Organic 2 Review Problem 79

Organic 2 Review Problem 79 - in B. This type of apparatus...

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METHODS AND MANIPULATION IO cm. in a small flat-bottomed flask which is placed over a motor containing a horizontally-rotating magnet. Distillation. This process is carried out in the apparatus shown in Figs. 36, 37 and 38. The distillation apparatus (Fig. 36) is of very general application and is made in one piece. Distillations on the semi-micro scale "can also be carried out in the simple pear-shaped distilling flask A (Fig. 37). The distillate is collected in the 'centrifuge-tube' B placed in the bottom of the vessel C. The latter is a boiling tube with a side-arm fused on at 45°. This arm is connected to that of the flask by a cork. A "cold finger" D serves to condense the vapour issuing from the side-arm of the flask. Distillation in this apparatus must be performed very slowly to ensure efficient condensation and collection of the distillate
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Unformatted text preview: in B. This type of apparatus is particularly suitable for liquids of high boiling-point and especially for substances that solidify on cooling. As the side-arm of A is not cooled, condensation is not usually likely to take place before the distillate reaches B. As this apparatus is virtually closed except for the groove in the cork of C, it is also con-venient for the distillation of pungent and lachrymatory materials (e.g., benzyl chloride). Groove FIG. 36. IO cm. FIG. 37. FIG. 38. All thermometers for semi-micro preparations must have very small bulbs. They may often be inserted into flasks through a short "collar" of rubber tubing in place of the customary corks. Distillation Technique. With all distillations on a semi-micro scale it is essential to heat the liquid so slowly that a "cushion" of its...
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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