to the ''Encyclopædia Britannica'' he succeeded in flying with one of these devices, an ornithopter in 1781, at Giessen, Germany. Further attempts were less successful. There is a legend that he only survived one of his flights in 1784 because he hit exactly upon a dung pile.Untucht, Peter (2003) ''Freiburg und die Regio'' DuMont-Reiseverlag, Cologne, Germanypage 164 , in German "Meerwein, the architect of the Prince of Baden, built an orthopteric machine, and protested against the tendency of the aerostats which had just been invented." (Verne, ''Robur'') Meerwein died in Emmendingen, as a result of a fall from a horse. Notes Sources :''This article is based in part on material from the German Wikipedia The German Wikipedia (german: Deutschsprachige Wikipedia) is the German-langu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meerwein's Salt
Triethyloxonium tetrafluoroborate is the organic oxonium compound with the formula CH3CH2)3OF4. It is often called Meerwein's reagent or Meerwein's salt after its discoverer Hans Meerwein. Also well known and commercially available is the related trimethyloxonium tetrafluoroborate. The compounds are white solids that dissolve in polar organic solvents. They are strong alkylating agents. Aside from the salt, many related derivatives are available. Synthesis and reactivity Triethyloxonium tetrafluoroborate is prepared from boron trifluoride, diethyl ether and epichlorohydrin: : 4 Et2O·BF3 + 2 Et2O + 3 C2H3(O)CH2Cl → 3 Et3O+ + B OCH(CH2Cl)CH2OEtsub>3 The trimethyloxonium salt is available from dimethyl ether Dimethyl ether (DME; also known as methoxymethane) is the organic compound with the formula CH3OCH3, (sometimes ambiguously simplified to C2H6O as it is an isomer of ethanol). The simplest ether, it is a colorless gas that is a useful precursor ... via an analogou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
