DISTILLATION OF STUMPWOOD. 



CRUDE PRODUCTS OF RETORT DISTILLATION. 



CRUDE WOOD TURPENTINE. 



•The crude wood turpentine is distilled from the wood during 

 first stage of the destructive distillation. During this first stage 

 distillation the turpentine passes over for the most part unchang 

 as it probably exists in the wood tissue. The crude first turpenti 

 therefore, is nearly free from pyroligneous bodies. It is often li; 

 in color, and usually possesses an agreeable odor. It has a spec 

 gravity of about 0.875 at 20° C, a refractive index of about 1.4 

 at the same temperature, and an initial boiling point of about 164° 



The crude second turpentine necessarily contains more of the py 

 ligneous or heat-decomposition products and of the heavier pine c 

 since the retort operator cuts the distillate at the first signs of 

 composition of the wood, indicated by the appearance of none 

 densable gases, and collects the remainder of the turpentine as " s 

 onds." The heat-decomposition products of the rosin and wi 

 constituents consist of acids, alcohols, ketones, phenols, aldehyt 

 etc., the nature and quantity of which depend on the temperat 

 and rate at which the turpentine stage of the distillation is conducl 

 This crude second turpentine is darker than the crude first, and 

 color is sharper and more suggestive of wood decomposition. It 

 a specific gravity of about 0.910 at 20° C, a refractive index of ab 

 1.4850 at the same temperature, and an initial boiling point of ab 

 130° C. (due to the presence of decomposition products). 



The difference between these two crude turpentines is well set f o 

 in Table 15. 



Table 15. — Products of dry distillation of crude turpentine at 160 mm. press 





Temperature of distillation 



C°C). 



First 

 turpen- 

 tine. 



Sec 



tur 



til 



Below 170 



Per cent. 

 9.3 

 52.8 

 16.0 



Per 



Between 170 and 175 









Between 180 and 185 







21.9 









The details of refining the crude turpentine are discussed 

 page 56. 



LIGHT OIL. 



The crude light oil is brownish black, has a sharp, penetrati 

 empyreumatic odor, an average specific gravity of about 0.99£ 

 refractive index of 1.514, each at 20° C, and an acid value of ab 

 29. Its average viscosity at 25° C. is 2.58° Engler. The yielc 

 about 4| gallons a cord of rich wood. Distilled in the ordin 

 manner at atmospheric pressure, using a fractionating column 

 has an uncertain initial boiling point, around 70° C, due to the pi 



