118 The Philippine Journal of Science im 



Determinations of acetone in the pyroligneous distillate were 

 neglected except for qualitative tests showing its presence. 

 Many of the distillates, especially those from the resinous woods, 

 contained aldehyde and higher ketonic bodies and substances 

 influencing the reduction of the iodide. For the determination 

 of the alcohol the method suggested by Stritar and Zeidler s 

 was used, but was afterward replaced by the modified methyl 

 iodide method. With the hardwoods free from light oil the 

 percentage could be taken from the specific gravity of the dis- 

 tillate according to the methods of Klar. 9 



The tars were classified as settled tars, dissolved or "boiled" 

 tars, and floating tars. 



The settled tar was the portion taken from the tar trap added 

 to that which settled at the bottom of the pyroligneous liquor. 

 Dissolved tars are those lighter portions dissolved in the pyro- 

 ligneous liquor, but separated by boiling off. The floating tars 

 were very light products found floating on the surface of the 

 distillate and in the scrubbing tower. They gave tests for 

 methyl alcohol, acetone methylated compounds, ketones, terpenes, 

 and neutral hydrocarbon oils. The total tar included all three 

 of the classes, and as such it was used as an analytical sample 

 in the case of each wood distilled. 



The composition of oils originating from the destructive 

 distillation of wood has been thoroughly studied by Fraps. 10 

 Working on tar from hardwood, he arrived at the following 

 results, which show the complex nature of a hardwood tar : 



(1) The wood oil examined is a mixture of a homologous series of dif- 

 ferent classes of compounds. 



(2) It probably contains the series of aldehydes CnH2nO, corresponding 

 to the series of saturated acids CnH^nCX', found in wood vinegar, which goes 

 up to and includes caproic acid. The quantity of aldehydes is so small 

 that only one could be positively identified, valeric aldehyde. Acetic alde- 

 hyde and propionic aldehyde have been found in wood oil by other investi- 

 gators, and these facts justify the first statement. It contains furfural in 

 minute quantity. 



(3) It contains the series of ketones CnHanO, of which dimethylketone, 

 methylethylketone, methylpropylketone, and probably methyl-H-butylketone 

 and diethylketone have been detected. 



(4) It contains the ring ketone, cyclopentanone, and other ring ketones. 



8 Zeitschr. f. aval. Chem. (1904), 43, 381. 



9 Loc. cit. 



"Fraps, G. S., Am. Chem. Journ. (1901), 25, 26. 



