EXPERIMENTAL WORK. 

 TREATMENT OF THE BLACK LIQUOR. 



17 



The black liquor and washings from the cooks were evaporated at 

 atmospheric pressure, dried in vacuum, and weighed. The residue 

 was then destructively distilled in round, hard-glass flasks, the prod- 

 ucts obtained being given in Table 3 on the basis of the dry liquor 

 and also of the wood. 



TABLE 3. Data on the dry distillation of black liquors. 



DISTILLATION OF OILS OBTAINED FROM THE DRY BLACK LIQUOR. 



The oils produced in distilling the dry black liquor were shaken 

 several times with a 9 per cent caustic soda solution until no more 

 was dissolved, for the purpose of separating creosote and other alkali 

 soluble oils, the alkali solution containing these being subsequently 

 acidified to insure separation of the oils. The oils insoluble in alkali 

 were then fractionally distilled from an ordinary still; that distilHng 

 below 250 C. was classed as rosin spirit, as is the commercial practice, 

 and that distilling from 250 to 400 C., after the more or less complete 

 separation of a crystalline body, retene, was classed as rosin oil. 

 Retene was present in all the fractions distilling at from 355 to 400 

 C., the largest quantity distilling between 388 and 393 C., or at the 

 boiling point of retene, 390 C. The retene was separated as far as 

 practicable from the rosin oils by chilling and cold pressing, but it is 

 relatively certain that this procedure did not completely separate it 

 from the oils, which in consequence contained some of it dissolved in 

 them. 



The results of the separation of the crude oils by the stated methods 

 are given in Table 4, and these are also stated as percentages on the 

 basis of both the dried liquor and the moisture-free wood. 



