THE DESTRUCTIVE DISTILLATION OF MANILA COPAL. 



By Benjamin T. Brooks. 

 (From the Chemical Laboratory, Bureau of Science, Manila, P. I.) 



INTRODUCTION. 



The investigation of the distillation products of Manila copal was 

 undertaken with the hope that some light would be thrown on the chem- 

 ical changes accompanying the process of manufacture of the resin into 

 varnish. It was expected that the distillation products themselves might 

 furnish some clue as to the nature of the substances in the resin. 



The success of modern varnish manufacture depends upon the ex- 

 perience and skill of the operator rather than on a scientific knowledge 

 of the materials used. The process of manufacture is essentially the 

 same as that described in books printed long before the development of 

 modern chemistrj^. 



There is little accurate information available regarding the practice 

 of modern varnish manufacturers. Although the resins used in the 

 manufacture of resin oil varnishes are derived from many different 

 species of trees and are of different ages when they come into the market, 

 the process of manufacture is practically the same in all cases. 



In order to make the resins soluble in linseed oil they are heated, 

 during which process they loose considerably in weight. The older fossil 

 resins are heated until they suffer a greater loss of weight than the softer, 

 more recent ones, but the statements as to what per cent of the whole 

 must be volatilized in each case vary within wide limits. 



Scheibler ' subjected "copal from Manila" to dry distillation and noted two 

 distinct stages in the process, the first being characterized by frothing and the 

 presence of water in the distillate. 



Tschirch 2 distilled two samples of Manila copal. The properties of the harder 

 sample described by him agree well with those of the material being studied in 

 this laboratory. He states that the dry distillation of the hard sample yielded 

 formic, acetic, and succinic acids among the products of decomposition. 



Friedburg " noticed that certain copals yielded a distillate having an odor 



'Ann. d. Chem. (Liebig) (1860), 113, 338. 

 "Arch. d. Pharm. (1902), 240, 202. 

 ■~Journ. Am. Chem. Soc. (1890), 22, 285. 

 95193— —3 203 



