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Chemical Properties

Pyridinium chlorochromate is orange crystalline powder

Uses

Oxidizing agent in organic synthesis.
PCC is pyridinium chlorochromate; PDC is pyridinium dichromate. Both are used in dichloromethane.

Uses

Pyridinium chlorochromate is usually used to oxidize an allylic methylene group.
Oxidation of primary alcohols to aldehydes

Pyridinium dichromate (PDC) or pyridinium chlorochromate (PCC) in anhydrous media such as dichloromethane oxidizes primary alcohols to aldehydes while avoiding overoxidation to carboxylic acids.

Reactions

Pyridinium chlorochromate (PCC) is a widespread used oxidation reagent but lacks of selectivity with unsaturated compounds. Furthermore, the workup procedure is quite tedious. Absorption of PCC onto silica gel improves the oxidation but then a reagent excess is necessary to reach appropriate rates. These drawbacks can be overcome by sonication leading to short reaction times and only an small excess of 1.2.-1.5 eq. of PCC is required. Using this reagent has been used to oxidise borneol to camphor in 85% yield.

reaction suitability

reagent type: oxidant

Purification Methods

Dry it in a vacuum for 1hour. It is not hygroscopic and can be stored for extended periods at room temperature without change. If the purity is very suspect, it can be readily prepared. [Corey & Scuggs Tetrahedron Lett 2647 1975, Piancatelli et al. Synthesis 245 1982.] (Possible CARCINOGEN.) § Available commercially on a polymer support.

Material Safety Data Sheet(MSDS)

Questions And Answer

• Synthesis

  The common method is to react chromium trioxide with hydrochloric acid to produce chlorochromic acid, followed by the addition of pyridine at 0 °C to obtain a stable orange-yellow Pyridinium chlorochromate solid:

  

  Specific reaction steps: Under stirring, chromium trioxide (100 g, 1 mol) is rapidly added to 6 N hydrochloric acid (184 mL, 1.1 mol). After 5 minutes, when the homogeneous solution has cooled to 0 °C, pyridine (79.1 g, 1 mol) is carefully added over a period of more than 10 minutes. The solution is recooled to 0 °C, yielding an orange-yellow solid. The solid is collected in a sintered glass funnel, filtered, and vacuum dried for 1 hour, yielding 250.5 g, 54% .;

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