Preface to the Second Edition
This book is a comprehensive introductory treatment of the organic chemistry laboratory. The student will be guided in doing numerous exercises to learn basic laboratory techniques. The student will then use many proven traditional experiments normally performed in the two-semester organic laboratory course.
Several trends in organic laboratory education have emerged since publication of the first edition. These trends are recognition of the pedagogical value of discovery experiments, the increased emphasis on molecular modeling and computer simulations, and the development of green experiments. All of these trends are incorporated into this book along with the use of traditional experiments.
Discovery experiments are given a special label in the Table of Contents and in each chapter where they appear. Discovery experiments incorporate the pedagogical advantages of inductive inquiry experiments with the ease of design found in expository experiments. Discovery experiments (or guided inquiry experiments) have a specific procedure designed to give a predetermined but unspecified result. Students use a deductive thought process to arrive at a desired conclusion. Students are “guided” by inferring a general scientific principle. Discovery experiments have been employed successfully in large laboratory sections, as well as in small classroom environments. Student interest is increased during discovery experiments because the result of the experiment is unknown to the student. The desired goal of discovery experiments is increased student learning. Discovery experiments can also provide the opportunity for individual reflection and class discussion and may involve students in developing and interpreting laboratory procedures. These features and advantages of discovery experiments have caused your text authors to emphasize discovery experiments in this edition of the text.
Molecular modeling by computer saw a revolution in the late 1990s with the advent of affordable, sufficiently fast personal computers with adequate memory. Computer modeling enhances the benefits of assembling molecular models using model kits. Use of these kits is still encouraged. However, gone are the days where students had to depend only on molecular model kits to represent molecules in three dimensions. While these models still have their uses, computer modeling programs now provide exciting visualization of molecules and calculation of physical properties and thermodynamic parameters. Where possible, it is desirable to incorporate computer modeling into organic laboratory programs. The exercises in this book can be done using relatively inexpensive commercial software from one or more providers.
Computer Simulation of Experiments
Another use of computers is for simulation of laboratory procedures and experiments. Demonstrations of laboratory techniques are available as clips on the CD accompanying this text. Simulations of experiments are useful as prelab exercises to familiarize students with the experiment and to enhance learning in the laboratory. Simulations are also useful as illustrations of experiments that are difficult to carry out in the undergraduate laboratory environment. Experiments that require special equipment, inert gaseous environments, or especially noxious and toxic reagents can be experienced by students through virtual experiments on the computer. Examples of such experiments are available on the CD accompanying this text.
Academic and industrial organic chemists have led an initiative to replace the use of organic solvents with aqueous solvents. They have encouraged the recycling of chemicals in order to reduce production requirements of chemicals. They have encouraged use of environmentally benign reagents in place of hazardous and toxic reagents where possible. In this text, there have been efforts to reduce quantities of toxic reagents and solvents wherever possible and to develop “green” experiments. For example, new Experiment 14.2 is on the use of indium reagents in aqueous solvents to accomplish coupling reactions similar to Grignard reactions. Another objective of green chemistry is to prevent waste. In this book, microscale and miniscale experiments are used in order to help minimize waste.
MICROSCALE AND MINISCALE TECHNIQUES
Microscale and miniscale organic techniques were first introduced two decades ago. However, changing over to new, smaller glassware and equipment has been slow in some laboratories for a number of reasons. One reason is the initial cost, but most institutions benefit by reduced costs of chemicals and hazardous waste disposal. The decision of whether to use a microscale procedure or a miniscale procedure often depends on the methods of characterization chosen by the instructor. This governs how much product is required for analysis. If a distillation is desired, a miniscale procedure is often chosen because of difficulties associated with distilling very small quantities of liquid. If an analysis of liquid products is to be done only by gas chromatographic analysis, a microscale procedure will cut down on costs of waste disposal.
NEW FEATURES IN THE SECOND EDITION
Accompanying a new section on molecular modeling, significant additions to this edition include expanded coverage of Diels-Alder chemistry, inclusion of enone chemistry with a chapter on enols, a new chapter on dicarbonyl compounds, and expanded coverage of heterocycles in the chapter on amines. New experiments and new options within experiments are included in many chapters. Many are discovery experiments. Among these are
Experiment 3.3, Relationships Between Structure and Physical Properties; Experiment 3.8, Purification and Analysis of a Liquid Mixture;
Experiment 5.1B, Miniscale Synthesis of Alkenes Via Acid-catalyzed Dehydration of 3,3-Dimethyl-2-butanol;
Experiment 9.1C, Microscale Reaction of Cyclopentadiene with Maleic Anhydride;
Experiment 9.1E, Reaction of Anthracene with Maleic Anhydride;
Experiment 14.2, Using Indium Intermediates: Reaction of Allyl Bromide with an Aldehyde;
Experiment 15.3, Photochemical Oxidation of Benzyl Alcohol;
Experiment 16.2, Nucleophilic Aliphatic Substitution Puzzle: Substitution Versus Elimination;
Experiment 17.1C, Microscale Horner-Emmons Reaction of Diethylbenzyl Phosphonate and Benzaldehyde;
Experiment 18.2A, Microscale Reduction of 2-Cyclohexenone;
Experiment 18.2B, Microscale Reduction of trans-4-Phenyl-3-buten-2-one;
Experiment 18.3, Catalytic Transfer Hydrogenation Miniscale Reaction of Cyclohexenone;
Experiment 21.1, Base-Catalyzed Condensations of Dicarbonyl Compounds;
Experiment 22.2, Synthesis of Pyrazole and Pyrimidine Derivatives;
Experiment 24.1, Exploring Structure-function Relationships of Phenols;
Experiment 26.1, Soap from a Spice: Isolation, Identification and Hydrolysis of a Triglyceride;
Experiment 26.2, Preparation of Esters of Cholesterol and Determination of Liquid Crystal Behavior;
Experiment 29.2, Multistep Synthesis of Sulfanilamide Derivatives as Growth Inhibitors;
Experiment 29.3, Structural Determination of Isomers Using Decoupling and Special NMR Techniques.
An instructor’s manual is available on the website accompanying this text. This manual includes directions for laboratory preparators, instructor’s notes for each experiment, solutions to problems, and prelab and postlab assignments. Test questions about many experiments are available on the web CT.
The website http://www.mhhe.com/schoffstall2 offers supportive backup for the organic laboratory course. It presents updated helpful hints for lab preparators and instructors, typical schedules, sample electronic report forms, sample quiz and exam questions, examples of lab lecture or material for self-paced prelab student preparation, and relevant links to other websites. Some additional experiments are available on the website.
We wish to acknowledge several individuals who have contributed to the second edition. Connie Pitman, laboratory technician at the University of Colorado Springs, has made numerous valuable comments about the experiments. She has also coauthored the Instructor’s Manual and Solutions Guide. Shirley Oberbroeckling has served as the Developmental editor and Joyce Watters as the Project Manager for this edition of the text. The following faculty and students have contributed to the second edition by testing experiments and suggesting improvements:
Robert A. Banaszak, Anna J. Espe, Sam T. Seal, Shannon J. Coleman, Shannon R. Gilkes, Molly M. Simbric, Daniela Dumitru, Patricia D. Gromko, Amy M. Scott, Tomasz Dziedzic, Paul J. Lunghofer, Rafael A. Vega, Justin A. Russok, Darush Fathi, and Michael Slogic.
We are grateful to the following individuals who served as reviewers for this edition. They are:
Monica Ali, Oxford College
Steven W. Anderson, University of Wisconsin - Whitewater
Satinder Bains, Arkansas State University - Beebe
David Baker, Delta College
John Barbaro, University of Alabama - Birmingham
George Bennett, Milikin University
Cliff Berkman, San Francisco State University
Lea Blau, Stern College for Women
Lynn M. Bradley, The College of New Jersey
Bruce S. Burnham, Rider College
Patrick E. Canary, West Virginia Northern Community College
G. Lynn Carlson, University of Wisconsin - Kenosha
Jeff Charonnat, California State University - Northridge
Wheeler Conover, Southeast Community College
Wayne Counts, Georgia Southwestern State University
Tammy A. Davidson, East Tennessee State University
David Forbes, University of South Alabama - Mobile
Eric Fossum, Wright State University - Dayton
Nell Freeman, St. Johns River Community College
Edwin Geels, Dordt College
Jack Goldsmith, University of South Carolina - Aiken
Ernest E. Grisdale, Lord Fairfax Community College
Tracy Halmi, Pennsylvania State Behrend - Erie
C. E. Heltzel, Transylvania University
Gary D. Holmes, Butler County Community College
Harvey Hopps, Amarillo College
William C. Hoyt, St. Joseph’s College
Chui Kwong Hwang, Evergreen Valley College
George F. Jackson, University of Tampa
Tony Kiessling, Wilkes University
Maria Kuhn, Madonna University
Andrew Langrehr, Jefferson College
Elizabeth M. Larson, Grand Canyon University
John Lowbridge, Madisonville Community College
William L. Mancini, Paradise Valley Community College
John Masnovi, Cleveland State University
Anthony Masulaitis, New Jersey City University
Ray Miller, York College
Tracy Moore, Louisiana State University - Eunice
Michael D. Mosher, University of Nebraska - Kearney
Michael J. Panigot, Arkansas State University
Neil H. Potter, Susquehanna University
Walda J. Powell, Meredith College
John C. Powers, Pace University
Steve P. Samuel, SUNY - Old Westbury
Greg Spyridis, Seattle University
Paris Svoronos, Queensboro Community College
Eric L. Trump, Emporia State University
Patibha Varma Nelson, St. Xavier University
Chad Wallace, Asbury College
David Wiendenfeld, University of North Texas
Linfeng Xie, University of Wisconsin - Oshkosh
We hope you find your laboratory experience profitable and stimulating.