Dr. W. Ramsay on Picoline and its Derivatives. 33 



C 12 H n Br 3 N 2 contains 56*73 per cent, of bromine. 



C 12 H 13 Br N 2 . 2 H Br contains 55*70 per cent, of bromine. 

 I am disposed to accept the latter formula as the correct one ; 

 for one atom of bromine introduced into the molecule of dipi- 

 coline would probably not destroy its basic property. 



Oxidation of Dipicoline. — Five grams of dipicoline were 

 oxidized in the usual manner with potassium permanganate. 

 The acids when separated from their lead salts, consisted : — (1) 

 of an acid, almost totally insoluble in water, alcohol, and ether, 

 and separating in amorphous flocks on evaporation of the 

 solution containing other acids, in which it dissolves sparingly ; 

 it gives off a smell of the polymerized bases when heated on 

 platinum foil ; and (2) a mixture of acids (certainly containing 

 no a-dicarbopyridenic acid), of which the quantity at my dis- 

 posal was too small to admit of fractional crystallization. These 

 acids also evolved a smell resembling that of dipyridine, when 

 heated. The lead and silver salts of these acids are white 

 insoluble precipitates. It is probable, from the fact of these 

 acids evolving the smell of dipyridine when heated, that 

 dipicoline, when oxidized, yields a polymeride of dicarbopyri- 

 denic acid. 



General Conclusions. 



1. Bases of the series C n H 2w _5 N are tertiary bases ; they 

 are not attacked by nitrous acid ; nor do they unite with more 

 than one molecule of a halogen compound of an alcohol 

 radical. 



2. They are unsaturated compounds, but have no great 

 tendency to form addition-compounds. The addition-com- 

 pounds are divisible into three classes : — (a) compounds in 

 which the base combines directly with an acid to form a salt ; 

 (b) compounds in which the base unites with two atoms of a 

 halogen, e. g. picoline chloriodide, C 6 H 7 N . CI I ; and (c) 

 those in which a salt combines with two atoms of a halogen, 

 in the pyridine series, as, for example, the diniodide of picoline 

 methyl-iodide, C 6 H 7 N . CH 3 1 . L, and with six atoms of a 

 halogen, as in the case of the hexiodide of dipicoline methyl- 

 iodide, C 12 H 14 N . (CH 3 1) 2 1 6 . 



3. Like the paraffins, they are not attacked by acid oxidizing 

 agents in the cold. They differ from paraffins by withstanding 

 such action even at a high temperature ; and this is probably 

 owing to the increased stability given to the molecule by 

 nitrogen, which renders them basic, and imparts to them the 

 property of forming salts. The heat of formation of these bases 

 is doubtless very high ; and when a still greater amount of 

 heat is evolved by their combination with acids, the sum of 



Phil. Mag. S. 5'. Vol. 6. No. 34, July 1878. D 



