ON A DIHYDRO-QUINOXALINE 131 



HYDROCHLORIC ACID SALTS 



A 



The salt obtained as a yellow powder by passing hydrochloric acid 

 gas into a benzene solution of the base showed itself upon analysis to be 

 impure. The color and general character would indicate that a mono- 

 hydrochloric acid salt had been formed. 



B 



On standing for several days over sulphuric acid in an exhausted 

 desiccator, an aqueous solution of the base gave long needle-shaped 

 crystals similar to those obtained with aqueous hydrobromic acid. 



ACID DETERMINATION 



0.1818 g. of the salt required 11.83 c - c - °f a 0.12626N. NaOH solution. 



C I2 H l6 N 2 - 2 HCl 



Computed Found 



2 £[0=27.9 per cent. 27.72 per cent. 



ACTION OF SULPHURIC ACID 



No sulphate of the base could be isolated from a solution of the 

 base in dilute sulphuric acid. A sulphate undoubtedly exists in the 

 solution, as shown by the characteristic yellow color due to the com- 

 plex ion, Ci 2 H l6 N 2 H. On standing, colorless crystals separate out, 

 which dissolve in water to a colorless solution, give the diamido-phena- 

 zine reaction with ferric chloride, and correspond, on analysis, to ortho- 

 phenylene-diamine sulphate. The sulphuric acid solution of the base 

 acquires a distinct odor of mesityloxide after standing. 



ANALYSIS OF THE CRYSTALS 



0.2933 g. substance required 19.86 c.c. of a .12626N. NaOH solution. 

 C 6 H 4 (NH 2 ) 2 -H 2 S0 4 .iiH 2 



Computed Found 



H 2 S0 4 =42.07 per cent. 41-85 per cent. 



PICRIC ACID SALT 



Alcohol solutions of the base and picric acid give canary-yellow 

 needles on being mixed. 



