642 



Yearboo\ of Agriculture 1949 



price could be made as attractive as 

 the pilot-plant studies indicate, the 

 demand for feed molasses from wood 

 could be tremendous. If livestock feed- 

 ing could be built up to the level al- 

 ready demonstrated as possible with 

 cane molasses ( about 3 pounds per day 

 per head for cows, somewhat more for 

 beef cattle, and somewhat less for 

 sheep), the amount of molasses used 

 for feeding could be increased at least 

 75 times. In theory, such a goal could 

 utilize the equivalent of about two- 

 thirds of all available wood residues. 

 Here, then, is a potential use for wood 

 residue that could consume large 

 quantities of it. 



The sugar solution resulting from 

 hydrolysis can also be fermented to 

 ethyl alcohol (grain alcohol). Bark- 

 free softwoods yield up to 60 gallons 

 of alcohol per ton of dry wood, and 

 hardwoods about 50 gallons. Bark may 

 be present up to 50 percent, but its 

 presence somewhat decreases the yield. 

 This alcohol is suitable for many in- 

 dustrial purposes. A large commercial 

 plant capable of processing 200 to 300 

 tons of wood residue a day in the man- 

 ufacture of ethyl alcohol has been built 

 on the Pacific coast. The short time 

 in which it has operated has demon- 

 strated the commercial possibilities of 

 the process. When shortages of petro- 

 leum products occur, the ethyl alcohol 

 produced at such plants could become 

 one of our chief motor fuels. It can, 

 under present conditions, be produced 

 from wood at about one-fifth of the 

 cost of producing it from grain. 



Only the hexose sugars are used in 

 making alcohol. The pentoses remain 

 in the stills after distillation. They may 

 be used for growing yeast or for con- 

 version to furfural, which is a chemi- 

 cal used as a solvent in oil and rosin 

 refining, in certain plastics, and re- 

 cently as a starting material in making 

 nylon. 



Tests are under way to determine 

 the food value of wood yeast. It is rich 

 in riboflavin, a vitamin, and conse- 

 quently should have greater food value 

 than is indicated by its high protein 



content alone. The production of wood 

 yeast thus also shows promise of de- 

 veloping into a sizable industry that 

 could use up large amounts of wood 

 residue. 



Different cultures and fermentation 

 conditions make possible the manufac- 

 ture of acetic, butyric, and lactic acid 

 from wood sugars and also acetone, 

 butyl alcohol, and butylene glycol. 

 Butyric acid is used in making cellu- 

 lose-butyrate plastics. Lactic acid is 

 used as a food preservative. Butyl alco- 

 hol and butylene glycol can be used in 

 making artificial rubber. Butylene 

 glycol would be a good antifreeze agent 

 for use in automobile radiators. 



When sugars are formed by the hy- 

 drolysis of wood, a residue of fine solid 

 lignin remains. This material, a sub- 

 stance that binds the wood fibers to- 

 gether in a tree, has a higher fuel value 

 than wood itself and may be burned as 

 a fuel in the processing plant. It shows 

 promise as a soil conditioner. When 

 agricultural crop residues decay, the 

 remaining humus is largely lignin, so it 

 is natural that lignin should have soil- 

 conditioning value. Lignin from wood 

 hydrolysis has not shown the value in 

 plastics found in other forms of lignin 

 recovered from paper manufacture. 



HYDROGENATION has been most ex- 

 tensively studied on isolated lignin, but 

 it may also be applied to all parts of 

 wood. In the process, the lignin is sus- 

 pended, or preferably dissolved, in an 

 organic liquid that itself does not react 

 with hydrogen and that will not de- 

 compose at the high temperatures used. 

 Most of the work to date has been done 

 on batch lots placed in small bombs. A 

 metallic or metallic-oxide catalyst is 

 used to promote the reaction. A com- 

 plex mixture of liquid products and a 

 tarlike residue are produced. 



The liquid consists of a mixture of 

 complex cyclic alcohols, phenolics, and 

 neutral oils. The cyclic alcohols, when 

 added to gasoline, show good anti- 

 knock properties. They are also good 

 solvents, and some of them have toxic 

 properties. The phenolics are a mix- 



