496 TRANSACTIONS OF SECTION B. 
Attempts to precipitate the coloured substances from solution give interesting 
results. Thus, by treating a concentrated alcoholic solution of a mixture of 
diphenylamine and p-nitrobenzaldehyde with water a red, semi-solid mass is 
obtained, which, however, on complete solidification, produced by agitation, is 
perfectly white. 
From analogy with compounds of amines and nitro-compounds, such as tri- 
nitrobenzene, picryl chloride, &c., prepared by previous investigators, it would 
appear that the colour of these mixtures under consideration is probably due to 
the combination of nitro-compound and amine in the liquid state only, and hence 
various physico-chemical investigations of the fused mixtures were undertaken. 
The following results were obtained in this connection :— 
1. No evidence was obtained of the separation of a compound in the solid state 
by cooling a fused mixture. 
2. No break was observed in the curve, densities : composition, either in the 
case of a mixture showing the phenomenon, or in the case of a mixture of 
trinitrobenzene and diphenylamine where a compound exists in the solid state. 
3. A very slight rise of temperature was observed when the fused constituents 
were mixed. 
4. No direct evidence of the formation of a compound was obtained by the 
determination of the viscosity : composition curve for one of the mixtures 
showing the phenomenon. 
4. The Influence of Chemical Constitution on the Thermal Properties 
of Binary Miatures. By Ernest VANSTONE. 
Binary mixtures of compounds of the type Ph a £ Ph have been investigated 
by the method of thermal analysis. Thermal diagrams have been obtained for 
mixtures of benzoin with each of the following substances :—Benzylaniline, 
benzylidene aniline, dibenzyl, azobenzene, benzil, hydrazobenzene, benzanilide, 
and also for mixtures of benzil with each of the following: Dibenzyl, 
azobenzene, stilbene, hydrobenzoin, benzanilide. The diagram for benzylidene 
aniline—benzanilide—has also been obtained. In all cases the thermal diagram 
has a V form, containihg one eutectic point. In no case was there any evidence 
of compound formation, but solid solutions are formed to a limited extent in 
all cases. For benzoin entectics both the temperature and concentration of the 
eutectic mixture is a function of the melting-point of the other constituent. 
This is seen from the table below :— 
Benzoin Lutectics. 
Eutectic | Concentration. 
Substance | M.P. Temp. Per cent. Benzoin 
| | 
ess | 2 
Deg. C. Deg. C. | 
Benzylanilines:. J mer) ieee ice me 34-2 32:4 3 
Benzylidene aniline cy Se 49°8 470 3 
DIbGAZy le juad mew.) eubewe pach met 51:2 50-2 | 35 
AzZobenzenos asuh i, jeoigp tenuis 66-2 | 63-3 6-0 
Benzil . eo wieSimotiw ee: Mak 94-2 840 17:8 
Hydrazobenzene . . . . 130°5 98-4 | 42 
iBenzanilide; 7.) |. ee) ee 160:8. | 116-6 / 64 
The molecular volumes of the various substances have been determined. It 
was found that at the temperature of the melting-point the unsaturated substance 
has often a greater molecular volume than the saturated substance. No relation 
could be found between molecular volumes and eutectic points. Binary mixtures 
of benzylidene aniline, benzyl aniline, stilbene and dibenzyl with these substances 
were also discussed. 
