Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download 5 Properties of Esters GOB Structures
Document related concepts
Transcript
16.5 Properties of Esters Ethyl acetate is the solvent in fingernail polish, plastics, and lacquers. Learning Goal Describe the boiling points and solubility of esters; draw the condensed structural formulas for the hydrolysis products. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Boiling Points of Esters Esters have • boiling points higher than those of alkanes and ethers. • boiling points lower than those of alcohols and carboxylic acids of similar mass. Because ester molecules do not have hydroxyl groups, they cannot hydrogen bond to each other. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Solubility of Esters in Water • Esters are soluble if they have two to five carbon atoms. As the number of carbons increases from five, their solubility in water decreases. • The partially negative oxygen of the carbonyl group forms hydrogen bonds with the partially positive hydrogen atoms of water molecules. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Acid Hydrolysis of Esters In acid hydrolysis, • an ester reacts with water to produce a carboxylic acid and an alcohol. • a water molecule provides an —OH group to convert the carbonyl group of the ester to a carboxyl group. • an acid catalyst and heat are required. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Acid Hydrolysis of Esters Aspirin that has been stored for a long time may undergo hydrolysis in the presence of water and heat. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Base Hydrolysis (Saponification) Base hydrolysis, or saponification, • is the reaction of an ester with a strong base in the presence of heat. • produces a carboxylate salt and an alcohol. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Solution Ethyl acetate is a solvent used in fingernail polish, plastics, and lacquers. Write the balanced chemical equation for the hydrolysis of ethyl acetate with NaOH. ANALYZE THE PROBLEM Given ester, base Need carboxylate salt and alcohol Write equation for reaction of ethyl acetate and NaOH, in sample problem 16.8 General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Study Check Write the balanced chemical equation when methyl acetate reacts with A. water, heat, and an acid catalyst. B. KOH and heat. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Solution Write the balanced chemical equation when methyl acetate reacts with A. water, heat, and an acid catalyst. B. KOH and heat. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc. Concept Map General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.
