Carboxylic Acids and Their Derivatives (Ester)

Nanoplasmonic Research Group

Organic ChemistryChapter 10

Part I

Carboxylic Acids (Gen-eral)

carboxyl group three ways to represent a carboxylic acid acid derivatives

• Organic Acids characterized the pres-ence of a carboxylic group

• Bronsted-Lowry acids: Proton donors• Salts or Anions: Carboxylates

Nomenclature• In IUPAC nomenclature: carboxylic

acids have an -oic acid suffix• In common nomenclature, the suffix is

usually -ic acid

Physical Properties of Carboxylic Acids

• Polar and form hydrogen bonds with each other

• At high T, in vapor phase, carboxylic acids usually exist as dimeric pairs

• Water solubility: Chain-length depen-dent

Acidity of Carboxylic Acids• The acidity can be explained by either

the stability of the acids or the stabil-ity of the conjugate base using induc-tive effect or resonance effect

• The stability of the acids: Inductive effect

• The stability of the conjugate base: Both

Synthesis of Carboxylic Acids

• Oxidation of Primary Alcohols and Aldehydes

• Hydrolysis of Nitriles, Esters, or Amides with The Addition of Acid or Base

Roles of Acid or Base !!!!!! (page 298, 10.15)

• Reaction of Grignard Reagents with Carbon Dioxide

Carboxylic Acids Derivatives(Ester)

• The R part of the -OR groups is named first , followed by the name of the acid, with the -ic ending changed to -ate

• Ocurrence: the flavor and fragrance of many fruits and flowers

• Hydrogen bond acceptor: Volatile than carboxylic acids

• Cyclic ester: Lactone

How to Prepare Ester ??- Fischer Esterification -

• Refluxing a carboxylic acid in an alco-hol, which acts as both solvent and reactant

• Since the reaction is an equilibrium, how to push the equilibrium to the right ????

le Chatelier’s principle !!!

How to Push the equilibrium to the right ?

- Fischer Esterification -

• Using the alcohol as a solvent (in large excess)

• Using Sulfuric Acid: It acts as an acid catalyst and as a dehydrating agent

• Distillation (boiling point)

What happens to Fischer Esterification ?

• Nucleophilic Acyl Substitution !!!• Please take a look at eq. 10.19 on

page 301• Protecting group• Tetrahedral intermediate

Reactions of Esters

• Saponification, Reduction, Ammonoly-sis, and Reaction with Grignard Reagent