Carboxylic Acids and Derivatives

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Carboxylic Acids and Derivatives

• Milbank High School

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Learning Objectives/Study Questions

• 1.What is the general structure for a carboxylic
  acid? An ester? An amide? What is the functional
  group for each of these classes of organic
  molecules?
• 2.How are the common names of carboxylic acids,
  esters, and amides determined? How are these
  compounds named using IUPAC nomenclature?
• 3.Why are the boiling points of carboxylic acids
  higher than those of alcohols of similar molar
  mass? How do the boiling points of esters and
  amides compare with alcohols of similar molar
  mass?

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Learning Objectives/Study Questions

• 4.How do the solubilities of carboxylic acids,
  esters, and amides of five carbons or less
  compare to the solubilities of comparable alkanes
  and alcohols in water?
• 5.How are carboxylic acids, esters, and amides
  prepared?
• 6.What typical reactions take place with
  carboxylic acids, esters, and amides?
• 7.What are some common carboxylic acids and
  esters and their uses?
• 8.What are phosphate esters? Why are they
  important?

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Carboxylic Acids The Functional Groups


                                                                                                   
                                                                                                   

                                                                                                   

• Carboxyl group
• Combo of the carbonyl and hydroxyl groups

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Amides/EstersDerivatives of carboxylic acids

                                                                                                   
                                                                                                   
                                                                                                   
                                                                                                   

                                                                                                   

• Amides
• Functional group has a nitrogen instead of an
  oxygen attached to the carbonyl group
• Esters
• Like an ether and carboxylic acid

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Common Carboxylic Acids Structures and Names



                     
                         
                                                                                

• Formic acid (methanoic acid)
• Ants
• Acetic acid (ethanoic acid)
• Vinegar
• Weak acid
• Propionic acid
• Butyric Acid (butanoic acid)
• Rancid butter
• Found in body odor

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Benzoic Acid/Dicarboxylic acids

                              

• Benzoic Acid
• Dicarboxylic acids
• Table 16.3
• Two carboxylic groups

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Preparation of Carboxylic Acids


                                                        
                                                 

• Final oxidation products of aldehydes and/or
  primary alcohols
• Our body oxidize alcohols to acids
• Liver converts ethanol to acetic acid

                                                 
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Physical Properties of Carboxylic Acids

• Colorless liquids with disagreeable odors
• Caproic acid
• Produced by skin bacteria
• Body odor, locker room smell
• High melting points
• Boiling points increase with the number of
  carbons
• 1-4 carbons soluble in water

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Physical Properties of Carboxylic Acids

                                         

• Sometimes carboxylic acids produce dimers
• Changes physical properties
• Lower freezing points and other properties

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Neutralization

• All carboxylic acids react with NaOH, KOH and
  other strong bases to form water-soluble salts
• RCOOH  NaOH(aq) ? RCOO-Na(aq)  H2O
• RCOOH  NaHCO3 (aq) ? RCOO-Na(aq)  H2O  CO2(g)

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Esters

• Derivatives of carboxylic acids
• Widely found in nature
• Pleasant odors
• Fruits and flowers
• -ic ending replaced by -ate

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Physical Properties

• Boiling point about same as those of ketones
• 3-5 carbons borderline for solubility (again)
• Uses
• Solvents (nail-polish remover)

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Preparation of Esters Esterification

                                                                                          

• Prepared by treating carboxylic acids with an
  alcohol in the presence of HCl or H2SO4

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Hydrolysis

                                                                                                             

                                                                                        


                                                                                        
                                                                                                             

• Alkoxy group (-OR) replaced by another group
• Basically the reverse of esterification

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Saponification

                                                                  

• Base is used to hydrolyze an ester

                                                   
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Amides

• Nitrogen atom attached to a carbonyl atom
• Naming
• -ic or oic replaced by amide

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Amides

                                                                                                                                        

• Naming Cont
• Name substituent attached to nitrogen
• Indicate with N

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Physical Properties of Amides

• Most are solids
• Colorless, odorless
• Soluble to about 5-6 carbons
• Very high boiling points
• Polar nature of amide group
• Formation of hydrogen bonds

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Synthesis of Amides

                                                                                                                                      

• Addition of ammonia to a carboxylic acid

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Hydrolysis of Amides


                                                                                                                           
                                                                                                                        

• Amide water carboxylic acid
• Can be basic or acidic