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Hans Freiherr [a] von Pechmann (1 April 1850 – 19 April 1902) was a German chemist, renowned for his discovery of diazomethane in 1894. [ 1 ] [ 2 ] Pechmann condensation [ 3 ] [ 4 ] and Pechmann pyrazole synthesis . [ 5 ]
The earliest beginnings of polyethylene-based pipes occur when German scientist, Hans von Pechmann, discovered a waxy residue at the bottom of a test tube, colleagues Eugen Bamberger and Friedrich Tschirner called it polymethylene but it was discarded as having no commercial use at the time. [14] 1904
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. [12] [a] [13] [b] When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH 2 − chains and termed it polymethylene.
1898: Synthesis of polyethylene, the most common plastic, by Hans von Pechmann [159] 1898: First synthesis of purine by Emil Fischer. He had also coined the word in 1884. [160] Early 20th century: Schlenk flask by Wilhelm Schlenk [161] 1900s: Haber process by Carl Bosch and Fritz Haber [133] 1902: Ostwald process by Wilhelm Ostwald [162]
in 1899 Hans von Pechmann added diazomethane to ether, and noted the formation of polymethylene, a type of polyethylene, identified in 1900 by Eugen Bamberger and Friedrich Tschirner, but had not realised that it has any commercial significance; ICI in Cheshire in England will, in 1933
Diazomethane is an organic chemical compound with the formula CH 2 N 2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound.In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost universally used as a solution in diethyl ether.
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Two German chemists also preceded Schlotterbeck in discovery of the reaction, Hans von Pechmann in 1895 and Viktor Meyer in 1905. [4] [5] The reaction has since been extended to the synthesis of β-keto esters from the condensation between aldehydes and diazo esters. [6] The general reaction scheme is as follows: General Scheme for Buchner Reaction
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