Cornforth reagent

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Structural formula
2 · Pyridinium ion Pyridinium ion
General
Surname Cornforth reagent
other names
  • Pyridinium dichromate
  • PDC
Molecular formula C 10 H 12 Cr 2 N 2 O 7
Brief description

orange to brown solid

External identifiers / databases
CAS number 20039-37-6
EC number 243-478-8
ECHA InfoCard 100.039.511
PubChem 2724130
Wikidata Q418276
properties
Molar mass 376.20 g mol −1
Physical state

firmly

Melting point

145-147 ° C

solubility

soluble in water

safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
03 - Oxidising 07 - Warning 08 - Dangerous to health 09 - Dangerous for the environment

danger

H and P phrases H: 272-317-350i-410
P: 201-220-273-280-308 + 313-501
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

The Cornforth reagent , systematically pyridinium dichromate ( PDC ), is the pyridinium salt of dichromic acid .

presentation

To prepare the Cornforth reagent, pyridine is added to an aqueous solution of chromium (VI) oxide .

properties

The Cornforth reagent is an orange to brown solid that melts at 145-147 ° C. It is easily soluble in many organic solvents .

use

It is a strong oxidant that the oxidation of alcohols to aldehydes or ketones used. The Cornforth reagent is related to the Collins reagent and pyridinium chlorochromate (PCC), both also pyridinium salts of hexavalent chromium compounds. Due to its toxicity , the Cornforth reagent is rarely used nowadays.

Individual evidence

  1. ↑ a b c d data sheet Cornforth reagent from AlfaAesar, accessed on June 5, 2010 ( PDF )(JavaScript required) .
  2. ↑ a b Datasheet Pyridinium dichromate from Sigma-Aldrich , accessed on March 23, 2011 ( PDF ).
  3. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling it falls under the group entry Chromium (VI) compounds, with the exception of barium chromate and compounds that are listed separately in this appendix in Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on June 11, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .
  4. ↑ a b c G. Tojo, M. Fernández: Oxidation of alcohols to aldehydes and ketones , 2nd edition, p. 86, Springer Verlag, Berlin, ISBN 0-387-23607-4 .
  5. ↑ Corey, EJ; Schmidt, G .: Useful procedures for the oxidation of alcohols involving pyridinium dichromate in aprotic media. In: Tetrahedron Letters 20 (1979) 399-402, doi : 10.1016 / S0040-4039 (01) 93515-4 .