Oxidation of Primary Alcohols with KMnO 4 with KMnO 4 two -hydrogens + MnO 2 precipitate
Oxidation of Primary Alcohols with K 2 Cr 2 O 7 with K 2 Cr 2 O 7
Oxidation of Side Chains Example KMnO 4
Carbonation of Grignard Reagents ( or Alkyllithium Compounds ) ( R-Li )
Formation of Nitriles and Hydrolysis DMSO H 2 SO 4 H2OH2O heat SN2SN2
or CO 2 CrO 3 H 2 SO 4 KMnO 4 H 2 SO 4 KMnO 4 NaCN acetone DIBAL or Rosenmund KMnO 4 Li or Mg H2OH2O H2OH2O H 2 SO 4 H2OH2O or KMnO 4 SYNTHESIS OF CARBOXYLIC ACIDS ( DUE TO LACK OF SPACE REACTION CONDITIONS ARE ABBREVIATED) KMnO 4 ( benzene = R sidechain = R’ ) This is all stuff you know! SOCl 2 Chap 19
Physical Properties of Carboxylic Acids
Physical Properties of Some Organic Compounds FormulaIUPAC Name Molecular Weight Boiling Point Water Solubility CH 3 (CH 2 ) 2 CO 2 Hbutanoic acid88164 ºCvery soluble CH 3 (CH 2 ) 4 OH1-pentanol88138 ºCslightly soluble CH 3 (CH 2 ) 3 CHOpentanal86103 ºCslightly soluble CH 3 CO 2 C 2 H 5 ethyl ethanoate8877 ºCmoderately soluble
Substituents with Electron-Withdrawing Resonance ( - R ) Effects -R substituents strengthen acids and weaken bases X Y
+R substituents weaken acids and strengthen bases Substituents with Electron-Releasing Resonance ( + R ) Effects hydroxy mercapto methyl amino fluoro bromo alkoxy acyloxy dialkylamino alkyl chloro iodo Y..
Substituents with Electron-Withdrawing ( - I ) Inductive Effects ( - I ) Inductive Effects -I substituents strengthen acids and weaken bases carboxyl alkoxycarbonyl acyl hydroxyl mercapto amino chloro nitro cyano sulfonic acid alkoxy dialkylamino trimethylammonium fluoro bromo iodo X
Substituents with Electron-Releasing Inductive ( + I ) Effects +I substituents weaken acids and strengthen bases methyl alkyl oxide carboxylate R
Benzoic Acid: pK a = 4.19 ortho meta para ortho meta para
Benzoic Acid: pK a =
Benzoic Acid: pK a = 4.19
Acidity of Carboxylic Acids CompoundpK a CompoundpK a HCO 2 H3.75CH 3 CH 2 CH 2 CO 2 H4.82 CH 3 CO 2 H4.74ClCH 2 CH 2 CH 2 CO 2 H4.53 FCH 2 CO 2 H2.65CH 3 CHClCH 2 CO 2 H4.05 ClCH 2 CO 2 H2.85CH 3 CH 2 CHClCO 2 H2.89 BrCH 2 CO 2 H2.90C 6 H 5 CO 2 H4.20 ICH 2 CO 2 H3.10p-O 2 NC 6 H 4 CO 2 H3.45 Cl 3 CCO 2 H0.77p-CH 3 OC 6 H 4 CO 2 H4.45
Reactions of Carboxylic Acids Nucleophiles that are also strong bases react with carboxylic acids by removing a proton first, before any nucleophilic substitution reaction can take place.
Nucleophilic acyl substitution reactions of carboxylic acids
Treatment of a carboxylic acid with thionyl chloride (SOCl 2 ) affords an acid chloride. This is possible because thionyl chloride converts the OH group of the acid into a better leaving group, and because it provides the nucleophile (Cl ¯ ) to displace the leaving group.
Although carboxylic acids cannot readily be converted into anhydrides, dicarboxylic acids can be converted to cyclic anhydrides by heating to high temperatures. This is a dehydration reaction because a water molecule is lost from the diacid.
ESTERIFIKASI ASAM KARBOKSILAT
Esterification of a carboxylic acid occurs in the presence of acid but not in the presence of base. Base removes a proton from the carboxylic acid, forming the carboxylate anion, which does not react with an electron-rich nucleophile.
Intramolecular esterification of - and -hydroxyl carboxylic acids forms five- and six-membered lactones.
Carboxylic acids cannot be converted into amides by reaction with NH 3 or an amine because amines are bases, and undergo an acid-base reaction to form an ammonium salt before nucleophilic substitution occurs. However, heating the ammonium salt at high temperature (>100°C) dehydrates the resulting ammonium salt of the carboxylate anion to form an amide, although the yield can be low.
The overall conversion of RCOOH to RCONH 2 requires two steps:  Acid-base reaction of RCOOH with NH 3 to form an ammonium salt.  Dehydration at high temperature (>100°C).
A carboxylic acid and an amine readily react to form an amide in the presence of an additional reagent, dicyclohexylcarbodimide (DCC), which is converted to the by-product dicyclohexylurea in the course of the reaction.
DCC is a dehydrating agent. The dicyclohexylurea by-product is formed by adding the elements of H 2 O to DCC. DCC promotes amide formation by converting the carboxy group OH group into a better leaving group.