ON THE STATE OF ORGANIC CHEMISTRY. 5 



4. The conversion of benzoic, toluylic, cuminic, and anisic acids into the 

 so-called benzamic, toluamic, cuminamic, and anisamic acids is a change 

 equivalent to that of acetic acid into glycocol,and is therefore the change of 

 a monatomic into a diatomic substance. We shall return hereafter to the 

 consideration of the formulas of glycocol and its analogues. 



The following are examples of the transformation of polyatomic into mon- 

 atomic compounds : — 



1. Lactic acid, C 3 H 6 3 (diatomic), reacts with pentachloride of phos- 

 phorus, giving chloride of lactyl*, C 3 H 4 0C1 2 . Chloride of lactyl is decora- 

 posed by water into hydrochloric and chloro-propionicf acids, — 



C 3 H 4 0C1 2 + H 2 0=C 3 H 5 2 C1+HC1, 



Chloride of lactyl. Chloropropionic 



acid. 



and chloropropionic acid is converted by nascent hydrogen into propionic 



acid (monatomic). This transformation of lactic into propionic acid is 



evidently the converse of the transformation of acetic into glycolic acid 



which is mentioned above. 



2. By similar reactions, salicylic acid, C 7 H 6 3 (diatomic), is converted 

 into chloride of salicyl, C 7 H*OCl 2 , and into chlorobenzoicj acid, C 7 H 5 2 C1. 



3. The action of iodide of phosphorus on glycerine, C 3 H s O 3 (triatomic), 

 gives iodopropylene, C 3 H 5 1, from which allylic alcohol, C 3 H 6 O (monato- 

 mic), can be easily obtained. 



Typical formulas being representations of reactions, it follows that if a sub- 

 stance affords two or more distinct kinds of reactions, either of formation or 

 of decomposition, it may be consistently represented by formulae deriving 

 from a corresponding number' of distinct types. 



Benzamide is a substance of this nature. Its formation by the reaction of 

 chloride of benzoyle, or of benzoate of ethyl, upon ammonia, its decomposi- 

 tion by alkaline hydrates, and many other reactions, all characterize it as de- 

 riving from the type ammonia ; accordingly it is commonly represented by 

 the formula 



C 7 H 5 O } 

 H VN. 

 H J 

 But when acted upon by pentachloride of phosphorus, it is decomposed pre- 

 cisely as though it derived from the type water, and gives rise to the chloride 

 of a radicle containing nitrogen, chloride of benzamidyl%, C 7 H 6 NCI. The 

 rational formula of benzamide which results from this reaction is 



C 7 H° N 1 HI 



tt \ O, deriving from the type tt \ O. 



The substance described by Williamson |] as chlorohydrated sulphuric acid, 

 S H O 3 CI, may, in like manner, be represented either as a chloride or as a 

 hydrate. Represented as a chloride^, it takes its place in the following series 

 of compounds containing the same radicle : — 



Chloride S H 0\ CI, Chlorohydrated sulphuric acid. 



Hydrate .... S ^ ° 3 1 O, Sulphuric acid. 



* Wurtz, Ann. Chem. Pharm. cvii. 194. 



t Ulrich, Ann. Chem. Pharm. cix. 268 ; Chem. Soc. Quart. Journ. xii. 23. 



% Chiozza, Ann. Chim. Phys. [3] xxxvi. 102. 



§ Gerhardt, Traite de Chimie Organique, iv. 762 ; Ann. Chim. Phys. [3] xlvi. 172. 



|| Proc. Roy. Soc. vii. 11. U Comp. Schiff, Ann. Chem. Pharm. cii. 144. 



