Aldehydes and Ketones
• The functional group in aldehydes and ketones is the carbonyl group.
O
R1
R2 or H
carbonyl group
Aldehydes and Ketones
• Except for formaldehyde, aldehydes have one H atom and one organic group
bonded to a carbonyl group.
O
H3C
O
O
H
ethanal
or
acetaldehyde
H
H
methanal
or
formaldehyde
H 3C
C
H2
H
propanal
or
propionaldehyde
• Ketones have two organic groups bonded to a carbonyl group.
H3C
O
O
O
C
C
C
CH 3
propanone
or
acetone
H2C
CH 3
CH 3
2-butanone
or
ethylmethylketone
H 2C
CH 3
CH 2
CH 3
3-pentanone
or
diethylketone
Aldehydes and Ketones
• Common names for aldehydes are derived from the name of the acid with the
same number of C atoms.
• IUPAC names are derived from the parent hydrocarbon name by replacing -e with
-al.
H3C
C
H2
H2
C
O
C
H2
C
pentanal
or
pentyl aldehyde
H3C
H
H3C
C
O
O
C
C
H
H
CH3
2,3-dimethylproponal
or
2,3-dimethylpropionaldehyde
benzanal
or
benzyl aldehyde
Aldehydes and Ketones
• The IUPAC name for a ketone is the characteristic stem for the parent
hydrocarbon plus the suffix -one.
• A numeric prefix indicates the position of the carbonyl group in a chain or
on a ring.
O
H3C
C
H2
H2
C
O
C
H2
C
CH3
2-hexanone
or
methyl pentyl ketone
H3C
H2
C
O
C
H2
C
C
H2
C
CH3
CH3
3-hexanone
or
ethyl propyl ketone
acetophenone
or
methyl phenyl ketone
Amines
• Amines are derivatives of ammonia in which one or more H atoms have been
replaced by organic groups (aliphatic or aromatic or a mixture of both).
• There are three classes of amines.
H
N
H
H
ammonia
H3C
N
H
primary
amine
H
H3C
N
H
CH3
secondary
amine
H3C
N
CH3
CH3
tertiary
amine
Carboxylic Acids
O
• Carboxylic acids contain the carboxyl functional group.
C
OH
O
• The general formula for carboxylic acids is:
– R represents an alkyl or an aryl group
C
R1
OH
• IUPAC names for a carboxylic acid are derived from the name of the
parent hydrocarbon.
– The final -e is dropped from the name of the parent
hydrocarbon
– The suffix -oic is added followed by the word acid.
• Many organic acids are called by their common (trivial) names which
are derived from Greek or Latin.
Carboxylic Acids
O
O
C
C
H
H3C
OH
methanoic acid
or
formic acid
ethanoic acid
or
acetic acid
O
O
H3C
H2
C
C
C
H2
OH
OH
propanoic acid
or
propionic acid
H3C
C
C
H2
OH
butanoic acid
or
butyric acid
Carboxylic Acids
• Positions of substituents on carboxylic acid chains are indicated by
numeric prefixes as in other compounds
– Begin the counting scheme from the carboxyl group
carbon atom.
• They are also often indicated by lower case Greek letters.
–  = 1st C atom
–  = 2nd C atom
–  = 3rd C atom, etc.
O
H3C H C
C
OH
CH3
CH3
O
C
C
OH
H3C H C
H2
2-methylpropanoic acid 3-methylbutanoic acid
or
or
-methylpropanoic acid -methylbutanoic acid
O
H2
H3C H C
C
C
C
OH
H2
CH3
4-methylpentanoic acid
or
-methylpentanoic acid
Nomenclature of Carboxylic Acids
• Dicarboxylic acids contain two carboxyl groups per molecule.
O
OH
C C
HO
O
oxalic acid
HO
O
O
O
C
C
C
C
H2
OH
malonic acid
HO
C
H2
H2
C
C
O
succinic acid
OH
Carboxylic Acids
• Aromatic acids are usually called by their common names.
• Sometimes, they are named as derivatives of benzoic acid which is
considered to be the "parent" aromatic acid.
HO
HO
O
benzoic acid
HO
O
O
Cl
p-chlorobenzoic acid
OH
O
OH
CH3
p-toluic acid
O
phthalic acid
Some Derivatives of
Carboxylic Acids
R1
O
O
O
C
C
C
O
R1
acid anhydride
R1
acid chloride
O
O
R1
C
Cl
O
ester
R2
R1
C
NH2
amide
When compounds contain more than one functional group, the order of precedence determines
which groups are named with prefix or suffix forms. The highest precedence group takes the
suffix, with all others taking the prefix form. However, double and triple bonds only take suffix
form (-en and -yn) and are used with other suffixes.
Functional group
Formula
Prefix
Suffix
1
Cations
e.g. Ammonium
–NH4+
-onioammonio-
-onium
-ammonium
2
Carboxylic acids
–COOH
carboxy-
-oic acid*
3
Carboxylic acid derivatives
Esters
Acyl chlorides
Amides
–COOR
–COCl
–CONH2
R-oxycarbonylchloroformylcarbamoyl-
-oyl chloride*
-amide*
4
Nitrites
Isocyanides
–CN
–NC
cyanoisocyano-
-nitrile*
isocyanide
5
Aldehydes
Thioaldehydes
–CHO
–CHS
formylthioformyl-
-al*
-thial*
6
Ketones
Thioketones
>CO
>CS
oxothiono-
-one
-thione
7
Alcohols
Thiols
–OH
–SH
hydroxysulfanyl-
-ol
-thiol
8
Amines
–NH2
amino-
-amine
9
Ethers
Thioethers
–O–
–S–
-oxy-thio-
Priority
Isomerism
• Isomers have identical composition but different structures
• Two forms of isomerism
– Constitutional (or structural)
– Stereoisomerism
• Constitutional
– Same empirical formula but different atom-to-atom
connections
• Stereoisomerism
– Same atom-to-atom connections but different arrangement in
space.
Structural Isomers
Stereoisomers: Geometric
Geometric isomers can occur when there is a C=C double bond.
Cis-2-butene
Trans-2-butene
Stereoisomers: Optical
• Optical isomers are molecules with
non-superimposable mirror images.
• Such molecules are called CHIRAL
• Pairs of chiral molecules are
enantiomers.
• Chiral molecules in solution can
rotate the plane of plane polarized
light.
• Chirality generally occurs when
a C atom has 4 different groups
attached.
Lactic acid
Chirality: Handedness in Nature
These molecules are non-superimposable mirror images.
Sugars: Related to Alcohols
• Sugars are carbohydrates, compounds with the formula Cx(H2O)y.
CHO
H OH
4
HO
HO
5
H
HO
3
H
H
2
HO
1
OH
OH
-D-glucose
H
H
H
1
OH
2
H
3
OH
4
OH
5
CH2OH
H OH
4
HO
HO
5
HO
1
3
H
H
2
OH
H
-D-glucose
Open chain form
What is the difference between a and b D-glucose?
OH
Sucrose and Ribose
H OH
HO
HO
HO
HO
H
OH
O
H
OH
O
H
H
CH2OH
-D-Glucose
H
HO
O
OH
Fructose
H
H
CH2 OH
H
OH
H
H
H
Deoxyribose,
the sugar in the
DNA
backbone.
Fats and Oils
H2 C
HC
H2 C
O
O CR
O
O CR
O
O CR
What is the
functional group in a
fat or oil?
R = organic group
with NO C=C bonds
C12 = Lauric acid
C16 = Palmitic acid
C18 = Stearic acid
R = organic group
with C=C bonds
C18 = oleic acid
H2 C
HC
H2 C
O
O CR
O
O CR
O
O CR
Fats and Oils
Fats with C=C bonds are usually LIQUDS
Oleic acid: a
monounsaturated
fatty acid
C=C bond
Trans Fatty Acids
•Oleic acid is a mono–unsaturated cisfatty acid
•Trans fatty acids have deleterious health
effects.
•Trans fatty acids raise plasma LDL
cholesterol and lower HDL levels.
C=C bond
Alpha-Amino Acids
H2N
H
O
C
C
OH
R
Amine
H
Alanine
H3C
C
Chiral -carbon
NH3
CO2
Acid
Peptides and Proteins
O
H 3N
OŠ
H CH3
Alanine
HOCH 2
H 3N
+
H
OŠ
O
Serine
peptide bond
– H2O
H
HOCH2
H
H 3N
O
N
H
O
OŠ
CH3
Adding more peptide links ---> PROTEIN
Polymers
• Giant molecules made by joining many small molecules called
monomers
• Average production is 150 kg per person annually in the U.S.
Polymer Classifications
• Thermoplastics (polyethylene) soften and flow when heated
• Thermosetting plastics — soft initially but set to solid when
heated. Cannot be resoftened.
• Other classification: plastics, fibers, elastomers, coatings,
adhesives
Polymer Preparation
• Addition polymers — directly adding monomer
units together
• Condensation polymers — combining monomer
units and splitting out a small water (water)
Types of Polyethylene
Linear, high density PE
(HDPE)
Branched, low density
PE, LDPE
Cross-linked PE, CLPE
Types of Polyethylene
Polymers based on Substituted Ethylenes, CH2=CHX
CH2CH
OH
CH2CH
n
polyvinyl alcohol
CH2CH
OCCH3 n
O
polyvinyl acetate
n
polystyrene
Table 11.12: others are PVC, acrylonitrile, polypropylene,
polymethyl methacrylate
Bubble Gum!
A copolymer
Styrene + butadiene
Condensation Polymers
O
n HOC
O
COH + n HOCH2CH2OH
terephthalic acid
O
C
ethylene glycol
O
COCH2CH2O
+ H2 O
n
Polyethylene terephthalate (PET), a polyester
Polyamides: Nylon
•Each monomer has 6 C atoms in its chain.
•A polyamide link forms on elmination of HCl
•Result = nylon 66
•Proteins are polyamides
Polymer Recycling Symbols
LDPE =
HDPE =
PP =
V=
Low density PE = 0.910-0.925 g/cm3
High density PE = 0.941-0.965
Polypropylene = 0.90
PVC (Vinyl chloride) = 1.30-1.58