- Zeisel determination
The Zeisel determination or Zeisel test is a
chemical test for the presence ofesters orethers in achemical substance [S Zeisel. "Monatshefte für Chemie" 6 (1885) p406.] [V Prey. "Chemische Berichte" 74 (1941) p350.] [Lange. "J Org Chem" 27 (1962) p2037.] . In a qualitative test a sample is first reacted with a mixture ofacetic acid andhydriodic acid in atest tube . The ensuing reaction results in the cleavage of the ether or the ester into analkyl iodide and respectively analcohol or ancarboxylic acid .By heating this mixture, the gases are allowed to come into contact with a piece of paper higher up the test tube saturated with
mercury(II) nitrate . Any alkyl iodide present will give a reaction with the mercury compound tomercury(II) iodide which has a red or yellow color.The reaction can also be used used determine the number of
methoxy (-OCH3) groups, [ [http://www.probertencyclopaedia.com/cgi-bin/res.pl?keyword=Ziesel+Reaction&offset=0 Ziesel Reaction] ] by distilling the iodomethane into a solution ofsilver nitrate , which precipitatessilver iodide . By filtering and weighing this precipitate it is possible to calculate the number ofiodine atoms and hence methoxy groups.Synthetic applications:
External links
* [http://acpcommunity.acp.edu/Facultystaff/hass/oc2web/lab/exp/qa/class/zeis.pdf Experimental procedure with anisole and methylbenzoate]
References
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