families containing the carbonyl group -...
TRANSCRIPT
Families Containing the Carbonyl Group
O
CZY
O
CCO
Family Y Z
aldehyde H or C H
ketone C C
carboxylic acid H or C -O-H
ester H or C -O-C
acid halide H or C -F,-Cl,-Br,-I
acid anhydride H or C
amide H or C -N
Carboxylic Acid Functional Group
Carbonyl + hydroxyl = “Carboxyl”
General Formula: R-COOH R C O O H =
The carbonyl carbon and oxygen are sp2 hybridized.The hydroxyl oxygen is sp3 hybridized.
Sources of Carboxylic Acids
Oxidation of Primary Alcohols and Aldehydes
R C O HH
HR C O H
OR C
OH
primary alcohol aldehyde carboxylic acid
[O][O]
Substituted Benzenes as a Source of Substituted Benzoic Acids
CO O
H
Benzoic Acid
MnO4-
Cr2O72-
Nomenclature of Carboxylic Acids
Names of the Simplest Carboxylic Acids
Compound Systematic Name Trivial (Common) Name
HCOOH Methanoic Acid Formic Acid
CH3COOH Ethanoic Acid Acetic Acid
CH3CH2COOH Propanoic Acid Propionic Acid
CH3CH2CH2COOH Butanoic Acid Butyric Acid
CH3CH2CH2CH2COOH Pentanoic Acid Valeric Acid
CH3CH2CH2CH2CH2COOH Hexanoic Acid Caproic Acid
CH3CH2CH2CH2CH2CH2COOH Heptanoic Acid Enanthic Acid
Systematic Nomeclature
CH3CH2CH2CHCH2COOH
CH33-methyl hexanoic acid
β-methyl caproic acid
CH2CHCOOH
NH22-amino-3-phenylpropanoic acid
phenylalanine
Oenanthe crocata
Water Dropwort
Physical Properties of Carboxylic Acids
Boiling Points - Higher than alcohols of similar
molecular weight
Carboxylic acids “self associate” through hydrogen bonds.
R CO
O HRC
O
OH
Water Solubility- More water soluble than ethers,
aldehydes, ketones and alcohols of similar molecular weight
Carboxylic acids have three opportunities for hydrogen
bonding.
R CO
O H
HO
H
Acidity of Carboxylic Acids
CCH2
H3C
O
OH + H
OH
HO
H
H +
CCH2
H3C
O
O_
propanoic acid
water
propanoate ion
hydronium ion
Acidity of Carboxylic AcidsCarboxylic acids are generally stronger acids than
phenols but weaker than mineral acids.
Chemical and Physical Properties of Carboxylic Acids
Carboxylic acids react with bases.
CH3C
O
OH + Na-OH
HO
H
CH3C
O
O_
Na+
acetic acid sodium acetate
Carboxylate salts are ionic and possess much higher boiling and melting points than those of the corresponding carboxylic acids
(Ionic forces are much stronger than secondary forces).
Sodium acetate: MP 324°C, solid at room temperature Acetic acid: MP 17°C, liquid at room temperature
Carboxylic acids that have 6 or more carbons are only slightly soluble or insoluble in water. Carboxylate salts are much more soluble than
their corresponding carboxylic acids because of their ionic nature.
Chemical and Physical Properties of Carboxylic Acids
Carboxylic acids have increased solubilities in neutral or basic environments because the acids are converted into
their carboxylate ions.
H3CCH2
CH2
CH2CH2
CH2CH2
C
O
OH
+ NaOH
H3CCH2
CH2
CH2CH2
CH2CH2
C
O
O_
+ H2O
Na+
H3CCH2
CH2CH2
CH2CH2
CH2C
O
OH H3CCH2
CH2CH2
CH2CH2
CH2C
O
O_
Soaps
Soaps are produced by a process called “saponification” (technically, “basic hydrolysis of fats”)
H2C
C
H2C
OH
O
O
C
C
O
O
C
O
C
C
O
O
C
O
-O
-O
-O
Na+
Na+
Na+
Hot aq NaOH
H2C
C
H2C
OHH
OH
OH
C
O
CH2CH2
CH2CH2
CH2CH2
CH2CH2
CH2CH2
CH2CH2
CH2CH2
CH3-ONa+
Soaps
Soaps are the sodium or potassium salts of long-chain fatty acids.
hydrophilic region
hydrophobic region
How Do Soaps Work?
micelle micelle+grease
Synthetic Detergents
S
O
O-ONa+
O
S
O
-ONa+
O
S
O
-ONa+
O
Sodium Dodecyl Sulfate (SDS)
Sodium Alkyl Benzene Sulfonate (ABS)
Sodium Dodecyl Benzene Sulfonate (LAS)
N+CH2
N+
Synthetic Detergents
Na+
O
O
O
O
OS
O
O
-O
O
O
O
HO
Carboxylic Acid Esters
R C
O
OH R’HO R C
O
R’O+ + H2OH+
Synthesized from a carboxylic acid and an alcohol:
carboxylic acid alcoholor
phenol
ester
condensation
Nomenclature base on parent alcohol and carboxylic acid:
CH3 C
O
OH CH3HO CH3 C
O
CH3OCH2CH2 + + H2O
methanolpropanoic acid methyl propanoate
hydrolysis
+ CH3CH2HOC
O
CH3CH2CHCH2CH3
OH
+
+
Carboxylic Acid EstersAdditional Nomenclature examples:
CH3 C
O CH3
CH2O
CH3
CH
C
O
CH3CH2OCH3CH2CHCH2CH3
C
OCH3
CH O CH3CH2CH2CH3
CH3 C
O
OH
CH3
CH2HO
CH3
CH
CH3
CH OH
CH3
C
O
CH3CH2CH2HO
acetic acid isobutyl alcohol isobutyl acetate
3-methyl pentanoic acid
ethyl alcohol ethyl 3-methyl pentanoate
isopropyl alcohol
butanoic acid isopropyl butanoate
C
O
OHC
O
HO CH3HO + excess
terephthalic acidH+
methyl alcohol
C
O
OCH3
dimethyl terephthalate
C
O
CH3O + 2 H2O
A Diester Synthesis
C
O
OHC
O
HO CH2CH2HO + excess
terephthalic acidH+
ethylene glycolethanediol
OH
C
O
OC
O
CH2CH2 O
n
A polyester
A Polyester Synthesis
Physical Properties of Esters
Ester molecules cannot hydrogen bond to each other.
Therefore, esters have much lower boiling and melting points than those of carboxylic acids.
Propanoic acid, bp 141°C Methyl acetate , bp 57°C
Esters are less soluble in water than are carboxylic acids because esters cannot form as many hydrogen bonds to
water molecules as can carboxylic acids.
CH3 C
O
OHCH2 CH3 C
O
CH3O
Physical Properties of Esters
The secondary forces in esters are weaker than those in aldehydes and ketones, and thus esters have lower melting
and boiling points.
Methyl acetate, bp 57°C Butanal, bp 76°C
Esters have about the same water solubilities as aldehydes and ketones because all three hydrogen bond to water equally well.
CH3 C
O
CH3O C
O
CH3CH2CH2 H
Esters Have Characteristic Odors
C
O
O C
O
OCH3C
O
OCH2CH3
Pear ApplePineapple
C
O
OHC
O
O
Raspberry Rum
C
O
O
Banana
C
O
O
C
O
OOrangePeach
Hydrolysis Reaction of Esters
Hydrolysis of Esters Under Acidic Conditions
R C
O
OH R’HOR C
O
R’O ++ H2O H+
ester carboxylic acid alcoholor
phenol
Notice that this is the reverse of the condensation reaction used to synthesize an ester !!
Hydrolysis Reaction of Esters
Hydrolysis of Esters Under Basic Conditions
R C
O
O-Na+ R’HOR C
O
R’O ++ NaOHH2O
esteralcohol
or phenol
carboxylate salt
H2O
R C
O
OH + NaOH[ ] The carboxylic acid is an intermediate but reacts with the
basic NaOH !!
Carboxylic Acids and Their Derivatives
Carboxylic Acid Anhydrides and Halides
R C
O
OH RC
O
HO R C
O
ORC
O
+ H2O+H+
Synthesis from a carboxylic acid:
R C
O
OH Cl”“H+ R C
O
Cl + H2O
Very unstable; very “reactive”Low boiling points and melting points
“Lachrymators”Generate the starting acids upon hydrolysis
carboxylic acid carboxylic acid carboxylic acidanhydride
carboxylic acid carboxylic acid chloride
Carboxylic Acid Anhydrides and Halides
Used to Synthesize Esters
CH3 C
O
OCH3C
O
+C
O
OH
O CH3C
O
C
O
OH
OH
ethyl alcohol acetyl chloride ethyl acetate
salicylic acid acetic anhydridesalicyl acetate
acetyl salicylic acidaspirin
CH3C
O
Cl
CH3CH2OH CH3C
O
CH3CH2O+
Cl H+
C
O
CH3HO+
CH3C
O
Cl
CH3CH2OH CH3C
O
CH3CH2O+
CH3 C
O
OCH3C
O
+C
O
OH
O CH3C
O
C
O
OH
OH
These highly reactive compounds are use to transfer the acetyl group to an alcohol group.
CH3C
O
Carboxylic Acid Anhydrides and Halides
Summary of reactivity of carboxylic acid related functional groups:
Acid Anhydrides
Acid HalidesCarboxylic Acid
EstersCarboxylic Acid
Amides Carboxylic Acids
Similar Derivatives of Inorganic Acids
CH3 C
O
OH HO S
O
OH
O
HO P
O
OH
OH
S
O
OCH3CH3O
O
P
O
OCH3CH3O
OCH3
C
O
OCH3CH3
C
O
OCH3C
O
CH3 OHS
O
O S
O
HO
O O
P
O
O OHP
O
HO
OH OH
acetic acid sulfuric acid phosphoric acid
methyl acetate dimethyl sulfate trimethyl phosphate
acetic anhydride pyrosulfuric acid pyrophosphoric acid
Similar Derivatives of Inorganic Acids
C
O
OCH3C
O
CH3 OHS
O
O S
O
HO
O O
P
O
O OHP
O
HO
OH OH
acetic anhydride pyrosulfuric acid pyrophosphoric acid
ANHYDRIDE LINKAGES
“REACTIVE LINKAGES”
“HIGH ENERGY BONDS”
What is ATP??