NEW BNGLARD ASSOCIATION of
CllEMlSTRY TEACBBRS
The Possibilities of the Wood-Chemical Industries in the Northeast' ROBERT S . ARIES Northeastern Wood Utilization Council, New Haven, Connecticut
WAAT DO WE KNOW ABOUT WOOD CHEMISTRY
T WOULD be difficult to fmd a substance that is so well known as wood and about which so little is known. Wood has been used since prehistoric time and is now our second largest industry. But this background has not stimulated such fundamental studies as have been devoted to rubber, steel, coal, or cotton. The result is that the lumber industry has not advanced proportionately, and some of the advances of other products have been a t the expense of wood. Dry wood is essentially about 70 per cent celluloses and 30 per cent lignin, and very small amounts of mineral and organic substances. The various species differ from each other mainly in the way these two substances, cellulose and lignin, are distributed and arranged; in other words, species diier structurally but are, chemically, quite similar. In this respect trees are related to all other plants and may be considered as just big, fast-growing, perennial but valuable weeds. More than a century ago Payen discovered cellulose, whose industrial significance has resulted in an enormous amount of research. This carbohydrate occurs in varied forms,' having the empirical formula CsHlo06. I t can be hydrolyzed to yield nearly the theoretical amount of glucose and therefore is regarded as being made up of anhydroglucose units. Various methods for the isolation of cellulose from the olant tissue denend
I
' Condensation of a paper delivered before the Sixth Summer
Conference of the New England Association of Chemistry Teachers, Connecticut College, New London, Connecticut, August 244, 1944. Editor's note: The author has a few copies of the complete paper, which at our request he has agreed to make available as long as they last. He may be addressed at P. 0.Box 1577, New Haven 6. Connecticut.
on the action of alkalies, acids, oxidizing agents, bacteria, and solvents. The chief noncellulosic component of wood is lignina complex material generally characterized by the method used in isolating it from the cellulose to which it serves as a binder. The field of lignin chemistry is relatively unexplored. and offers tremendous opportunities to chemists as it is considered the Iargest waste in the United States. The so-called hemi-celluloses present in wood include polymeric forms of hexose and pentose sugars, oxidation products such as uronic acids, etc. In addition, wood contains smaller amounts of resins, terpenes, fats, nitrogenous matter, tannin, coloring matter, and mineral ash. CHEMISTRY IMPROVES WOOD ITSELF
We know that other cellulose products such as paper and cotton may be flameproofed, waterproofed, strengthened, hardened, and made rotproof and verminproof and resistant to chemical attack. Chemists appreciate that wood can also be given these properties as well as a wide, if not a wider, variety of structural changes than are possible for paper, cotton, or most other substances, plastics included. It may be of interest to mention the better known chemical treatments of wood as an introduction to those not so well known and to those that, though still concepts, may have far-reaching import to the lumber industry. Wood treatment; exclusive of conversion, may be classified into four divisions: 1. Preservation, which includes flameprwfing; sap-stain prevention; preservation from insects, rot, and chemical attack. 2. "Reassembly," that is, taking the wwd apart and putting
the properties we want it to have and we are no longer limited to its natural characteristics. Thin sections can be given strength without the use of heavier dimensions. Treated wood can be readily bent and shaped. It would eliminate the sticking drawer, door, or window. With proper effort, progressiveness, and support of chemical research by the lumber industry, Much time could be devoted to any one of these wood should be able to stay in the race even when divisions or to an individual item. The chemist can metals, plastics, and glass, too, come back as chalprevent wood from burning by the use of ammonium lengers. phosphates, borax, and other chemicals. In the field WOOD HYDROLYSIS-THE CHEMISTS' DREAM of wood preservation we use coal-tar creosote, zinc chloride, Wolman salts, copper, mercury, and other The largest potential field for the utilization of wood compounds among which is pentachlorophenol, dis- as a raw material for the chemical industries appears covered in America, h$ve heen very effective in con- to be offeredby hydrolysis with acid substances into a trollmg decay and t e n t e s . host of substances. The present severe shortage of In connection with drying and seasoning, chemists ethyl alcohol which will probably continue for a number again may be of help. If the surface of lumber is kept of years centers our attention on this versatile chemical from shrinking during drying, checking is prevented. material. Wood may be kept from shrinking by introducing a There are two ways for making ethyl alcohol from chemical that will either keep the surface moist and wood. One is to ferment i t from wood sugars obtained swollen during drying, or one that will enter the wood by hydrolysis of wood waste just as grain alcohol is structure and prevent the fibers from shrinking during fermented from corn or molasses. This process has drying. The chemical must be highly soluble in water, assumed considerable importance in Europe, the prodnoncorrosive, nontoxic, stable, available, not cause ucts including both alcohol and yeast with a high dampenhg or "sweating" of the lumber in humid nutritive value which is used as feed for dairy cows and weather, nor aflect tools, and, above all, i t must be cattle. inexpensive. Urea has proved very satisfactory as a The Northern Wood Utilization Council has been seasoning agent and is now being used throughout the looking for some time into the application of this process United States on most commercial species of softwoods in our area. An alcohol plant utilizing the modified and hardwoods. It has also been found that urea- Scholler process is being constructed a t present on the treated wood is somewhat less flammable and less Pacific Coast, but it is felt by us that on account of the susceptible to decay and stain than untreated wood. smaller tonnages of wood waste available in our area, we should concentrate our efforts on the production of cattle feed, which necessitates less control and may Impregnated wood is obtained by treating wood with yield valuable by-products such as vitamins. Work resin so that the resin actually penetrates the wood is being done by one of our members in this direction, cells. This "impreg" is almost swell, shrink, and which may prove to be of vital importance to the decay proof. By compressing the wood after impreg- economy of the Northeast. On the average, a New England hillside will grow nating it, we obtain a hard, dense substance with a beautiful grain showing through a permanent gloss about 75 cubic feet of wood per acre per year or 1.25 l i e that of a polished marble. This is "compreg" tons, whiie it would produce less than 20.bushels of corn which has some of the properties of mild steel. In the or a half bale of cotton if that were a t all possible. The not too distant future we might witness "compreg" carbohydrate content of wood could be converted to which has been impregnated with lignin resins also protein, thus bridging a gap in the economy of so-called poor lands. A ton of wood yields, by hydrolysis, about derived from wood, thus forming a real "wood iron." The peacetime uses of compreg should be numerous. 1100 lb. of sugar. By the addition of 250 lb. of amSince it can be bonded to ordinary wood in a single monium sulfate or 100 lb. of urea and 50 lb. of superoperation without compressing the latter, itplight make phosphate, 500 lb. of yeast can be grown. This would a hard yet resilient' tile flooring. Its solidity and be cheap protein produced without sticking a plow into durability and unscratchable natural polish, impervious the ground. Another way of making alcohol from waste wood is to cigarettes and alcohol, show a big future. Recently, Dr. J. F. T. Berliner from Du Pout has by utilizing sulfite pulping liquors, amounting to 500,000 developed commercially a chemically transmuted wood tons in the Northeast, which contain up to 3 per cent by impregnation with methylolurea which is capable of cellulose "sugars" dissolved in the liquor along with of reacting with the wood cellulose with an internal the lignin. Yeast fermentation of the liquor is now formation of a resin. Actually we are no longer dealing standard practice in most European mills. Such a plant is now in operation in Canada, using the Ontario with wood. Pine can be made as hard or harder than maple; Paper Company's wastes. Another one will be under in other words, we have means of endowing wood with construction on the Pacific Coast. Our Council was it together again in a new form such as plywood, laminated wood. plastics, etc. 3. Drying or seasoning, which includes chemical seasoning and .end sealing. 4. Alteration of mechanical properties, which includes stabilizing of dimension, hardening, increasing strength and wear. chemical bending; resin impregnation, and compregnation.
instrumental in interesting several pulping mills in the Northeast in the process, but Washington finally decided not to build any new recovery plants. At present our Secretary, Mr. Edgar L. Heermance, is trying to rally all the mills for cooperative research into the problem of uses for waste sulfite liquors. In this field we expect to cooperate with the newly formed Council for Stream Improvement which will pursue intensive reoearch on the problem. However, the production of alcohol from wood in the United States raises several technical, economic, and political questions which complicate the picture. At the present price of farm products, the rock bottom price for alcohol from grain is 50 cents per gallon. The grain surplus fluctuates from year to year and does not look as excessive in 1944 as i t did several years ago. Under present conditions, there might be a serious grain shortage if we have to feed the starving world during and after the war. However, there is enough sawmill and pulp-mill waste in the United States and Canada to make about 2,500,000,000 gallons a year
or five times as much as the 1943 alcohol production in the two countries. Ethyl alcohol could also be used as a motor fuel, as it raises the octane rating of gasoline. The norinal consumption of gasoline in North America amounts to 20,000,000,000 gallons annually. Some specialists predict for the not too distant future a depletion of our petroleum supplies with a resulting increased cost for gasoline derived through imports, distillation of bituminous shales, or hydrogenation of coal. If these trends are reasonably correct and if research can further lower the cost of production of alcohol from wood, there would be a potential alcohol market which would require about 900,000,000 cords of wood annually to supply! However, due to the availability of imported oil, shale oil as well as oil obtained by the hydrogenation of coal, we may have to go through a great deal of further development work before such an event occurs. REFERENCE
WISE, L. E., "Wood Chemistry," Reinhold Publishing Cow., New Yark, 1944.
