1865.] Researches on Ethers. No. I. 203 



the introduction of propyl into carbonic acid ; 2ndly, by the substitution 

 of ethyl for hydrogen in acetic ether ; and Srdly, by the replacement of 

 hydrogen by methyl in acetic ether. The ethers of these acids may be thus 

 represented : 



C 3 H 7 



rcH 3 



h 



oc 3 H 5 o ) cr 



[OC 2 H 5 



Propyl-carbouic ether. Ethacetic ether. Dimethacetic ether. 



Are these acids identical, or are they isomeric? We hope shortly to be 

 able to answer this question decisively. 



Synthesis of Caproic Ether. 



The production of a dimethacetic compound, as above described, obviously 

 points out a reaction by which caproic or diethacetic ether can be obtained. 

 It is only necessary to act upon disodacetic ether with iodide of ethyl, to 

 obtain, with the greatest facility, the compound in question : 



C 2 H 5 

 C 2 H 3 



a +2NaI 



.OO.H. OC 2 H 5 



Disodacetic ether. Diethacetic or caproic ether. 



Diethacetic ether boils constantly at 151 C. The boiling-point of 

 ordinary caproic ether is stated by Lerch to be 120, and by Fehling 162. 

 These numbers differ so widely that it is impossible to use them for com- 

 parison. Its specific gravity at C. is '8822 (according to Fehling the 

 density of caproic ether is '882 at 18 C.), and its vapour-density 5 '00, 

 the theoretical number being 4'98. On analysis it yielded numbers 

 corresponding with the above formula. Diethacetic ether possesses a 

 peculiar and somewhat pleasant odour, somewhat resembling oil of pepper- 

 mint ; it is insoluble in water, but miscible in all proportions with alcohol 

 and ether. Treated with alcoholic potash it is readily decomposed, 

 yielding alcohol and potassium diethacetate, and by distilling the latter 

 with dilute sulphuric acid, diethacetic acid distils over and floats on the 

 surface of the water which accompanies it. This acid reddens litmus- 

 paper powerfully, is very sparingly soluble in water, and emits a peculiar 

 odour, quite different from that of ordinary caproic acid. Boiled with 

 water and carbonate of silver it yields, on filtration and evaporation in 

 vacuo, splendid fern-like crystals, which, after pressing between folds of 

 blotting-paper and drying in vacuo, with the exclusion of light, are perfectly 

 white, with a satiny lustre ; they possess great elasticity, and are remark- 

 ably like asbestos. In a strong light they rapidly become brown. Sub- 



VOL. XIV. R 



