Download carbonyl group

Hydrocarbon Derivatives
Aldehydes
Ketones
Carboxylic Acids
Esters
Carbonyl Group
• >CO
• oxygen attached to carbon by double
covalent bond
• strong dipole-dipole forces
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
drop the -e (in ane ending) to –al
• never need #’s for aldehydes
– functional group always on end C
O
HCH
H
=
OH

HCH + H2
aldehydes created by
dehydrogenating an alcohol

O
HCH
O

H
HCCH
H
methanal
common name = formaldehyde
ethanal
common name = acetaldehyde
Acetaldehyde
• carcinogenic compound
– component of cigarette smoke
• natural component of many over-ripe fruits
• contributes to odors such as:
– rosemary, daffodil, bitter orange, camphor, angelica,
fennel, mustard, & peppermint
CH3CH2CH2CHO
CHO ending indicates 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
+
-
H
+
H
aldehydes are polar!
↑ bp over alkane with same C’s
H-bonding with H2O which ↑ solubility in water
Ketones
• carbonyl group: >C=O
– located on C in middle of chain instead of at end
• general format:
=
O
RCR'
R and R‘: represent hydrocarbon chain
- may or may not be the same
Naming Ketones
• nearly always have number (except 3C’s)
• take corresponding alkane name:
drop -e (from ane ending) & add -one
• # gives location of functional group: >C=O
– (lowest possible #)
=
H O H
HCCCH
H
H
propanone
common name = acetone
=
O
CH3CH2CH2CCH3
2-pentanone
Aldehydes & Ketones
• known for appealing tastes & smells
– flavorings in food & candy
– fragrances in perfumes
– examples: vanilla & cinnamon
Properties of Aldehydes & Ketones
• aldehydes & ketones:
– contain C=O group
• polar (soluble in water)
• boiling point:
– higher than alkanes (same # C’s)
– lower than alcohols (same # C’s)
Carboxylic Acids
• general formula:
• contains:
=
O
RCOH
– carbonyl group AND hydroxyl group
bonded to same C
acidic H+1
dissociation of acetic acid
Remember all acids dissociate in water!
- carboxylic acids are electrolytes!
CH3COOH(l) + H2O(l) 
CH3COO-1(aq)+ H+1(aq)
Carboxylic Acids
=
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 (carboxylic acid)
Which of the following is a
non-electrolyte?
A.
B.
C.
D.
HCl
CH3COOH
NaOH
CH3OH
correct answer is D (alcohol)
Naming Carboxylic Acids
• never needs number:
– functional group always at end
• find name corresponding hydrocarbon
drop -e (from ane ending) & add -oic + acid
=
O
HCOH
1 C  methane
methanoic acid
sting from 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
– produced in overworked muscles & causes pain
– poly(lactic acid) – biodegradable polymers used
as sutures in internal surgery
Properties of Carboxylic Acids
• contain -COOH group
• H bonded to O therefore hydrogen bonding
– bp ↑ over corresponding alkane
• form H bonds with water so smaller acids
are very 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 an O bridge
– both in middle of chain
Esters
• esters are POLAR
– due to carbonyl group & O bridge
• no H-bonding
– no FON
• form as product of chemical reaction
between organic acid and an alcohol
Esters
=
O
• RCOR‘ or RCOOR’
reaction between carboxylic acid & alcohol:
• carbonyl group & “R” come from carboxylic acid
• bridging O & R’ come from alcohol
Esters
• responsible for many distinctive odors
•
•
•
•
•
pineapple
banana
orange
apple
wintergreen
Naming Esters
• name hydrocarbon branch bonded to O bridge
first
prefix –yl
• base name derived from branch containing
carbonyl group
– count up all C’s in this branch including the C in
the carbonyl
– hydrocarbon base name
drop the -e (from ane ending) & add -oate
name this branch 1st
=
O
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
methyl butanoate
apple
O
=
CH3CH2CH2CH2CH2CH2CH2CH2-O-C-CH3
bridge O
name this branch 1st
octyl ethanoate
orange