Putting Unused Wood to 



643 



ture of those suitable for plastics and 

 some that are not. Means of separating 

 them have not yet been found. 



The neutral oils are of the hydrocar- 

 bon type. Part of them may prove suit- 

 able for lubricating purposes, and all 

 as fuels. 



The proportions of these three types 

 of chemicals formed in the process 

 may be varied with the hydrogenating 

 conditions. 



Wood may also be hydrogenated in 

 aqueous alkaline suspension. The lig- 

 nin forms compounds of the types just 

 described. When the hydrogenation 

 conditions are mild, the cellulose left 

 is a pulp residue; when severe, the cel- 

 lulose is broken down into sugars and 

 glycerine. The industrial possibilities 

 of such a glycerine-forming process 

 must await further research. 



Before the hydrogenation of either 

 lignin or cellulose can become an in- 

 dustrial reality, methods for carrying 

 on the process in continuous-flow 

 equipment will have to be developed. 

 The possibilities of commercial hydro- 

 genation, however, are promising. One 

 is to hydrogenate the lignin residue 

 from a wood-hydrolysis ethyl-alcohol 

 plant to obtain an optimum yield of 



neutral oils. Such a plant, it is esti- 

 mated, could produce, by the combined 

 methods, from a ton of dry wood about 

 110 gallons of liquid fuel consisting 

 chiefly of ethyl alcohol and neutral oils, 

 together with some methyl alcohol and 

 furfural. 



With all these possibilities, the chem- 

 ical processing of wood residues may 

 well be expected to expand rapidly in 

 the next few years. 



ALFRED J. STAMM, a Californian, 

 joined the Forest Products Laboratory 

 in 1925 and at present is chief of the 

 Division of Derived Products. He has 

 published a number of research papers 

 on such subjects as particle size in 

 emulsions, capillary structure of wood, 

 wood and cellulose-liquid relation- 

 ships, swelling and its prevention, elec- 

 trical properties of wood, and molecu- 

 lar properties of cellulose and lignin. 

 Dr. Stamm has degrees in chemistry 

 from the California Institute of Tech- 

 nology and the University of Wiscon- 

 sin. In 1928 he studied in the Uni- 

 versity of Upsala, Sweden, in order to 

 apply the ultracentrifuge technique to 

 the study of the molecular weight of 

 cellulose. 



PUTTING UNUSED WOOD TO WORK 



C. V. SWEET 



Every time a saw chews through 

 a log, it spits aside sawdust. Whenever 

 a planer dresses the roughness off a 

 board, it throws off shavings. Square- 

 edged lumber is made only at the cost 

 of slabs, edgings, and trims. For every 

 log put through the sawmill a consid- 

 erable tonnage of wood fiber is left in 

 the forest. Even the digesters of pulp 

 mills disgorge as unusable sizable quan- 

 tities of the wood fed into them. And 

 so it goes with nearly every operation 

 concerned with harvesting and con- 

 verting trees into useful things. 



Those unused materials generally 

 have been called waste, not in the sense 



that they signify neglect or carelessness 

 but in the sense that they are not eco- 

 nomically usable. If there is use for 

 them, the margin of profit may be 

 discouragingly narrow, the necessary 

 investment for equipment may be pro- 

 hibitive, or the expense of handling and 

 hauling the raw material to one point 

 may be excessive. 



Theoretically, there is a use to which 

 practically every type of unused wood 

 is or can be put. The problem is in 

 finding profitable ways of doing it on 

 an adequate basis. 



Only in relatively recent years have 

 we come to regard those unused forms 



