GLYCEROL. 49 



By treating glycerol with sodium dissolved in alcohol a crys- 

 talline deposit of the composition CgH^NaOj, CjHgO is formed, 

 which, when heated at 100° in a current of hydrogen, loses 

 alcohol. It is a white amorphous powder, very hygroscopic and 

 immediately decomposed by water. Calcium, strontium, and 

 barium hydroxides are freely soluble in glycerol, and form 

 glyceroxides, which may be dissolved in water ; the aqueous 

 solutions do not give precipitates with carbonic anhydride. 



By the action of hydrochloric and hydrobromic acids, mono- 

 and dichlor-hydrin and mono- and dibrom-hydrin are produced. 

 There are two possible mono-chlor- and mono-brom-hydrins : 

 thus — 



CH2CI CH2(0H) 



CHOH and CHCl 

 CH2(0H) CHalOH) 



and similarly two di-hydrins : thus — 



CH.Cl CH2CI 



CH(OH) and CHCl 

 CHjCl CHjCOH) 



Both compounds are simultaneously produced. 



By the action of alkalies on both the dichlor-hydriiis, epichlor- 

 CH2CI 

 hydrin CH \ q is produced. 

 CH2 



A mono-iod-hydrin also appears to be produced by the action 

 of hydriodic acid. 



The penta-chloride and penta-bromide of phosphorus produce 

 trichlor- and tribrom-hydrins, which are the a-/3-7-trichlor- and 

 a-/?-y-tribrom-derivatives of propane. 



Phosphorus tri-iodide or concentrated hydriodic acid produce 

 a mixture of allyl and iso-propyl iodides with propylene. 



By the action of dehydrating agents acrolein, acrylic aldehyde, 

 C.jH^O is formed. 



Glycerol is very soluble in water and alcohol, but insoluble in 

 ether and chloroform. 



Cholesterol, C.,,,H4.,0H, is a mono-hydric alcohol, containing 

 one unsaturated bond. This is shown by its combination with 

 two atoms of bromine to form dibrom-cholesterol, CogH^gBrjOH. 

 unchanged. It is Icevo-rotatory, having an [«]„ — 36'6 [Drag- 

 endorff) or — 31-6 {Liiideiimeycr). 



It is easily soluble in hot alcohol, crystallising out on cooling 

 in characteristic plates ; occasionally from alcohol and more 

 often from ether it is obtained in needles. 



(Iholesteryl acetate, melting point 92°, is obtained by the action 

 of acetic anhydride on cholesterol. The benzoate is obtained by 



