In the Laboratory edited by
Cost-Effective Teacher
Harold H. Harris University of Missouri—St. Louis St. Louis, MO 63121
Practical Origami in the Microscale Organic Lab Daryl L. Ostercamp Department of Chemistry, Concordia College, Moorhead, MN 56562
A routine task in microscale organic synthesis is the isolation and drying of several hundred milligrams of crystalline product. Laboratory texts (1–3) commonly recommend air drying, using a desiccator, or placing the sample in an oven if necessary. One author (3) suggests, in addition, shining an infrared heat lamp on the crystals. Support for the sample may be provided by filter paper, unglazed porcelain, a watch glass, a Petri dish, an aluminum weighing dish, or an evaporating dish. We have found that a simple paper boxlet (Fig. 1), folded so as to leave a “handle” at each end, is a splendid container.1 A sample may be allowed to air dry at room temperature, or if the melting point is sufficiently high, placed under an infrared lamp. CAUTION: Careless positioning of the lamp could cause the paper to ignite or the crystals to melt. In addition to the low spillage associated with a box, one may use the “handles” to record information: student name, tare weight, compound name, melting point, etc. My students and I have used this technique quite successfully for many years, not only in undergraduate labs but also in research. One begins by cutting letter-size paper in half lengthwise. Widthwise cuts are then made so as to create eight rectangles in all, each approximately 10.7 × 7.3 cm. Subsequent steps are illustrated in Figure 2 and given below. 1. Shallow inward folds (1.0 cm, AG and BH) are made lengthwise. 2. Deeper inward folds (2.5 cm, CD and EF) are made on the ends. The rectangle is now flattened (Fig. 2). At this point, pertinent data may be recorded just below lines AB and GH. 3. The first boxlet corner is created by lifting points C and J (Fig. 2) so that lines CM and MJ are superimposed vertically. Outward folding occurs along diagonal MI, with point I coming to rest outside on line JK. In the same manner, lines DN and NK form a second vertical corner, with point L coming to rest outside, again on line JK. 4. A final outward fold along line JK secures one end of the boxlet, creating handle ABJK. 5. Appropriate repetition of steps 3 and 4 at the opposite end completes the boxlet.
Acknowledgment I am grateful to a reviewer’s suggestion for the paper’s title. Note 1. Larger paper boxes can be used, with due regard for structural integrity.
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1.5 cm
1 cm 1.5 cm
1 cm
Figure 1. Dimensions of the boxlet.
G
H
E
F
C I
C
D
A
B
M
N
J
K
A
D L
B
Figure 2. Folding points.
Literature Cited 1. Pavia, D. L.; Lampman, G. M.; Kriz, G. S.; Engel, R. G. Introduction to Organic Laboratory Techniques, A Microscale Approach, 2nd ed.; Saunders: Philadelphia, 1995; Technique 5. 2. Wilcox, C. F., Jr.; Wilcox, M. F. Experimental Organic Chemistry, A Small-Scale Approach, 2nd ed.; Prentice- Hall: Englewood Cliffs, NJ, 1995; Section 8.2. 3. Ault, A. Techniques and Experiments for Organic Chemistry, 5th ed.; Waveland: Prospect Heights, IL, 1994; Section 15.
Journal of Chemical Education • Vol. 75 No. 11 November 1998 • JChemEd.chem.wisc.edu
