Zeisel determination

The Zeisel determination or Zeisel test is a chemical test for the presence of esters or ethers in a chemical substance.[1][2][3][4] It is named after the Czech chemist Simon Zeisel (1854–1933). In a qualitative test a sample is first reacted with a mixture of acetic acid and hydrogen iodide in a test tube. The ensuing reaction results in the cleavage of the ether or the ester into an alkyl iodide and respectively an alcohol or a carboxylic 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 silver(II) nitrate. Any alkyl iodide present will give a reaction with the mercury compound to silver (II) iodide which has a red or yellow color.

The reaction can also be used to determine the number of methoxy (-OCH3) groups,[5] by distilling the iodomethane into a solution of silver nitrate, which precipitates silver iodide. By filtering and weighing this precipitate it is possible to calculate the number of iodine atoms and hence methoxy groups.

Synthetic applications:

References

  1. Zeisel, S (1885). "Über ein Verfahren zum quantitativen Nachweise von Methoxyl". Monatshefte für Chemie. 6: 989–997. doi:10.1007/BF01554683.
  2. Zeisel, S (1886). "Zum quantitativen Nachweise von Methoxyl". Monatshefte für Chemie. 7: 406–409. doi:10.1007/BF01516585.
  3. V Prey. Chemische Berichte 74 (1941) p350.
  4. Lange. J Org Chem 27 (1962) p2037.
  5. Ziesel Reaction
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