Nov.,
1915
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
has recently been instrumental in calling the attention of manufacturers to the fact t h a t Oklahoma and Texas contain large quantities of Osage orange' which can be used very cheaply as a source of a valuable yellow dye for textiles and leather. The enormous leather industry is dependent not only upon the use of vegetable dyestuffs but especially upon the tannins obtained from hemlock, oak, chestnut and other materials. Certainly the preparation of tanning material involves the most delicate physical and chemical, as well as biological, operations, a s has been shown by the work of Proctor, Stiasny, Levi, Balderston and others. That the production and consumption of ethyl alcohol in the United States is an important activity is emphasized by the fact that the taxes on distilled spirits and fermented liquors amounted in 1913 to S223,000,000,which was over 6 j per cent of the entire internal revenue of the country. It will be recalled that over IOO years ago Braconnot carried out a n investigation in which wood was hydrolyzed by acids into glucose, which was then fermented into ethyl alcohol. In recent years, this problem has been studied energetically by Simondson, Classen, Cohoe, Ewen and Tomlinson and others, and four plants were erected in the United States. Three of these failed but the experience gained thereby and the research work on this problem by the Du Pont de A-emours Powder Company and the Forest Products Laboratory have now made the outlook for this industry very bright. It is believed that a plant could now be constructed under proper conditions of location, transportation, and other such factors, which would make possible the manufacture of ethyl alcohol from sawdust a t a price which would allow it to compete with the production of ethyl alcohol from molasses. Especially important in this connection is the discovery by the Forest Products Laboratory that western larch contains about IO per cent of a galactan yielding only galactose. If fermentation methods can be devised for the commercial conversion of galactose into ethyl alcohol, the western larch butts, which are a t present waste material, will become a very cheap source of alcohol. The increased efficiency of alcohol a t high pressures in internal combustion engines may thus place this material in a position where it can compete with gasoline when this becomes scarcer. The preservation of woods in railroad ties, telegraph poles, heavy bridge timbers, structural timbers, and in houses, is one of the most important phases of forest conservation before the public today. In this preservation over ~oo.ooo,ooogallons of coal-tar creosote, water-gas-tar creosote, and mixtures of these chemicals with petroleum residues are used. Aqueous solutions of zinc chloride, sodium fluoride, copper sulfate, and many other inorganic chemicals are also used very widely. bIillions of dollars are thus involved in a n industry whose business it is primarily to preserve this investment. It follows then that chemical methods must be developed for the analysis of the creosotes, and that chemical studies should lead to the manufacture of better materials a t lower cost. The Forest Products Laboratory has made investigations on the analysis of creosotes and the isolation of their many constituents, together with tests of the toxicity of these compounds toward wood-destroying fungi, and these researches have shown that great improvements could easily be made in the preservation of wood by the use of better specifications for the materials and methods of treatment. In the above paragraphs, only a few of the industries involving the utilization of chemical methods in the use of waste wood have been discussed. But daily the problems along these lines are being extended and the future will probably show that the application of chemistry t o the utilization of forest products extends into nearly every field of human endeavor. FOREST PRODUCTS LABORATORY A X D UNIVERSITY OF WISCOSSIN MADISON
THIS JOURNAL.6
(1914), 462.
*915
THE TANNIN CONTENT O F PACIFIC COAST CONIFERS By H. K BEKSONA N D THOS G. THOMPSON
The tannin extract industry of the United States utilizes for its raw material chestnut wood and the bark of the Eastern hemlock and the chestnut oak. From these species a standard extract containing 2 5 per cent tannin is manufactured, annually amounting t o over ZOO,OOO,OOOlbs. An equal or greater quantity of extract is either imported, or made from materials imported, of which quebracho is of chief importance. I n view of the large sources of available supply of tannin-containing materials on the Pacific Coast, a study n a s made of the tannin content of Western hemlock, Douglas fir and Western spruce. WESTERN HEMLOCK
The Western hemlock extends from Slaska to Marin County, California, and eastward, in some places, as far as bIontana, thriving in the cool, moist climate characteristic of western Washington and Oregon. It grows along with spruce, cedar and fir, often being left as useless by the timber cutters. An excellent example of the distribution of these trees is found in a recent survey of the merchantable timber of the Olympic h'ational Forest It was found that out of this forest, containft. of timber, 35 per cent was n'estern heming ~j,~oo,oOO,ooo lock, 37 per cent Douglas fir, and the remainder spruce and cedar The bark of the Western hemlock is thinner than that of the Eastern hemlock, but, as is commonly known, it contains a higher tannin content. This fact was first brought to the attention of the Washington public in 1893 when several samples of the bark were submitted to Dr. H. UT.Wiley, who reported the following analyses: SAMPLE hloisture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Total so!ids.. . . . . . . . . . . . . . . . . . . . . . . . . . Soluble solids., . . . . . . . . . . . . . . . . . . . . . . . Reds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Son-tannins... . . . . . . . . . . . . . . . . . . . . . . . Available t a n n i n s . . . . . . . . . . . . . . . . . . . . . . \%700dyfiber.. . . . . . . . . . . . . . . . . . . . . . . . .
Ashford 10.55 24.03 22.55 1.44 6.59 16.00 65,42
Enumclaw 10.01 22.16 20.58 1.58 5.76 14.86 6 i . 83
The first results that were published' calling attention to the differences in percentage of the tannin content of the n'estern and Eastern hemlock were the following analyses made by H. G. Tabor of hemlock bark from trees in Washington, Pennsylvania and Quebec: WashSOURCE: ington T a n n i n , . . . . . . . . . . . . . . . . . . . 17.04 Son-tannin.. . . . . . . . . . . . . . . 6.40 Reds...................... 1.56 Woody fiber.. . . . . . . . . . . . . . 75.00
Pennsylvania 13.28 7,52 3.48 i5,72
Quebec 10.16 4.56 1.52 83.36
iVestern hemlock bark has been used as the exclusive tanning agent in a t least one tannery in Washington for a number of years. This concern manufactures chiefly skirting leather for saddles. I t s larger use has been prevented by the lack of tanneries, due to economic reasons, rather than unsuitableness. The prevailing cost of hemlock bark f . 0 . b. tannery has been $1 I.j o per cord. EXPERIMENTAL
Inasmuch as few references to the tannin content of Douglas fir and J\'estern spruce could be found, and as far as is known no effort has ever been made to demonstrate the tannin content of sawmill waste from these species, an experimental study was undertaken. PREPARATION OF SAMPLE-The sawmill Waste taken for analysis consisted of bark, slabs, and sawdust from the crosscut saws. Samples of IOO lbs. were taken for the bark, from 100 to 150 lbs. for slabs, and about z j lbs. for the sawdust. The bark and the slabs were each reduced in a Mitts and Merrill chipper and the chips quartered to obtain an average sample. Before subjecting the sample to analysis it was further reduced to a fine powder in a Grumbaugh mill. 1
H i d e and Leather, June 24, 1893
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
916.
EXTRACTION OF SAMPLE-The apparatus used for extraction is shown in Fig. I. From 50 t o 7 j grams of the sample were placed in the percolator R A . The flask B contains the water for extraction. On boiling, t h e s t e a m flowed through the tube C, and entered the percolator where partial condensation occurred in D. Boiling water continC ually drops upon the material in A until i t reaches the height indicated by E, after which it is returned to the boiling vessel B. To prevent rifts or channels in the sample, the latter was mixed with broken glass before extraction, and t o prevent particles of bark or wood from siphoning over with the liquid, a small perforated porcelain disk and glass wool were placed over the outlet tube. It was found advisable t o use as large an outlet tube for the condenser as possible and to spread glass wool or wire gauze over the top of the I sample in the percolaFIG. I tor. Both the extraction and the analysis were made in accordance with the Official Method of the American Leather Chemists’ Association. TANNIN COXTENT OF DOUGLAS FIR
TABLE I-TANNIN
CONTENT OF
Sawmill Sawmill bark slab 14.92 Totalsolids. . . . . . . . , . _ . . . 14.75 13.02 Soluble solids . . . . . . . . . . . . 1 3 . 3 6 1.39 1.90 Reds . . . . . _ . ..., , . , , , , .. . 7.10 Nan-tannins ..... . , , . , . 7.02 5.92 Tannin . . , , . .. 6.34 6.91 Moisture . . . . . . . .. . . 9 . 0 6
......... .....
_...
DOUGLAS FIR Fresh Cambium hark 11.31 9.36 1.95 6.74 2.62 14.27
II
of the logs is available but it is probable that they were floated in water a longer period than in the case of the fir logs. While check analyses were made, time did not permit as complete an examination as for fir. The results of the analysis, reported on a dry basis, are given in Table IT. TABLE11-TANNIN CONTENTOF WESTERNSPRUCE Sawmill bark
SAMPLE:
. . . . . . . . . . _ 12.83
. . . . . . . . . . . 12.30 N o n - t a n n i n s . .. . . . . . . . . . . . . . . . , . Tannin... , .. . . ., . . . . . . . . . . . . . . . Moisture
6.42 5.88 15.23
Sawmill slab 11.25 10.38 0.87 6.79 3.69 9.15
TANNING VALUE OF FIR EXTRACT
The fir chips from the bark and slabs not required for were extracted by the West Coast Tanning Company, and several skins tanned in the resulting extract. desirable leather was produced, having a color similar obtained from oak tannin.
samples Seattle, A very to that
COMMERCIAL POSSIBILITIES FOR FIR EXTRACT
When it is remembered t h a t the tannin content of chestnut wood is 6.62 per cent, it appears that the low cost of fir slabs containing a n average of j per cent tannin should make the use of fir slabs a possible raw material for the tannin extract industry. It is known to the writers that fir slabs can be purchased from some of the mills at as low a cost as 75 cents per cord. In mills located in large cities, where they are sold for fuel, the cost is usually $1.50 to $2.00 per cord. Compared with Western hemlock bark a t $I I .50 per cord, it is found that three cords of fir slabs will yield as much as one cord of hemlock bark b u t at less than one-half the cost of the bark. CONCLUSIONS
I-The tannin content of fir sawmill waste is above j per cent while that of spruce is above 4 per cent. 11-It is believed that fir waste is a suitable material for use in the tannin extract industry. LABORATORY OF INDUSTRIAL UNIVERSITY OF
CHEMISTRY
WASHINGTON,
SEATTLE
- YIELD OF BY-PRODUCTS FROM DESTRUCTIVE DISTILLATION OF SOME WESTERN CONIFERS ~
~~~
B y H. K . BENSONAND MARCDARRIN
The extract obtained from the Douglas fir was reddish brown in all cases except from the freshly cut bark which was yellowbrown and contained a yellow precipitate. The logs from which the samples were obtained had been cut for a period of eight months and during a portion of this time they were in water. However, the bark of the Douglas fir is so thick t h a t there is probably very little loss of tannin by leaching in floating the logs t o the sawmills. From the yields given in Table I, it is shown t h a t the cambium layer, which is dark brown in seasoned wood and yellow-brown in freshly cut wood, contains most of the tannin. When a sample of bark is taken from a seasoned log not all of the cambium layer is taken. The slab, however, contains the cambium layer in its entirety with a relatively small quantity of wood in addition t o the bark proper. The analyses of various samples appear in Table I, the results being reported on the dry material. SAMPLE:
V O ~7., NO.
layer 21.96 19.28 2.68 9.36 9.92 20.59
Sawdust 5.78 4.40 1.38 3.34 1.06 15.51
TANNIN CONTENT OF WESTERN SPRUCE
The extract from spruce was a clear brown in color. The bark is much thinner than in fir. On account of remoteness of the mill from which the samples were obtained no history
The utilization of forest wood and mill waste by destructive distillation has been attempted in the Pacific Northwest on a commercial scale, but without success. It has accordingly been thought worth while t o undertake a study of the yields obtained from various species and from various classes of waste wood from a given species. For this purpose an experimental plant for operation on a semi-commercial scale was erected, cooperatively, by the United States Forest Service and the University of Washington. The design of this plant has already been described.l This plant was operated by chemists detailed by the United States Forest Service, in cooperation with the University of Washington. This paper presents a resum6 of results obtained in a series of runs, part of which were made by G. M. Hunt, and part by Marc Darrin, chemists in Forest Products, United States Forest Service. SPECIES AND CLASSES OF WOOD USED
For Douglas fir three classes of wood were distilled: ( I ) common run mill waste; (2) selected mill waste; (3) common run stump wood. I n the case of the Western yellow pine both common run stumps and common run mill waste were distillled while for Western hemlock only the common run mill waste was used for distillation. Before final and conclusive results covering the Western conifers can be obtained, similar studies of selected Western yellow pine and of spruce should be made. 1
THISJOURNAL, 6 (1913), 935.
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