YoTTNG— i^^ofe on Azeotropic Mixtures. 25 



latter, 32-3 degrees. Also the boiling point of the toluene-ethyl alcohol 

 azeotropic mixture is only 1'6 degrees lower than that of the alcohol. It 

 would not be possible to say off-hand whether toluene and methyl alcohol 

 would be likely to form an azeotropic mixture or not, and this c^uestion will 

 be discussed later. 



Alcohols, hydrocarhons, and xuater. — It has been stated that methyl alcohol 

 does not form an azeotropic mixture with water, and it is found that no 

 ternary azeotropic mixture is formed with methyl alcohol, water, and either 

 hexane, benzene, or toluene. 



Five alcohols of the methyl alcohol series have been observed to form 

 ternary azeotropic mixtures of minimum boiling point with normal hexane 

 and water ; four certainly, and one (secondary butyl alcohol) probably with 

 benzene and water, and five with toluene and water. 



The alcohols which it is advisable to consider are given in the table 

 (p. 26), the capital letters, A, W, H, B, and T, referring to the alcohol, water, 

 hexane, benzene, and toluene respectively. The boiling points of the pure 

 alcohols and of the known binary and ternary azeotropic mixtures are given 

 under the respective headings. The boiling points of the heterogeneous 

 mixtures of the hydrocarbons and water and of the hydrocarbons themselves 

 are : — 



Hexane and water (H.W.), 61'55". 



Benzene and water (_B.W.), 69"25". 



Toluene and water (T.W.), 84-1°. 



Hexane, 68-95°. 



Benzene, 80'2°. 



Toluene, 110-6°. 



In the three graphs (figs. 1 to 3) the boiling points of the known binary 

 and ternary azeotropic mixtures are plotted against those of the alcohols. 



Little need be said about the boiling points of the alcohol -water mixtures. 

 If the A.W. curves were extrapolated, they would intersect the liorizontal line 

 representing the boUiug point of methyl alcohol at a temperature higher than 

 64-7°, showing that no azeotropic mixture of this alcohol with water is 

 possible. On the other hand, the curve clearly approaches, but would not 

 intersect, the vertical line representing the boiling point of water ; in other 

 words, all the higher alcohols form azeotropic mixtures with water. 



