DISTILLATION OF STUMPWOOD. 37 



The yield of calcium acetate is approximately but one-fourth of 

 that generally obtained in distilling the best hardwoods. Probably 

 on a commercial scale the yields would be somewhat less than those 

 shown by the analyses. The yield of wood alcohol also is but one- 

 fourth of that generally obtained in hardwood distillation. 



PRODUCTS OBTAINED IN REFINING CRUDE TURPENTINE. 



REFINED TURPENTINE. 



In order to separate the valuable turpentine constituents of the 

 crude turpentines from the pyroligneous and resinous heat-decompo- 

 sition products of the wood, the crude turpentines are first treated with 

 caustic soda, which combines with acids and resinifies the aldehydes 

 arid phenols, forming nonvolatile compounds. By a subsequent steam 

 distillation the turpentine and pine oil are recovered. Just as in the 

 case of the original retort distillation of the wood, the oily products 

 of the steam distillation are separated into several fractions. The 

 first product is called " first grade " or " first-quality refined turpen- 

 tine." The receivers are changed at a certain point (page 58), and 

 the distillate which then comes over is called " refined second- 

 quality turpentine." This has distilling temperature limits somewhat 

 higher than those accepted for true commercial wood turpentine. 

 Finally, the receivers are changed again, the last of the distillate be- 

 ing called " pine-oil fraction." 



On refining crude first turpentine a yield of approximately 80 per 

 cent of refined first-grade turpentine is obtained, most of which dis- 

 tils between 170° and 175° C. From crude second turpentine the 

 yield of refined first-quality turpentine lies in the neighborhood of 

 43 per cent. The other distillates from the crude turpentines are as 

 follows: From crude first turpentine, 5^ per cent refined second- 

 quality turpentine fraction and 7-J per cent pine-oil fraction; from 

 crude second turpentine, 13 per cent refined second turpentine and 

 12 per cent pine-oil fraction. 



