TRIMETHYLAMIN T E HYDROCHLORIDE. 257 



From these data it follows that the heat given off by the 

 union of potash with hydrochloric acid exceeds by -f 47 that 

 given off by trimethylamine (p. 118), which gives for the com- 

 bination of this base in solution with dilute hydrochloric acid, 

 the value + 9, which results agree with that given above. 



We also see, by the above numerical experiments, that the 

 potash entirely, or almost entirely, displaces the trimethylamine 

 in its acid compounds. It seems, however, that there are some 

 indications of division 



C 3 H 9 N (1 eq. = 2 litres) + NH 3 HC1 (1 eq. = 2 litres) - 2'33\ M M ,_ , . 

 NH 3 (1 eq. = 2 litres) + C S H 9 NHC1 (1 eq. = 2 litres) + M7/ M 



The division of the acid between the two bases is here 

 evident. It is no doubt due to the formation of dissolved 

 hydrates of trimethylamine as mentioned above, and also of its 

 hydrate, which is discussed further on. Without entering 

 further into this point, we will content ourselves with saying 

 that we deduce from these figures, for the heat of neutralisation 

 of trimethylamine by hydrochloric acid, + 8 -95. 



The three values found agree, viz. 8 '9, 9, 8*95. They are 

 lower by about a third than the heats of neutralisation of potash 

 by the corresponding acids ; they are even lower than the results 

 obtained with ammonia. Their numerical values approximate, 

 on the contrary, to the heats of neutralisation of the same acids 

 by hydroxylamine and by aniline, bases which are much weaker 

 than ammonia. 



Again, we find 



C 3 H 9 N (1 eq. = 8 litres) + C0 2 (44grms. in 26 litres) liberates + 4-4 

 C 3 H 9 NHC1 (1 eq. = 2 litres) + Na 2 C0 3 (1 eq. = 2 litres) - M7 



The last value indicates the transformation of trimethylamine 

 chloride into sodium chloride, the strong base, i.e. the soda, 

 taking the strong acid, i.e. the hydrochloric acid, as it happens 

 also between ammonium chloride and sodium chloride, and for 

 the same reasons. 1 If we suppose the reaction to be total, we 

 deduce from it that C0 2 in solution, + C 3 H 9 N in solution, 

 would give off -f- 4'1 in the presence of 4 litres of water. 



In the presence of 17 litres of water the experiment gave a 

 lower value, which seems to indicate the gradual dissociation 

 of the carbonate by dilution, always as with ammonia. 2 



8. Trimethylamine hydrochloride. The heat of formation of 

 this salt has already been given in a state of solution. In order 

 to estimate it in a solid state the heat of solution was determined 

 upon a fine specimen, supplied by M. Vincent, carefully dried 

 upon blotting paper, under a bell glass over sulphuric acid. 



1 For discussions of reactions of this order, see "Essai de Me'canique 

 Chimique," torn. ii. pp. 712 and 717. 



2 Annales de Chimie et de Physique," 4 a seVie, torn, xxxix. pp. 477-485. 



3 



