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Alcohol Reactions

Alcohol Reactions. Alcohol Reactions. Conversions to esters (Acetate Lab) Reactions with hydrogen halides Acid-catalyzed hydrations. Esterification. O. O. R'COH. R'C OR. Esterification. condensation Fischer esterification acid catalyzed reversible. H +. +. +. RO H. H 2 O. O.

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Alcohol Reactions

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  1. Alcohol Reactions

  2. Alcohol Reactions Conversions to esters (Acetate Lab) Reactions with hydrogen halides Acid-catalyzed hydrations

  3. Esterification

  4. O O R'COH R'COR Esterification condensation Fischer esterification acid catalyzed reversible H+ + + ROH H2O

  5. O + COH CH3OH H2SO4 O COCH3 Example of Fischer Esterification 70% yield based on benzoic acid 0.1 mol 0.6 mol + H2O

  6. O O R'CCl R'COR Reaction of Alcohols with Acyl Chlorides High yields Not reversible when carried outin presence of pyridine. + + ROH HCl

  7. CH3CH2 O O2N OH CCl CH3 CH3CH2 O NO2 OC CH3 Example + pyridine (63%)

  8. O O O O R'COCR' R'COR R'COH Reaction of Alcohols with Acid Anhydrides analogous to acyl chlorides + + ROH

  9. O O + C6H5CH2CH2OH F3CCOCCF3 O C6H5CH2CH2OCCF3 Example pyridine (83%)

  10. Reactions of Alcohols “Poor”

  11. Reactions of Alcohols Oxidation Conversion to ethers

  12. Oxidation of Alcohols

  13. O O Secondary alcohols from H2O O OH RCHR' RCR' Oxidation of Alcohols Primary alcohols RCH2OH RCH RCOH

  14. Strong Oxidizing Agents In aqueous solution: Mn(VII) Cr(VI) KMnO4 CrO3/ H2SO4 = H2CrO4 K2Cr2O7 / H2SO4 = H2Cr2O7 Oxidize 1o alcohols to carboxylic acids. Cannot stop at aldehydes.

  15. H OH H2SO4 Na2Cr2O7 H2O O O (85%) Aqueous Cr(VI) FCH2CH2CH2CH2OH H2SO4 K2Cr2O7 H2O FCH2CH2CH2COH (74%)

  16. Question • Treatment of 1-propanol with K2Cr2O7, H2SO4, and heat will produce: • A) B) • C) D)

  17. Question What is the product of the following reaction?

  18. Specialized Oxidizing Agents[Nonaqueous Sources of Cr(VI)] Used in CH2Cl2 Pyridinium dichromate (PDC) (C5H5NH+)2 Cr2O72– Pyridiniumchlorochromate (PCC) C5H5NH+ ClCrO3– “Collins Reagent” Jones Reagent: CrO3/ H2SO4 acetone (does not affect Carbon=Carbon double bonds; oxidizes 2o alcohols to ketones)

  19. N + H O CH3(CH2)5CH Example: Oxidation of a Primary Alcohol with PCC ClCrO3– PCC CH3(CH2)5CH2OH CH2Cl2 (78%)

  20. Question • What is the product of the reaction of 1-butanol with PCC in CH2Cl2? • A) B) • C) D)

  21. Question What is the product of the following reaction?

  22. (CH3)3C CH2OH O (CH3)3C CH Example: Oxidation of a Primary Alcohol with PDC PDC CH2Cl2 (94%)

  23. Question • For the following reaction, select the statement that best describes it. RCH2OH + PDC [(C5H5NH+)2 Cr2O72–] ® • A) The alcohol is oxidized to an acid, and the Cr(VI) is reduced. • B) The alcohol is oxidized to an aldehyde, and the Cr(VI) is reduced. • C) The alcohol is reduced to an aldehyde, and the Cr(III) is oxidized. • D) The alcohol is oxidized to a ketone, and the Cr(VI) is reduced.

  24. Conversion of Alcohols to Ethers

  25. RCH2O CH2R H OH RCH2O CH2R H OH Conversion of Alcohols to Ethers Acid-catalyzed Referred to as a "condensation" Equilibrium; most favorable for primary alcohols H+ +

  26. H2SO4, 130°C Example 2CH3CH2CH2CH2OH CH3CH2CH2CH2OCH2CH2CH2CH3 (60%)

  27. via: H •• + O •• O •• H O H Intramolecular Analogue HOCH2CH2CH2CH2CH2OH Reaction normally works well only for5- and 6-membered rings. H2SO4 130° (76%)

  28. Question • When 1-propanol is treated with Na2Cr2O7/H2SO4 followed by treatment with CH3OH, H2SO4 the product isolated is: • A) propanal B) propanoic acid • C) propanol D) methyl propanoate

  29. Question Classify the following as oxidation, reduction or neither oxidation or reduction Oxidation Reduction Neither oxidation or reduction I: a, c, d; II: e, f; III: b I: a, d, e; II: c, f; III: b I: c, d, e; II: a, f; III: b I: c, f; II: a, d, e; III: b I: c, e;II: a, d, f; III: b

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