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Experiment 6:

Experiment 6:. EXTRACTION of ANALGESICS. Objectives. To learn the techniques of acid-base extraction, drying organic solvents, and vacuum filtration. To separate aspirin from acetaminophen using the extraction technique.

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Experiment 6:

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  1. Experiment 6: EXTRACTION of ANALGESICS

  2. Objectives • To learn the techniques of acid-base extraction, drying organic solvents, and vacuum filtration. • To separate aspirin from acetaminophen using the extraction technique. • To determine the efficiency of separation and the purity of compounds using HPLC analysis.

  3. Before coming to lab… • Watch the following videos to help you understand the techniques that will be used. • Extraction http://www.wonderhowto.com/how-to/video/how-to-do-a-liquid-liquid-extraction-in-the-chemistry-lab-259811/view/ • Vacuum Filtration http://video.google.com/videoplay?docid=-4541453194468704643#docid=1104445520143750871 • Drying Organic Solvents http://www.wonderhowto.com/how-to/video/how-to-dry-an-organic-solution-in-the-chemistry-lab-259802/view/

  4. ACTIVE INGREDIENTS— GOODY’S POWDERS 500 mg/powder 325 mg/powder

  5. ACID–BASE EXTRACTION—CHEMICAL EQUATIONS

  6. ACID–BASE EXTRACTION FLOW CHART

  7. USING A SEPARATORY FUNNEL • Be sure the stopper is tightly sealed before inverting! • Always keep one finger on the stopper! • Be sure the stopcock is in the horizontal position (closed) before adding any liquid!

  8. VACUUM FILTRATION TECHNIQUE • Always clamp the suction flask to a ring stand! • Run the red vacuum hose to the yellow vacuum line to pull suction! To vacuum line…

  9. DRYING ORGANIC SOLVENTS • Add a small amount of MgSO4 to the organic solution and swirl. • If the MgSO4 continues to clump and sink to the bottom, continue to add. • If the MgSO4 settles out of solution slowly (like a snow globe), the solution is dry.

  10. OVERVIEW • Perform acid/base extraction using separatory funnel. • Isolate ASPIRIN and ACETAMINOPHEN in separate flasks. ACETAMINOPHEN (O) ASPIRIN SALT (A) A O

  11. OVERVIEW ACETAMINOPHEN… • Dry organic layer with MgSO4. • Suction filter to remove MgSO4 from liquid. • Evaporate liquid on hotplate. • Reweigh to obtain final weight & calculate % recovery. • Dissolve solid in REAGENT acetone. • Submit HPLC sample. • Transfer to large sample vial and submit to instructor until next lab period.

  12. OVERVIEW • ASPIRIN… • Add acid to recover solid aspirin. • Suction filter to recover solid aspirin. • Submit HPLC sample. • Secure aspirin in large filter paper and submit to instructor until next lab period. • NEXT LAB PERIOD… • Obtain final weight of aspirin. • Calculate % recovery. • Prepare sample for melting point analysis.

  13. THEORETICAL RECOVERY • For this experiment, we dissolved 2 Goody’s powders in 25 mL of ethyl acetate. • In each Goody’s powder, there is 0.500 g of aspirin and 0.325 g of acetaminophen. • Theoretical Recovery: • 0.500 g per powder X 2 powders = ? g of Aspirin • 0.325 g per powder X 2 powders = ? g of Acetaminophen

  14. PERCENT RECOVERY • After the product has been dried sufficiently, the ACTUAL YIELD can be determined. • In theory, you should be able to recover 100% of each compound, however this is not always the case. • In order to determine the success of your recovery, the percent yield is calculated as follows: • Percent recovery : actual recovery (g)X 100 theoretical recovery (g)

  15. Table 6.1: Experimental Results

  16. Table 6.2: HPLC Results • Samples containing a single compound are considered PURE samples, while those containing both compounds are considered MIXED (IMPURE) samples. • Be sure to attach both sample chromatograms to final lab report!

  17. SAFETY CONCERNS • Acetone and ethyl acetate are extremely flammable! Wear safety goggles at all times and use extreme caution when heating! • Hydrochloric acid is corrosive!

  18. WASTE MANAGEMENT • The drying agent (MgSO4) and filter paper should be placed in the container labeled “SOLID WASTE” provided in the hood. • Place all liquid waste in the container labeled “LIQUID WASTE”.

  19. IN LAB QUESTIONS…(The following questions should be answered in laboratory notebook.) • Draw a complete mechanism for the reaction which occurs between aspirin and 10% NaHCO3 using actual chemical structures and mechanism arrows to indicate electron flow.

  20. IN LAB QUESTIONS…(The following questions should be answered in laboratory notebook.) • Draw a complete mechanism for the reaction which occurs between acetaminophen and 10% NaOH using actual chemical structures and mechanism arrows to indicate electron flow.

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