( 284 ) 
Fig. 1 
| _M 
250) INE el 
Leh 
OE 
aa 
240) Pe 
Temperature. 
0 100 
Mo L 9/9. 
Acetaldehyde. 
the whole of the equilibria of 
phases from that point of view. 
Such a system has now been 
investigated in my laboratory by 
Dr. HoLLMANN of Dorpat. It is the 
systemacetaldehyde--paraldehyde, 
which has the further advantage 
of not undergoing molecular trans- 
formation except in the presence 
of a catalyzer and so behaves 
like a system with two components, 
whilst it undergoes transformation 
rapidly enough on addition of a 
trace of sulphuric acid to appear 
as a system with only one com- 
ponent. It becomes possible, thus, 
for the first time to obtain a general 
insight into the position which 
equilibria with apparently one 
component occupy among the sys- 
tems with two components. 
The chief results of the research 
are the following. 
First of all the solidification 
phenomena of mixtures of acetal- 
dehyde and 
investigated. 
paraldehyde were 
As is well known, 
paraldehyde in a pure state melts 
Paraldehyde, at 12°.55 (point B). This melting 
point is lowered by addition of acetaldehyde along to the curve BLDC, 
which continues until the liquid consists almost entirely of acetaldehyde. 
With the aid of the apparatus of Prof. KAMRERLINGH Ones *) the 
melting point of acetaldehyde was determined at — 118°.45 (A). 
The melting point line of acetaldehyde does not extend further than 
— 119°.9 (C) where it meets that of the paraldehyde. C'is therefore 
a eutectic point, 
Melting point. 
Be ANA SS 
EENS 
De a ED 
Gases 
Ae Sees 
1) LADENBURG gave — 120°. 
0/ 
/, Paraldehyde. 
100 
88.1 
67.6 
1.4 
0 
