Oxidation with chromium(VI) complexes: Difference between revisions

Revision as of 12:40, 20 June 2011

Revision as of 12:46, 20 June 2011

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==Experimental conditions and procedure==

===Typical conditions===

Reagent-grade pyridine is usually sufficient for the preparation of PDC and PCC. Although these reagents may darken over time, their loss in activity is minimal.{{WhatClarify|date=June 2011}} Isolated reagents should be stored in a desiccator in the dark. Care should be taken when adding chromium trioxide to pyridine, as ignition of pyridine has been known to occur. Celite® or silica gel may be used to facilitate the removal of polymeric chromium byproducts from the reaction mixture; these adsorbents also serve as convenient buffer systems and [[desiccant]]s.

Reduced chromium residues can be removed from glassware with concentrated HCl or 10–15% aqueous HF. Solid chromium waste should never be thrown away, as residual CrO₃ may ignite. Chromium(VI) reagents are toxic and should be handled with care in a well-ventilated fume hood.