32 



BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE. 



ence of water and other low-boiling constituents, which rises rapidly 

 to 160° C. The complex nature of this material is indicated by its 

 wide temperature range when subjected to distillation. Typical 

 results are shown in Table 16. 



Table 16. — Distillat 



Ion data 



of composite crude light oil. 





Material distilling between — 



Amount. 



Material distilling between — 



Amount. 



55° and 120° C 



Per cent. 

 3.5 

 13.6 

 21.1 



230° and 350° C 



Per cent. 

 54.3 



120° and 180° C... 





1.8 



180° and 230° C... 





5.7 









On subjecting the various samples of crude light oil to dry dis- 

 tillation at atmospheric pressure, using a fractionating column, an 

 average of 34.5 per cent was found to distil below 225° C. Of the 

 total distillate an average of 1.8 per cent was aqueous. This aque- 

 ous portion, as well as the lighter portions of the oily distillate, con- 

 tains quantities of acetic acid, methyl alcohol, and acetone. The 

 difficulty of their recovery in a state pure enough for quantitative 

 estimation is such, however, that it is as yet possible only to esti- 

 mate the quantities of these bodies present. 



On treating the distillate obtained below 225° C. with an excess 

 of 20 per cent alkali solution, a marked contraction in volume of the 

 oil and decided heating were observed. When the oil thus treated 

 was steam distilled to exhaustion, 87 per cent (1.3 gallons a cord) 

 of total distillate was recovered as a rather sharp-smelling, light- 

 yellow oil having an uncertain initial boiling point of about 125° C. 

 On dry distilling this steam-distilled oil, 60 per cent passed over 

 below 175° C, and the remainder distilled up to 250° C. In its 

 behavior on distillation it shows a close resemblance to rosin spirits. 



By treating the crude light oil with alkali and distilling with 

 steam as in the refining of the crude turpentine, 10 per cent (0.4 

 gallon a cord) of the oil is recovered as refined rosin spirits dis- 

 tilling at from 130° to 200° C. and 20 per cent as a pine-oil fraction 

 distilling at from 175° to 275° C. The pine-oil fraction distilling 

 at from 175° to 275° C. has a lemon-yellow color like refined pine 

 oil, but an unpleasant, altogether different odor, and can not be con- 

 sidered as pine oil, except perhaps in certain of its constituents. 

 Fifty per cent of it distils below 200° C. 



The residue from this steam distillation of the crude light oil 

 forms a heavy emulsion with the alkali present. On the addition of 

 acid about 10 per cent of the original oil separates out as a heavy tar 

 that settles to the bottom. The remaining oil has about the density of 

 water, slowly floating to the top, is dark, and has a mild odor. 



Distilled in a vacuum of from 10 to 20 mm., 80 to 85 per cent 

 (3.2 to 3.4 gallons a cord) of the crude light oil is recovered as a 



