Hydrocarbon Derivatives
Aldehydes, Ketones,
Carboxylic Acids, & Esters
Carbonyl Group
• >CO
• Oxygen attached to carbon by double
covalent bond
• Strong dipole
Aldehydes
O

• General formula: RCH or RCHO
• Carbonyl group always at end of aldehyde
• Find name of alkane with same # of C’s
– change the -e to -al
• Never need #’s for aldehydes
– Functional group always on end C
O
HCO H
H
=
H

Aldehyde comes from
Dehydrogenated Alcohol
HCH

O
HCH
Methanal
common name = formaldehyde
O

H
HCCH
H
Ethanal
common name = acetaldehyde
Acetaldehyde
• Carcinogenic compound
• Natural component of many ripe fruits
• Contributes to odors such as:
– rosemary, daffodil, bitter orange, camphor, angelica,
fennel, mustard, & peppermint
• component of cigarette smoke
CH3CH2CH2CHO
Ends in CHO so it’s
an aldehyde
4 Carbons so base name is butane
Drop -e and add al  butanal
Properties of Aldehydes O
R
C=O
+

H
R
H
C=O
+
-
Aldehydes are polar! This ↑ bp
Hydrogen bonding in H2O ↑ solubility
H
+
H
Ketones
• Carbonyl group: >C=O
– located within C chain instead of at end
• General Format:
=
O
RCR'
R and R' may or may not be the same
Naming Ketones
• Nearly always have number
• Take corresponding alkane name:
– Drop -e & add -one
• Number gives location of >C=O
– (Lowest possible #)
=
H O H
HCCCH
H
H
2-propanone
Common name = acetone
=
O
CH3CH2CH2CCH3
2-pentanone
Aldehydes & Ketones
• Known for appealing tastes & smells
– Used as flavorings in food & candy
– Used as fragrances in perfumes
– Vanilla & cinnamon = aldehydes
Properties of Aldehydes & Ketones
• Aldehydes & ketones:
– contain C=O group
– molecules polar (soluble in water)
• Boiling point:
– higher than alkanes (if same # C’s)
– lower than alcohols (if same # C’s)
Carboxylic Acids
Acidic H+
=
O
• General Formula:
RCOH
• Contains: carbonyl group & hydroxyl group
bonded to same C
• H is acidic; so ionizes in water!
• Carboxylic Acids are electrolytes!
Ionization of Acetic Acid
CH3COOH + H2O  CH3COO-1 + H3O+1
Table R
=
O
• General Format: R-C-OH
or
R-COOH
Which of the following is an
electrolyte?
A.
B.
C.
D.
CH3OH alcohol
CH3COOH
CH2O aldehyde
C 3H 6O
ketone
Correct answer is B, the carboxylic acid
Which of the following is a
nonelectrolyte?
A.
B.
C.
D.
HCl
CH3COOH
NaOH
CH3OH
Correct answer is D, an alcohol
Naming Carboxylic Acids
• Never needs number:
– functional group always at end
• Find name corresponding hydrocarbon
– Drop -e & add -oic + acid
=
O
HCOH
1 C  methane
Methanoic acid
Sting in red ants, bees
O
=
H
HCCOH
H
2 C  ethane
Ethanoic Acid
Acetic acid
CH3CH2CH2CH2COOH
5 C’s  pentane
so the name is pentanoic acid
Common carboxylic acids
• Acetic acid – vinegar
– produced in doughs leavened with specific yeast
(ex: sourdough bread)
•
•
•
•
Citric acid
Tannic acid
Ascorbic acid
Lactic acid
– Poly(lactic acid) – biodegradable polymers
used as sutures in internal surgery
Properties of Carboxylic Acids
• Contain -COOH group
• H bonded to O therefore hydrogen bonds
– Leads to ↑ bp over corresponding alkane
• form H bonds with water so smaller acids
are pretty soluble in water
Esters
=
O
• General format: RCOR‘
• R and R‘ = hydrocarbon branches
– Can be same or different
• Esters contain carbonyl group and a bridge O
– both in middle of chain
• Esters are POLAR
• No H bonded to O so no H-bonding
Esters
=
O
• RCOR‘ or RCOOR’
• Combination of carboxylic acid & alcohol
• carbonyl group and “R” come from the
carboxylic acid
• bridging O and the R’ come from the alcohol
Esters
• Responsible for many distinctive odors
•
•
•
•
•
Pineapple
Banana
Orange
Apple
Wintergreen
Naming Esters
• Name hydrocarbon branch bonded to the
bridge O first
– branches end in –yl
• Base name derived from branch containing
carbonyl group
– count up all C’s in this branch including the C in
the carbonyl
• Find the hydrocarbon base name
– drop the -e and -oate
O
=
name this branch 1st
CH3CH2C─O─CH3
Carbonyl
Group
Bridge O
Methyl Propanoate
Bridge O
=
O
CH3CH2CH2COCH2CH3
Name this branch 1st
Ethyl Butanoate
• Pineapple
=
O
Bridge O
CH3COCH2CH2CH2CH2CH3
Name this branch 1st
Pentyl Ethanoate
• Banana
=
O
CH3OCCH2CH2CH3
Bridge O
Name this branch 1st
4 C’s on the other side: but
Methyl butanoate
• apple
O
=
CH3CH2CH2CH2CH2CH2CH2CH2-O-C-CH3
Bridge O
Name this branch 1st
2 C’s on the other side: eth
Octyl Ethanoate
• orange