Synthesis of Benzoin, Thiamine as a Catalyst

Dissolve 1.2 g of thiamine hydrochloride in 4 mL of water and add 12 mL of ethanol, place the flask in cold ice water bath and start adding 4 mL of 2.5M sodium hydroxide solution with stirring. Then add 6.24 g of benzaldehyde with stirring and let the mixture stand for 24 h, filter and put the solution into a freezer to crystallize all of the product out. Combine the filtrates and recrystallize the crude benzoin in hot ethanol.


Addition of sodium hydroxide solution

Addition of benzaldehyde

The solution after 9h

The mixture after 9 h

The mixture after 24 h

Filtration of the mixture

Recrystallization from ethanol

The pure product

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