Amines, Aldehydes, Ketones

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Chemistry B11
Chapter 16,17 18 Amines, Aldehydes, Ketones
and Carboxylic Acids
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Amines
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Amines

• Amines
• Are derivatives of ammonia NH3.
• Contain N attached to one or more alkyl
  (Aliphatic amine) or aromatic groups (Aromatic
  amine).
• CH3-NH2 CH3-NH-CH3

-NH2 amino group
NH2
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Amines
Amines are divided into the three groups
depending the number of carbon groups bonded to
nitrogen. CH3
CH3
? ? CH3NH2 CH3NH CH3NCH3
Tertiary 3
Secondary 2
Primary 1
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Naming Amines
IUPAC name 1 amines
Same method as we did for alcohols. - Drop the
final -e of the parent alkane and replace it by
-amine. - Use a number to locate the amino
group (-NH2) on the parent chain.
3
1
5
3
2
4
6
1
2
4
3
1
2
2-propanamine
3-chloro-2-butanamine
1,6-hexanediamine
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Naming Amines
Common name Names of alkyl groups (In
alphabetical order) amine CH3CH2NH2
ethylamine CH3NH CH3 dimethylamine
CH3 CH3NCH2CH3 ethyldimethylami
ne
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Aniline (common name)
NH2
Aniline
NH2
NH2
NH2
2
2
1
1
2
1
CH3
3
3
3
CH3
4
4
Cl
NO2
3-Methylaniline
4-Nitroaniline
4-chloro-3-Methylaniline
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Naming Amines
IUPAC name 2 and 3 amines

• Take the largest group bonded to nitrogen as the
  parent amine.
• Name the smaller group(s) bonded to nitrogen, and
  show their location on nitrogen by using the
  prefix N.

N,N-Dimethylethanamine
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Heterocyclic amines
When N is one of the atoms of a ring.
Pyrrolidine
Pyridine
Nicotine
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Physical properties of Amines

• They have unpleasant odors (rotting fish like
  ammonia).
• They are polar compounds.
• Difference electronegativity between N - H (3.0
  2.1 0.9)
• 3. 1 and 2 amines have hydrogen bond with each
  other (N-H).
• Weaker than alcohols (O-H).
• 3 amines do not have hydrogen bond (no H
  atom).
• Boiling point alkanes lt Amines lt Alcohols
• Almost soluble in water (hydrogen bonding).

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Chemical properties of Amines
They are weak bases (like ammonia) react with
acids.
(to form water-soluble salts)
Some amines present in our blood and make it
basic approximately (pH 7.4).
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Chemical properties of Amines

• Aliphatic amines are weak bases by comparison
  with inorganic bases
• such as NaOH, they are strong bases among organic
  compounds.

Aliphatic amines are stronger base than aromatic
amines.
(slightly stronger than NH3)
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Examples
Complete each acid-base reaction and name the
salt formed.
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Examples
Complete each acid-base reaction and name the
salt formed.
Solutions
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Aldehydes Ketones
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Carbonyl group
Aldehydes
Ketones
Carboxylic acids
Esters
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Aldehydes and Ketones
O

C

• In an aldehyde, at least one H atom is attached
  to a carbonyl group.
• In a ketone, two carbon groups are attached to a
  carbonyl group.

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Naming Aldehydes
Step 1 Select the longest carbon chain that
contains the carbonyl group (CO).
Step 2 Number from the end nearest CO group.
Step 3 Change the ending of parent alkane from -e
to -al. No number for carbonyl group CO (it
always comes first).
Step 4 Give the location and name of each
substituent (alphabetical order) as a prefix to
the name of the main chain.
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Naming Aldehydes

• Common names for the first two aldehydes use the
  prefixes form (1C) and acet (2C) followed by
  aldehyde.
• O O O
• 
  
• H-C-H CH3- C -H CH3-CH2- C -H
• methanal ethanal
  propanal
• (formaldehyde) (acetaldehyde)

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• O
• CH3-CH-CH2- C-H 3-Methylbutanal
• O
• Cl-CH2-CH2- C-H 3-chloropropanal

CH3
3
4
1
2
3
2
1
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Naming Ketones
Step 1 Select the longest carbon chain that
contains the carbonyl group (CO).
Step 2 Number from the end nearest CO group.
Step 3 Change the ending of parent alkane from -e
to -one. Use the number to show the location of
CO.
Step 4 Give the location and name of each
substituent (alphabetical order) as a prefix to
the name of the main chain.
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Naming Ketones

• In the common name, name the alkyl groups
  alphabetically attached to the carbonyl group and
  add the word ketone.
• O O
  
• CH3 - C -CH3 CH3-C-CH2-CH3
• propanone
  2-butanone
• (dimethyl ketone) (ethyl methyl ketone)

1
2
3
4
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Cl
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(No Transcript)
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Physical properties of Aldehydes and Ketones

• Strong odors (ketones have pleasant odor).
• They are polar compounds.
• Only dipole-dipole interaction (no hydrogen
  bond).
• Low boiling point compare to amines and alcohols.
• Soluble in water (no soluble in nonpolar
  compounds).

C-O 3.5-2.5 1
Higher than alkanes.
H
O
d
H
Hydrogen bond with water.
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Chemical properties of Aldehydes and Ketones
1. Oxidation only for aldehydes (no ketones).
O
K2Cr2O7

CH3-CH2-CH2-CH2-C-OH
H2SO4
Pentanoic acid
K2Cr2O7 Oxidizing agent
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Chemical properties of Aldehydes and Ketones
2. Reduction

• Like reducing the alkene (C C) to alkane (C
  C)
• Reduction of an aldehyde gives a primary alcohol
  (-CH2OH).
• Reduction of a ketone gives a secondary alcohol
  (-CHOH-).

O


CH3-CH2-CH2-CH2-C- H
CH3-CH2-CH2-CH2-CH2- OH
Pentanal
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Chemical properties of Aldehydes and Ketones
NaBH4
Sodium borohydride produces hydride ion H-
Reducing agent
Reduction mechanism
-
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Carboxylic Acids
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Carboxylic Acids
A carboxylic acid contains a carboxyl group,
which is a carbonyl group attach to a hydroxyl
group. carbonyl
group O ??
CH3 COH hydroxyl group or CH3COOH
carboxyl group
CH3CO2H
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Naming Carboxylic Acids

• In the IUPAC name of carboxylic acids, the e
  in the name of the longest chain is replaced with
  oic acid.
• The common names use prefixes form- and acet-
  for two first carboxylic acid.
• H-COOH methanoic acid formic acid
• CH3-COOH ethanoic acid acetic acid
• CH3-CH2-COOH propanoic acid
• CH3-CH2-CH2-COOH butanoic acid

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Naming Carboxylic Acids

• Number the chain beginning with the carbon of the
  carboxyl group.
• Because the carboxyl carbon is understood to be
  carbon 1, there is no need to give it a number.

CH2 CH3
CH3
1
3
1
2
CH3-CH-CH2-COOH
CH3-CH2-CH-COOH
2-Ethylbutanoic acid
3-Methylbutanoic acid
O
4
1
5
1
4-Aminobenzoic acid
5-Hydroxylhexanoic acid
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Naming Dicarboxylic Acids

• Add the suffix -dioic acid to the name of the
  parent alkane that contains both carboxyl groups
  thus, -ane becomes -anedioic acid.
• The numbers of the carboxyl carbons are not
  indicated because they can be only at the ends of
  the chain.

O
O
O
1
1
3
2
O
Ehanedioic acid
Propanedioic acid
O
O
O
O
1
1
5
1
6
4
O
O
Butanedioic acid
Pentanedioic acid
Hexanedioic acid
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Physical properties of Carboxylic Acids

• 1- The carboxyl group contains three polar
  covalent bonds
• CO, C-O, and O-H. So they are so polar.
• 2- Carboxylic acids have higher boiling points
  than other types of organic compounds (with same
  molecular weight) because of hydrogen bonding.
• 3- They are more soluble in water than alcohols,
  ethers, aldehydes, and ketones because of
  stronger hydrogen bond.
• 4- Liquid carboxylic acids have sharp and
  disagreeable odors.
• 5- They taste sour (exist in pickle, lime and
  lemon).

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Fatty Acids

• Long, unbranched chain carboxylic acids are found
  in animal fats, vegetable oils, or phospholipids
  of biological membranes.
• Most have between 12 and 20 carbons in an
  unbranched chain.
• In most unsaturated fatty acids, the cis isomer
  is usually existed and the trans isomer is rare.
• Unsaturated fatty acids have lower melting points
  than their saturated counterparts.

Cis
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Fatty Acids
Saturated fatty acids are solids at room
temperature.
Packed together ? Maximum London dispersion forces
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Fatty Acids
Unsaturated fatty acids are liquids at room
temperature.
Can not packed together ? London dispersion forces
Cis
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Esters
In an ester, the H in the carboxyl group is
replaced with an alkyl group.
O ?? CH3 CO CH3 ester group
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Soaps

• Natural soaps are sodium or potassium salts of
  fatty acids.
• They are prepared from a blend of tallow and palm
  oils (triglycerides).
• Triglycerides are triesters of glycerol.
• the solid fats are melted with steam and the
  water insoluble triglyceride layer that forms on
  the top is removed.

CH2 CH CH2
OH
OH
OH
1,2,3-Propanetriol (glycerol, glycerin)
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Soaps

• Preparation of soaps begins by boiling the
  triglycerides with NaOH. The reaction that takes
  place is called saponification.
• Boiling with KOH gives a potassium soap.

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Soaps
Hydrophobic part nonpolar
Hydrophilic part polar in contact with
environment.
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Soaps
When soap is mixed with dirt (grease, oil and
), soap micelles dissolve these nonpolar,
water-insoluble molecules.
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Chemical properties of Carboxylic Acids
1- They are weak acids. Substituents of high
electronegativity, especially -OH, -Cl, and
-NH3, near the carboxyl group increase the
acidity of carboxylic acids. 2- Reaction with
bases
react with NaOH, KOH, NH3, and other strong
bases to form water-soluble salts.
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Chemical properties of Carboxylic Acids
3- Fischer Esterification - A carboxylic acid
reacts with an alcohols to form an ester. -
Using an acid catalyst like concentrated sulfuric
acid.
Best way to prepare an ester.