Chemistry:Benzyl potassium

Benzyl potassium

Names
Other names Potassium benzyl
Identifiers
CAS Number	2785-29-7
3D model (JSmol)	Interactive image
ChemSpider	10675000
PubChem CID	11083915
InChI InChI=1S/C7H7.K/c1-7-5-3-2-4-6-7;/h2-6H,1H2; Key: OQLLVOGBAKFMIS-UHFFFAOYSA-N InChI=1/C7H7.K/c1-7-5-3-2-4-6-7;/h2-6H,1H2;/rC7H7K/c8-6-7-4-2-1-3-5-7/h1-5H,6H2 Key: OQLLVOGBAKFMIS-QPGMTJJQAI
SMILES [K]Cc1ccccc1
Properties
Chemical formula	C7H7K
Molar mass	130.231 g·mol−1
Appearance	Orange solid
Hazards
Main hazards	Ignites in air
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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Benzylpotassium is an organopotassium compound with the formula C₆H₅CH₂K. It is an orange powder. Like organo-alkali metal reagents in general, benzyl potassium is highly reactive, so much so that it reacts with most solvents. It is highly air sensitive.

Synthesis

One early synthesis proceeds by two-step transmetallation reaction via p-tolylpotassium:

(CH₃C₆H₄)₂Hg + 2 K → 2 CH₃C₆H₄K + Hg

CH₃C₆H₄K → KCH₂C₆H₅

A modern synthesis involves the reaction of butyllithium, potassium tert-butoxide, and toluene. Although potassium hydride can also be used as a strong base for preparing potassium salts, benzyl potassium has the advantage of being molecular and hence more fast-acting.