organic chemistry functional groups: - aldehydes - ketones
TRANSCRIPT
Functional Groups:
- Aldehydes- Ketones- Organic Acids- Esters- Amines- Amides
AldehydesAldehydes
Group is always on a terminal C – no need to specify Group is always on a terminal C – no need to specify location by numberlocation by numberCondensed it is symbolized by a -CHO group at the Condensed it is symbolized by a -CHO group at the end of the formulaend of the formulaC = O is known as a carbonyl groupC = O is known as a carbonyl group– Drives the physical and chemical properties of these Drives the physical and chemical properties of these
compoundscompoundsAldehydes have characteristic scents and tastesAldehydes have characteristic scents and tastes– Cinnamon is an exampleCinnamon is an example
AldehydesAldehydes
Drop the –e from the end of the Drop the –e from the end of the alkane and add –al; C=O is C #1alkane and add –al; C=O is C #1
Name these two compounds:
Methanal(formaldehyde)
Butanal
KetonesKetones
Like the aldehydes the Functional group is the Like the aldehydes the Functional group is the carbonyl group C=Ocarbonyl group C=OContains an alkyl group on either side of the C=OContains an alkyl group on either side of the C=O– In aldehydes one side is an alkyl group the other is HIn aldehydes one side is an alkyl group the other is H
Often used as a solventOften used as a solvent– Acetone is one exampleAcetone is one example
Naming KetonesNaming Ketones
Number the C chain so C=O has the lowest #Number the C chain so C=O has the lowest #Drop the final e from the alkane name and add -oneDrop the final e from the alkane name and add -one
Name these compounds:
C-C-C-C-CC
o3-hexanone
4-methyl-2-pentanone
PropertiesPropertiesBoth aldehydes & ketones haveA carbonyl functional group.
C=O is polar & their compounds Are polar. This leads to:
-Higher B.P’s than non-polar molecules
-Lower than alcohols that can H-bond w/ each other
-Can not H-bond between each other but can H-bond to solvents like water - Lower MW compounds are appreciably soluble in water
Propanone Propanal
PropertiesProperties
ButaneButane DiethylDiethyletherether
PropanalPropanal PropanonePropanone 1-propanol1-propanol
M.W.M.W. 5858 5858 5858 5858 6060
B.P (deg.C)B.P (deg.C) 00 3535 4949 5656 9797
SolubilitySolubilityg/100g Hg/100g H22OO
Insol.Insol. 88 1616 FullyFullymisciblemiscible
Fully Fully misciblemiscible
Organic AcidsOrganic Acids
Condensed form is written –COOHCondensed form is written –COOH– A carbonyl group and a hydroxyl group bonded to CA carbonyl group and a hydroxyl group bonded to C– Known as a Known as a carboxyl groupcarboxyl groupA terminal functional groupA terminal functional groupThe carboxyl group is an organic acid. The carboxyl group is an organic acid. – It is the H on the end of COOH that is donated as a It is the H on the end of COOH that is donated as a
proton (Hproton (H++))– What is left is the anion What is left is the anion R-COOR-COO--
Carboxylic acids ionize in water to form a proton andA carboxylate anion
Naming Organic AcidsNaming Organic Acids
The carboxyl group is a The carboxyl group is a terminalterminal group group– no need to give it a number. It’s always on C #1no need to give it a number. It’s always on C #1
Drop the –e from the alkane name and add Drop the –e from the alkane name and add –oic–oic acidacid
Name this compound:
Butanoic acid
Naming Organic AcidsNaming Organic Acids
Name this compound:
Butanoic acid
Name this compound: 2,4-dimethylhexanoic acid
C-C-C-C-C-COOH C C
Some Common Carboxylic acidsSome Common Carboxylic acids
HC=O OH
Methanoic acid“formic acid”
CH3C=O OHEthanoic Acid“Acetic Acid”
The sting of ants Vinegar
C-C-C-COOHButanoic acid
Rancid butter smell
- Sharp or noxious smells
- polar and can form 2 hydrogen bonds with themselves and with water
Physical propertiesPhysical properties
C-C=O OH
HOO=C- C
C-C=O OH
HO H
This leads to high B.P. and high solubility in water- 1st four acids are totally miscible in water
Comparison of propertiesComparison of propertiesButane Diethyl
etherPropanal Propanone 1-propanol ethanoic
M.W.M.W. 5858 5858 5858 5858 6060 6060
B.P B.P (deg.C)(deg.C)
00 3535 4949 5656 9797 118118
SolubilitySolubilityg/100g g/100g HH22OO
Insol.Insol. 88 1616 FullyFullymisciblemiscible
Fully Fully misciblemiscible
FullyFullymisciblemiscible
EstersEsters
Esters are derivatives of Carboxylic acidsEsters are derivatives of Carboxylic acids– Combination of an Alcohol and an AcidCombination of an Alcohol and an Acid– The The alcohol alcohol provides the alkyl portion of the ester nameprovides the alkyl portion of the ester name– Esters are polar but can not form hydrogen bonds with Esters are polar but can not form hydrogen bonds with
one anotherone another– BP’s of esters are lower than alcohols or acids with BP’s of esters are lower than alcohols or acids with
similar masssimilar mass
Physical propertiesPhysical properties
Butanal Butanone Methyl ethanoate
1-butanol PropanoicAcid
M.W.M.W. 7272 7272 7474 7474 7474
B.P (deg.C)B.P (deg.C) 7676 8080 57.557.5 118118 141141
PropertiesPropertiesEsters have Esters have distinctive odorsdistinctive odors (flowers, flavors etc.) (flowers, flavors etc.)- - Function of which alcohol is combined with which acidFunction of which alcohol is combined with which acid
AlcoholAlcohol AcidAcid EsterEster FragranceFragrance
EthanolEthanol Butanoic acidButanoic acid Ethyl butanoateEthyl butanoate PineapplePineapple
PentanolPentanol Ethanoic acidEthanoic acid Pentyl ethanoatePentyl ethanoate BananaBanana
OctanolOctanol Ethanoic acidEthanoic acid Octyl ethanoateOctyl ethanoate OrangeOrange
MethanolMethanol Salicylic acidSalicylic acid Methyl salicylateMethyl salicylate wintergreenwintergreen
MethanolMethanol Butanoic acidButanoic acid Methyl butanoateMethyl butanoate appleapple
Naming EstersNaming Esters
Esters are not a terminal group but they are Esters are not a terminal group but they are unique because of the carboxyl group therefore unique because of the carboxyl group therefore the carbonyl carbon is considered to be C #1the carbonyl carbon is considered to be C #1Name the group attached to the hydroxyl oxygen Name the group attached to the hydroxyl oxygen first (the alkyl group)first (the alkyl group)Next name the carboxylate carbon chain, Next name the carboxylate carbon chain, dropping the –e and adding –oatedropping the –e and adding –oateWritten condensed format is RCOOR’Written condensed format is RCOOR’
O CH3-C-O-CH2-CH2-CH-CH3 CH3
3-methylbutyl ethanoate
Ethyl butanoate
Name this compound:
Name this compound:
2-methylbutyl ethanoate
(Not IUPAC)
What alcohols and acids produce the above esters?
(Not IUPAC)
AmideAmide
Like esters the amide functional group is a Like esters the amide functional group is a derivative of carboxylic acidsderivative of carboxylic acids– OH replaced by the amine groupOH replaced by the amine group
The amide group is a terminal groupThe amide group is a terminal groupImportant biological moleculesImportant biological molecules– Links amino acids together to form proteinsLinks amino acids together to form proteins
Amide Physical PropertiesAmide Physical Properties
-Amides have very high BP’s due to strong intermolecular hydrogen bonding
- higher than similar esters and acids- H-bonding can occur between N, H and O
CH3 – C=O NH2
CHCH33COOCHCOOCH33 CHCH33COOHCOOH CH3COONHCH3COONH22
B.P. (deg. C)B.P. (deg. C) 57.557.5 118118 221221
AmideAmide
Take the name of the alkane with the same number of Take the name of the alkane with the same number of carbon atomscarbon atomsDrop the –e from the alkane name and add –amideDrop the –e from the alkane name and add –amideAmide carbon is carbon #1 when naming side chainesAmide carbon is carbon #1 when naming side chaines
Ethanamide
Name this compound:
C-C-C=O C NH2
2-methylpropanamide
AminesAmines
Nitrogen is the functional part of an amineNitrogen is the functional part of an amineNitrogen can form three bonds (just like NHNitrogen can form three bonds (just like NH33))– One must be to the carbon chainOne must be to the carbon chain– The other two bonds can be to Carbon and/or HThe other two bonds can be to Carbon and/or H22
C-C-NH2 or
PrimaryAmine
C-C-N-H or CSecondaryAmine
C-C-N-C CTertiaryAmine
Physical properties of AminesPhysical properties of Amines
Like ammonia, amines are polar compounds
H:N-H H
H can also be CarbonBased groups
And like ammonia, amines are Bronsted-LoweryBases
- both are Proton acceptorsH+
Physical properties of AminesPhysical properties of Amines
H:N-H H
- Since amines can act as proton acceptors reaction With a proton donor like HCl will lead to a salt, i.e. an ionic compound
HCl + H:N-H H
Cl- H +
Physical Properties of AminesPhysical Properties of Amines
Amines can hydrogen bond like alcohols or Carboxylic acids
- Contains N and H- H-bonding raises the B.P. but it is not
as high as the alcohols or acids
HC-C-N H
HN-C-CH
Ethanoic Ethanoic acidacid
EthanolEthanol Ethyl Ethyl amineamine
B.P. (deg B.P. (deg C)C)
118118 7878 1717
Tertiary amines have higher BP’s than secondary and secondary is higher than primary
Physical properties of AminesPhysical properties of Amines-Amines can H-bond with water
-Leads to high water solubility up to about 6CMethylAmine
EthylAmine
PropylAmine
ButylAmine
Sol(g/100g H20)
v. Sol Totallymiscible
TotallyMiscible
v. sol
-Amines have very strong odors- Methyl and ethyl amine smells like ammonia-Higher MW amines often have a fishy smell
-Aromatic amines are generally toxic-Readily absorbed through skin often with fatal results
AminesAmines
Need #’s to designate the location of the amineNeed #’s to designate the location of the amineName your carbon chain as an alkane, drop the –Name your carbon chain as an alkane, drop the –e and add –aminee and add –amineIf there are 2 amines indicate their location and If there are 2 amines indicate their location and add –diamine to the alkane nameadd –diamine to the alkane name
2-butanamine
Name this compound:
C-C-C-C-C-CN N
1,3-hexadiamine
Amino AcidsAmino Acids
If you have a “N” and a COOH it is an amino acidIf you have a “N” and a COOH it is an amino acid
Related to amines are the Amino Acids
GLYCINE
Since the amino group is a proton acceptor and theCarboxylic acid is a proton donor amino acids areActually NH3
+ and COO-.