CARBOXYLIC ACID

• Carboxylic acids


  The presence of hydroxyl group and another carbon atom attached to the carboxyl carbon atom
• Acyl derivative


  The -OH group is replaced by a different group
• Naming carboxylic acids


  1. Select the longest chain containing the carboxyl group

  2. Name the parent chain by changing the "-e" to "-oic acid"

  3. Number the parent chain by assigning the number 1 to the carboxyl carbon atom

  4. Determine other substituents present and their locants
• Low molecular mass carboxylic acids

  • Liquids at RT
  • Sharp or unpleasant odors
• Long chain acids


  • Wax-like solids
• Carboxylic acids


  • Polar
  • Form hydrogen bonds to other carboxylic groups or other molecules
  • Relatively high boiling points
  • Low MM = soluble in water
• Acidic properties of carboxylic acids

  • Carboxylic acids react with bases to form water soluble metal carboxylates (RCO2-Na+)
  • Weaker acid than mineral acids
  • More acidic than alcohol and phenol
• Reactions of carboxylic acids

  1. Hydrolysis: Reaction with H2O to form carboxylic acid

  2. Alcoholysis: Reaction with ROH to form ester

  3. Aminolysis: Reaction with NH2 or amine to form amide

  4. Reduction: Reaction with hydride reducing agent to form ROH

  5. Grignard reaction: Reaction with organomagnesium reagent to form ROH
• Nucleophilic acyl substitution


  1. Nucleophile addition

  2. Alkoxide is protonated leading to ROH

  3. Nucleophile addition

  4. Alkoxide expels a leaving group forming carbonyl compound
• Carboxylic acid derivatives


  Acyl carbon bonded to a group -Y (leaves as a stable anion)
• The more electron-poor the C=O carbon, the more readily the compound reacts with nucleophiles
• Carboxylate ions


  • Ionic compound in which the negative ion is a carboxylate ion
  • The (+) ion is named first, followed by the name of the (-) carboxylate ion
• Carboxylate salts


  • Sodium propanoate
• Naming carboxylate salts


  Drop the "-ic acid" from the name of the parent chain and replace it with "-ate"
• Carboxylate salts are commonly used in the food industry as preservatives. They DO NOT directly kill microorganisms. However, they prevent further growth and proliferation by increasing the pH of the foods in which they are used.
• Esters


  The hydrogen atom of the -OH group is replaced with an alkyl or aryl group
• Naming esters


  1. Name the alkyl group attached to the oxygen atom

  2. Identify the carboxylic acid and replace "-ic acid" with "-ate"
• Reactions of esters


  1. Hydrolysis: Under acidic conditions, esters produce acid and ROH

  2. Saponification: Under basic conditions, esters produce acid salt and ROH
• Amines


  Organic derivative of ammonia (NH3) where one or more alkyl, cycloalkyl, or aryl groups are attached to the nitrogen atom
• Naming amines


  1. Replace the "-e" with "-amine"

  2. Indicate the position of attachment of the nitrogen atom

  3. Precede other groups attached to the nitrogen atom with "N-" or "N,N-"
• Amides


  Organic derivative of carboxylic acid where the -OH group of the carboxyl group is replaced with an amino or substituted amino group
• Naming amides


  1. For unsubstituted -NH2 group, replace the "-oic acid" or "-ic acid" with "-amide" or replace "-carboxylic acid" with "-carboxamide"

  2. For substituted -NH2 group, identify the substituent/s then the parent amide, with substituents preceded by "N-"
• Amides


  • 2-chloro-2-methylpropanamide
  • N,N-dimethylethanamide
• Properties of amines


  • Methylamines & ethylamines are gases at RT
  • High MM amines are liquids with raw fish smell
  • 1° and 2° amines form hydrogen bonds
  • Exhibit basic properties due to ability of the unshared paired electron pair on the amine nitrogen atom to accept proton in acidic solutions
  • Tertiary amines do not exhibit basic properties
• Properties of amides


  • Unbranched amides are solids at RT with high BP due to strong hydrogen bonds
• Condensation polymers are formed with monomers (diacids and diamines) joined together by amide linkages
• Naming acyl halides and cyclic carboxylic acids

  1. Identify the acyl group and then the halide

  2. For cyclic carboxylic acids, drop the "-carboxylic acid" and replace it with "-carbonyl"
• Symmetrical anhydrides


  Replace the word "acid" with "anhydride"
• Unsymmetrical anhydrides


  Cite the 2 acids alphabetically and then add the word "anhydride"
• Naming simple acyclic nitriles

  Replace the suffix "-e" from alkane to "-nitrile", with the nitrile carbon assumed at carbon 1
• Naming complex nitriles


  Replace the "-ic acid" or "-oic acid" with "-onitrile" or replace "-carboxylic acid" with "-carbonitrile"