Carboxylic Acids Unit 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 Ants  Used in dyeing and finishing textiles and many other uses!  Acetic Acid – Naturally produced by us  Aka vinegar – many uses  Propanoic Acid – in Greek, means “first fat”  Grain Preservative and antifungal  Butyric Acid – Naturally occurring – Greek for butter  Smells like vomit 

Preparation of Carboxylic Acids – You already know this  Oxidation of aldehydes O KMnO4 O R-C-H R-C-OH RCHO KMnO4 RCO 2 H

Example  Form Pentanoic Acid (S,C,N)

Reactions of Carboxylic Acids 1.Halogenation: RCO 2 H + X 2  RXCO 2 H + HX ArCO 2 H + X 2 FeX3 ArXCO 2 H + HX Form 2,3,4 – trichloroheptanoic acid (str,cond) O Cl Cl Cl O C-C-C-C-C-C-C-OH + 3Cl 2  C-C-C-C-C-C-C-OH +3HCl CH 3 (CH 2 ) 5 CO 2 H + 3Cl 2  CH 3 (CH 2 ) 2 (CHCl) 3 CO 2 H + 3HCl

Examples of Halogenation Form paraiodobenzenoic acid (str) + I 2 FeI3 + HI I

Reactions of Carboxylic Acids 2. Nitration of benzanoic acid ArCO 2 + HNO 3 H2SO4 ArNO 2 CO 2 H + H 2 O Form metanitrobenzanoic acid (str,cond)

Reactions of Carboxylic Acids Acid Salt formation can be done 2 ways… 1.RCO 2 H + M°  ArNO 2 CO 2 H + H 2 O Metal can be same 7 as before

Examples React ethanoic acid with sodium (str,name,cond) O O 2C-C-OH + 2Na  2(C-C-O - )Na + + H 2 2CH 3 CO 2 H+2Na  2(CH 3 CO 2 - )Na + +H 2 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 – 2 nd Way! 2. Carboxylic acid + metal hydroxide  acid salt + water RCO 2 H + MOH  (RCO 2 - )M + + H 2 O 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 + SOCl 2  R-C-Cl + SO 2 + HCl RCO 2 H + SOCl 2  RCOCl + SO 2 + 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 + SOCl 2  C-C-C-C-C-C-Cl + SO 2 +HCl CH 3 (CH 2 ) 4 CO 2 H + SOCl 2  CH 3 (CH 2 ) 4 COCl + SO 2 +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 + H 2 O 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 + H 2 O CH 3 (CH 2 ) 3 COH + NH 3  CH 3 (CH 2 ) 3 CONH 2 + H 2 O To Name Amides: pentanimide 1.Drop –e from corresponding alkane 2.Add –amide

Conversions to Esters Fischer Esterification O O R-C-OH + R’-OH H2SO4 R-C-O-R’ + H 2 O RCO 2 H + R’OH H2SO4 RCO 2 R’ + H 2 O Carboxylic acid + alcohol  ester + 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 + H 2 O CH 3 CH 2 CO 2 H + CH 3 (CH 2 ) 2 CH 2 OH H2SO4 CH 3 CH 2 CO 2 (CH 2 ) 3 CH 3 + H 2 O 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)