THE AMINES. 
521 
§§ 679-681.] 
Aii alkaline liquid can be freed from volatile amines by steam dis¬ 
tillation ; methyl, dimethyl, and trimethyl amines can be separated from 
isobutylamine and isoamylamine by taking advantage of the fact that 
the two latter can be shaken out by chloroform or ether and distilling. 
There are several methods of quantitatively determining the three 
first-mentioned amines and the almost always present ammonia. One of 
the best is due to Bresler, improved by Francis 1 and Bertheaume. 2 
The bases, converted into chlorides and dried at 110°, are weighed, then 
dissolved in the least possible dilute hydrochloric acid, mixed with some 
20 grms. of silver sand, dried in a vacuum over sulphuric acid, and ex¬ 
hausted with hot chloroform, which extracts alone di- and trimethyl- 
hydrochloride. After weighing the dried chloroform extract, the salts 
are dissolved in water, the solution cooled to 0°, and an ice-cold solution 
of iodine in potassic iodide added, and the periodide of trimethylamine 
sucked off through a glass-wool filter. The crystals are dissolved in 
sodium thiosulphate, the solution alkalised and distilled, and the distil¬ 
late titrated with acid. The dimethylamine periodide remaining in the 
mother liquor is treated in a precisely similar manner. Ammonia and 
monomethylamine, left behind mixed with sand after extraction with hot 
chloroform, are treated by the process of Francis. A solution of the 
free bases is shaken with vellow mercuric oxide : the ammonia is fixed 
by the latter ; the filtrate and washings contain only methylamine. 
§ 679. Methylamine, CH 3 NH 2 .—This is a gas at ordinary temperatures ; it is 
inflammable, and possesses a strong ammoniacal odour. It has been found in herring 
brine, and is present in cultures of the comma bacillus ; it has also been found in 
poisonous sausages, but it is not in itself toxic. 
It forms crystalline salts, such as, for example, the hydrochloride, the platino- 
chloride (Pt=41-4 per cent.), and the aurochloride (Au=53-3 per cent, when anhy¬ 
drous). The best salt for estimation is the platinochloride, insoluble in absolute 
alcohol and ether. 
§ 680. Dimethylamine, (CH 3 ) 2 NH.—Dimethylamine also is a gas ; it has been 
found in various putrefying substances. It forms crystalline salts, such as the 
hydrochloride, the platinochloride (Pt=39-1 per cent.), and an aurochloride (Au = 
51-35 per cent.). It is not poisonous. 
In Brieger’s process it may occur in both the mercuric chloride precipitate and 
filtrate. From cadaverine it may be separated by platinum chloride ; cadaverine 
platinochloride is with difficulty soluble in cold water and crystallises from hot water, 
while dimethylamine remains in the mother liquor. From choline it may be 
separated by recrystallising the mercuric precipitate from hot water. From methyl¬ 
amine it may be separated by converting into chloride and extracting with chloro¬ 
form ; dimethylamine chloride is soluble, methylamine chloride insoluble, in 
chloroform. 
§ 681. Trimethylamine, (CH 3 ) 3 N.—Trimethylamine in the free state is an alkaline 
liquid with a fishy odour, boiling at 9-3° ; it is not toxic save in large doses. 
It occurs in the stinking goosefoot ( Chenopodium vulvaria), in hawthorn flowers, 
in ergot, and in herring brine and in putrefying substances. It is a product of the 
decomposition of choline, betaine, and neuridine, when these substances are distilled 
with potash. 
1 J. Pharm. Chim., vi. 517, 523, 1907 : Compi. rend., cl. 1063. 
2 J. Pharm. Chim., vii. 1910. 
