308 ETHER 



ETHER, C 8 H 10 2 (C*H 10 0). 8yn. Sulphuric ctJier, Oxide of ctln/L Wlylic or Vinic 

 ether, &c. &c. By this term is known tho very volatile fluid produced by the action 

 on alcohol of substances having a powerful affinity for water, such as sulphuric acid. 



Preparation on small scale. A capacious retort with a moderate-sized tubulatiuv is 

 connected with an efficient condensing arrangement. Through tho tubulature passes 

 a tube connected with a vessel full of spirit, sp. gr. 0-83. The tube must have a stop- 

 cock to regulate the flow. A mixture being made of five parts of alcohol of the density 

 given above, and nine parts of oil of vitriol, it is to be introduced into the retort, an' I 

 a lamp-flame is to be so adjusted as to keep the whole gently boiling. As soon as tlm 

 ether begins to come over, the stopcock connected with the spirit reservoir is to be 

 turned sufficiently to keep the fluid in the retort at its original level. 



Preparation on large scale. The apparatus is to be arranged on the same principle, 

 but, for fear of fracture, may be constructed of cast iron, lined with sheet load in the 

 part containing tho mixture. The chief disadvantage of this arrangement is its 

 opacity, whereby it becomes impossible to see the contents of the retort, and there- 

 fore not so easy to keep the liquid at its original level. In this case the quantity dis- 

 tilling over must be noted and the flow of spirit into the retort regulated accordingly. 

 The most convenient mode of proceeding is to have a large stone bottle with a tubu- 

 lature at the side near the bottom (like a water filter) to hold the spirit. A tube passes 

 from the bottle to the retort. It has at the end, near the retort or still, a bend downwards 

 leading into the tubulature. If a glass still bo used, it must for safety be placed in a 

 sand-bath. The distillate obtained, either on the large or small scale, is never pure 

 ether, but contains sulphurous and acetic acids, besides water and alcohol. To 

 remove these, the distillate is introduced, along with a little cream of lime, into a largo 

 separating globe, such as that mentioned under BROMINE. The whole is to be well 

 agitated, and the lime-solution then run off by means of the stopcock. The purified 

 ether still contains alcohol and water, to remove which it should be rectified in a 

 water-bath. The fluid will then constitute tho ether of commerce. If the second 

 distillation be pushed too far the ether will, if evaporated on the hand, leave an un- 

 pleasant after-smell, characteristic of impure ether. If wished exceedingly pure, it 

 must be shaken up in the separating globe, with pure water. This will dissolve 

 the alcohol, and leave tho ether, contaminated only by a little water, which may be 

 removed by digestion with quicklime and redistillation at a very low temperature on 

 a hot water-bath. 



Pure ether is a colourless mobile liquid, sp. gr. 071. It boils at 95 F. The 

 density of its vapour is 2'56 (calculated). Gay-Lussac found it 2'586. 



The word ' ether,' like that of alcohol, aldehyde, &c., is now used as a generic term 

 to express a body derived from an alcohol by the elimination of water. Many chemists 

 write the formula C 4 H 5 0, and call it oxide of ethyl in the same manner as they regard 

 alcohol as the hydrated oxide of the same radical. But there is no just reason for 

 departing from the law we have laid down with reference to the formulae of organic 

 compounds. We shall therefore write ether C 8 H 10 2 (C 4 H 10 O). This view has 

 many advantages. We regard, with Gerhardt and Williamson, ether and alcohol as 

 derived from the type water. Alcohol is two atoms of water in which one equivalent 

 of hydrogen is replaced by ethyl ; ether is two atoms of water in which both atoms 

 of hydrogen are replaced by that radical. But there arc a large class of compound 

 ethers procurable by a variety of processes. These ethers were long regarded as salts 

 in which oxide of ethyl acted the part of a base. Thus, when butyrate of soda was 

 distilled with alcohol and sulphuric acid, the resulting product was regarded as buty- 

 rate of oxide of ethyl. The compound ethers are regarded as two atoms of water in 

 which one equivalent of hydrogen is replaced by the radical of an alcohol, and tho 

 other by the radical of an acid. In addition to those, there are others more closely 

 resembling tho simple ethers. They are founded also on tho water type, both atoms 

 of hydrogen being replaced by alcohol radicals, but by different individuals. They 

 are called mixed ethers. The following formulae show tho chemical constitution of all 

 these varieties placed for comparison in juxtaposition with their type : 



H~l P*TTO P*TT*"l PTTs 1 



I nz ^ a ' 02 ^ " I nz *-" Ja - I nz 



H/ u C 4 H S / U C 2 IP/ U C 8 H 7 2 / U 



Water (2 eqs.) Common ether. Metbylo-ethylic ether. Butyric ether. 



Hi C 2 H 5 7 C 2 H 5 ~I C-'H 5 > 



HJ C 2 H$ CH/ C'H'o[ 



In the above formulae the first represents tho typo water. The second common 

 ether, the two equivalents of ethyl replacing tho two of hydrogen. In tho third. AVI 

 have a mixed ether, one of tho equivalents of hydrogen being replaced by ethyl and 

 tho other by methyl. The fourth illustration is that of a compound ether : one of tho 



