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Carboxylic acids: R-COOH, R-CO 2 H, Common names : HCO 2 H formic acid L. formica ant CH 3 CO 2 H acetic acid L. acetum vinegar CH 3 CH 2 CO 2 H propionic acid G. “first salt” CH 3 CH 2 CH 2 CO 2 H butyric acid L. butyrum butter R C OH O
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Page 1: Lecture# COOH

Carboxylic acids:

R-COOH, R-CO2H,

Common names:

HCO2H formic acid L. formica ant

CH3CO2H acetic acid L. acetum vinegar

CH3CH2CO2H propionic acid G. “first salt”

CH3CH2CH2CO2H butyric acid L. butyrum butter

CH3CH2CH2CH2CO2H valeric acid L. valerans

R COH

O

Page 2: Lecture# COOH

Carboxylic acids, common names:

CH3(CH2)4CO2H caproic acid L. caper goat

CH3(CH2)5CO2H ---

CH3(CH2)6CO2H caprylic acid

CH3(CH2)7CO2H ---

CH3(CH2)8CO2H capric acid

CH3(CH2)9CO2H ---

CH3(CH2)10CO2H lauric acid oil of lauryl

Page 3: Lecture# COOH

5 4 3 2 1C—C—C—C—C=Oδ γ β α used in common names

CH3CH2CH2CHCOOH

BrCH3CHCH2COOH

CH3

bromovaleric acid -methylbutyric acid

isovaleric acid

Page 4: Lecture# COOH

COOH

COOH COOH COOH

CH3

CH3CH3

benzoic acid

o-toluic acid m-toluic acid p-toluic acid

special names

Page 5: Lecture# COOH

IUPAC nomenclature for carboxylic acids:

parent chain = longest, continuous carbon chain that contains the carboxyl group alkane, drop –e, add –oic acid

HCOOH methanoic acid

CH3CO2H ethanoic acid

CH3CH2CO2H propanoic acid

CH3

CH3CHCOOH 2-methylpropanoic acid

BrCH3CH2CHCO2H 2-bromobutanoic acid

Page 6: Lecture# COOH

Dicarboxylic acids:

HOOC-COOH oxalic acid

HO2C-CH2-CO2H malonic acid

HO2C-CH2CH2-CO2H succinic acid

HO2C-CH2CH2CH2-CO2H glutaric acid

HOOC-(CH2)4-COOH adipic acid

HOOC-(CH2)5-COOH pimelic acid

Page 7: Lecture# COOH

CO2H

CO2H

CO2H

CO2H

CO2H

CO2H

CCOOHH

CCOOHH

CCOOHH

CHHOOC

phthalic acid isophthalic acidterephthalic acid

maleic acid fumaric acid

Page 8: Lecture# COOH

salts of carboxylic acids:

name of cation + name of acid: drop –ic acid, add –ate

CH3CO2Na sodium acetate or sodium ethanoate

CH3CH2CH2CO2NH4 ammonium butyrate

ammonium butanoate

(CH3CH2COO)2Mg magnesium propionate

magnesium propanoate

Page 9: Lecture# COOH

HOC

OH

O

NaOC

ONa

O

HOC

ONa

O

carbonic acid sodium bicarbonatesodium hydrogen carbonate

sodium carbonate

NaHCO3

Na2CO3

Page 10: Lecture# COOH

Carboxylic acids, syntheses:

1. Oxidation of primary alcohols

RCH2OH + K2Cr2O7 RCOOH

2. Oxidation of arenes

ArR + KMnO4, heat ArCOOH

3. Carbonation of Grignard reagents

RMgX + CO2 RCO2MgX + H+ RCOOH

4. Hydrolysis of nitriles

RCN + H2O, H+, heat RCOOH

Page 11: Lecture# COOH

1. oxidation of 1o alcohols:

CH3CH2CH2CH2-OH + CrO3 CH3CH2CH2CO2H n-butyl alcohol butyric acid 1-butanol butanoic acid

CH3 CH3

CH3CHCH2-OH + KMnO4 CH3CHCOOH isobutyl alcohol isobutyric acid2-methyl-1-propanol` 2-methylpropanoic acid

Page 12: Lecture# COOH

2. oxidation of arenes:

CH3

CH3

H3C

CH2CH3

KMnO4, heat

KMnO4, heat

KMnO4, heat

COOH

COOH

HOOC

COOH

toluene benzoic acid

p-xylene terephthalic acid

ethylbenzene benzoic acid

+ CO2

note: aromatic acids only!

Page 13: Lecture# COOH

3. Carbonation of Grignard reagent:

R-X RMgX RCO2MgX RCOOH

Increases the carbon chain by one carbon.

Mg CO2 H+

CH3CH2CH2-Br CH3CH2CH2MgBr CH3CH2CH2COOHn-propyl bromide butyric acid

Mg CO2 H+

C

O

O

RMgX + R CO

O-+ +MgX

H+

R CO

OH

Page 14: Lecture# COOH

CH3

Br

Mg

CH3

MgBr

CO2 H+

CH3

COOH

p-toluic acid

CH3

Br2, hvCH2Br

MgCH2MgBr

CO2

H+

CH2 COOH

phenylacetic acid

Page 15: Lecture# COOH

4. Hydrolysis of a nitrile:

H2O, H+

R-CN R-CO2H heat

H2O, OH-

R-CN R-CO2- + H+ R-CO2H

heat

R-X + NaCN R-CN + H+, H2O, heat RCOOH1o alkyl halide

Adds one more carbon to the chain.R-X must be 1o or CH3!

Page 16: Lecture# COOH

CH3

Br2, hvCH2Br

NaCN

CH2 CN

H2O, H+, heat

CH2 COOH

CH3CH2CH2CH2CH2CH2-BrKCN

CH3CH2CH2CH2CH2CH2-CN

H2O, H+, heat

CH3CH2CH2CH2CH2CH2-COOH

1-bromohexane

heptanoic acid

toluene

phenylacetic acid

Page 17: Lecture# COOH

CO2H

CH2OH

CH3

Br

C N

MgBr

KMnO4, heat

KMnO4

MgCO2; then H+

H2O, H+, heat

Page 18: Lecture# COOH

carboxylic acids, reactions:

1. as acids

2. conversion into functional derivatives

a) acid chlorides

b) esters

c) amides

3. reduction

4. alpha-halogenation

5. EAS

Page 19: Lecture# COOH

as acids:

a) with active metals

RCO2H + Na RCO2-Na+ + H2(g)

b) with bases

RCO2H + NaOH RCO2-Na+ + H2O

c) relative acid strength?

CH4 < NH3 < HCCH < ROH < HOH < H2CO3 < RCO2H < HF

Page 20: Lecture# COOH

2. Conversion into functional derivatives:

)a acid chlorides

R COH

O SOCl2

or PCl3orPCl5

R CCl

O

CO2H + SOCl2 COCl

CH3CH2CH2 CO

OH

PCl3CH3CH2CH2 C

O

Cl

Page 21: Lecture# COOH

)b Esters

Direct Esterification H+

RCOOH + R´OH RCO2R´ + H2O

-reversible and often does not favor the ester

-use an excess of the alcohol or acid to shift equilibrium

-or remove the products to shift equilibrium to completion

Indirect” Esterification:

RCOOH + PCl3 RCOCl + R´OH RCO2R´

-convert the acid into the acid chloride first; not reversible

Page 22: Lecture# COOH

C CO

O

CH3

+ H2O

SOCl2

CCH3OH

O

OH+ CH3OH

O

Cl

H+

Page 23: Lecture# COOH

)c amides

“indirect” only!

RCOOH + SOCl2 RCOCl + NH3 RCONH2

amide

Directly reacting ammonia with a carboxylic acid results in an ammonium salt:

RCOOH + NH3 RCOO-NH4+

acid base

OH

O

3-Methylbutanoic acid

PCl3

Cl

O NH3

NH2

O

Page 24: Lecture# COOH

CO

OH

PCl3C

O

ClC

O

NH2

NH3

NH3

amide

CO

O NH4

ammonium salt

Page 25: Lecture# COOH

3. Reduction:

RCO2H + LiAlH4; then H+ RCH2OH

1o alcohol

Carboxylic acids resist catalytic reduction under normal conditions.

RCOOH + H2, Ni NR

CH3CH2CH2CH2CH2CH2CH2COOH

Octanoic acid(Caprylic acid)

LiAlH4 H+

CH3CH2CH2CH2CH2CH2CH2CH2OH

1-Octanol

Page 26: Lecture# COOH

CH2 CO

OH

H2, PtNR

LiAlH4

H+

CH2CH2OH

Page 27: Lecture# COOH

4. Alpha-halogenation: (Hell-Volhard-Zelinsky reaction)

RCH2COOH + X2, P RCHCOOH + HX X α-haloacid X2 = Cl2, Br2

COOH

Br2,PNR (no alpha H)

CH3CH2CH2CH2COOH + Br2,P CH3CH2CH2CHCOOH

Brpentanoic acid2-bromopentanoic acid

Page 28: Lecture# COOH

RCH2COOH + Br2,P RCHCOOH + HBr

Br

NH2OH

RCHCOOH RCHCOOH

RCH=CHCOOHRCH2CHCOOH

Br

aminoacid

NaOH;then H+

NH3

KOH(alc)

then H+

Page 29: Lecture# COOH

5. (-COOH is deactivating and meta- directing)

CO2H

CO2H

NO2

CO2H

SO3H

CO2H

Br

NR

HNO3,H2SO4

H2SO4,SO3

Br2,Fe

CH3Cl,AlCl3

benzoic acid