15-1 Principles and Applications of Inorganic, Organic, and Biological Chemistry Denniston, Topping, and Caret 4 th ed Chapter 15 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Power Point to Accompany

15-2 Functional Group Formulas

15-3 Functional Group Formulas-2

Acids: Structure and Properties Low molecular weight acids are water soluble due to hydrogen bonding with water.

15-5 Acids: Boiling points Low molecular weight acids have abnormally high boiling points due to dimer formation via H bonding.

15-6 Acids: Boiling points-2 Derivative boiling points vary with the ability to hydrogen bond.

15-7 Acids: Common Names formic acid acetic acid butyric acid

15-8 Acids: IUPAC Names Start numbering at the COOH carbon Replace the -e of the alkane name with oic acid. Name the acid: IUPAC: 3-bromobutanoic acid (Common:  -bromobutyric acid)

15-9 Examples of Carboxylic Acids Stearic acid, found in beef fat Citric acid, found in citrus Fruits and part of the central cycle of metabolism Lactic acid, found in sore muscles and yogurt.

15-10 Reactions of Carboxylic Acids Carboxylic acids are prepared by oxidation of primary alcohols and aldehydes.

15-11 Reactions of Acids-2 1. Carboxylic acids are weak Lowry- Bronsted acids. 2. Acids form acid derivatives. a) acid chlorides b) esters (to follow) c) amides d) anhydrides

15-12 Reactions of Acids-3 1. Acids react with water to form solutions that are weakly acidic.

15-13 Reactions of Acids-4 Acids form salts with bases. The salts react with strong mineral acids to give the original organic acid.

15-14 Acids Form Esters 2b. Carboxylic acids react with alcohols to form esters, an important group in biochemistry. The reaction requires an acid catalyst. The reaction is an equilibrium reaction.

Esters Structure and Physical Properties Esters are mildly polar Many have pleasant aromas E. g. isoamyl acetate=banana oil ethyl butanoate=pineapple aroma Boil at approximately the same temperature as carbonyls with comparable molecular weight.

15-16 Esters: IUPAC Names 1. Name the alkyl group attached to the oxygen atom first. (Alcohol part of the ester) 2. Base name for the acid part of the structure from the longest chain ending in the C=O. Change the oic acid of the acid name to oate and add this to the name in 1 as a second word.

15-17 Esters: IUPAC Names- 2 A = ethyl propanoate B = methyl benzoate

15-18 Ester Reactions: Preparation Carboxylic acids react with alcohols to give esters. The reaction is catalyzed by strong mineral acid.

15-19 Ester Reactions: Hydrolysis The main reaction of esters is hydrolysis, reaction with water. However, the uncatalyzed reaction is slow and either mineral acid or base is used as a catalyst. When stoichiometric base is used, the reaction is called saponification (soap making).

15-20 Esters Acid hydrolysis: the products are the acid and an alcohol. Substitution here!

15-21 Esters Base hydrolysis (saponification): the products are the acid salt and an alcohol. Substitution here! A salt in basic solution.

15-22 Esters: Saponification (Soap making) Saponification (soap making) is basic hydrolysis of fats

15-23 Esters: Condensation Polymers Polyesters are condensation polymers formed by eliminating a small molecule (e. g. H 2 O) when combining a diacid and a diol. Polyethylene terphthalate (PETE) is used to make Mylar, shatterproof plastic bottles, and polyester fabric.

15-24 Polethylene terphthalate Terphthalic acid 1,2-ethanediol Continued condensation at each end Repeating unit of the polymer

Acid chlorides and Acid Anhydrides Acid chlorides are named: by replacing the –ic acid ending of the common name with –yl chloride. by replacing the –oic acid ending of the IUPAC name with –oyl chloride. ethanoyl chloride (acetyl chloride) 4-chlorobenzoyl chloride (p-chlorobenzoyl chloride)

15-26 Acids Chlorides Carboxylic acids form acid chlorides which are good acyl group transfer reagents.

15-27 Acid chlorides-2 Acid chlorides react with water (hydrolysis) to reform the acid. Substitution of the OH for the Cl occurs at the acyl carbon. Substitution here!

15-28 Acid chlorides-3 Acid chlorides react with alcohols to form esters. Substitution of the OR for the Cl occurs at the acyl carbon. Substitution here!

15-29 Acid Anhydrides Symmetrical anhydrides are named by replacing the -acid ending of the acid with –anhydride. ethanoic anhydrice acetic anhydride

15-30 Acid Anhydrides-2 Anhydrides are formed using the reactions below.

15-31 Acid Anhydrides-3 Acetic anhydride reacts with alcohols to give acetate esters.

15-32 Anhydrides-4 Acetic anhydride reacts with amines to give amides.

Phospho and thioesters Phosphoric acid reacts with alcohols to give esters. The ester can then react with a second or third acid to give phosphoric acid anhydrides. ADP and ATP of biochemistry fame are the important examples of phosphoric acid esters.

15-34 Phosphoric acid esters Ester bond Anhydride bonds

15-35 Thioesters In biochemistry, acetyl coenzyme A (CoA-SH) reacts with acyl groups to “activate” them for further biological reaction by forming a thioester.

15-36 The End Acids and Derivatives