Multiscale Operational Organic Chemistry A Problem-Solving Approach to the Laboratory Course

To the Instructor This book is a multiscale laboratory textbook based on the third edition of Operational Organic Chemistry. -A Problem-Solving Approach to the Laboratory Course. Every experiment and minilab can be performed by students using either standard scale glassware, such as that available in an organic chemistry lab kit with 19/22 standard-taper joints, or microscale glassware, such as that in a microscale lab kit with 14hO standard-taper joints and threaded connectors. Most of the microscale experiments could be performed successfully with alternative microscale glassware, such as that provided in a Williamson lab kit (described in Microscale and Macroscale Organic Experiments, D.C. Heath and Co.). However, some might need to be scaled down further, and the instructor would have to provide additional instructions regarding the use of the glassware. Some organic chemists regard a microscale experiment as one involving approximately 0.1 g of the limiting reactant. Dealing with such small quantities can be discouraging to students with standard scale fingers, who tend to end up with a drop or a few grains of product, if any. I have adopted a more flexible definition of a microscale experiment as one that can be performed with the glassware available in a typical microscale lab. In writing this textbook, I have been guided by my convictions that students (1) perform better in the organic laboratory course if they master the major lab operations early and apply them throughout, (2) learn organic chemistry better if they keep their minds engaged by approaching each experiment as a problem-solving exercise, and (3) perform any task better if they are sufficiently motivated. Part I of this book is devoted to experiments designed to teach the basic laboratory operations, where an operation, as used here, is a process that uses one or more basic lab techniques-such as heating, cooling, or vacuum filtration-to accomplish some end, such as the purification of a solid. Once students have mastered the major operations by completing the appropriate experiments in Part I, they should be ready to apply those operations in Part II, which contains a large selection of experiments that are correlated with topics found in most organic chemistry lecture textbooks. This operational approach helps students understand that an organic synthesis, for example, is not a unique phenomenon that can be experienced only by mechanically following a detailed "recipe." Rather, it is the outcome of a logical sequence of interrelated operations adapted to the requirements of the synthesis. In addition to teaching lab skills, the experiments in this book are designed to help students develop the observational and critical thinking skills that are essential prerequisites for a successful career in science and in virtually every other profession. From the student's viewpoint, the purpose of each major experiment is the solution of a problem through the application of scientific methodology. Before each experiment, the student must first define the problem based on information provided in a hypothetical Scenario. After a preliminary reading of the experiment, the student should be able to develop a working hypothesis regarding its outcome. During the experiment, the student gathers and evaluates evidence bearing on the problem and, as necessary, reevaluates and revises the hypothesis based on experimental observations and data. Finally, the student tests the hypothesis by obtaining a melting point, a spectrum, a gas chromatogram, or by some other means, and arrives at a conclusion. Because of the level at which most undergraduate organic chemistry are taught, the problems must, of necessity, be kept relatively simple and (with a few exceptions) should not be compared to "real" research problems tackled by professional chemists. It is not the intent of this book to make every student a research chemist; most students who takLehman, John W. is the author of 'Multiscale Operational Organic Chemistry A Problem-Solving Approach to the Laboratory Course', published 2001 under ISBN 9780130154958 and ISBN 0130154954.