SOLUTION OF SUCCINIC ACID IN WATER 
525 
pipettes the tips were protected by small muslin filters. These 
portions were transferred to tarred glass-stoppered weighing 
bottles and the weight of the solution was determined. The 
samples were then transferred to small Erlenmeyer flasks, boiled 
water added and then titrated to a faint pink color by means of 
the standard alkali. In every case the final titration was made 
with the dilute sodium hydroxide. From the data thus obtained 
were calculated the solubilities. 
The heats of solution of succinic acid in the solvents used have 
been calculated by means of the well-known van’t Hoff isoehore, 
InCg - InCi 
Q T2— Ti 
~ RT 2 - Ti 
where R is the gas constant (1.985 cals.). C 2 and C x are the sol- 
ubilities at the absolute temperatures T 2 and T ly respectively, 
and Q is the molar heat of solution produced by dissolving one 
gram-mole of the acid in one hundred grams of the solvent. By 
a mathematical rearrangement, 
2.3026X1.985XT,XT I C, 
Q = y y logic. Q ca l s - 
Succinic acid is but slightly dissociated in water and practic- 
ally not at all in the alcohols. This relation will give, therefore, 
a close approximation to the heats of solution of the acid in the 
solvents under consideration.. 
The results obtained are given in the accompanying table. 
Each solubility value given is the mean of three or four separate 
values which do not differ by more than a few hundredths of a 
gram per one hundred grams of solvent. 
TABLE I. 
Solubility of Succinic Acid. 
Solvent 
In Grams Per 100 
Grams of Solvent 
In Moles Per 100 
Moles of Solvent 
Molar Heat 
of Solution 
25° 
30° 
35° 
to 
Oi 
o 
30° 
35° 
Qi 
Q 2 
Water - _ 
8,368 
10.295 
12.821 
1.277 
1.571 
1.956 
7442.5 
8142.6 
Methyl Alcohol 
20.460 
23.076 
26.260 
5.552 
6.262 
7.125 
4320.4 
4796.9 
Ethyl Alcohol 
9.996 
11.492 
.’3.185 
3.899 
4.483 
5.143 
5230.7 
5101.0 
"—Propyl 
4.806 
5.665 
6.664 
2.445 
2.882 
3.391 
5905,4 
6027.4 
" — Butyl 
3.179 
3.817- 
4.464 
1.995 
2.395 
2.801 
6572.7 
5804.4 
tert — Butyl 
8.504 
9.687 
10.949 
5.336 
6.079 
6.871 
4680.0 
4542.1 
Iso — Butyl 
2.532 
3.062 
3.646 
1.589 
1.921 
2.288 
6825.7 
6478.7 
Iso — A.myl 
2.146 
2.570 
3.133 
1.601 
1.918 
2.338 
6474.3 
7352.0 
