Below is the procedure for Benzoin Condensation of Benzaldehyde. Use the procedure information to fill in the reaction stoichiometry table. Please show the calculation.
Procedure: In a 10 mL round bottom flask (or a small Erlenmeyer flask), dissolve 0.35 g of thiamine hydrochloride in 0.75 mL of water. To this solution add 3.0 mL of 95% ethanol and then cool the resulting solution in an ice-water bath. To the cooled solution slowly add cold aqueous solution of NaOH (3 M, 0.75 mL) over a 7 – 10 minute period (swirl the flask after each addition). Add 2.12 g of benzaldehyde, swirl, and check the pH of the reaction mixture with pH paper. The pH of the reaction mixture should be between 8 and 9. At a pH<8 the reaction will be very slow, and at a pH>9 a Cannizzaro reaction will become competitive.
Using a beaker of water heated to 60–70 °C, heat the reaction mixture for one hour while maintaining the internal temperature at 60–63 °C. Allow the reaction mixture to cool to room temperature and then cool it further to 5–10 °C. A white precipitate should appear. Some oil (which is probably a mixture of starting materials and reaction by-products may also form on the surface). Collect the crude product by suction filtration and wash it with 5 mL of ice-cold water. Recrystallize the product from 95% ethanol, using a minimum amount of the hot solvent to dissolve the product. Determine the weight, percent yield, and melting point of the product. Record and interpret the IR spectrum of the product.
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