Acid Base Extraction

Objective:

The goal of this lab is to seperate organic compounds though a separatory funnel. The mixture of compounds includes anthracene, ethyl 4-aminobenzoate, and benzoic acid. This method allows for seperation through differences in chemical properties.






Procedure:


  1. Weigh 1.5g of anthracene, benzoic acid, and ethyl amino benzoate.

  2. Dissolve his in 60mL of ethyl acetate. If the solid doesn’t dissolve after stirring at 5-10mL of ethyl acetate. Then gravity filter solids that dont dissolve after stirring that.

  3. Transfer the solution in a respiratory funnel

  4. Add 30mL of 3M HCL to the separatory funnel. Stopper and shake the separatory funnel, venting frequently to avoid the buildup of excess pressure.

  5. Put the separatory funnel in a ring strand, remove the stopper and let the layers completely separate. Drain the bottom layer into a flask label “acid extract” flask. Attempt to drain the aqueous layer so the interface is trapped in the stop cock.

  6. Add 30mL of 3M NaOh to the separatory funnel, shake and vent the funnel.

  7. Allow to layers to separate completely and then drain the bottom layer in the flask “Basic extract”, drain the top layer into the flaks “organic”

  8. Cool the acidic extract in an ince bath and basify with 6M NaOH. “This isnst the sam econcentratction of aqueus HCL solution that you used in the extractions”. Use 1.1-1.2 molar equivlanets relative to the amount of HCL added. Ensure to check the pH of the solution to make sure its basic. Leave the flask in the ice bath for 20 mins for precipatate to form

  9. Then collect preciptate with vacuum filtration by poruding the solution in the center of the filter paper. Wash the solids with ice cold water

    • Ensure to prewet the filter paper with Di water

  10. Put the solid in tared, label vialed and place in the oven for 30 mins. When it dries obtain the mass and melting point

  11. Then cool the basic extract in the ice bath and acidify with 6M HCL. Use 1.1-1.2 molar equvalents relivatve to the amount of NaOH added. Make sure the pH is acidic.

  12. Collect with vacuum filtration by pouring solution into the filter paper and wash with ice cold water.

  13. Again place the solid in taredm labeled vial and place the open vial in the laboratory oven in 30 mins to dry. Then weigh and collect melting point

  14. To the organic layer, add anhydrous magnesium sulfate and swirl gently. Continue adding magnesium sulfate and swirling till the additional drygen agent no longer forms clumps.

  15. Remove drying agent by gravity filtration into a 100mL recovery flask. Evaporate the filtrate using the rotary evaproate until a dry solid is obtained

  16. Collect the solid in a vial and then weigh it and collect melting point.