Question

For the portion of the procedure shown below, create a flow chart for the acid-base extraction at the end of the Grignard Reaction. Start your flow chart with the crude reaction (see below) mixture before addition of HCl and continue it until the product is recovered. Depict the desired organic product, in its correct form at each step of the procedure.

Crude reaction mixture procedure for reference: To the flask add Mg turnings (120 mg, 4.94 mmol) to the flask followed by anhydrous tetrahydrofuran (~10 mL). Add 1-bromo-4-fluorobenzene (500 L, 4.55 mmol, dispensed via an Eppendorf pipette) directly to the flask, followed by ~5 drops of 1,2-dibromoethane. Reflux the reaction mixture for ~30 min, stirring the mixture rapidly during the process. The start of the reaction is indicated by a slight turbidity of the solution. The mixture may become more turbid as the reaction proceeds and eventually may turn a pale yellow. Allow the reaction mixture to cool to room temperature after the reflux period.

Procedure for extraction:
With stirring, add water (~10 mL) followed by aq. 6 M HCl solution (~3 mL) dropwise. Add diethyl ether (~10 mL) and stir the mixture until any remaining solids dissolve. Transfer the two-phase mixture to a separatory funnel and shake vigorously to further extract the product into the organic layer. Isolate the organic layer and extract the aqueous layer with diethyl ether (~5 mL). Combine the organic layers and extract them with aq. 5 % NaOH solution (2 × ~10 mL portions). Isolate the appropriate layer and acidify with aq. 6M HCl solution. Isolate the solid product by vacuum filtration on a small plastic filter funnel and rinse it with ice-cold water (2 × 5 mL).

Example flow Chart:
Mixture RCOH, RNH2, unfunctionalized cpd. 5% NaOH soln. Organic phase Aqueous phase Base (RNH) Unfunctionalized cpd Conjugate base of carboxylic acid [RCO, ] 5-10% aq. HCI soln. 5-10% aq. HCI soln. Remove organic phase Aqueous phase Crude carboxylic acid RCOH Crude Unfunctionalized cpd Recrystallize Conjugate acid of base [RNH3]+ 5% NaOH soln. Crude base RNH2 Recrystallize Pure carboxylic acid RCO2H Pure Unfunctionalized cpd Recrystallize Pure base RNH2

Answer 1

Mo add arheydrous tetrahydrofuran l-bromo-4-fluorobenzene, 1,2-dibromo ethans Slight turbidity I start) D pale yellow (and) EM HS, diethyl ether , H₂O organic phase Aqueous phase 50% Nach Appropriate organic phase EMHY Aqulou Salid CS Scanned with CamScanner