. Elements of modern chemistry . sulphuric acid on alcohol. A mixture of 9 parts of con-centrated sulphuric acid and 5 parts of alcohol of 90 per cent,is heated in a flask, A (Fig. 122), and a small, continuousstream of alcohol is allowed to flow into this mixture throughthe funnel-tube a. The temperature of the liquid, indicated bythe thermometer t, should not exceed 140 or 145°. The vapordisengaged is condensed in a Liebigs condenser, B, through ETHYL OXIDE. 489 which a stream of cold water flows continually. Under theseconditions, a mixture of ether and water collects in the re-ceiver D, to
. Elements of modern chemistry . sulphuric acid on alcohol. A mixture of 9 parts of con-centrated sulphuric acid and 5 parts of alcohol of 90 per cent,is heated in a flask, A (Fig. 122), and a small, continuousstream of alcohol is allowed to flow into this mixture throughthe funnel-tube a. The temperature of the liquid, indicated bythe thermometer t, should not exceed 140 or 145°. The vapordisengaged is condensed in a Liebigs condenser, B, through ETHYL OXIDE. 489 which a stream of cold water flows continually. Under theseconditions, a mixture of ether and water collects in the re-ceiver D, together with a little alcohol, and towards the closeof the operation, a small quantity of sulphurous acid gas isdisengaged. The product is purified by washing with milk oflime, and then with pure water, after which it is rectified overcalcium chloride on a water-bath. Fig. 122 represents theapparatus used for public demonstration; in the arts, the opera-tion is conducted on a large scale in apparatus of an Fig. 122. Theory of Etherification. —The transformation of alcoholinto ether is a true dehydration, brought about by the sul-phuric acid. 2() = (C^H^)^O + WO Williamson clearly proved that it is effected in two distinctphases; in the first, ethylsulphuric acid and water are formed. Alcohol. Sulphuric acid. Ethylsulphuric acid. 490 ELEMENTS OF MODERN CHEMISTRY. In the second, another molecule of alcohol reacts with theethylsulphuric acid; ether is formed and sulphuric acid isregenerated. C2H5^ C2H5^ _ cms^^ , H^^^4 jj>bU* + jj>0 = C2H5>C> + H^^^ Ethylsulphuric acid. Alcohol. Ether. Sulphuric acid. Hence the ether and water collected in the receiver are pro-ducts of two distinct phases of the reaction. Ethylsulphuricacid is continually formed and as continually decomposed,regenerating sulphuric acid ready to act upon new por-tions of alcohol. However, although the operation is con-tinuous, it cannot go on indefinitely, for the mixture
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