342 
Wisconsin Academy of Sciences , Arts and Letters. 
Nitrosochlorides , Nitrosates, Nitrolctmines. 
History: 
According to Wallach 2 Bunge was the first to prepare a nitrosyl chlor¬ 
ide derivative of a terpene. Tilden, 3 however, was the first who examined 
it more carefully and described it. Thus he obtained from the class of 
“ terpenes ” (pinene) an optically inactive nitroso chloride which melted 
at 103 ’, and which, by splitting off hydrogen chloride was converted into 
the characteristic nitroso terpene, melting at 129°. From the class of 
“ citrenes ” (limonene) he obtained an isomeric, optically active nitroso 
chloride, v/hich, by splitting off hydrogen chloride, was converted into a 
nitroso derivative (“ nitroso herperidene ”) isomeric with “ nitroso ter¬ 
pene,” and whose melting point was 70-71°. These reactions henceforth 
characterized Gladstone’s 4 “ terpenes ” and “ citrenes,” and the identity 
of herperidene, carvene and citrene could no longer be doubted. Til- 
den’s method of preparing the nitroso chlorides by passing nitrosyl 
chloride into a solution of terpene, however, was very defective. Neither 
did Tilden surmise that his “ herperidene nitrosyl chloride ” was a mix¬ 
ture. 
In 1885 Goldschmidt 5 showed that the oxime from carvol was chem¬ 
ically identical with “ nitroso herperidene ” of Tilden. Soon after (1888) 
Wallach 6 taught how to prepare the nitroso chlorides in large quanti¬ 
ties with the aid of hydrochloric acid and amylnitrite, also the prepar¬ 
ation of the nitrolamines. Fully as important was the discovery that 
the nitroso chlorides were mixtures and that they could be separated 
into the a and fi compounds (1889). 7 
Preparation. 
Wallach’s method of preparation is as follows: “ To 5 cbcm. of limo¬ 
nene, 7 cbcm. of amyl nitrite (or 11 cbcm. of ethyl nitrite) and 12 cbcm. 
of glacial acetic acid are added, and to this solution, kept cold in a. 
freezing mixture, a solution of 6 cbcm. of crude muriatic acid in 6 cbcm. 
of glacial acetic acid is carefully added in small quantities. Finally 5 
cbcm. of alcohol are added.” The great solubility of the a — and the 
sparing solubility of the (5 — compound admit of an easy separation of 
the two nitroso-chlorides. 
Physical Properties. 
a-Nitrosochlorides. 
The limonene u-nitroso-chlorides crystallize in tabular crystals of 
the monoclinic system 9 . The dipentene derivative does not crystallize 
as well 10 . The + and — u-nitroso-chloride melt at 103—104°, whereas 
the dipentene derivative melts at 78° n , but congeals to a crystalline mass 
immediately after, and melts a second time at L03-104 0 . The limonene 
derivatives are soluble in about an equal weight of chloroform and twice 
