^Appendix. 



dred degrees Fahrenheit, and this, it is submitted, is organic 

 synthesis. Coal is a very simple if not completely mineralized 

 mixture of carbon with bituminous hydrocarbon, and it seems a 

 misnomer to style as " destructive distillation" the formation of 

 the aromatic group from such material. It is formative distilla- 

 tion : prolific beyond parallel in the action of heat upon ele- 

 ments. 



It may be safely stated in general terms that the formation 

 of the aromatic compounds, from the elements, outside of living 

 bodies is assured. And there are now at least four aromatic sub- 

 stances manufactured on a large scale from coal-tar ; one being 

 anilin and its homologues, and the other three being vegetable 

 educts, benzoic acid, alizarin, and salicylic acid. 



The manufacture of benzoic acid from napthalin is carried 

 on through two steps, namely : 



1. Oxidation, by hot nitric acid, to phthalic and oxalic 

 acids. 19 



2. Removal of the elements of carbonic anhydride from 

 phthalic acid, by heating with lime in a close vessel. 20 



Successive substitutions.* 



OH 



H 

 C 



(O 



OH 



Phthalic acid. Benzoic acid. 



In the manufacture of alizarin from anthracene, there is : 

 i. Oxidation to anthraquinone. 



(19) C JO H 8 +8O=C 8 H 6 O 4 + H 2 C,,0 4 . 



(20) C 8 H 6 4 =C 7 H 6 2 



* One side of the double ring is broken up; its four points of CH being 

 oxidized to four serni-molecules of carboxyl, two of which enter into the 

 phthalic acid, the other two uniting as oxalic acid. 



