Carboxylic AcidsUnit 6

General Formula

RCOOH and ArCOOH

Functional Group =

O

C -OH

Common Names…1C – Formic Acid (Methanoic Acid)

From Formaldehyde (methanal)

2C – Acetic Acid (Ethanoic Acid)From Acetaldehyde (ethanal)

3C – Propanoic Acid (Propanoic Acid)From Propanaldehyde (propanal)

4C – Butyric Acid (Butanoic Acid)

From Butyraldehyde (butanal)

Uses – Just FUN Facts – Not Tested!

Formic Acid – First Isolated from AntsUsed in dyeing and finishing textiles and many

other uses!

Acetic Acid – Naturally produced by usAka vinegar – many uses

Propanoic Acid – in Greek, means “first fat”Grain Preservative and antifungal

Butyric Acid – Naturally occurring – Greek for butterSmells like vomit

Preparation of Carboxylic Acids – You already know this

Oxidation of aldehydes

O KMnO4 O

R-C-H R-C-OH

RCHO KMnO4 RCO2H

Example

Form Pentanoic Acid (S,C,N)

Reactions of Carboxylic Acids

1.Halogenation: RCO2H + X2 RXCO2H + HX

ArCO2H + X2 FeX3 ArXCO2H + HX

Form 2,3,4 – trichloroheptanoic acid (str,cond)

O Cl Cl Cl O

C-C-C-C-C-C-C-OH + 3Cl2 C-C-C-C-C-C-C-OH

+3HClCH3(CH2)5CO2H + 3Cl2CH3(CH2)2(CHCl)3CO2H + 3HCl

Examples of Halogenation

Form paraiodobenzenoic acid (str)

+ I2 FeI3 + HI

I

Reactions of Carboxylic Acids

2. Nitration of benzanoic acid

ArCO2 + HNO3 H2SO4 ArNO2CO2H + H2O

Form metanitrobenzanoic acid (str,cond)

Reactions of Carboxylic Acids

Acid Salt formation can be done 2 ways…

1.RCO2H + M° ArNO2CO2H + H2O

Metal can be same 7 as before

Examples

React ethanoic acid with sodium (str,name,cond)

O O

2C-C-OH + 2Na2(C-C-O-)Na+ + H2

2CH3CO2H+2Na2(CH3CO2-)Na+ +H2

Sodium ethanoate

Examples

To name acid salts:

1.Name Metal ion

2.Drop –ic acid and add –ate

Ex: React butyric acid with magnesium (str,cond,name)

Acid Salt Formation – 2nd Way!

2. Carboxylic acid + metal hydroxide acid salt + water

RCO2H + MOH(RCO2-)M+ + H2O

React butanoic acid with magnesium hydroxide (str,cond, name prod)

Example

React propanoic acid with aluminum hydroxide (str, cond, name product)

Other Reactions of Carboxylic Acids

Convert carboxylic acids to “functional derivatives”

Functional Derivative – an organic compound containing the acyl group O

Acyl group = RCO = R-C-

Conversion to acid chlorides

O O

4. R-C-OH + SOCl2 R-C-Cl + SO2 + HCl

RCO2H + SOCl2 RCOCl + SO2 + HCl

Carboxylic acid + thionyl chloride acid chloride + sulfur dioxide + hydrogen chloride

Examples

React hexanoixc acid with thionyl chloride (s,c,np) O O

C-C-C-C-C-C-OH + SOCl2C-C-C-C-C-C-Cl + SO2+HCl

CH3(CH2)4CO2H + SOCl2 CH3(CH2)4COCl + SO2+HCl

To name acid chlorides:

1.Drop –ic acid

2.Add –yl chloride

Conversion to amides

5. Converting carbox. Acids to amides

O H O H

R-C-OH + H-N-H R-C-N-H + H2O

Carboxylic acid + ammonia amide + water

Example

Rct pentanoic acid w/ammonia (s,c,np) O H O H

C-C-C-C-C-OH + H-N-H C-C-C-C-C-N-H + H2O

CH3(CH2)3COH + NH3 CH3(CH2)3CONH2 + H2O

To Name Amides: pentanimide

1. Drop –e from corresponding alkane

2. Add –amide

Conversions to Esters

Fischer Esterification

O OR-C-OH + R’-OH H2SO4 R-C-O-R’ + H2O

RCO2H + R’OH H2SO4 RCO2R’ + H2O

Carboxylic acid + alcoholester + water

Example

React propanoic acid with butanol (s,c,np) O O

C-C-C-OH + C-C-C-C-OH H2SO4 C-C-C-O-C-C-C-C + H2O

CH3CH2CO2H + CH3(CH2)2CH2OH H2SO4 CH3CH2CO2(CH2)3CH3+ H2O

butyl propanoate

Naming Esters

To Name Esters:

1.Name R’ side as chain (from alcohol)

2.Drop – ic acid add – ate

EX: form Propyl Butanoate (s,c,nr)