1 Amides and Amines: Organic Nitrogen Compounds Chapter 25 Hein * Best * Pattison * Arena Colleen Kelley Chemistry Department Pima Community College © John Wiley and Sons, Inc. Version 1.0

2 Chapter Outline 25.1 Amides: Nomenclature and Physical Properties 25.2 Chemical Properties of Amides 25.3 Polyamides: Condensation Polymers Urea 25.5 Amines: Nomenclature and Physical Properties 25.6 Preparation of Amines 25.7 Chemical Properties of Amines 25.8 Sources and Uses of Selected Amines

3 Nitrogen-Containing Compounds The amines and amides are the two major classes of nitrogen-containing compounds. Amines isolated from plants form a group of compounds called alkaloids. –Quinine, caffeine Amides are nitrogen derivatives of carboxylic acids. –Nylon, proteins

4 Amides: Nomenclature and Physical Properties

5 Carboxylic acids react with ammonia to form ammonium salts. When heated, ammonium salts of carboxylic acids lose a molecule of water and are converted to amides:

6 IUPAC Rules for Naming Amides 1.The IUPAC name is based on the longest carbon chain that includes the amide group. 2.Drop the –oic acid ending from the corresponding IUPAC acid name. 3.Add the suffix –amide.

7 Naming Amides

8 When the nitrogen of an amide is connected to an alkyl or aryl group, the group is named as a prefix preceded by the letter N:

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10 Physical Properties of Amides Except for formamide (methanamide), a liquid, all other unsubstituted amides are solids at room temperature. Many are odorless and colorless. Low molar-mass amides are soluble in water, but solubility decreases quickly as molar-mass increases.

11 The amide functional group is polar, and nitrogen is capable of hydrogen bonding.

12 Chemical Properties of Amides

13 Hydrolysis of Amides

14 Polyamides: Condensation Polymers

15 Polyamides Polyamides are condensation polymers. Proteins are biological polyamides. Nylon-66 is a synthetic polyamide.

16Urea

17 Urea The body disposes of nitrogen by the formation of a diamide known as urea. Urea is a white solid that melts at 133 C. It is soluble in water and therefore is excreted from the body in the urine.

18 Amines: Nomenclature and Physical Properties

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20 IUPAC System for Naming Amines 1.The IUPAC system names simple amines by using the name of the alkane (omitting the final –e) and adding the ending –amine. CH 3 CH 2 NH 2 ethanamine CH 3 CH 2 CH 2 NH 2 1-propanamine

21 2.Secondary and tertiary amines are named as N-substituted primary amines by using the longest carbon chain as the parent name.

22 Common Names of Amines

23 Heterocyclic Compounds Ring compounds in which the atoms in the ring are not all alike are known as heterocyclic compounds. The most common heteroatoms are oxygen, nitrogen, and sulfur.

24 Physical Properties of Amines Amines are capable of hydrogen bonding with water. They have odors: –Methylamine and ethylamine = strong ammoniacal odor –Trimethyamine = ‘fishy’ odor –High molar-mass amines = obnoxious odors

25 Preparation of Amines

26 Preparation of Amines 1.Alkylation of ammonia and amines 2.Reduction of amides and nitriles 3.Reduction of aromatic nitro compounds

27 Alkylation of Ammonia and Amines The substitution of alkyl groups for hydrogen atoms of ammonia can be done by reacting ammonia with alkyl halides.

28 Reduction of Amides and Nitriles CH 3 CH 2 C  N  CH 3 CH 2 CH 2 NH 2 H 2 /Ni

29 Reduction of Aromatic Nitro Compounds

30 Chemical Properties of Amines

31 Chemical Properties of Amines 1.Alkaline properties of amines 2.Salt formation 3.Formation of amides

32 Alkaline Properties of Amines Amines are bases and produce OH - ions in water.

33 Salt Formation An amine reacts with a strong acid to form a salt.

34 Formation of Amides Primary and secondary amines react with acid chlorides to form substituted amides.

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