707 
1907-8.] Nitric Anhydride as a Nitrating Agent. 
decide whether all the tartaric acid which took part in the reaction was 
converted into the dinitrate. 
17*7 grams of very finely powdered tartaric acid were mixed with 30 
grams of nitric anhydride. After removal of the nitric acid in vacuo over 
solid caustic soda, the weight was 27 3 grams. 
On treatment with ether in a Soxhlet tube, 1*2 grams remained undis- 
solved, and 26'0 grams of pure dinitrate were obtained. 
According to the equation, 2 6 ‘4 grams of dinitrate should be obtained 
from 16'5 grams of tartaric acid, so that there is a difference of about 15 
per cent, between the weight as calculated from the formula and the weight 
of dinitrate actually obtained. 
Prepared in this way the dinitrate is a white crystalline powder which 
decomposes like gun-cotton when touched with a hot glass rod. It is quite 
stable if kept perfectly dry, but on exposure to the air it is gradually 
reconverted into tartaric acid, with evolution of fumes of nitric acid. 
The solution in water decomposes rapidly into oxalic acid. Very little 
tartaric acid is formed. 
The wet ethereal solution decomposes into diketo-succinic acid, as 
described by Kekule.* 
On warming the dinitrate with aqueous alcohol, tartronic acid is 
obtained.]* Some tartronic ester was prepared from tartronic acid made in 
this way, and was purified from oxalic ester by fractionation in vacuo. 
Analyses and determinations of boiling point proved its identity with 
tartronic ester prepared in other ways. 
There can therefore he no doubt of the identity of tartaric acid dinitrate, 
prepared by means of nitric anhydride, with the acide nitrotartrique of 
Dessaigne. 
The action of nitric anhydride on other hydroxy acids is at present 
under investigation. 
* Ann., 221, 247. t Ber., x., 1789. 
{Issued separately November 13, 1908.) 
