338 ODOROGKAPHIA. 



Phenyl salicylate. This ethereal salt, known as Sa2ol, was 

 first obtained by Seifert* by heating salicylic acid and phenol with 

 phosphorous oxychloride. A better yield is obtained ]jy employing 

 the sodium salts, and it is now manufactured by heating the 

 product of the action of carbon dioxide on sodium phenate with 

 phosphorous pentachloride or oxychloride. Salol crystallises in 

 rhombic prisms which are odourless and melt at 42^-42^-5 ; the 

 dilute alcoholic solution, however, has an odour resembling that of 

 wintergreen oil. It is used in medicine as a substitute for 

 salicylic acid, over which it possesses many advantages in this 

 respect. 



In the preparation of Salol from salicylic acid and phenol, or 

 from sodium salicylate and phenol-sodium, instead of subjecting 

 them to the action of phosphorous oxychloride or pentachloride, the 

 acid sulphates of the alkalies may be used.f These exercise a 

 strong dehydrating action, salol being formed. As solvents and 

 diluents benzene and toluene are used, being recovered by 

 distillation. The reaction follows a similar course when 

 dioxynaphthalin or gaultheria oil takes the place of phenol. It 

 has been suggested that these improvements in the manufacture 

 of salol may open the way for the preparation of a large number 

 of similarly constituted organic compounds. 



Methylsalicylic acid was first prepared by Grabe:|: in the 

 following manner : — Two parts of methyl salicylate are heated 

 to 100^-120^ C. wdth one part of caustic potash and three or four 

 parts of methyl iodide, the product distilled in order to remove 

 methyl alcohol and methyl iodide, and the residue then extracted 

 with caustic soda and precipitated with hydrochloric acid. Any 

 adhering salicylic acid is removed by boiling with an excess of 

 milk of lime, insoluble basic calcium salicylate being precipitated, 

 while calcium methylsalicylate remains in solution and is 

 then decomposed by hydrochloric acid. Methylsalicylic 

 acid crystallises from hot water in large, monoclinic 

 tablets, and from alcohol in prisms, which melt at 98*5 

 and decompose above 200^ C. into carbon dioxide and 

 anisol. On heating with concentrated hydrochloric acid, it is 

 resolved into salicylic acid and methyl chloride. Cahours obtained 



* Journ. Prakt. Cheni. [2], xxxi., p. 462. 



t Pharm. Centralhalle, 2oth Oct., 1888, p. 530. 



X Ann. Cliem. Pharm., cxxxix., p. 137. 



