ALKYL IODIDES HAROLD S. KING 89 



DETAILED DESCRIPTION OF APPARATUS 



The cylindrical separatory funnel A is 1200 c.c. in volume 

 and holds 2 kg, of loose iodine crystals. A funnel of a different 

 volume may be used if such a one is not available. A piece of 

 perforated platinum foil B, or a mat of coarse glass wool is put 

 in the bottom to prevent clogging of the stopcock by iodine 

 crystals or solid impurities. The stopcock C should be as large 

 as 5 mm. in bore as a further precaution. 



For the production of up to 4 kg. of alkyl iodide, a 5 liter, 

 round bottom, short ring neck, pyrex flask D is used. For 

 larger quantities a flask up to 12 liters in capacity may be sub- 

 stituted. The reaction flask is heated by an oil bath. 



The tube E should be 2.5 cm. in diameter. This has been 

 found sufficiently large to allow the vapors to rise without in- 

 terrupting the return of the distillate. It is the same diameter 

 as that recommended by Adams and Voorhees for the lower 

 part of their special apparatus. 



The tube F should be 4 cm. in diameter to allow for pre- 

 liminary condensation. A space is left below the point where 

 tube E enters to act as a reservoir for the distillate. 



The stopcock G should be 2 or 3 mm. in bore. It was 

 found convenient to use for this purpose, the stopcock from a 

 small, broken, separatory funnel. Funnels in this condition 

 are usually all too common about the laboratory. The tube 

 from this stopcock is connected to the top of the iodine container 

 by a rubber stopper. The bottom of the tube is flush with the 

 bottom of the stopper so that the liquid will flow down the sides 

 of the container instead of forming a channel through the middle 

 of the iodine. Not as much difficulty from this source is en- 

 countered when a cylindrical rather than a globular separatory 

 funnel is used. 



A condenser H is attached through a rubber stopper. It 

 should be 2.5 cm. in diameter and, when making methyl iodide, 

 at least 210 cm. long. The condenser should be well cooled 

 with a strong stream of water. In hot weather especially there 

 will be some loss of methyl iodide through the condenser. If 



