Orgo lab exam 2

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  1. what is reluxing?
    heating while letting the product/solvent condense back into the reaction mixture so that the liquid product or solvent does not evaporate
  2. what is the reagent forms the diazonium salt from the amine?
    diazonium salts are formed by nitrous acid, HONO,
  3. What form is the reagent added to form diazonium salt?
    added as sodium nitrite in acid.
  4. how can you tell that the reaction of the formation of diazonium salt is complete?
    when the diazonium formation is complete, the nitrite that is left over will immediately react with the starch-iodide paper.
  5. how do you remove excess reagent from the reaction that formed diazonium salt?
    At that point, urea can be added to destroy the excess HONO.
  6. what is the use of K2CO3?
    neutralizes acid
  7. What is the purpose of using of sat. NaCl?
    helps remove water from non aqueous phases during washing
  8. what is the purpose of using tetramethylsilane?
    NMP standard
  9. what is the purpose of using CDCl3?
    NMR solvent, which has no H that would give its own signal
  10. what products were synthesized by recrystillization?
    no products were synthesized by recrystallization because it is a physical means of separation.

    products in experiment 1, m-nitromethylbenzoate and aldol reactions were purified by recrystallization after they were synthesized
  11. what is the principle behind chromatography?
    that sample is moved in a mobile phase past a stationary phase.  the compound dissolved in the mobile phase interact to different extents with the stationary phase so that they take different times to pass through the phase
  12. thin-layer chromatography
    - the mobile phase is the solvent and the stationary phase is the silica gl stuck to the plate. the components are detected and compared to a standard, or by Rf value
  13. gas chromatography
    sample is vaporized to pass with the mobile gas phase (helium) past the liquid stationary coating inside the tubing. as compounds interact with the stationary phase they take varying amounts of time to pass trough the column to the detector. these times are compared to a standard.
  14. paper chromatography
    works similarly to thin-layer chromatography except there is paper as the stationary phase
  15. what is some of the information on a material safety data sheet ( MSDS) ?
    the MSDS tells physical properties, storage conditions, handling precautions, disposal procedures, toxicity information, ect.
  16. how is the specificity of nitration in the p-nitromethlybenzoate reaction controlled?
    `do on ice.  this prevents ortho and para addition and dinitration since the ester group deactivates the ring
  17. what methods are used for IR?
    direct use of liquids
  18. what are some advantages for using IR?
    easiest to control amount and not get background

    KBr pellet, grinding solid with kBR and using press to get a semi translucent pellet
  19. what are some disadvantages to using IR?
    hard to get good pellet but no extraneous peaks from KBr.

    mineral oil easier to get suspension of solid but have to ignore mineral oil absorbances
  20. which experiments use with intermediates



    diazonium salt
    NO2- m-nitromethylbenzoate

    enolate- p-anisal-acetophenone

    diazonium salt- methyl salicylate
  21. chemical test: aq. HCL

    positive for:

    positive test:
    positive for : amines

    positive test: dissolve
  22. chemical test: aq. NaOH

    positive for:

    Positive test:
    positive for: acids/phenols

    positive test: dissolve
  23. chemical test: red litmus

    positive for:

    positive test:
    Positive for : amines

    positive test: turns blue
  24. chemical test: blue litmus

    positive for:

    positive test:
    Positive for: acids/phenols

    positive test: turns red
  25. chemical test: 2, 4-dinitrophenylhydrazine

    positive for:

    positive test:
    positive for: ketones/ aldehydes

    positive test: yellow precipitate
  26. chemical test: tollens (AgNO3 in NH3/NaOH)

    positive for:

    positive test:
    positive for: aldehydes

    positive test: silver mirror
  27. chemical test: Chromic anhydride in acetone

    test for:

    positive test:
    test for: primary and secondary alcohols/ aldehydes

    positive test: turns green or blue
  28. chemical test: Lucas (Zncl2, in HCl)

    test for:

    positive test:
    test for: secondary and tertiary alcohols

    • positive test: 3- immediately cloudy
    • 2- cloudy after heat
  29. chemical test: bromine water

    test for:

    positive test:
    test for: phenols and anilines (alkoxyaromatic)

    positive test- take a while to change  color
  30. chemical test: Hinsber (benzenesulfonyl chloride in KOH)

    test for:

    positive test:
    test for: primary and secondary amines

    • positive test: 1- single phase, ppt. with acid
    • 2- ppt. both water and acid
  31. chemical test: hydroxylamine/ Fe+3

    test for:

    positive test:
    test for: esters

    positive test: magenta
Card Set:
Orgo lab exam 2
2013-03-28 15:01:58

lab exam
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