ALDEHYDES. KETONES. 493 



The actual decomposition is, however, somewhat more complicated, 

 numerous intermediate bodies and other decomposition products 

 being formed at the same time. 



Chloral is a colorless, oily liquid, having a penetrating odor and an 

 acrid, caustic taste; its specific gravity is 1.5, and its B. P. 95 C. 

 (202 F.). 



Hydrated chloral, Chloralum hydratum, CC1 3 .CH(OH) 2 =164.12. 

 When water is added to chloral the two substances combine, heat is dis- 

 engaged, and the hydrate of chloral is formed, which is a crystalline, 

 colorless substance, having an aromatic, penetrating odor, a bitter, 

 caustic taste, and a neutral reaction ; it is freely soluble in water. 

 alcohol, and ether, also soluble in chloroform, carbon disulphide, 

 benzene, fatty and essential oils, etc. ; it liquefies when mixed with 

 carbolic acid or with camphor; it melts at 58 C.(136 F.),and boils 

 at 95 C. (203 F.), and also volatilizes slowly at ordinary temperature. 



Chloral, and its hydrate, are decomposed by weak alkalies into 

 chloroform and a formate of the alkali metal : 



C 2 HC1 3 + KHO : KCHO 2 + CHC1 3 . 

 Chloral. Potassium Potassium Chloroform. 



hydroxide. formate. 



This decomposition was believed to take place in the animal body, and 

 especially in the blood, whenever chloral was given internally, but recent in- 

 vestigations seem to contradict this assumption. There is no chemical antidote 

 which may be used in cases of poisoning by chloral, and the treatment is, 

 therefore, confined to the use of the stomach-pump and to the maintenance of 

 respiration. 



Analytical reactions for chloral. 



1. Chloral or hydrated chloral heated with potassium hydroxide is 

 converted into potassium formate and chloroform, which latter may 

 be recognized by its odor. (See explanation above.) 



2. Heated with silver nitrate and ammonium hydroxide a silver- 

 mirror is formed on the glass. 



3. Heated with Fehling's solution a red precipitate is formed. 

 See also reactions 2 and 6 for chloroform. 



Acrylic aldehyde, CH 2 = CH.C (Acrolein), may be obtained by 

 the careful oxidation of allyl alcohol, or by the dehydrating action 

 of potassium acid sulphate on glycerin : 



C 3 H 8 3 - 2H,0 = C 3 H 4 0. 



It is also formed by the destructive distillation of glycerin, which is a 

 constituent of fats. Hence, acrolein is formed when fats are heated 



