Question

Why did you wash the ether solution with sodium bicarbonate? Write chemical equations for the reactions that took place. b. At which purification steps was the unreacted methanol removed in the reaction? Some of it may have been removed in more than one place. c. Three-Step Synthesis of Methyl Anisate (Step 3) 0 CHOH. Н.so, cat.) Wear gloves. Methanol is poisonous. Ether is an anesthetic, so don't breathe it. Sulfuric acid is a strong corrosive acid. Wash any you spill on you off with lots of water Procedure Again you are following a procedure for an analog of methyl anisate. Adjust your calculations accordingly You are substituting anisic acid for benzoic acid. The amounts of reagents used for this procedure will depend on the mass of benzoic acid that you use in the reaction. Use no more than 3 g of it! It is also critical that your benzoic acid is completely dry, since this reaction is an equilibrium process and water in a wet sample will drive the reaction in the reverse direction, reducing your yield of product. For each gram of benzoic acid you will need 8 mL of methanol; for each 20 mL of methanol, you will need 1 mL of concentrated H2S04. Consider the total volume of this mixture, and choose a round-bottomed flask that holds about twice that volume; in other words, choose a flask so that it is about half full. Put the three materials in the proportions described above into the round- bottomed flask with a couple of boiling chips, and attach a reflux condenser to form a reflux apparatus. Heat the reaction mixture at reflux for 1 hour Pour the reaction mixture into a 150 mL beaker containing about 50 mL an ice/water slurry and stir. Once the ice is melted, transfer the mixture to your separatory funnel. Rinse the beaker with 30 mL of ether, and add the ether to the separatory funnel. Cap the funnel, invert it and release the pressure. Gently "shake and vent" a few times, and allow the layers to separate. Drain the water layer out into the 150 mL beaker, and pour the ether layer into a 125 mL Erlenmeyer flask. Return the water layer to the separatory funnel, and extract it with another 30 ml portion of ether. Drain the water layer out through the stopcock. Combine the two ether extracts in the separatory funnel, and wash them sequentially with 20 mL of water, 20 mL of sodium bicarbonate solution, and 20 mL of saturated sodium chloride solution. Transfer the ether layer to the 125 mL Erlenmeyer flask, and add 2 spatulas full of anhydrous magnesium sulfate or sodium sulfate. Cork the flask, and swirl it occasionally for about 5 minutes. Filter off the magnesium sulfate or sodium sulfate through a plug of cotton in a funnel into your dlean, dry 100 mL round-bottomed flask (as shown in prelab). Remove the ether on the rotary evaporator. Using a pipette, transfer your product into a clean, dry, pre-weighed product vial, and measure its mass. Carefully smell your product: how would you describe the odor?

Answer 1

Ether is washed by sodium by carbonate to neutralize the unreacted compounds like some acid. Further, washing with 5% sodium bicarbonate may produce carbon dioxide gas in the separatory funnel. It is extremely important to vent the funnel immediately upon inverting and before shaking.
NaHCO3+ Acid= CO2+ Na2CO3+ H2O