ETHER (otherwise called ETHYLIC ETHER, VINIC ETHER, and SULPHURIC ETHER) is prepared from alcohol by the action of sulphuric acid at an elevated temperature. On.the small scale the apparatus which may be employed for the purpose is the retort and receiver, into which a mixture of equal weights of spirits of wine, or rectified spirit and oil of vitriol, or, by volume, 2 of alcohol and 1 of sulphuric acid, are placed, and heat being cautiously applied, a liquid distils over, which consists of ether and water. In a short time the contents of the retort begin to blacken, and the operation must be stopped or the distillate will become contaminated with sulphurous acid. On the large scale a modification of the process is carried on, which renders it theoretically a "continuous process," though, practically, there is a limit to the amount of ether dis tilled over.
The conversion of alcohol into ether and water (HO) by oil of vitriol (HOSO3), was at one time considered to be due simply to the strong affinity of the oil of vitriol for water, which enabled it to take possession of the one atom of water, the elements of which form the only difference in the ultimate composition of alcohol and ether. This simple mode of explaining the process of etherification, however, does not acknowledge that the atom of water is not retained by the oil of vitriol, but is given off side by side with the E. in mechanical solution therewith. The theory of the proc ess now generally accepted is too complex for introduction here.
E. is a colorless, transparent, volatile liquid of great mobility and high refractive power, and possessing a fragrant odor, and a fiery, passing to a cooling, taste. When pure, it has the specific gravity 720 (water = 1000) at 60 F., though the commercial specimens are never free from water and alcohol, and have the density 740. It boils at 04.8° F. (the commercial at 06°), and yields a very dense vapor, the specific gravity of which is 2586, as compared with air 1000. Wlieu reduced to a temperature of — 24° F., E. freezes. It volatilizes spontaneously when placed in an unconfined position, as in the palm of the hand, and vaporizes so quickly as to produce intense cold. Indeed, when water is covered with E., and the latter assisted in its evaporation by being blown upon, it escapes so readily as to reduce the temperature of the water to 32° F., when it
freezes. It is very inflammable, burning with a yellow-white flame; and mixed with air or oxygen, it gives rise to a dangerous explosive mixture, and hence great care requires to be taken in its distillation to keep all lights and fires out of the room where the vapors are condensing. When E. is added to its own bulk of water, briskly agitated, and allowed to settle, the two liquids appear to separate again; but it is found that the E. has taken up one-eighth of its volume of the water, whilst the latter has dissolved the same quantity of ether. It is readily miscible with alcohol in all proportions. E. is one of the best solvents for the oils and fats, and hence is employed in analysis for the solution and separation of the oils from other organic matters, as in the analysis of oil cakes, etc. It is also a good solvent of iodine, sulphur, phosphorus, and of strychnine, and other alkaloids, as well as of corrosive sublimate, and other salts.
E. is useful in the preparation of freezing mixtures, and the mixture of E. and solid carbonic acid gives rise to the lowest temperature which has as yet been attained. When inhaled by man and the lower animals, E. first produces stimulating and intoxi cating effects, but afterwards it gives rise to drowsiness, accompanied by complete insensibility, which entitles E. to be regarded as an important anaesthetic agent; and, indeed, for some time it was the only agent used for producing anresthesia (q.v.) in operations, but has been entirely superseded by the employment of chloroform.
E. enters into combination with many acids, forming compound ethers, possessing great fragrancy; the more important of which are given in the following table: Acetic Ether Butyric Ether Pine-apple Oil.
Caproic Ether Essence of Melons.
Rutic Ether Pelargonic Ether . Essence of Quinces.
(Enanthic Ether C4HSO,Ci4II,302, Wine Oil. There are other ethers, in which ordinary E. is not one of the members, as Amyl Acetic Ether.... Ciollii0,C4HsOs Jargonelle Pear Oil.
Amyl Valerianic Ether Apple Oil.
Methyl Salicylic Ether.:; 011.of Winter Greens.