APOSORBIC ACID. 187 



Decompositions. Heated to 175, citric acid is con- 

 verted into aconitic acid, water being eliminated. 

 When distilled it yields citraconic anhydride. Oxi- 

 dizing agents decompose it, yielding carbonic anhy- 

 dride, oxalic, acetic, and formic acids. Chlorine and 

 bromine decompose the free acid and its alkaline salts 

 in aqueous solution, forming chlorine or bromine sub- 

 stitution-products of methyl acetate, together with 

 chloroform or bromoform. 



SEVENTH GROUP. 



Alcohols which are derived from the hydrocarbons 

 by the replacement of five hydrogen atoms by five 

 hydroxyl groups are not known. Only one penta- 

 tomic acid is known. It is bibasic. 



AposorUc Add, C 5 H 8 7 = C 3 H 3 (OH) 3 | QQ'O! Is 



formed, together with tartaric and racemic acids, by 

 the oxidation of sorbine (p. 197) with nitric acid. 

 Colorless laminse or pointed rhombohedral crystals; 

 easily soluble in water ; fuses at 110, at the same 

 time giving oft' water; decomposes completely at 170. 



EIGHTH GROUP. 



A. HEXATOMIC ALCOHOLS, C w II 2n + 2 6 . 



Only such hexatomic alcohols are known that are 

 derived from hexyl hydrides. Of these there can 

 exist four isomeric modifications, of which two, man- 

 nite and dulcite, are known. Mannite is undoubtedly 

 a derivative of normal hexyl hydride, and has the con- 

 stitution expressed by the formula CH 2 .OH.CH.OH. 

 CH.QILCILOH.CH.01LCH 2 .OH. Dulcite appears to be 

 a derivative of ethyl-isobutyl (p. 30) ; and has, hence, 



