MR JAMES DEWAR ON THE OXIDATION PRODUCTS OF PICOLINE. 191 



potassium salt, seems to be the most powerful. Having on a former occasion 

 employed this reagent to effect the oxidation of phenol alcohol, I naturally 

 investigated the action effected on these nitrile bases. I found that the whole 

 of the members of this series of compounds could be readily oxidised by the 

 use of this substance. The higher members of the series were oxidised more 

 readily than the lower, but in all cases it was effected with ease and rapidity. 

 The following is a description of the apparatus used in the experiments on the 

 oxidation products of these substances and of the mode of conducting the 

 operation. A flask, about three litres in capacity, was connected by a wide 

 tube with a large reversed Liebig's condenser, so as to effect a rapid condensa- 

 tion of volatile products and their immediate return to the field of chemical 

 action. The flask having been placed on a sand bath, 150 grms. potassium 

 permanganate, 1^ litres water, and 25 grms. picoline were introduced, and the 

 whole heated to near the boiling point. The reaction began suddenly, with 

 great evolution of heat, necessitating the removal of the source of external heat. 

 The reduction of the permanganate was completed in half an hour. After the 

 contents of the flask had cooled, the oxide of manganese was separated by 

 filtration from the strongly alkaline liquid, and washed repeatedly with boiling 

 water. The alkaline liquid was then transferred to a flask, and the basic sub- 

 stances distilled off*. The residual alkaline liquid was then concentrated by 

 evaporation to 200 c.c. and 300 c.c. and dilute sulphuric acid (containing 70 per 

 cent. H 2 S0 4 ) added to it. After standing for some time this acid liquid became 

 thick from a deposit of long white crystalline needles of a complex of new 

 acids. In different experiments the relative proportions of the reacting sub- 

 stances were considerably varied, but the yield of the new acids in every case 

 was small, a large portion of the picoline having been completely oxidised, while 

 some of it had remained unacted upon. This must always be the case, as a 

 large quantity of the original base, from the violence of the reaction, was driven 

 away from the flask, and, when condensed, it fell back into a boiling liquid of 

 increasing alkalinity, in which the base was comparatively insoluble. After 

 separating, by filtration, the new crystalline acid referred to, the filtrate was 

 transferred to a retort, and the volatile acids distilled off. 



General Eesults of Oxidation. — When the dilute alkaline fluid was taken 

 immediately after the permanganate was exhausted, it was found to contain 

 carbonate of potassium. When neutralized with hydrochloric acid and chloride 

 of calcium added, a white precipitate of oxalate of calcium was obtained. The 

 oxalate was mixed with a small quantity of some higher acid, probably malonic, 

 as the per-centage of lime found was 36 3, oxalate containing 38 -3 per cent. 

 The quantity of volatile acid produced by the reaction was small. The 

 presence of nitric and acetic acids, however, was readily proved. The surplus 

 base remaining after the oxidation operation was transformed into the double 



