Add 5 mL of ice-cold 1.0 M HCl, stir, and cool in ice for 10 minutes. If a semi-solid forms, you may need to continue stirring the cold mixture for a few minutes. Isolate the product by filtration with a funnel, and wash with 1-2 mL of water.
Scrape the crude product into a 30 mL beaker, add a magnetic stir bar, 1 mL of 95% ethanol, and heat with stirring at 70-80°C. Add additional ethanol, 10 drops at a time, until the solids have dissolved. Cool to room temperature, and scrape the inside of the flask with a glass rod to induce crystallization. Once crystallization has begun, cool in ice for ten minutes, isolate your product by filtration on a Hirsch funnel, and wash with 1 mL of ice cold ethanol. Dry for 5 minutes in the funnel, then scrape onto a filter paper and let dry for 10 minutes.
Obtain the mass, melting point and IR of your recrystallized product.
Caution
Sodium hydroxide is hygroscopic in nature. Cap the vial immediately after every use. Do not over heat in step 3, over heating may cause a black tar substance that is due to the decomposition of your product to form.
B. green chemistry experimental procedure
Pre-heat your water bath to 60-70°C.
Place a stir bar and 0.4 g of 4-nitrobenzaldehyde and 0.3 g of acetophenone in a 10 mL round bottom flask. NOTE: Acetophenone is a liquid with a density of 1.03 g/mL. Weigh out 0.10 g of sodium hydroxide and crush into a powder with a spatula or the flat bottom of a 5 mL conical vial. Add the powdered NaOH to the 10 mL round bottom vial with the other reagents. Grind the "semi-solid" mixture with a glass stirring rod at 60-70°C until thoroughly mixed, and continue grinding for a further two minutes. Wait 5 minutes, and then grind again for two more minutes. Repeat for three more cycles of grinding and waiting.
After grinding the reaction mixture for a total of ten minutes, add 5 mL of ice-cold 1.0 M HCl, stir, and cool in ice for 10 minutes. If a semi-solid forms, you may need to continue stirring the cold mixture for a few more minutes. Isolate the product by filtration on a Hirsch funnel, and wash with 1-2 mL of water.
Scrape the crude product into a 30 mL beaker, add a magnetic stir bar, 1 mL of 95% ethanol, and heat with stirring at 70-80°C. Add additional ethanol, 10 drops at a time, until all the solids have dissolved. Cool to room temperature, and scrape the inside of the flask with a glass rod to induce crystallization. Once crystallization has begun, cool in ice for ten minutes, isolate your product by filtration on a Hirsch funnel, and wash with 1 mL of ice-cold ethanol. Dry for 5 minutes in the funnel, then scrape onto a watch glass and allow it to dry for 10 minutes.
Obtain the mass, melting point and IR of your recrystalized product.
One sample will be taken for NMR studies.
Caution
Carefully grind the NaOH. Do not add ethanol in the first step. Ethanol is required only during recrystalization.
Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’work (including your laboratory partner) or misrepresent your own data (see honor code).
Name(Print then sign): ___________________________________________________
