Reduction of Benzil Flashcards
What are the safety hazards of this experiment?
Sodium Borohydride (NaBH4) is strong reducing agent; toxic and irritants to skin and eyes
what is the molar mass of benzil (C6H5CO)2?
210.23 g/mol
What is the purpose of ethanol?
ethanol will solubilize benzil.
What is the purpose of sodium borohydride?
NaBH4 will reduce a ketone to a secondary alcohol
What is the purpose of diluting the hot solution with hot water to the point of cloudiness?
Water donates hydrogens for the oxygens on the cyclic intermediate in order to create two hydroxy groups.
Why is meso-hydrobenzoin formed in greater amounts than the other two enantiomeric isomers?
the nature of the dual carbonyl reduction and stability of the cyclic intermediate. The boron complex engages in a frontside attack, resulting in equal and opposite stereocenters. The enantiomers are also less likely to form due to steric crowding.
What is the molar mass of meso-hydrobenzoin?
214.27 g/mol
What is the first step of this reaction?
dissolve benzil in a test tube with ethanol. cool it in ice to enourage a suspension.
what is the second step of this reaction?
add sodium borohydride to the suspension. when the benzil has reaction with the sodium borohydride, the yellow color will disappear.
what is the third step of this reaction?
after 10 minutes, add water and heat solution until it boils. After it boils, add hot water to dilute the solution until it goes cloudy. Perform a vacuum filtration to extract the product.
