Chemical Education Today
Book & Media Reviews Experiments in Organic Chemistry, 2nd Edition by Richard K. Hill and J. Barbaro Contemporary Publishing Co., Raleigh, Inc., 2000. ISBN 089892-218-6. $29.95 reviewed by Eugene Gooch
Yet another sophomore organic lab manual, you ask? Why on earth should this be? It is difficult to offer a unique product in such a well-established market. With the increasing popularity of desktop publishing, more and more lab instructors choose to write their own manuals rather than be constrained by commercially available products. There is also a traditional set of lab techniques and experiments which has for decades remained mostly unchanged, so why re-invent the wheel? Well, those who do not wish to go to the trouble of writing their own manual will be pleased to discover that Hill and Barbaro offer some alternatives to other manuals you may have seen. For the traditionally inclined, all the common separation techniques are included, and the selection is unremarkable. Syntheses for cyclohexene, diphenylacetylene, Grignard and Diels–Alder reactions, the venerable benzaldehyde/acetone crossed aldol, the Fisher esterification, and synthesis of aspirin are provided. For variety, some syntheses offer a choice of targets; four different amides can be made, and four different aromatics can be nitrated. But there are some innovations that should not be overlooked. A notable inclusion is a dozen syntheses labeled “mystery reactions.” In these experiments, students are not informed of the identity of their product. They are told that the product is one of 4–10 possibilities listed in a table, and that they are required to find out its identity by methods ranging from simple melting point to derivatization to IR or NMR analysis. Two of the mystery reactions are the Hofmann rearrangement and the Cannizzaro reaction. Similarly, students are not told in advance but are required to determine which product isomer predominates in each of the nitrations mentioned earlier. Organic qualitative analysis (QA) is a subtle presence in the book. Instead of there being a single QA section involving extended work over several weeks, some individual procedures appear as components of different experiments. The Diels–Alder reaction includes a microwave option that appeared in this Journal (1). The synthesis of glucose pentaacetate is followed by an NMR experiment using J values to determine which anomer is the major product; oddly, the authors omit any discussion of the anomeric effect so common in carbohydrates and derivatives, so students may not understand why the more stable conformation of a compound could contain two adjacent diaxial groups. This book has other positive features. Descriptions of basic techniques are clear, concise, and readable. Figures are included, none are very complex, and many are well annotated. The discussion of theoretical yield is exemplary. 1320
Directions for most synthesis experiments are also clear and detailed—both macro and microscale procedures are provided in most cases. In several places the authors deftly help students avoid common pitfalls; for example, students are directed to add cyclohexene to a bromine solution so they don’t miss the decolorization. Students get multiple reminders to avoid common traps such as discarding layers after performing solvent extractions. Safety instructions are clear, frequent, and adequately detailed. Explicit, detailed directions are given on pooling of organic waste for proper disposal. An instructors’ manual is available upon adoption of the text. Pagination is done by a unique system. The book is divided into sections with general information (G), lab techniques (T), ordinary experiments (E), and mystery experiments (M). Each page starts with a letter, then a hyphenated number. For example, E 6-3 is the third page of experiment six. No text is without its shortcomings, but there aren’t many mistakes. The authors assert that “The mole percentage composition of a mixture can be obtained directly…by comparing GC peak areas of the various components…” This is true only for FID detectors and even then some compounds can be exceptions. The authors make no mention of relative response factors, which are needed for TCD, ECD, and even some MS detectors. On page T 7-2, normal phase TLC is described adequately but the subsequent discussion of what is apparently reverse-phase (RP) TLC lacks any mention of a difference in the stationary phase. On the next page, Figure 2 is evidently a RP plate, but RP chromatography is not discussed until page T 8-5 (GC separations). On page E 6-3, a figure shows a reflux setup with water running through the condenser as usual, which contradicts directions to not run water through the condenser. There are no suggested time allotments for experimental procedures, either in the manual or in the instructor’s book. A lab instructor may have a different point of view from the authors. For most syntheses, the physical constants are given for the substances involved; no effort is made to encourage students to look up this data in handbooks; they can simply transcribe the tables. On page T 5-3 where solvent extraction is discussed, the value given for an example of KD is too high to convince students that multiple extractions with smaller batches of solvent are more effective than single extractions. Despite concerns about the carcinogenicity of CH2Cl2 expressed in experiment 4A (where ethyl acetate is substituted), CH2Cl2 is used without comment in a number of subsequent experiments. Overall, this lab manual is worth earnest consideration. If its features aren’t sufficiently attractive, one can just get busy and write one’s own manual…. Literature Cited 1. Bari, S. S.; Bose, A. K.; Chaudhary, A. G.; Manhas, M. S.; Raju, V. S.; Robb, E. W. J. Chem. Educ. 1992, 69, 938.
Eugene Gooch is in the Department of Chemistry, Elon University, Elon, NC 27244;
[email protected].
Journal of Chemical Education • Vol. 79 No. 11 November 2002 • JChemEd.chem.wisc.edu
