Modification of the Adams' Method of Preparing 

 Alkyl Iodides. — By Harold S. King, A.B. (Harv.), 

 Assistant Professor of Chemistry, Dalhousie University, 

 Halifax, Nova Scotia. 



(Read 21 April, 1924) 



INTRODUCTION 



The alkyl iodides are among the most important of organic 

 reagents. Usually their cost ready prepared is high in compar- 

 ison with the price of the ravi/ materials. In most laboratories 

 these reagents, especially methyl and ethyl iodides, are prepared 

 as needed. Consequently any simplification in the procedure 

 for their production is desirable. Adams and Voorhees have 

 published a very satisfactory method in The Journal of the 

 American Chemical Society, Vol. XLI. pp. 789-798, (May, 1919). 

 This method is based on the reaction between an alcohol, phos- 

 phorus, and iodine. A mixture of red and yellow phosphorus, 

 together with the alcohol corresponding to the iodide which is 

 to be prepared, is boiled in a flask fitted with a special apparatus 

 for dissolving iodine in the condensed vapors from the distilla- 

 tion and introducing the iodine gradually as as olution into the 

 reaction flask. With this apparatus the preparation of alkyl 

 iodides is smoothly and almost automatically accomplished. 



The special apparatus, however, is rather too complicated 

 to be made in the laboratory and somewhat expensive to have 

 constructed by a professional glassblower. The purpose of this 

 paper is to suggest a form which, it has been found, is simple 

 enough for the average student to build, yet which works as 

 efficiently. The accompanying cut illustrates the special appa- 

 ratus in its simplified form. The iodine holder is a separatory 

 funnel A, which is fitted to the reaction flask D by a rubber 

 stopper. Through this stopper also extends a glass tube E, in 

 which the vapors pass upward and the excess of the distillate 

 flows down. This tube leads into a larger tube F, the lower end 

 of which is constricted to join a stopcock which leads into the 

 top of the separatory funnel. To the upper end of tube F is 

 attached an efficient reflux condenser H. 



