January 27,1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS 
(7) Transformation of ammonia nitrite in solution into 
nitrate :— 
This transformation and that of any other dissolved 
nitrite into a nitrate of the same base, which several 
authors believe occurs in nitrification, disengages about 
27,000 units of heat. 
These figures show that the formation of the oxyge¬ 
nated compounds of nitrogen by the oxidation of am¬ 
monia is always accompanied bv a disengagement of 
heat it can, therefore, always take place without the 
assistance of any external energy,—a circumstance 
which, in the case of certain of the oxides of nitrogen, 
happens only when they are formed by using free nitro¬ 
gen. Hence these oxides are much more easily obtained 
by setting out with ammonia. 
Reciprocally—but this is foreign to the question of 
nitrification—the formation of ammonia by the reaction 
of hydrogen with the different oxides of nitrogen, always 
■disengages more heat than the same formation effected 
by moans of free nitrogen, a fact which explains the 
much greater facility of the former reaction. 
Various experiments to see if free ammonia could be 
oxidized directly by the air at ordinary temperatures, 
with the aid of time, have all proved unsuccessful. In 
spite of these negative trials, the oxidation of ammonia 
during nitrification cannot, apparently, be called in ques¬ 
tion ; but the conditions which preside over it are still 
only imperfectly known. 
Integral transformation of ammonia into potassium 
nitrate:— 
The ammonia having oxidized into ammonia nitrate, 
this salt becomes transformed by the potassium car¬ 
bonate into potassium nitrate and ammonia carbonate, 
with an absorption of about 3000 heat-units per equiva¬ 
lent of nitrate. The ammonia carbonate passes oft' from 
the solution by evaporation and diffusion, and, in an un¬ 
limited atmosphere, the ammonia separates from the 
•carbonic acid, and becomes oxidized into ammonia nitrate 
under the same influences as those which have effected 
the first oxidation; then, by repetition of this series 
of changes, the whole of the ammonia becomes converted 
into potassium nitrate. 
The transformation of ammonia nitrate into calcium 
or magnesium nitrate is effected by means of similar re¬ 
actions, with this difference, however, that the double 
decompositions may take place between the ammonia 
nitrate and the earthy carbonates held in solution by 
carbonic acid. Magnesium carbonate may also be held 
in solution by forming a double salt with the ammonia 
carbonate. 
Disregarding the intermediate transformations, the 
heat disengaged by the nitrification of ammonia into 
potassium nitrate— 
2 NH 3 -f 8 O + (C0 3 K 0 + n Aq) 
= 2 (NO a K + «Aq) + 3 H 2 0 + C0 2 
may be directly calculated, and is found to amount to 
221,000 heat-units.* This number differs very little 
from that corresponding to the formation of dilute nitric 
acid. The excess, about 4000 heat-units, represents the 
difference between the heat-of-combination of dilute 
nitric acid and that of carbonic gas with potash. It is 
from this again evident that natural nitrification, once 
provoked, can be continued under the same conditions— 
namely, the presence of alkaline or earthy carbonates— 
without the assistance of any external energy. 
This assistance, however, is not wanting, for the oxi¬ 
dation of the organic matters, nitrogenous and non- 
nitrogenous, proceeds simultaneously with that of the 
ammonia derived from them, and adds to the quantity 
of heat disengaged. The fact that the presence of an 
alkali, free or carbonated, facilitates the absorption of 
oxygen by organic matter, is also explicable by thermic 
considerations. For the oxidation of organic matters 
* Ammonia and carbonic acid both gaseous; potassium 
•carbonate and nitrate both in solution. 
G09 
! engenders acids, the formation of which, and their simul- 
(taneous combination with the alkali, disengage more 
heat than would be liberated by the formation simply of 
the same acids in the free state. For example, the 
change of alcohol into potassium acetate disengages 
14,000 heat-units more than its change into free acetic 
| acid. 
The disengagement of heat is further added to by the 
oxidation itself becoming often more profound under the 
j influence of this additional work ; such is the case with 
! alcohol. It is necessary to raise the temperature of the 
alcohol considerably, to cause it by itself to absorb oxy¬ 
gen, and produce aldehyd and acetic acid. But by 
placing the alcohol in presence of an alkali, as well as of 
| oxygen, it is oxidized gradually at ordinary temperatures, 
and forms, not only acetic acid, but even oxalic acid, or 
; rather an oxalate. Now the metamorphosis of alcohol 
into potassium oxalate in solution disengages 164,000 
1 heat-units more (per equivalent of alcohol) than its meta- 
j morphosis into acetate. 
An analogous condition of things can be shown to be 
produced in nitrification, upon the hypothesis that ni¬ 
trates can result from the direct oxidation of nitrogenous 
organic matters. It will be sufficient, to take a well- 
defined example, to make an approximate calculation of 
the heat disengaged in the nitrification of hydrocyanic 
acid, or rather of potassium cyanide,—a calculation of 
some interest in itself, on account of the frequent pre¬ 
sence of cyanides in bricks and other nitrifiable materials. 
From the equation—- 
2 (CNK + «Aq) + 10 O 
= 2(N0 3 Iv + #Aq) + 2 C0 2 , 
the calculation can be made as follows :— 
1st. Separation of alkaline cyanide into potash and 
hydrocyanic acid, all being in solution : 
Andrews, —7200 heat-units; Thomsen, 
— 5600; the author’s unpublished ex¬ 
periments, —5920 ; number adopted. — 6000 
2nd. Separation of the water and the acid, both liquid: 
From the author’s experiments, for a 
dilute solution. — 800 
3rd. Oxidation of pure and liquid hydrocyanic acid : 
2 CNH + 5 O = 2 C0 2 + H,0 + N 2 
From author’s experiments .... + 332,000 
4th. N 2 + 5 O = H 2 O + n Aq = 2 N 0 3 H 
+ «Aq..+ 55,400 
5th. Union of dilute nitric acid with dis¬ 
solved potash.+ 29,600 
Total heat disengaged . . +410,000 
This quantity refers to the nitrification of potassium 
cyanide, with the formation of dissolved nitre ; it is 
nearly double that of the heat disengaged in the nitrifi¬ 
cation of ammonia at the expense of dissolved potassium 
carbonate; such an excess is in great part due to the 
oxidation of the carbon, and will probably be likewise 
found in the oxidation of other nitrogenous organic 
matters. 
Gaseous hydrocyanic acid* would disengage 429,000 
heat-units in furnishing two equivalents of potassium 
nitrate; ammonia hydrocyanide in solutionf would dis¬ 
engage 317,000 heat-units for two equivalents of nitre 
formed. 
All three numbers exceed that which corresponds to 
the oxidation of ammonia alone (221,000); it may, there¬ 
fore, be accepted that nitrification must be facilitated by 
the simultaneous oxidation of the carbon contained in 
the organic substance. 
* The author has found the heat of vaporization of this 
acid equal to 5700 heat-units (for one equivalent). 
f The author has found that the union of hydrocyanic acid 
with ammonia, both in solution, disengages 1600 heat-units. 
