38 Alcohol and its Compounds. 



filled with pieces of glass heated to redness. The product, 

 according to Liebig, is aldehyde, an inflammable gas, and 

 water, with a slight deposit of charcoal. By passing 

 this product into a vessel, half filled with ether, the alde- 

 hyde is retained in solution. If ammonia, passed through 

 a tube filled with fused potash and quicklime, is allowed to 

 saturate the ether, the sides of the vessel are speedily 

 covered with brilliant crystals, which are compounds of 

 aldehyde and ammonia. Aldehyde may be also procured by 

 distilling four parts of spirit of wine, sis parts peroxide of 

 manganese, six of sulphuric acid, and four of water. The 

 receiver must be kept very cool, as aldehyde is extremely 

 volatile. The process should be stopped whenever the pro- 

 duct becomes acid, which happens when six parts have 

 come over. This product mixed with its weight of chloride 

 of calcium, is distilled to three parts. The three parts are 

 again rectified with their own weight of the chloride, when 

 the resulting product is free from water and alcohol. It 

 should then be mixed with twice its volume of ether, and 

 saturated with a stream of ammoniacal gas, taking care to 

 cool the receiver and to place between the vessel supplying 

 the ammonia, and the ether vessel, a safety jar, so as to avoid 

 the danger from the rapid absorption : Crystals speedily 

 appear, which, when purified by ether, consist of ammo- 

 nia and aldehyde, and are termed by Liebig, atnmonial- 

 dehyde. The same compound may be obtained by passing 

 chlorine through dilute alcohol, distilling and rectifying 

 over chloride of calcium, and saturating with ammonia. 

 A considerable quantity of aldehyde is also formed by the 

 action of spongy platinum upon the vapour of alcohol, as 

 ascertained by Dbbereiner. Aldehyde is easily prepared, 

 from its ammoniacal combination, by dissolving two parts 

 of the compound in its weight of water, and heating it, 

 mixed with three parts of sulphuric acid and four of water, 

 in a retort over a water-bath. The product is hydrous 

 aldehyde, which is rectified over chloride of calcium. It 

 is necessary to cool the vessels when these two substances 

 are brought in contact ; because, much heat is disengaged, 

 and the aldehyde boils, when re-distilled, at a temperature 

 of 86°. 



It is a colourless liquid, limpid like water ; very volatile ; 

 gp. gr. -790: boiling point, 71°-i at 28-82; smell ethereal 



