CAMPHOR, NATURAL AND SYNTHETIC 63 



consumed by this important industry. The presence of o"i per 

 cent, chlorine remaining in synthetic camphor is said to render 

 it unsuitable for the manufacture of celluloid, so that manu- 

 facturers of synthetic camphor are set a sufficiently high standard 

 of purity. 



The Chemistry and Constitution of Camphor 



Camphor is a derivative of the important class of organic 

 compounds called terpenes, the parent substances of which are 

 unsaturated hydrocarbons possessing the empirical formula 

 C 5 H S . The terpenes are divided into four classes : 



1. Hemiterpenes, C 5 H S . 



2. Terpenes, Ci H 16 . 



3. Sesquiterpenes, C 15 H 2 4. 



4. Polyterpenes, (C 5 H S ) S . 



The second class is the most important, and it is to this class 

 that camphor belongs. In considering the constitution of 

 camphor — a question which has occupied the attention of 

 chemists for many years — we must briefly review its most 

 important reactions and decompositions, and then pass on to its 

 synthesis from pinene. 



Camphor is a saturated compound having the formula C 10 H 16 O. 



It is a ketone; i.e. contains the group ~yC— CO— CA . The 



evidence for this consists in its ability to react with hydroxylamine 

 forming an oxime (camphoroxime Ci H 16 = NOH). Further it is 

 reduced (by sodium and alcohol, or electrolytically) to borneol, 

 which possesses the character of a secondary alcohol, 

 QH 16 = CHOH. When distilled with phosphorus pentoxide, 

 camphor yields the hydrocarbon cymene C 10 H 14 (I.), whose con- 

 stitution is known to be para-methyl-isopropyl-benzene. 



CH, - CH — CHo 



C, n H lfi O - HX> 



'10"16 







CH 3 



Camphor. (I.) Cymene. 



This same cymene complex (a benzene nucleus with methyl 

 and isopropyl in para position to one another) is therefore 

 assumed to be present also in camphor. On boiling with iodine, 



