Organic Chemistry, 6 th edition Paula Yurkanis Bruice Chapter 24 Catalysis Brian L. Groh Minnesota State University, Mankato Mankato, MN Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following is/are common types of catalysts used in organic reactions? 24.1 A.Acid catalysts B.Base catalysts C.Nucleophilic catalysts D.Metal ion catalysts E.All of the above Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following is/are common types of catalysts used in organic reactions? 24.1 A.Acid catalysts B.Base catalysts C.Nucleophilic catalysts D.Metal ion catalysts E.All of the above Enzymes are also becoming more commonly used in organic reactions. Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following is an intermediate in the acid catalyzed hydrolysis of an ester? 24.2 D intermediates A, B, and C E intermediates B and C Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following is an intermediate in the acid catalyzed hydrolysis of an ester? 24.2 D intermediates A, B, and C E intermediates B and C The ester oxygen in “A” is less basic than the carbonyl oxygen. Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following are intermediates in base catalyzed transesterification of a methyl ester? 24.3 E intermediates A and D Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following are intermediates in base catalyzed transesterification of a methyl ester? 24.3 E intermediates A and D Initial attack by ethoxide gives A and formation of D leads to generation of more ethoxide. Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which of the following is not true of metal-ion catalysis?24.5 Bruice: Organic Chemistry, © 2011 Pearson Education, Inc. A.It can make a reaction center more susceptible to receiving electrons B.It can make a leaving group a weaker base, and therefore a better leaving group C.It can increase the rate of a hydrolysis reaction by increasing the nucleophilicity of water, as in C D.It can increase the reaction rate by changing the mechanism of the reaction. E.It can increase the rate of a reaction by removing a proton from the reactant.

Which of the following is not true of metal-ion catalysis?24.5 Bruice: Organic Chemistry, © 2011 Pearson Education, Inc. A.It can make a reaction center more susceptible to receiving electrons B.It can make a leaving group a weaker base, and therefore a better leaving group C.It can increase the rate of a hydrolysis reaction by increasing the nucleophilicity of water, as in C D.It can increase the reaction rate by changing the mechanism of the reaction. E.It can increase the rate of a reaction by removing a proton from the reactant. – This is a base catalyst.

A.Acid B.Base C.Nucleophilic D.Metal ion E.None of the above What type of intramolecular catalysis is operating in the following reaction? 24.7 Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

What type of intramolecular catalysis is operating in the following reaction? 24.7 Sulfur displaces the chloride ion by intramolecular nucleophilic attack. A.Acid B.Base C.Nucleophilic D.Metal ion E.None of the above Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which factor(s) contribute to the catalytic activity of enzymes? 24.8 A.Reacting groups are brought together at the active site in the proper orientation. B.Amino acid side chains serve as catalysts. C.Metal ions in the active site act as catalysts. D.Amino acid side chains stabilize transition states and intermediates. E.All of the above. Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.

Which factor(s) contribute to the catalytic activity of enzymes? 24.8 A.Reacting groups are brought together at the active site in the proper orientation. B.Amino acid side chains serve as catalysts. C.Metal ions in the active site act as catalysts. D.Amino acid side chains stabilize transition states and intermediates. E.All of the above. Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.