322 SALICYLIC ALDEHYDE. 



easily soluble in alcohol and ether, soluble in concen 

 trated sulphuric acid, forming a deep red solution. 

 Monobasic acid. Its barium salt yields benzhydrol 

 (p. 316) when subjected to destructive distillation. 



Benzoylbenzoic acid, C U IW = C 6 II 5 .CO.C 6 H 4 . 

 COOH. Is formed by the oxidation of benzyltoluene 

 with potassium bichromate and sulphuric acid. Beau 

 tiful, lustrous laminae ; easily soluble in ether and alco 

 hol ; very difficultly soluble in cold water, somewhat 

 more easily in hot water ; fuses at 194 ; sublimes. 



f The barium salt, (C 14 H 9 3 ) 2 Ba + 2H 2 0. Crystal 

 lizes in fascicular needles or in laminae. Difficultly 

 soluble in cold water, more easily in hot water. 



Benzhvdrylbenzoic acid, C 14 H 12 3 =C 6 IRCH(OH). 

 C 6 H 4 .CO.OH. Is formed by the action of nascent 

 hydrogen (zinc and hydrochloric acid) on benzylbenzoic 

 acid. Much more easily soluble in water than the 

 preceding acid ; easily soluble in alcohol and ether ; 

 fuses at 164-165. 



Benzylbenzoic acid, r C 14 IP 2 2 = C 6 H 5 .CH 2 .CTI 4 .CO. 

 OH. Is formed by heating benzhydrylbenzoic acid 

 with hydriodic acid in sealed tubes, for several hours, 

 at 160 ; also by direct oxidation of benzyltoluene with 

 dilute nitric acid. Crystallizes from alcohol in laminae 

 or needles of satin lustre ; difficultly soluble in cold 

 water, more easily in hot water, easily soluble in ether, 

 alcohol, and chloroform ; fusing point, 154-155 ; sub- 

 limable. Its salts do not crystallize. 



Salicylic aldehyde (Ortho-oxybenzylic aldehyde, 

 Salicylous acid) C 7 H 6 2 = OTI 4 j ^ Q Occurs in all 



parts of the herbaceous spiraeas, and in the larvae of 

 chrysomena populi. Is produced by the oxidation of 

 saligenin, salicin, and populin (see Glucosides). Color- 



