university of silemany school of science chemistry department

Rearrangement of benzilic acidPrepared by:Aras jabar & shaxawan rahimuniversity of silemany school of sciencechemistry department

Content:Introduction Preparation of benzilRearrangement of benzilic acidMechanismMigrationIR spectrumProperty of benzilic acidHazardouse of benzilic acid

IntroductionBenzilic acid will be prepared by causing a rearrangement of a -diketone benzilThe major condition of this rearrangement ,we must have 1,2--diketone

Preparation of benzil

Rearrangement of benzilic acid

Mechanism

Nucleophilic additionrearrangement phenyl migrationproton transfer

Rearrangement

Migratory aptitude

> >

Rearrangement of nitro benzil

If we have cyclic compound

IR spectrum for benzil

IR spectrum for benzilic acid

Property of ProductBenzilic acid is a white crystalline aromatic acid soluble in many primary alcohols. It can be prepared by heating mixture of benzil, alcohol and potassium hydroxide. The other preparation way is through benzaldehyde, which dimerizates to benzil and it is further transformed by benzilic acid rearrangement to benzilic acid.

application

Doering extended the reaction to the formation of the corresponding ester by replacing the normal alkali by alkoxides. Thus benzil may directly be converted into alkyl benzilate by treatment with sodium alkoxide.

application

The reaction may be used for the preparation of -hydroxy acids from the easily accessible starting materials. It is important to note that as the ethoxide and isopropoxide ions reduce benzil to benzoin these reagents do not carry out benzilic rearrangement.

Hazardous of Benzilic AcidPotential Acute Health Effects: Very hazardous in case of skin contact (irritant), of eye contact (irritant). Hazardous in case of ingestion, of inhalation. Inflammation of the eye is characterized by redness, watering, and itching. Skin inflammation is characterized by itching.Chemical stability : Stable under recommended storage conditions.Hazardous combustion products : Under fire conditions, hazardous fumes will be present and product flammable at high temperature and product of combustion (CO,CO2).

Thank you