530 M. Schwanert on Camphrene. 



30 grammes of milk-sugar and 60 of bromine were enclosed in 

 a champagne-bottle with J a litre of water ; the bottle was closed 

 by a caoutchouc stopper which was wired down, and the whole 

 heated in boiling water until the mixture was colourless. The 

 product was treated with oxide of silver, the filtrate treated with 

 sulphuretted hydrogen, and the filtrate from this converted into 

 the cadmium salt, which crystallizes in small masses. From 

 this salt the acid was obtained by treatment with sulphuretted 

 hydrogen. When evaporated to a syrup, it crystallizes in groups 

 of needles, which, dried over sulphuric acid, are pulverulent. 

 The acid is highly hygroscopic ; it is soluble in alcohol, but not 

 in ether; heated on platinum, it burns with the smell of sugar. 

 It reduces silver-solutions and alkaline solutions of copper. The 

 formula of the acid is G 6 H 10 O 6 . 



The ammonia-salt, € 6 'H 9 NH 4 O 6 + 3H 2 0, and the soda-salt, 

 € 6 H 9 NaO 6 + 3H 2 0, crystallize well; the potash-salt is highly 

 deliquescent. With the exception of a lead-salt there are no 

 other salts than those with 1 equiv. of base, although it is very 

 improbable, from the large quantity of oxygen it contains, that 

 it is monobasic. It has the same formula as Wurtz/s diglycol- 

 ethylenic acid*, and for the present the authors propose for it 

 the name Isodiglycolethylenic acid. It is probable that in its 

 formation milk-sugar takes up bromine, 



Q6 Rio O 6 ' + Br 2 = C 6 H 10 O 5 Br 2 + O, 



just as Kekule found f that fumaric acid combined directly with 

 bromine : this bromine compound then gives with oxide of silver 

 the acid, in accordance with the following reaction : 



€ 6 H 10 O 6 Br 2 + Ag 2 O=€ 6 H 10 O 6 +2AgBr. 



Schwanert J has investigated camphrene, first obtained by 

 Delalande by the action of sulphuric acid on camphor, and 

 subsequently examined by Chautard. It is best prepared by 

 heating camphor with four parts of sulphuric acid for five or six 

 hours at a temperature of 100°. If the heating is not so long 

 continued, much camphor remains unchanged ; if longer, a pro- 

 found decomposition is set up. 



The product of this reaction is mixed with a large quantity of 

 water, by which an oil is separated which swims on the surface. 

 This is camphrene, but it contains a large quantity of undecom- 

 posed camphor. It is freed from this first by rectification, in 

 which process an oil goes over that almost solidifies from the 

 quantity of camphor it contains. The distillate between 220° 

 and 240° contains less camphor ; it is purified by heating it in a 



' * Phil. Mag. S. 4. vol. xx. p. 293. f Ibid. vol. xxii. p. 306. 



X Liebig's Annalen, September 1862. 



