104 
DR. T. E. THORPE AND MR. J. W. RODGER ON THE RELATTOXS 
propyl isopropyl ethers. The total range of boiling-point was from 85° to 90° (uncor.), 
while the boiling-point of clipropyl ether is 90°'7 (Za.nder, ‘ Annalen,’ 214, 163). 
This product showed, a,s far as distillation can show, the presence of far greater 
proportions of isomeric compounds than the mixed ethers prepared from the same 
propyl alcohol in the manner presently to be described ; this appears to confirm the 
view expressed above of the tendency to the formation of mixed ethers in these 
processes, and the consequent augmentation of the proportions of isomeric compounds 
present in the alcohol employed. The preparation of di-isobutyl ether by this process 
was also attempted by using naphthalene sulphonic acid, but the difficulty of complete 
etherification and the very impure product formed caused the process to be abandoned. 
Excluding the method depending upon the action of silver oxide upon alkyl iodides 
(Erlexmeyer, ‘ Annalen,’ 126, 306; Linnemann, ‘ Annalen,’ 161, 37), the only other 
available processes are those based upon the condensation of alcohol with alkyl halides 
in the presence of an alcoholate or hydroxide of an alkyl metal, or of triethylamine. 
The last-named substance was employed by Reboul (‘ Compt. Rend.,’ 93, 69). As 
his method involves the use of sealed tubes, and does not prevent the formation of 
olefine, it was not tried. 
The method described by Chancel (‘Compt. Rend.,’ vol. 68, p. 726; ‘ Annalen,’ 
vol. 151, p. 305), and previously used by Balard, has the advantage of dis23ensing 
with metallic sodium, and has consequently been frequently employed. Chancel 
prepared methyl, ethyl, projjyl, and amyl propyl ethers by acting upon a mixture 
of propyl alcohol and powdered caustic potash with the alkyl iodide. The formation 
of the dipropyl ether, which is the only one fully described, was attended with the 
production of much propylene, especially in the presence of excess of alkali. The 
boiling-points given are so widely different from those of Dobriner and other 
subsequent investigators that Chancel’s ethers must have been very impure, 
probably from the presence of undecomposed iodide. Lieben and Rossi (‘Annalen,’ 
vol. 158, p. 167) tried Chancel’s process, using butyl iodide with caustic potash 
and ethyl alcohol, and found that two-thirds of the iodide was converted into ethyl- 
butyl ether. Saytzew (‘Journ Prakt. Chem.,’ (2), vol. 3, p. 88), using the same 
substances and a similar method obtained an amount of butylene representing about 
one-fourth of the iodide employed. Markownikopf (‘ Annalen,’ vol. 138, p. 374), 
obtained ethyl isopropyl ether as a bye-product in the action of potassium cyanide in 
alcoholic solution upon isopropyl iodide. He observed that the amount of ether 
])roduced increased with the strength of alcohol employed, reaching the maximum 
with absolute alcohol. 
In tiding this method, roughly-powdered caustic potash was added to propyl 
alcohol in a flask, and after cooling, ethyl iodide was poured in. The mixture was 
warmed on a water-bath under a reflux condenser; the action rapidly became very 
vigorous, and a considerable quantity of gas was evolved. After some time, when 
the reuction appeared to be complete, the licjuid portion was distilled off and treated 
