to make use of this principle in extracting the rosin 

 from the wood. A mild treatment was necessary 

 to prevent undue attack of the actual wood by the 

 alkali. The fact that turpentine and pine oil are 

 volatile with steam at temperatures far below 

 their boiling points suggested carrying out the 

 preliminary extraction at low steam pressures, there- 

 by allowing separation of the volatile oils. After 

 removal of the rosin and turpentine the wood 

 could be steamed with stronger alkali under more 

 severe conditions, for the production of paper 

 pulp. 



In addition to the investigation of the factors 

 affecting such a treatment of the wood, it was 

 important to determine the quality and yields of 

 the products and to provide for their purification. 



Historical 



There have been a number of suggestions for 

 the utilization of resinous materials involving the 

 principle of alkali extraction. 



Craighill and Kerr (U. S. Patent 817,960, Apri 

 17, 1906) have patented a process by which the 

 chipped wood is treated first with a small volume 

 of liquor containing an amount of caustic soda 

 "just sufficient to saponify the rosin and oils and 

 neutralize the (volatile) acids without dissolving 

 other extractive matters of the wood." Steam is 

 admitted long enough to distil the terpenes; 

 water is then added in order to submerge the chips 

 in alkaline solution, and steaming is continued 

 until saponification of rosin is complete. This solu- 

 tion is then drawn off and the chips treated with 

 a stronger caustic solution for the production of 

 paper pulp. 



J. Aktschourin (French Patents 432,998, Aug. 

 5, 1911, and 433,424, Aug. 11, 1911; Ger. Pats. 

 248,275, July 12, 1912 and 257,015, Jan. 12, 1913) 

 provides for the extraction of resinous material 

 by heating with dilute alkali below 100C. at sev- 

 eral atmospheres pressure. The lower temperature 

 lessens the attack of the lignin. The liquor is 

 drawn off and cooled to precipitate a certain amount 

 of emulsified resin and rosin soap. The filtrate 



14 



