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Functional Groups:
- Carboxylic Acids - Esters - Amides
- Aldehydes- Ketones- Amines
Mr. Shields Regents Chemistry U17 L02
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Organic AcidsOrganic Acids
Condensed form is written –COOHCondensed form is written –COOH– A A carbonyl groupcarbonyl group and a and a hydroxyl grouphydroxyl group bonded to same C bonded to same C– Known as aKnown as a carboxyl groupcarboxyl group– An organic acidAn organic acid
The Carboxyl group is always a terminal functional The Carboxyl group is always a terminal functional groupgroup
33
Carboxylic acids ionize in water to form a proton andA carboxylate anion
A Weak Acid
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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 no need to give it a number. It’s always on C #1C #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
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Naming Organic AcidsNaming Organic Acids
Name this compound:
hexanoic acid
C-C-C-C-C-COOH
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- Sharp or noxious smells
- polar molecule that can form 2 hydrogen bonds with themselves or 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
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EstersEsters
Esters are derivatives of Carboxylic acidsEsters are derivatives of Carboxylic acids
– Combination of an Acid and an AlcoholCombination of an Acid and an Alcohol
– The The alcohol portionalcohol portion provides the “Alkyl” part of the ester provides the “Alkyl” part of the ester namename
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Naming EstersNaming Esters
Esters are not a terminal group but the carbonyl carbon Esters are not a terminal group but the carbonyl carbon is considered to be C #1is considered to be C #1
Name the group attached to the hydroxyl oxygen first Name the group attached to the hydroxyl oxygen first (the alkyl group)(the alkyl group)
Next name the carboxylate Next name the carboxylate carbon chaincarbon chain, dropping the –, dropping the –e and adding –oatee and adding –oate
Written condensed format is RCOOR’Written condensed format is RCOOR’
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PropertiesProperties
Esters have Esters have distinctive odorsdistinctive odors (flowers, flavors etc.) (flowers, flavors etc.)- It’s a f- It’s a function of which alcohol is combined withunction of which alcohol is combined with
which acidwhich acid
Alcohol Acid Ester Fragrance
EthanolEthanol Butanoic acidButanoic acid Ethyl butanoateEthyl butanoate Pineapple
PentanolPentanol Ethanoic acidEthanoic acid Pentyl ethanoatePentyl ethanoate Banana
OctanolOctanol Ethanoic acidEthanoic acid Octyl ethanoateOctyl ethanoate Orange
MethanolMethanol Salicylic acidSalicylic acid Methyl salicylateMethyl salicylate wintergreen
MethanolMethanol Butanoic acidButanoic acid Methyl butanoateMethyl butanoate apple
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O CH3-C-O-CH2-CH2-CH2-CH3
butyl ethanoate
Ethyl butanoate
Name this compound:
Name this compound:
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AmideAmide
Like esters the amide functional group is a Like esters the amide functional group is a derivative of carboxylic acidsderivative of carboxylic acids– The -OH is replaced by the amine groupThe -OH is replaced by the amine group
The amide group is a terminal groupThe amide group is a terminal group
Important biological moleculesImportant biological molecules– Links amino acids together to form proteinsLinks amino acids together to form proteins
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Amide Physical PropertiesAmide Physical Properties
-Amides have very high BP’s due to strong H-bonding-Intermolecular hydrogen bonding possible
- H-bonding can occur between N, H and O
CH3 – C=O NH2
CHCH33COOCHCOOCH33 CHCH33COOHCOOH CH3CONHCH3CONH22
B.P. (deg. C)B.P. (deg. C) 57.557.5 118118 221221
- BP’s are higher than similar esters and acids
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AmideAmide
Take the name of the alkane with the same Take the name of the alkane with the same number of carbon atomsnumber of carbon atoms
Drop the –e from the alkane name and add –amideDrop the –e from the alkane name and add –amide
Ethanamide
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AldehydesAldehydes
This group is always on a terminal C – so no need to This group is always on a terminal C – so no need to specify location by numberspecify location by number
Condensed 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 formula
Aldehydes have characteristic scents and tastesAldehydes have characteristic scents and tastes– Cinnamon, bannana, apple, raspberry flavors are Cinnamon, bannana, apple, raspberry flavors are
examplesexamples
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AldehydesAldehydes
To name aldehydes drop the –e To name aldehydes drop the –e from the end of the alkane and from the end of the alkane and add –al; C=O is C #1add –al; C=O is C #1
Name these two compounds:
Methanal(formaldehyde)
Butanal
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KetonesKetones
Like the aldehydes the Functional group is the Like the aldehydes the Functional group is the carbonyl group C=Ocarbonyl group C=O
Contains 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
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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-C o3-hexanone
2-pentanone
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AminesAmines
Nitrogen is the functional part of an amineNitrogen is the functional part of an amine
Nitrogen can form three covalent bonds (just like NHNitrogen can form three covalent bonds (just like NH33))– One must be to a carbon chainOne must be to a 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 C-C-N-H or C
C-C-N-C C
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Physical properties of AminesPhysical properties of Amines
Like ammonia, amines are polar compounds
And like ammonia, amines are Bronsted-Lowery Bases
- i.e they’re Proton acceptors H:N-R H
H+
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Physical properties of AminesPhysical properties of Amines
-Since amines can act as proton acceptors the reaction with a proton donor like HCl leads to an Ionic Compound
H:N-R H
HCl + H:N-R H
Cl- H +
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Physical properties of AminesPhysical properties of Amines-Amines can H-bond with water
-Leads to high water solubility up to about 6C
Methyl
Amine
Ethyl
Amine
Propyl
Amine
Butyl
Amine
Sol
(g/100g H20)
v. Sol Totally
miscible
Totally
Miscible
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
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Naming AminesNaming Amines
Need #’s to designate the location of the amineNeed #’s to designate the location of the amine
Name your carbon chain as an alkane, drop the –Name your carbon chain as an alkane, drop the –e and add –aminee and add –amine
2-butanamine
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Some nasty DIAMINES …Yuk!
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Amino AcidsAmino Acids
If you have an “-NHIf you have an “-NH22” and a COOH in one molecule it is an amino ” and a COOH in one molecule it is an amino acidacid
Related to both amines and acids are the Amino Acids
GLYCINE(Gly or G)
Since the amino group is a proton acceptor and theCarboxylic acid is a proton donor, amino acids areActually NH3
+ and COO-.
Smallest of the20 amino acidsCommonly Found in ProteinsAminoethonaoic acid
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Another Amino AcidAnother Amino Acid
Alanine (Ala; A)Alanine (Ala; A)
O O
HH33C-CH-C-OHC-CH-C-OH
NH2
2-aminopropanoic acid