5. D. Darling and R. F. Brown University of Southern
California Los Angeles
Standard Taper Lab-Kit for Undergraduate Organic Chemistry
All
inexpensive versatile ground-glassjoint kit has proved to be very satisfactory for the introducbory organic laboratory work a t USC. A modern melting point apparatus also is available for use with a set of well-integrated new and old cxperiment,s. The 24/40 joint mas selected as practical aud nlost convenient to use with a Hershberg stirrer and to clamp with t,kree-pronged clamps. Three flasks without necks were chosen, with capacities of 50, 200, and 500 ml. A compact Claisen adapter was also added. The condenser and condenser-column each have 200-nun jackets. The latter serves as a multifunctional piece (see figures1). Corks are used to hold the thermometer and the dropping funnel in place (Fig. 2). Although the arrangement of t,he thermometer might require slightly more time to reach equilibrium, this was deemed insignificant for a simple distillat,ion. For materials boiling over 200°C, a small amount of
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Figure 1.
Simple dirtillotion apparatus
glass wool suffices to insulate the head. A diagonal hole through the cork will bring the thermometer bulb into the month of the joint. The hole is easily bored with the help of an aluminum jig. A hole is machined in a piece of aluminum in. in diameter and s/,6 in, thick, to fit a softened No. 10 cork. This hole is 3/8 in. deep, with walls tapered a t go, and 25/32 in. in diameter a t the mouth. A second hole to fit a cork borer is then drilled from the opposite side at an 1 We wish to thank Professor S. F. Darling of Lawrence University for the photographs of the apparatus.
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in. angle of 101' from the snrfare, with its center from Lhe edge of the plece. The condensers are short, hut they may be used in tandem for steam distillations w~thoutproducing an unwieldy system. The 24/40 joint has not increased the size of the apparatus; in fact a direct comparison with apparatus made from 19/22 joints shows that in the former the path lengths are equal to, or considerably less, than the 19/22-jointed apparatus. A plain-glass curved adapter is attached to the condenser with a piece of Gooch rubber tubing (see figures) to direct the condensate. Vacuum distillations
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Journal of Chemicol Education
Figure 2.
Appardur for the dehydration of cyclohexonoi.
have been carried out by inserting the end of the curved adapter, through a rubber stopper or neoprene adapter, into a suction flask. The condenser-column, which is of slightly larger diameter than a West condenser, is packed with stainless steel sponge when used for fractionation. The packing and unpacking is done with a piece of tubing2 having a hook fastened at one end. Sponge cut into pieces 1 in. X 3 / r in. X 3/An. are most easily inserted and withdrawn. Round seamleas brass tubing, a/la in. O.D.; 0.042-in. wall.
The kita is vresently being used by 150 students in the undergadiate laboratory and by 15 students in an advanced laboratory, where it serves as the nucleus for a much larger kit. The initial student reaction has been very favorable and our objectives have been met
a t a minimum cost. =Our supplier has been: West Glass Corporation, 9822 St,, South Elmonte, California, They have indicated that the kit or individual pieces of the kit are now ino~udedin their catalog.
Volume 42, Number 5, May 1965
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