Carboxyic Acids and Esters

  1. General structure of carboxyic acids
    R-C-(=O)- OH
  2. Two functional groups present in carboxyic acids:
    • 1.carbonxyl
    • 2.hydroxyl
  3. Physical Properties of Carboxyic Acids
    • Low molecular weights are liquids at room temp C1----C4
    • C12---C20 are solids and are called fatty acids
    • The acids are usually associated w/ an unpleasant aroma (sweat, sauerkraut)
  4. Boiling points
    • 1. carboxyic acids
    • 2.alcohols
    • 3.aldehydes and ketones
    • 4.alkenes and ethers
  5. Solubility
    • Short chain acids are very soluble in water
    • They can form hydrogen bonds b/w the carboxyl group (or hydroxyl) and water
    • More than C6 tend to be insoluble
  6. Dimers
    2 identical molecules bonded together with a hydrogen bond
  7. Sources of carboxylic acids
    oxidation of ethanol or ethanal
  8. fomula for carboxylic acid
    primary alcohol+[O]-->aldehyde+[O]-->carboxylic acid
  9. Nomenclature for carboxylic acids
    • Find the longest carbon chain containing the COOH group
    • -the carboxyl carbon is #1 (so no numbering needed)
    • Drop -e from the alkane add -oic acid
    • Number and name any branches or substituents
  10. IUPAC Priority
    • 1. Carbocylic acid
    • 2. Aldehyde
    • 3. Ketone
    • 4. Alcohol
    • 5. Amine
    • 6. Alkene= Alkyne
    • 7. Alkane
    • 8. Ether
  11. Ethanedioic acid
    • Oxalic acid
    • simplest dicarboxylic acid
    • found in spinach, rhubarb, and cabbage
  12. 2-hydroxypropanoic acid
    lactic acid
  13. 2,4- hexadicneoic acid
    sordic acid
  14. alpha hydroxy
    • glycolic acid
    • <10% in skin care products
  15. tricarboxylic acids
    citric acid
  16. o-hydroxybenzoic acid
    salicylic acid
  17. Carboxylic anion
    the most important property of the acids is there acidic behavor. carboxylic acids behae as weak acids. the general reaction w/ water followes (see notes)
  18. equation for the formation of carboxylic acid salts
    ex. propionic acid + sodium hydroxide-> sodium proanoate + water

    acid+hydroxide---> salt+water
  19. naming salts
    • the positive ion is named first, followed by a serparate word giving the name of the negitive ion
    • drop -e and add -oate
  20. Conversion back to a carboxylic acid
    react thw salt w/ a solution of a strong acid such as hydrochloric or sulfric
  21. equation for the conversion of sodium acetate back to acetic acid
    salt + strong acid---> acid + salt
  22. Uses for these salts
    • their solubility is much greater in water than that of the acid they are derived from
    • (benzoic acid 3.4g/L)(Na benzoate 550 g/L)
    • drugs and meds that contain acid groups are usu. marketed as Na & K salt. this greatly enhances the wase of absorption by the body
  23. reaction of carboxylic acids w/ a strong base
    acetic acid+ strong base--> salt + water
  24. General formula for acid chlorides
  25. Formation of acid chlorides
  26. Naming acid chlorides
    drop -e and add -oyl and add chloride to the end
  27. General formula for acidic anhydrides
  28. acid anhydrides formation
    formed from the combination of 2 acids and the loss of water
  29. hydrolysis
    splitting with the addition of water
  30. Look at notes for formulas for hydrolysis of anhydrides
    almost done =)
  31. Esters
    • neutralization
    • acid+base--->salt+water
    • Note: the name of the cation came from the base is nameed first in the salt
  32. General Formula for esters
  33. Properties of Esters
    • cannot form H+ bonds w/ one another b/c they lack a H+ bonded to the O atom
    • the BP's are much lower than those of alcohols & acids of comparable molecular mass
    • water molecules can form H bonds to esters through the O atom present in the ester functional group. B/c of this, low molecular weight esteres are water soluble
  34. Ester Formation #1
    carboxylic acid + alcohol--->
    carboxylic acid+alcohol---> ester+water

    R-C(=O)-OH+ ROH--->R-C(=O)-O-R+H2O
  35. Naming Ester
    • OH of the acid is replaced w/ the OR from the alcohol
    • -Name the R group like a side chain
    • -Then name the acid portion w/ -oate ending
  36. Ester formation #2
    acid chloride+alcohol--->
    acid chloride+alcohol-->ester+ hydrogen chloride

    R-C-(=O)-Cl+R-OH---> R-C-(=O)-OR+HCl
  37. Ester formation #3
    acid anhydride+alcohol--->
    acid anhydride+alcohol--->ester+ carboxylic acid
  38. Hydrolysis of esters
  39. Preparation of aspirin
    salicylic acid+acetic anhydride--->
    salicylic acid+acetic anhydride--->acetylsalicylic acid (ASH)+ acetic acid

    (equation in notes)
  40. Preparation of nitroglycerin
    glycerol+ nitric acid--->
    glycerol+nitric acid--->nitroglycerin+water
  41. ester of inorganic acids
    esters of phosphoric acid are found in living organisms
  42. Look at equations for phosphoric acids
    ALL DONE!!! =)
Card Set
Carboxyic Acids and Esters
Carboxyic Acids and Esters