METHODS OF PRODUCTION. 13 



and washed out of the pulp, which, after suitable treatment, may 

 be disposed of in several ways. The removal of the turpentine by 

 this process is exceedingly rapid, and it is claimed that from the 

 boiling alkali solution the turpentine may be removed by some proc- 

 esses in from 10 to 15 minutes. 



REFINING WOOD TURPENTINE AND WOOD OILS. 



The crude oil obtained by any distillation process is redistilled or 

 refined before it is marketed. Crude oils from the destructive process 

 are agitated with alkali whereby the greater part of the phenols, 

 cresols, and related bodies are dissolved, and separated by settling 

 from the turpentine, rosin spirits, and rosin oils, which are run off 

 and separated by redistillation with steam as steam-distilled wood 

 turpentine is. This is usually done in a copper-pot still of suitable 

 size, live steam being conducted directly into the crude oil. Ordina- 

 rily this distillation is not conducted with care, and but little attempt 

 is made to insure that the wood turpentine obtained does not contain 

 considerable quantities of the heavier "pine oils." Distillation is 

 usually continued until the oil passing over shows "bead" or until 

 the specific gravity is about 0.8800 or 0.9000 at 15.5 C. 



Recently at a number of plants more care has been exercised in 

 refining and the product is distilled with steam several times from 

 a pot still. Such careful refining is, of course, expensive and the 

 yield is much reduced, but the product complies closely in specific 

 gravity and behavior^pn distillation and evaporation with standard 

 specifications for turpentine. The crude oil yields on redistillation, 

 as this is commonly practiced, from 60 to 80 per cent of wood 

 urpentine. As will be seen from the analyses (Table 1, p. 58), these 

 oils contain notable quantities of heavier oils, and but few of them 

 an be considered high-grade wood turpentine. 



The pine oils from steam distillation are also redistilled with steam 

 and are marketed in two grades, white and yellow or straw colored. 

 Their specific gravity ranges from 0.8890 to 0.9600; refractive index 

 From 1.470 to 1.500 and they begin to distill at from 165 to 180 C. 

 Distillation is generally complete at from 215 to 240 C. and by 

 far the larger quantity of most pine oils distills between 190 and 225. 

 The crude, destructively distilled oils, after being agitated with 

 alkali and washed with water to remove phenols, cresols, etc., are 

 separated into at least three fractions, preferably in a column still. 

 The first fraction, distilling at from 80 to 150 C., consists essentially 

 of the lighter constituents of rosin spirits with some turpentine and is 

 contaminated with small portions of substances derived from the 

 breaking up of the wood. The fraction boiling at from 150 to 180 

 3. is destructively distilled wood turpentine, that boiling at from 170 

 to 180 C. to 230 to 250 C. constitutes the pine oils with the heavier 



