orgolab FINAL A++++

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orgolab FINAL A++++
2011-05-06 01:42:09

I hope this test has health insurance
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  1. What is the derivative of the unknown ester in exp 11b?
    3,5-dinitrobenzoate derivative of the ester
  2. Nitro groups are (polar/nonpolar)
  3. What indicates the boiling point of the sample in exp 11b?
    When the last bubble exits the glass bell, the vapor pressure of the sample is equal to the atmospheric pressure. This is the boiling point
  4. What is placed into the capillary tube?
    Glass bell;it should be submerged below the surface of the liquid and glass should be inverted
  5. What to avoid when taking refractive index?
    Do not touch prism. Use kimwipe and EtOH to clean prisms after use
  6. When preparing derivative in exp 11b?
    Ensure the layers are completely separted and dry organic layer over anhydrous sodium sulfate
  7. What is the chemical name for OFF?
  8. What is the starting material in the OFF exp?
    carboxylic acid. OFF is the corresponding amide of diethylamine
  9. What is the purpose of the OFF exp?
    synthesize OFF and to illusrate the synthesis of an amide via an acid chloride and to work up a feaction using multiple extractions
  10. What will happen if amine solution is added to quickly or needle is allowing amide to drip inside Claisen head in exp 12?
    reaction will smoke violently
  11. What will damp glass wool do?
    It will scavenge HCl vapors
  12. How is the anhydrous ether added in exp 12?
    Via syringe using the septum
  13. Why do you wash the reaction mixture of N,N-diethyl m-toluamide with two portions of NaOH solution?
  14. Because it will thoroughly remove any residual m-toluic acid and acid chloride.
  15. How would you remove impurities in OFF exp?
    Diethylamine impurity can be removed by extracting with HCl

    Thionyl chloride is removed with the addition of H2O, which forms HCl(neutralized by NaOH) and SO2

    Acid chloride reactions with NaOH to form the salt of the carboxylic acid, and is soluble in the aqueous layer.
  16. Why cant the amide be made directly from the acid and the amine?
  17. Why can't the amide be made directly from the acid and the amine?
    The amide can be made directly from the acid and the amine, but it is not a convenient lab synthesis given high temperatures is involved. The acid is reacted with a base to form a salt. The salt is then converted to the carboxylic amide when the salt is heated to very
  18. Why is excess base used?
    To neutralize acid and drive reaction forward
  19. What are the layers when extracting?
    Aqueous layer is bottom and organic layer is top
  20. What does the aldol condensation use?
    The reactiving of the carbonyl functionality to build new carbon-carbon bonds
  21. What is the main characteristic of carbonyl functionality?
    It is dipolar. Oxygen is more electronegative than carbon, resulting in the polarization of the carbon-carbon pi bond.
  22. Carbonyl carbon is susceptible to attack by?
  23. Why does the alpha carbon become more acidic due to presence of carbonyl functionality?
    The hydrogens will be more acidic because of + charge inductively.

    Conjugate base after deprotonation will be stablilzed by resonance to the elonate anion
  24. When is dehydration more favored in aldol reaction?
    If product formed has extended conjugation or if the dehydration product precipitates out of solution.
  25. What does mixed or crossed aldol condensation refer to?
    Cases in which two carbonyl compounds are the reactants
  26. Example of aldol condensation?
    Ritalin; simpledehydration of the aldol product leads to Ritalin
  27. Purpose of double aldol condensation?
    Isolate dehydration product and recrystallize from a suitable solvent
  28. Why are ketones less reactive than aldehydes in aldol condensation?
    The carbonyl group of ketones is sterically and electronically not as susceptible to nucleophilic attack as is the carbonyl function of aldehydes
  29. Why can't aldehydes react with themselves?
    Because they have no alpha hydrogens
  30. Will ketones undergo aldol condensation twice?
    • Yes, because they are symmetric;
    • High conjugation of product favors dehydration
  31. What to do if solution in exp 14 is still cloudy or little precipitate is formed?
    heat reaction mixture in a hot water bath
  32. Which will undergo aldol condensation?
    acetone, 3-pentanone, acetophenone, cyclohexanone because they have alpha hydrogens

    formaldehyde and benzophenone will not
  33. How can LeChatelier's principle be used to increase yield of a reaction?
  34. Le Chatelier’s principle can be used to increase the yield of the reaction by removing product as it is being formed, which will force the reaction to shift to the product side. This can be accomplished through distillation, in which the reaction would shift to the right to make more product in order to keep the reaction at equilibrium, thus increasing the yield.
  35. Why are ketones less reactive in aldol condensation? How can aldol condensation of acetone by manipulating to obtain a good yield?
    Ketones are less reactive in aldol condensations because the carbonyl group is more sterically hindered in comparison to aldehydes. This makes a nucleophilic attack less likely, and the nucleophile attacks the alpha hydrogens of the ketone, which in turn creates a new nucleophile that attacks the reagent that is less hindered. Using an excess of the less hindered reagent will drive the reaction forward and lead to a reasonable yield of product.
  36. How is adipic acid synthesized?
    • By oxidative cleavage of the C=C bond in cyclohexene.
    • Dicarboxylic acid is synthesized from an alkene
  37. What is green chemistry?
    The design and use of methods to eliminate or reduce health and environmental hazards in the manufacture and use of chemicals
  38. Why is adipic acid important?
    It is important chemical in food flavorings and in the synthesis of nylon-6,6.
  39. Why is hydrogen peroxide used instead of potassium permanganate?
    H2O2 is greener oxidant as potassium permanganate creates large quantities of MnO2 waste
  40. Permanganate and tungstate ions are?
  41. (T/F) Cyclohexene is acting as its own organic solvent for adipic acid reaction.
    True. You should reflux so that condensation of the cyclohexene happens at the bottom of the condenser
  42. (T/F) If phase catalyst or unreacted cyclohexene is pipetted off, the product will not crystallize
  43. (T/F) Phase catalyst and sodium tungstate will be reused
    False. because exp is on small scale.
  44. Where should
  45. Where should liquid be pipetted off in adipic acid exp?
    Pipet from a point below the surface of the reaction mixture but above the ily phase transfer catalyst
  46. What are 12 green chemistry principles?
    Prevention; Atom economy; Less hazardous chemical sytheses; Design Safer Chemicals; Safer Solvents and Auxiliaries; Design for Energy Efficiency; Use Renewable Feedstocks;Reduce Derivatives; Catalysis; Design for Degradation; Real-Time Analysis for Pollution Prevention; Inherently Safer Chemical for Accident Prevention
  47. Describe industrial preparation of adipic acid
  48. Industrial preparation of adipic acid is made from a mixture of cyclohexanol and cyclohexene, called ketone-alcohol oil. This oil is reacted with nitric acid to make adipic acid. Side products of this reaction include glutaric and succinic acid, as well as nitrous oxide.
  49. Discuss nitrous oxide in terms of its role as an atmospheric pollutant
    Nitrous oxide is thought to be greenhouse gas, as it reacts with oxygen to make nitric oxide. This is harmful because nitric oxide reacts with ozone, thus destroying the ozone layer and contributing to global warming.
  50. (T/F) Synthesize dicarboxyluc acid from an alkyne
    False. Synthesize from an alkene
  51. (T/F) Water is the only side product formed in adipic acid reaction
  52. Why is the use of Nitric acid harmful in the synthesis of adipic acid?
    It releases nitrous oxide into the atmosphere which is a geenhouse gas
  53. Why is H2O2 a better oxidant than potassium permanganate?
    H2O2 forms water as waste while potassium permanganate forms toxic waste
  54. Why stir adipic acid reaction mixture as fast as possible?
    In order for the catalyst to act on the mixture of both the organic and aqueous layers