106 
DR. T. E. THORPE AND HR. J. W. RODGER OX THE RELATIONS 
una.voidable, the bromide, or sometimes the chloride, should be substituted for the 
iodide. 
The second of these conclusions finds some support in the work of Silva Compt. 
Rend.,’ 81, 323), who showed that when a mixed ether is decomposed by hydriodic 
acid the higher radicle becomes an alcohol and the lower an iodide. 
Although the rule given may seem obvious in view of the known instability of the 
higher alkyl iodides, it is shown above that in practice it has been generally disre¬ 
garded. A possible reason for this is the increasing difficulty of dissohung sodium as 
we ascend the series of alcohols. In the work recorded below, it was not found 
po.ssible in any reasonable time to dissolve more than one molecular proportion of 
sodium in two or three of propyl or isobutyl alocohols. The consequent waste of 
alcohol may be obviated by the use of the following continuous process, by means of 
which the conversion of alkyl iodides and alcoholates into ether can be carried out 
in almost theoretical proportions. 
A WuRTZ flask of about a litre capacity has the side-tube (which should be nearly 
at right angles to the neck) lengthened to about a metre, and this surrounded by 
the outer tube of a condenser for nearly its whole length to secure efficient conden¬ 
sation. The flask is placed on a water-bath, and by inclining it until the condenser 
slopes upward at some 30° with the horizontal we have a reflux apparatus, while a 
simple rotation through 60° downwards adapts it for distillation. 
Placing it with the condenser sloping upwards, 150 grams of the alcohol (propyl or 
isobutyl) is introduced through the neck, which is fitted with an easily-removable 
cork. A clean dry bottle, wide mouthed and stoppered, is tared, and about 30 grams 
of clean sodium put into it. It is again weighed, so that at any time the amount used 
can be ascertained ; if dry and well-stoppered, oxidation is only superficial. Some 
pieces are cut off and introduced into the flask ; it dissolves rapidly at first with 
evolution of heat. More sodium is added at intervals, taking care not to use more 
than can be dissolved within a reasonable time; say 20 to 22 grams for 150 grams 
alcohol. The water-bath is heated, as if the solution be allowed to cool it solidifies. 
Directly the sodium has dissolved, the cork in the neck is replaced by one carrying a 
bent tap-funnel, in which the iodide (methyl or ethyl) is placed. This is allowed to 
flow in small portions into the thick liquid ; the flask is gently rotated to prevent 
the heavy iodide sinking to the bottom and causing violent bumping, and in a 
moment the whole mass becomes clouded by the separation of sodium iodide. The 
whole of the iodide is gradually added in this way, the amount being that calcu¬ 
lated for three-fourths of the sodium present. With this proportion, though but 
little more than equimolecular, there was never a trace of iodide in any of the 
distillates. 
After a short digestion the condenser is turned down without interrupting the 
boiling, and the ether distils over. It is accompanied with but little alcohol, possibly 
on account of the alcoholate still in solution raising the boiling-point. Directly the 
