ANALYSIS, REFINING, AND COMPOSITION. 



41 



portion of the distillation; a large part boils below the usual boiling 

 point of turpentine, and the specific gravity over the complete range 

 of the distillation is higher than any portion (except the residue) 

 of a refined turpentine should be. All the fractions were also 

 colored and had very disagreeable odors. It was seen that no sepa- 

 ration by distillation alone could give a distillate suitable for a 

 refined turpentine, and therefore it 

 was necessary to give a chemical treat- 

 ment before refining by distillation. 

 The crude was therefore agitated with 

 caustic soda solution at 55 C. until 

 action ceased. The cessation of action 

 is shown by treating a small amount 

 of the crude with additional caustic 

 soda at the same temperature without 

 any resultant change in the color of 

 the caustic solution. 



The analysis of the crude treated 

 in this manner is given in figure 31. 

 The proportion of material boiling 

 below 155 C. was decreased consid- 

 erably, the specific gravity of all the 

 fractions was decreased, and the color 

 and odor of all fractions improved. 

 The index of refraction curve was, 

 however, somewhat irregular, and 

 all the fractions still retained some 

 disagreeable odor. That portion of 

 the distillate between 11 per cent and 

 64 per cent was more suitable for a 

 refined turpentine than that above 

 or below, and it was therefore de- 

 cided to separate the treated crude 

 into 11 per cent heads. 53 per cent hearts, and 36 per cent tails. 



160 165" 170" 175" 180 185 190 195 

 O & &7 .68 9 90 91 92 .93 



O U68 U70 1472 U14 U76 U78 U80 



FIG. 31. Boiling point, specific 

 gravity, and index of refraction 

 curves for crude turpentine No. 3, 

 after treatment with caustic soda 

 solution. 



DISTILLATION. 



The crude was run into the still at a speed of 25 gallons per hour, 

 and the speeds of the heads and hearts were maintained respectively, 

 as nearly as possible, at 11 per cent of 25, or 2.75 gallons per hour, 

 and 53 per cent of 25, or 10.75 gallons per hour. During this dis- 

 tillation great difficulty was experienced in regulating the speed of 

 the products, and the effects of this are seen in the composition of 

 the products. 



