372 CONSIDERATION OF CARBON COMPOUNDS. 



like a strong acid, forming salts known as picrates, most of which are 

 explosive. 



Phenacetin, Para-acetphenetidin, C 6 H 4 .0(C 2 H 3 ) .NH(C 2 H 3 0) . When mono- 

 nitrophenol, C 6 H 4 .NO 2 .OH, is treated with reducing agents, the oxygen of 

 N0 2 is replaced by hydrogen, and amido-phenol, C 6 H 4 .OH.NH 2 , is formed. 

 The methyl ether of this compound, C 6 H 4 .O(CH ;j ).NH 2 , is known as anisidin, 

 and the ethyl ether, C 6 H 4 .O(C 2 H 5 ).NH.,, as phenetidin. By the action of glacial 

 acetic acid upon para-phenetidin, one hydrogen atom in NH 2 is replaced by 

 acetyl, C 2 H 3 O, when para-acetphenetidin is formed. The compound is used as 

 an antipyretic under the name of phenacetin. 



It is a colorless, odorless, tasteless powder, sparingly soluble in water, readily 

 soluble in alcohol ; it fuses at 135 C. (275 F.). Fresh chlorine water colors a 

 hot aqueous solution first violet, then ruby-red. The same color is obtained by 

 boiling 0.1 gramme of phenacetin with 1 c.c. of hydrochloric acid for one 

 minute, diluting with 10 c.c. of water, filtering when cold, and adding 3 drops 

 of solution of chromic acid. 



Resorcin, Resorcinum, C 6 H 4 (OH) 2 (Resorcinol, Meta-dihydroxy- 

 benzene). The formula indicates that this compound is a di-atomic 

 phenol. It is formed by fusing different resins, such as galbanum, 

 asafoetida, etc., with caustic alkalies, but it is also obtained syntheti- 

 cally from benzene. 



Resorcin is a white, or faintly-reddish, crystalline powder, having a some- 

 what sweetish taste and a slightly aromatic odor; it fuses at 118 C. (244 F.), 

 boils at 276 C. (529 F.), and is soluble in less than its own weight of water. 

 A dilute solution gives with ferric chloride a bluish- violet color. Resorcin, 

 when heated for a few minutes with phtalic acid in a test-tube, forms a 

 yellowish-red mass, which, when added to a dilute solution of caustic soda, 

 forms a highly fluorescent solution. Other fluorescent compounds are obtained 

 by heating resorcin with very little sulphuric and either citric, oxalic, or 

 tartaric acid, dissolving in a mixture of water and alcohol and supersaturating 

 the solution with ammonia. Resorcin is largely used in the manufacture of 

 certain dyes. 



Cymene, C 10 H 14 or C 6 H 4 .CH 3 .C 3 H 7 (Para-mdhyl-propyl-benzene). 

 This hydrocarbon occurs in the oil of thyme and in the volatile oils 

 of a few other plants ; it has also been made synthetically ; it is a 

 liquid of a pleasant odor, boiling at 175 C. (347 F.). 



Cymene is of special interest, because it is closely related to the 

 terpenes and camphors, from all of which it may be obtained by 

 comparatively simple processes. 



Terpenes, C 10 H 16 . This term is applied to the various isomeric 

 hydrocarbons of the composition C 10 H 16 , which are often looked upon 

 as compounds formed by direct addition of hydrogen to cymene. 



