534 
IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
EXPERIMENTAL. 
Dicyandiamide was prepared by the method of Soil & Stutzer 7 
from commercial calcium cyanamide supplied by the American 
Cyanamide Co., of Niagara Falls, Ontario. The product was ob- 
tained in large white crystals, melting at 209° (corr.). Succiny- 
losuccinic ester, prepared in the usual way from diethyl suc- 
cinate and sodium, was suspended in ten times its weight of 
water and an ecpial volume of 5 per cent sodium hydroxide so- 
lution was added. After the ester had dissolved to a bright 
yellow solution, dicyandiamide, equivalent in amount to two 
molecules for every molecule of succinylosuccinic ester, was added 
in the solid form, and the mixture was gradually warmed on an 
electric stove. As the temperature rose, the dicyandiamide went 
into solution and at about 50° a pale yellow granular precipi- 
tate began to form. Heating was continued until the mixture 
just began to boil. After cooling, the precipitate was filtered 
with suction, washed with water, dilute hydrochloric acid, alco- 
hol and finally ether, and dried in the oven at 100°. The yield 
was 37 per cent of the theory. In a second and third prepara- 
tion, equal weights of dicyandiamide and succinylosuccinic ester 
were used, and the yields on the basis of the latter substances 
were 72 per cent and 61 per cent respectively. 
The mother liquor was bright red, the color evidently being 
due to an oxidation process, since the red appeared first at the 
surface of the solution in contact with the air. This color turned 
yellow on acidifying and then back to the- original red on the 
addition of alkali. 
Like the other n a phthotetr azine derivatives described, this con- 
densation product is characterized by its insolubility in the 
neutral solvents and by its infusibility. At about 320° it dark- 
ens in color without melting. Analysis of the product gave 
the following results : 
The condensation consists in the elimination of two molecules 
of water and two of alcohol, between one of succinylosuccinic 
N 
C 
H 
Found 
37.2 
48.5 
2.7 
Calc, for Ck Hs N s O, 
37.8 
48.6 
3.0 
7 Soll & Stutzer, loc. cit. 
