6 BTJLLETIX 983, TJ. S. DEPARTMENT OF AGPJCtT.TUEE. 



market for it. In addition, the waste as it comes from the mill is 

 usually a mixture of all forms, and any attempt at separation, except 

 perhaps a simple blowing or screening to remove the very fine stuff, 

 will increase the cost of the raw material to a prohibitive figure. 

 Therefore, in any satisfactory process for the utilization of mill waste, 

 it must be possible to handle any and all forms of waste as it comes 

 from the mill. 



Except in factories using onfy one or two species of wood, or in mills 

 cutting only a few similar species, such as the "yellow pine" (long- 

 leaf, shortleaf, and loblolly) of the South, the differences in quality 

 and form of the waste have operated against its efficient utilization. 

 This is because many processes, such as pulp and paper making or 

 destructive distillation, require a particular species in order to give a 

 yield and quality of product that will make the processes commercially 

 feasible. 



Woods of all species and forms, however, have one point in com- 

 mon — they all contain more or less cellulose, which makes up the 

 fibers of the wood, along with an incrusting substance called lignin. 

 A chemical utilization of this cellulose would overcome the objec- 

 tions stated above as to the form of the material, length of the fiber, 

 and species, provided the amount of cellulose present was sufficient 

 to give a yield of alcohol that could be handled profitably on a com- 

 mercial scale. 



PROCESSES FOR THE MANUFACTURE OF ALCOHOL FROM WOOD. 



The processes used for the production of ethyl alcohol from wood 

 may be grouped into two general classes: Hydrolysis of wood into 

 fermentable sugars by the use of dilute acid (preferably mineral acid) 

 as a catalyzer, and solution processes, in which the wood is dissolved 

 in concentrated acid and the diluted solution is then subjected to 

 hydrolysis. 



The first process consists, in general, of digesting sawdust or hogged 

 and shredded wood with a dilute mineral acid under 60 pounds or 

 more of steam pressure. This converts part of the wood into a 

 mixture of pentose and hexose sugars. The latter are then fermented 

 into ethyl alcohol. 



Processes of the second class, involving the use of concentrated 

 sulphuric acid and in which the wood is actually dissolved by the 

 acid, as in the Ekstrom 5 process, have not received commercial 

 attention, notwithstanding the fact that Flechsig 6 many years ago 

 showed that cotton cellulose could thereby be converted into dex- 

 trose and alcohol almost quantitatively. The more recent work of 



5 French Patent No. 380358; German Patents Nos. 193112 and 207354. 



6 Zeit.fiir Physiol, chemie., 1882. 



