Download - Hydrocarbon Derivatives
Hydrocarbon Derivatives
AldehydesKetones
Carboxylic AcidsEsters
Carbonyl Group
• >CO
• oxygen attached to carbon by double covalent bond
• strong dipole-dipole forces
AlAldehydes
• general formula: RCH or RCHO
• carbonyl group alwaysalways at end of aldehyde
• find name of alkane with same # of C’s– change the -e (in ane ending) to -alal
• never need #’s for aldehydes – functional group always on end C
O
HCH H
=
OOH
HCH + H2
aldehydes created by
dehydrogenating an alcohol
HCH
Omethanal
H HCCH H
O
ethanalcommon name = acetaldehyde
common name = formaldehyde
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
CHO ending indicates aldehyde
4 carbons so base name is butane
drop -e and add al butanal
Properties of Aldehydes
C=OR
H
C=OR
H
++
-- -
++
aldehydes are polar! ↑ bp over alkane with same C’s
H-bonding with H2O which ↑ solubility in water
H HO
+
-
Ketones
• carbonyl group: >C=O– located onon C in middle of chain instead of at end
• general format:
R and R‘: represent hydrocarbon chain - may or may not be the same
RCR'
=
O
Naming Ketoneones
• nearly always have number
• take corresponding alkane name:
– drop -e (from ane ending) & add -one
• # gives location of functional group: >C=O
– (lowest possible #)
H O HHCCCH H H
= propanonecommon name = acetone
CH3CH2CH2CCH3
=
O
2-pentanone
Aldehydes & Ketones
• known for appealing tastes & smells
– used as flavorings in food & candy– used as fragrances in perfumes– vanilla & cinnamon are aldehydes
Properties of Aldehydes & Ketones
• aldehydes & ketones: – contain C=O group – molecules polar (soluble in water)
• boiling point: – higher than alkanes (same # C’s) – lower than alcohols (same # C’s)
Carboxylic Acids
• general formula: RCOHH
• contains: carbonyl group AND hydroxyl group bonded to same C
• H is acidic; so ionizes in water! – carboxylic acids are electrolytes!carboxylic acids are electrolytes!
=
O Acidic H+
Ionization of Acetic Acid
CH3COOH(l) + H2O(l)
CH3COO-1(aq)+ H3O+1(aq)
Carboxylic Acids
• general format: R-C-OH
or
R-COOH
O
=
Which of the following is an electrolyte?
A. CH3OH
B. CH3COOH
C. CH2O
D. C3H6O
correct answer is B (carboxylic acid)
alcohol
aldehyde
ketone
Which of the following is a non-electrolyte?
A. HCl
B. CH3COOH
C. NaOH
D. CH3OH
Correct answer is D (alcohol)
Naming Carboxylic Acids
• nevernever needs number:– functional group always at end
• find name corresponding hydrocarbon– drop -e (from ane ending) & add -oic + acid
HCOH=
O
1 C methane methanoic acid sting from red ants, bees
HHCCOH H
=
O
ethanoic acid acetic acid
2 C ethane
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
• general format: RCOR‘
• R and R‘ = hydrocarbon branches
– can be same or different• esters contain carbonyl group and an O bridge
– both in middle of chain• esters are POLAR
• no H-bonding
=
O
Esters
• RCOR‘ or RCOOR’
combination of carboxylic acidcarboxylic acid & alcohol:alcohol:
• carbonyl group & “R” come from carboxylic acid
• bridging O & R’ come from alcohol
=O
Esters
• responsible for many distinctive odors
• pineapple
• banana
• orange
• apple
• wintergreen
Naming Esters
• name hydrocarbon branch bonded to O bridge 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 (from ane ending) & add -oate
CH3CH2C─O─CH3
=
O
carbonyl group
bridge O
name this branch 1st
methyl propanoate
CH3CH2CH2COCH2CH3
=
O
name this branch 1st
ethyl butanoate
bridge O
pineapple
CH3COCH2CH2CH2CH2CH3=
O bridge O
name this branch 1st
pentyl ethanoate
banana
CH3OCCH2CH2CH3
=
O
bridge O
name this branch 1st
4 C’s on the other side: but
methyl butanoate
apple
CH3CH2CH2CH2CH2CH2CH2CH2-O-C-CH3
O=bridge O
name this branch 1st
2 C’s on the other side: eth
octyl ethanoate
orange