PROCESS FOR THE PREPARATION OF SUBSTITUTED BENZILIC ACID FROM SUBSTITUTED BENZILS
申请人:MESHRAM Harshadas Mitaram
公开号:US20100249451A1
公开(公告)日:2010-09-30
The classical process for the rearrangement of substituted benzil to benzilic acid is performed in the presence of sodium or potassium hydroxide as a base using ethanol-ether as a medium. The reaction requires reflux temperature for complete conversion. However, these bases containing metallic ions and generate metallic containing effluent waste which may require additional expenditure for treatment. Moreover, because of corrosive nature of base, and use of flammable solvent, the safety measures are needed during large scale production. Another method also reported for benzilic acid rearrangement at 380° C. which is practically not feasible. The present invention describes the use of quaternary ammonium hydroxides as a base for the rearrangement of the substituted benzils to benzilc acids. It also avoids the use of solvent and reaction can be carried out at relatively lower temperatures. Because of the solvent free reaction condition it reduces the mass/volume of reaction mixture.
Ionic liquid in conjugation with KOH brings about an efficient, one-pot, green synthesis of α,α-diarylglycolic acids in reasonably high yields from aromatic aldehydes undersolvent-free condition using conventional heating as well as microwave irradiation.