TABLE 2 

 Distribution of Rosin after Alkali Extraction 



[Results expressed in Percentages of Total Rosin 

 in Original Wood Ether Extract =32.1 per cent.] 



Experiment Number 



Fraction. Form of Rosin. 34 5 6* 7 

 Direct Extract Direct Cooling 



Soap Ppt 48.2 70.7 65.5 59.2 53.3 



Filtrate 18.0 5.9 8.7 20.2 8.4 



Direct Extract Strengthening to 6 

 to 8% NaOH 



Soap Ppt 63.5 75.0 72.0 76.5 59.4 



Filtrate 2.7 2.8 2.8 2.8 2.3 



Direct Extract Total Rosin as Soap 66.2 77.2 74.5 79.4 61.7 



1st Wash Liquor. .Sol. Rosin Soap. .. 11.7 10.6 11.2 9.7 10.0 



2nd Wash Liquor .. Sol. Rosin Soap. .. 2.9 3.4 2.5 2.9 4.4 



Washed Chips. . Unsaponified Rosin.. 7.8 0.15 0.9 0.14 8.0 



Balance 11.4 8.6 10.9 7.9 15.9 



* Extraction of Smaller Chips with NaOH. 

 Extraction of Larger Chips with Na2CO3. 



Reclaiming of Rosin 



Table 2 shows the distribution of the rosin con- 

 tent of the wood after alkali extraction and wash- 

 ing. The analytical results have been expressed 

 as percentages of the total rosin in the original 

 wood as determined by extraction with ether. 



As already mentioned, the direct extract was 

 aliquoted and treated in two ways. Some por- 

 tions were allowed to cool directly; others 

 were treated with additional caustic soda to 

 precipitate the soap more completely and leave 

 a supernatant liquor, which would represent a solu- 

 tion available for the final soda cook in industrial 

 practice. Where solution of the rosin was complete, 

 from 75 to 79 per cent was removed in the first 

 draining. Of this amount from 96 to 97 per cent 

 was recovered in the form of soap precipitate by 

 strengthening the liquor with caustic soda to from 

 6 to 8 per cent. The sodium resinate remaining in 

 solution was of course dependent on the solubility 

 of the soap in the strong alkali, and on this account 

 was practically a constant quantity 2.3 to 2.8 per 

 cent of the total. The percentage would be re- 

 latively higher in the case of leaner woods, but 

 the actual loss is comparatively small. This un- 

 recovered rosin would be carried through the soda 

 cook and would be of some advantage as fuel in 

 the final incineration involved in the recovery of 

 alkali from the waste pulping liquors. 



44 



