NEF. NITROPAllAPFINE SALTS. 129 



That nitrous oxide was present was shown by its characteristic 

 reactions, and by passing a known volume of the gas over heated cop- 

 per, whereby au equal volume of nitrogen was obtained. 



In order to determine the amount of acetaldehyde quantitativi ly, 

 the same apparatus is used except that the distilling flask, instead of 

 being connected with an azotometer, is connected with a condenser 

 and a well cooled receiver containing water. About one half of the 

 solution in the distilling flask is then boiled off, and the distillate in 

 the receiver is treated with powdered calcic carbonate to remove 

 traces of acetic acid, and then again distilled over. The second dis- 

 tillate thus obtained is perfectly neutral to test paper, and is heated 

 for four hours in a sealed tube at 100° with an excess of silver oxide.* 

 The silver acetate formed is boiled out with water, and the amount 

 determined by evaporating the aqueous solution. 



1.5 grams sodic nitroethane gave 1.8 grams silver acetate, or G9.7% 

 of the theoretical amount. 



A portion of the silver acetate, recrystallized from water and dried 

 at 80-90°, gave the following result on analysis : 



0.3552 gram substance gave 0.2297 gram silver. 



Theory for 



CIIaCO^Ag Found. 



Ag 64.67 64.67 



Sodic nitroethane has thus been split pretty smoothly, on treatment 

 with an acid, according to the following equation : 



2 CH3CH = N-ONa + H2SO, = 2 CH3CHO + NsO-f HgO + NagSO,. 

 II 

 O 



The amount of acetaldehyde obtained (69.7% of the theory) is 

 undoubtedly somewhat less than the actual amount formed in the 

 reaction, since a slight loss of aldehyde can hardly be avoided in the 

 above operations. It was shown qualitatively that nitrous acid, acetic 

 acid, and hydroxylamine are side products in the above reaction. 

 Entirely analogous results are obtained if hydrochloric acid, instead 

 of sulphuric acid, is used in the reaction. 



* A preliminary experiment with pure acetaldehyde showed that this method 

 is well adapted for the quantitative determination of aldehyde. 1 gram acetal- 

 dehyde (bpt. 23°), 20 c.cm. water, and 8.3 grams silver oxide, heated in a sealed 

 tube at 100° for one hour, gave 3.1 grams silver acetate corresponding to 81.7 per 

 cent of tlie theory. Traces of unchanged aldehyde were noticed on opening the 

 sealed tube. 



VOL. XXX. (n. S. XXII.) 9 



