DISTILLATION OF STUMP WOOD. 33 



clear, brownish-red oil that darkens on standing and has a creosote 

 odor. The residuum from this distillation is a hard pitch. Ke- 

 peated rectification of this light oil has given a series of fractions 

 ranging from 166 to 176. The fraction from 174 to 176 gives 

 an oily bromin addition product. Apparently it adds hydrochloric 

 acid gas to form needlelike crystals after standing a number of days, 

 but all attempts to make a nitrosyl chlorid were fruitless. 



The yield of crude light oil, compared to that of heavy oil, is 

 small. Since the light oil differs but little from the heavy oil, 

 it probably will be found expedient to collect and market or work 

 it up along with the heavy oil in the operation of a commercial 

 plant. One application to which this crude oil may be put is as a 

 vehicle for cheap paints and shingle stains, and other such pur- 

 poses for which certain of the creosote oils are now used. 



HEAVY OIL. 



The properties of the heavy oil which results chiefly from the 

 destructive distillation of rosin resemble strongly those of rosin oil. 

 The crude oil also contains decomposition products of the wood tis- 

 sue, to which extent it is like wood creosote and rosin oil. The 

 crude heavy oil is slightly heavier than water (average density 

 of 1.048 at 20 C.), is brownish black, and has a penetrating, creosote- 

 like odor. The average viscosity at 25 C. is 11.9 Engler. Like 

 the light oil, it is comparatively unknown and untried, and there- 

 fore lacks a well-established market value. 



Heavy oil is one of the important products obtained in the dis- 

 tillation of resinous woods. The yield is exceedingly variable, run- 

 ning from about 75 gallons a measured cord of very rich stump- 

 wood to as little as 16 gallons from dead, down wood. Making up 

 a large proportion of the total volume of oil recovered, its disposal 

 to the best advantage possible is essential to the profitable operation 

 of a commercial plant where the process is similar to that employed 

 in this investigation. Consequently, certain experiments, looking to 

 the most probable means by which an enhancement in the value of 

 the crude oil may be expected, were conducted. 



From the results of laboratory work it was found that in sepa- 

 rating its low-boiling fraction by distilling at atmospheric pressure 

 from a flask fitted with a Hempel column, distillation begins at an 

 uncertain initial temperature of about 85 or 90 C., with an average 

 recovery of 25 per cent (8.7 gallons a cord) below 225 C. This 

 fraction is quite similar to the corresponding fraction obtained from 

 the crude light oil. 



The crude heavy oil can be used with some success for flotation 

 purposes. In other fields of industry it must be sold largely in com- 

 petition with products commonly obtained from coal tars such as 

 60953 21 3 



