504 M. Schwanert on the Action of Nitric Acid on Camphor. 



Camphresic acid has the appearance above described only 

 when it is at once completely evaporated. If its aqueous solu- 

 tion is allowed to stand in vacuo over sulphuric acid, it is 

 gradually deposited as a solid, white, granular mass. 



When camphresic acid is subjected to destructive distillation, 

 an acid aromatic distillate passes over which contains acetic 

 acid and acetone; at about 200° C. an oily distillate con- 

 denses in the retort-neck, while carbonic acid is disengaged, and 

 after a short time tabular crystals are deposited. If then the 

 temperature is raised to 270°, a white crystalline sublimate con- 

 denses in the neck of the retort, and some quantity of porous 

 charcoal is left. The quantity of this oil is greater the slower 

 the heat is applied, and the more carefully it is kept between 

 180° and 200° C. 



When the mother-liquor is poured off from the crystals and 

 distilled, it passes over completely between 200° and 210°. It is 

 a clear pale yellow thickish liquid, with an aromatic odour, 

 heavier than water, but not soluble in it ; it dissolves, however, in 

 alcohol, and has then a powerful acid reaction. It is a tribasic 

 acid, of the formula € 10 H 14 4 ; considering the mode of its 

 formation, Schwanert names it pyro camphresic acid. It forms 

 amorphous salts with barium and lead. 



The tabular crystals which are formed in crude pyrocamphresic 

 acid dissolve readily in alcohol, and may be purified by treating 

 their alcoholic solution with animal charcoal. They then form 

 transparent rhombic plates which melt at 89° C. ; they dissolve 

 in hot water with a rotatory motion. This body is also a tribasic 

 acid, but contains 2 atoms less of H 2 Othan camphresic acid, and 

 has thus the formula G 10 H 10 9 5 ; Schwanert names it metacam- 

 phresic acid. 



The white crystalline sublimate which forms in the neck of 

 the retort when camphresic acid is heated from 220°-270° C, is in 

 all its properties identical with anhydrous camphoric acid. 



The action of pentachloride of phosphorus, concentrated sulphuric 

 acid, and sulphuric anhydride on camphresic acid gave no definite 

 results. Bromine decomposes it, forming carbonic acid, a bro- 

 minated acid, and bromoform. A body resulting from the action 

 of hydriodic acid on it is still under investigation. 



None of the salts of camphresic acid crystallize. When cam- 

 phresate of calcium is subjected to destructive distillation, it 

 yields pjhorone. 



Camphresic ether, € 10 H 11 (£ 2 H 5 ) 3 G 7 ,was obtained by the action 

 of iodide of ethyle on camphresate of silver. Biethylcamphresic 

 acid, € ,0 H 12 (€ 2 H 5 ) 2 9 7 , was obtained along with some of the 

 ether, when a solution of camphresic acid in absolute alcohol was 

 saturated with hydrochloric acid gas. The acid was removed from 



