Carboxylic Acids

Carboxylic AcidsUnit 6

General Formula

RCOOH and ArCOOHFunctional Group =OC -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 Ants

Used 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-OHRCHO KMnO4 RCO2H

ExampleForm Pentanoic Acid (S,C,N)

Reactions of Carboxylic Acids

1.Halogenation: RCO2H + X2 RXCO2H + HXArCO2H + X2 FeX3 ArXCO2H + HXForm 2,3,4 – trichloroheptanoic acid (str,cond) O Cl Cl Cl OC-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 acidArCO2 + HNO3 H2SO4 ArNO2CO2H + H2OForm metanitrobenzanoic acid

(str,cond)

Reactions of Carboxylic Acids

Acid Salt formation can be done 2 ways…1.RCO2H + M° ArNO2CO2H + H2OMetal can be same 7 as before

ExamplesReact 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 ion2.Drop –ic acid and add –ateEx: 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 OAcyl group = RCO = R-C-

Conversion to acid chlorides

O O4. R-C-OH + SOCl2 R-C-Cl + SO2 + HClRCO2H + SOCl2 RCOCl + SO2 + HClCarboxylic acid + thionyl chloride acid

chloride + sulfur dioxide + hydrogen chloride

Examples

React hexanoixc acid with thionyl chloride (s,c,np) O OC-C-C-C-C-C-OH + SOCl2C-C-C-C-C-C-Cl + SO2+HClCH3(CH2)4CO2H + SOCl2 CH3(CH2)4COCl + SO2+HClTo name acid chlorides:1.Drop –ic acid2.Add –yl chloride

Conversion to amides

5. Converting carbox. Acids to amides O H O HR-C-OH + H-N-H R-C-N-H + H2OCarboxylic acid + ammonia amide + water

Example

Rct pentanoic acid w/ammonia (s,c,np) O H O HC-C-C-C-C-OH + H-N-H C-C-C-C-C-N-H + H2OCH3(CH2)3COH + NH3 CH3(CH2)3CONH2 + H2OTo Name Amides: pentanimide1. Drop –e from corresponding alkane2. Add –amide

Conversions to Esters

Fischer Esterification O OR-C-OH + R’-OH H2SO4 R-C-O-R’ + H2ORCO2H + R’OH H2SO4 RCO2R’ + H2OCarboxylic acid + alcoholester + water

Example

React propanoic acid with butanol (s,c,np) O OC-C-C-OH + C-C-C-C-OH H2SO4 C-C-C-O-C-C-C-C + H2OCH3CH2CO2H + 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 – ateEX: form Propyl Butanoate (s,c,nr)