Jan.,1 9 2 1
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
61
TAWE 111-BINARY SYSTEM:'I'RINITROTOLUENX$-O-NITROTOLUENE THE PREPARATION AND ANALYSIS OF A CATTLE FOOD Per cent by Weight Freezing CONSISTING OF HYDROLYZED SAWDUST' TNT ONT Point Solid Phase 0 100 -4.450 By E. C. Sherrard and G. W. Blanco 8-ONT 4.77 95.23 9.17 90.83 FORESTPRODUCTS LABORATORY, U. S. DEPARTMENT o s AQRICU~TURE. 15.28 84.72 -8.7 MADISON,WISCONSIN 0 100 -10.35 95.23 a-ONT -12.00 4.77 Although the Forest Products Laboratory has con90.83 -13.3 9.17 -0.2 25 75 sidered for some time the advisability of invescigating 10.2 1 70 30 40 60 25.7 the nutritive value of hydrolyzed sawdust, it was not 50 50 until the severe drouth, which occurred last year in 60 40 TNT 70 30 the Northwest, called our attention t o the pressing 80 20 65.1 10 73.0 90 need of such a material t h a t t h e investigation was 100 0 80.35
a n d P-ONT falling a t -9.7' and 19.j per cent T N T , a n d the eutectic for T N T and a-ONT falling a t -1 5.6' and 1 6 per cent T N T . I n obtaining these freezing points we used the seed of the stable ONT in every mixture.
undertaken. The product described in this paper was prepared b y this laboratory, and fed t o three dairy cows b y the Wisconsin College of Agriculture with highly gratifying results. While the experiment is yet in the preliminary stages, i t is deemed advisable t o describe the process of manufacture and present the analysis of the original and digested sawdust. PREPARATION OF MATERIAL
too
O0
-f oo
TNT
ONT F I ~ 3.
.
SUMMARY
I n this Paper we have given the d a t a for three binary systems of t h e nitrotoluenes, one of these nitrotoluenes having two crystal forms. I n one case i t was possible to follow the freezing-point curve for t h e metastable form right t o the eutectic point.
The sawdust was eastern white pine obtained from a mill in Minnesota, and was representative of the waste obtained from mills cutting this species. N o effort was made t o remove bark or other foreign substances t h a t ordinarily are present in this material. The sawdust was treated in the same way as for the production of ethyl alcohol from wood; t h a t is, i t was digested with 1.8 per cent sulfuric acid for 1 5 or 2 0 min. under a steam pressure of about 1 2 0 lbs. per sq. in. Sufficient water was added along with the sawdust t o raise the ratio of water t o dry wood to about 1.251. After the steam pressure had been blown off t o atmospheric pressure, the treated sawdust was removed from the digester, and a large portion of the acid liquor removed b y means of the centrifuge. The centrifuged material was then placed in towers, and the remainder of the sugar and sulfuric acid extracted with hot water. The leach water was mixed with the centrifuged liquor, and the whole almost neutralized with calcium carbonate. After the sludge had settled, the liquor was decanted or, if necessary, filtered, and evaporated under reduced pressure t o the consistency of a thick sirup. The leached material from the towers was screened through a 6-mesh screen t o remove the larger uncooked pieces of wood, and the screenings dried by spreading on the floor in a thin layer. The air-dried hydrolyzed dust was then mixed with the sirup referred t o above, and the whole dried t o about 1 2 per cent moisture. Early in t h e experiment, when we were dependent upon the air drying of the finished product, considerable loss of sugar was experienced. For instance, in Cook No. 139, 21.2 per cent of the dry weight of t h e original wood was converted into sugar. The final wood meal, however, contained only 16.39 per cent of sugar calculated upon the dry weight of the product. This loss of almost 5 per cent sugar was partly due t o t h e mechanical treatment and partly t o a slow fermentation of the sugar in the moist product during the early stages of drying. Table I shows the decrease of sugar 1 Presented before the Division of Industrial and Engineering Chemistry at the 60th Meeting of the Amerisan Chemical Society, Chicago, Ill., September 6 to 10, 1920.
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M J S T R Y
62
in samples containing Over 1 2 per cent of moisture, upon standing from I t o 2 mo. at ordinary room temperature. TABLE I-CHANGE COOK
No. 134 135 137 139 143 145
DATE 7/3/19 7/3/19 7/3/19 7/21/19 7/31/19 8/15/19
I N SUGAR CONTENT UPON n R Y I N 0
Moisture Percent
Sugar Per cent
14.76 22.48 30.57 18.77 7.00 15.74
13.61 13.76 16.39 18.06 14.96 15.88
Moisture Per cent
Sugar Per cent
9/22/19 9/22/19 9/22/19
8.70 9.82 11.06
13.23 16.62 13.35
9/29/19 9/29/19
7.88 7.55
13.85 15.40
DATE
I t will be noted t h a t in the samples containing I 5 per cent or less of water, but little change in sugar concentration occurs upon standing. A gradual decrease in sugar occurred in all samples t h a t were air-dried.
Vol. 13, No.
I
During the course of t h e experiment it was found desirable t o determine the relative ease with which the sugar and acid could be removed from t h e centrifuged hydrolyzed wood. This was because of t h e desirability of removing almost all of the sulfuric acid and of leaching out as little sugar as possible. Under ideal conditions a minimum quantity of water should b e used, thus lessening t h e volume t o be evaporated eventually. Since it was also important t h a t a complete analysis be made of the original wood and the wood after treatment, proportionate quantities of the centrifuged dust and liquor were taken from Cook No. 164 a n d the process completed on a laboratory scale, t h u s avoiding some of the losses usually experienced in working with large quantities. LEACHING E X P E R I M E N T
I n order t o determine the quantity of water necessary t o remove t h e greater part of t h e sulfuric acid, 6.06 lbs. of the' centrifuged digested sawdust, corresponding t o 2.81 lbs. of dry material, were placed in two percolators, and 2.81 Ibs. of water added t o t h e first. The percolate was collected, weighed, and transferred t o the second percolator. T h e percolate from the second percolator was again weighed and t h e acidity, specific gravity, and sugar determined. It is regretted t h a t equal extraction periods were not used, but because of the laboratory hours this was found t o be impracticable. The acidity is expressed in degrees, and represents the number of cc. of 0.1 N sodium hydroxide solution required t o neutralize I O cc. of the extract. The sugar was determined as dextrose by means of t h e method recommended by the U. S. Bureau of Chemistry1 with one or two minor modifications. This method is briefly as follows:
0
/
No
2 3 o f €xrrocr/ons
I
I
EXTRACTION OF SUGAR AND SULFURIC ACID
I n order t o overcome this difficulty, a drying oven was installed and the moisture in both t h e leached dust and final product reduced t o less t h a n 1 5 per cent before storing. No loss in sugar has been noticed in this material, even after storage of several months. T h a t t h e sugar content is but slightly lowered during the drying is shown b y Table 111. The temperature of the oven remained alhnost constant, but considerable rise in temperature was noted in the dust. T h e temperature of the latter was taken b y a thermometer, the bulb of which was covered with the drying material.
The sugar solution is carefully neutralized with anhydrous sodium carbonate and allowed to stand for about 3 hrs. The precipitated material is filtered off, and the clear filtrate diluted so t h a t 25 cc. will contain not more than 0 . 2 5 0 g. of dextrose. Thirty cc. of copper sulfate and 30 cc. of alkaline tartrate solution, prepared according to Allihn's modification of Fehling's solution, are mixed in a 2 5 0 cc. beaker with 60 cc. of water, and heated to boiling. Then 25 cc. (duplicate) of the solution to be examined are added and the boiling is continued for 2 min., taking the time when one-half of the 2 5 cc. of solution has been added. The precipitated cuprous oxide is readily filtered in a porcelain Gooch crucible with asbestos pad, and washed thoroughly with hot water without any effort to transfer the precipitate to the filter. The cuprous oxide is dissolved in I to 1.5 cc. of nitric acid (sp. gr. 1.42),the asbestos filtered off, and washed thoroughly with hot water. The copper filtrate, which has been diluted to approximately 225 cc., is warmed to 60 to 6.5' C., and electrolyzed for 1.5 to 2 hrs., using a current density of 1.0 amp. per sq. dcm. of platinum gage cathode, and an e. m. f. of 1.6 volts. The cathode is removed while the generator is still running, dipped into three changes of hot distilled water, and finally washed with alcohol and ether. Afterward the electrode is dried for 3 min. at I Q ~ O C., allowed t o cool, and weighed. From the amount of copper deposited the quantity of reducing material can be calculated in terms of dextrose by referring to Allihn's tables. 1
Bureau of Chemistry, Bulletin 107, 49.
Jan.,1 9 2 1
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R T ’
63
TABLE11-RESULTS FROM LEACHING EXPERIMENT
Wakr Used Lbs.
No.
I
2.81
I1
2.81
IV
2 81
V
2 81
2.81
Started---
-Finished-
I -
PI
3/26/20 11 15 A M . 3/26/20 3.20p.~. 3/27/20 8.40A.M. 3/28/20 12 35 P M . 3/29/20 9 00 A X
P2
3/26/20 3 15 P.M 3/27/20 8 : 2 5 A.M. 3/28/20 12:30P.M. 3/29/20 8 30 A X . 3/30/20 9 00 A.M
PI
3/26/20 3 15 P.M 3/27/20 8: 15 A.M. 3/28/20 12:30PM. 3/29/20 8 30 A M 3/30/20 8 30 A.M.
P2
3/27/20 8:15 A.M 3/28/20 12.30 P.M. 3/28/20 8.30A.M. 3/30/20 8 30 A M 3/31/20 8 30 A X
-TimePI P r Hrs. Hrs.
$:;
.....
.....
..... .....
.....
.....
..... ..... .....
5
Unpublished bulletin,
..... .....
17
1.625
0 545
23.0’
1.032
5.37
9 40
10 34
2.645
2.240
21.2”
1.029
5.01
36.02
37.64
28
20
2.710
2.630
13.4’
1.018
3.10
26.15
27.86
20
24
2.755
2 715
6.9O
1 010
1.69
15.02
15 23
24
24
2 760
2 725
3.1’
1.004
0 71
6 25
6 89
..... .....
.....
.....
.....
.....
Acidity
28
-tt;
Weight Lbs.
Per cent Per cent Total Reducing Total Sulfuric Sugar Sugar Acid SP. Gr. Per cent Removed Remeved
from Pn--
4
TABI.E 111-ANALYSIS OF SAMPLB FOOD DURING DRYINGIN KILN Total Ratio Time-Temperature Reducing Soluble Sugar Kiln Food Moisture Sugars Solids Total to Date Hour ’ C. C. Per cent Per cent Per cent Sol. Solids 1 1 :30 A.M. 75 Started 60.23 18.63 26.15 71.3 4/9 LToon 75 32 ..... ..... 4/9 1:30 P.M. 73 39 ..... ..... ..... ..... 4/9 2:00 P.M. 41 ..... 75 ..... 4/9 73 2:30 P.M. 42 4/9 73 3:OO P.M. 39 ..... ..... 3 :30 P.M. 74 43 55.62 17.54 27.04 65.0 4:OO P.M. 75 44 ..... ..... ..... 4/9 75 4:30 P.M. 43 ..... ..... 75 7:30 P.M. 48 50.38 17.17 24.99 68.75 11 :30 P.M. 75 17.14 23.52 72.9 48 45.59 75 16.84 77.6 48 40.93 %O 3 :30 A.M. 23.02 17.17 51 35.50 4/10 7 :30 A.M. 71 24.80 69.3 9:00 A.M. 57 4/10 75 ..... ..... 9:30 A.M. 4/10 70 59 ..... 1o:Oo A M . 78 4/10 60 ..... 75 4/10 11 :oo A.M. 60 76 63’ i4:6? 4/10 Noon 17.53 25.28 69.5 6:OO P.M. 79 4/10 66 14.79 17.49 24.87 70.03 82 4/10 12:oO P.M. 16.57 24.25 68.4 78 4.36 79 4/11 16.53 67.2 6:OO A.M. 77 4.43 24.69 82 4/11 82 2.94 Noon 16.51 65.0 25.55
.....
-Obtained
17
I t will be noted from Table I1 and from the extraction curves t h a t all but 2.04 per cent of the total acid used is removed b y the fifth washing. Since only 1.8 per cent sulfuric acid was used in the cook, there remains 0.026 per cent of acid in the finished stock food, The liquor obtained by centrifuging the residue after t h e final extraction contained 1.9 per cent of t h e total sulfuric acid, so t h a t in actual practice it would be possible t o remove practically all of the acid either by centrifuging or b y pressing. The sulfuric acid concentrations used in the table and curves were calculated from t h e total acidity using the ratio of sulfuric acid t o volatile acid as 4.2 : 3, as determined by Kressman. The sugars were found t o leach with a little more difficulty, since 7.16 per cent of the total amount remained in t h e residue after t h e fifth washing. This, however, makes no difference in the final product, since the sugar is not appreciably changed by drying. The liquor obtained from the extraction was combined with the original digester or centrifuge liquor, and the whole neutralized with dry calcium carbonate. No change in t h e sugar concentration was noticeable after neutralization. The mixed liquors were evaporated under reduced pressure t o a thick sirup, and t h e sirup mixed with the partially dried, extracted dust which had previously been screened through a &mesh sieve. The moist mixture was then placed in a n oven and dried. Although t h e per cent of total reducing sugars decreased somewhat during the drying, t h e fact t h a t the total soluble solids remained almost
~
Quaqtity Obtamed from PI Lbs.
..... ..... .....
constant indicates t h a t volatile reducing substances were removed and t h a t the sugar remained practically unchanged. The progress of the drying experiment may be observed from Table 111. After drying, the material contained considerable finely powdered dust. The s‘ize of these particles was roughly determined by screening. Total weight of material screened Material retained by 80-mesh screen Materialretainedby 100-meshscreen Material through a 100-mesh screen
= 671 g. = 499 g. = 74.36 per cent = 13 g. = 1 . 9 3 per cent = 151 g. = 22.50 per cent
Any loss of wood meal t h a t occurs in handling consists mostly of fine material, due t o its sifting through the bags or loosely made containers. It was therefore analyzed separately, in order t o determine its relative value as compared with t h a t of the coarser material. T h e portion t h a t passed through t h e 100-mesh screen was kept separate. The coarser material t h a t was retained b y t h e Ioo-mesh screen was ground t o pass through a n 80-mesh screen but t o be retained by a roo-mesh. This was found t o be impracticable, owing t o the fact t h a t the coarse material ground itself away on the screen and but little remained. Because of this trouble, all of t h e coarse material was ground t o pass a Ioo-mesh screen. I n this way two portions of the wood meal were obtained: The portion t h a t passed through the IOOmesh screen before grinding, labeled “unground food through IOO mesh,” and the ground portion labeled “ground food through I O O mesh.” For the purpose of comparison a sample of the original white pine sawdust was ground, and t h e portions passing through 80-mesh and Too-mesh screens were used for analysis It should be borne in mind t h a t this analysis is not comparable t o the average wood analysis since no effort was made t o eliminate bark or other undesirable portions of the wood. I n fact the material used was typical sawmill waste, and contained all the foreign substances common t o this product. The two samples of stock food and the two samples of unhydrolyzed sawdust were analyzed according t o A. W. Schorger’s method.’ I n both the untreated wood and the final product the percentage of ash is higher in the fine material. This is due possibly t o the presence of sand and earth t h a t was contained in the original sawdust. I t will be noticed in examining the analyticaldata in Table I V t h a t the hot and cold water and alkali1
THISJOURNAL, 9 (1917). 556.
64
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 TABLEIV-ANALYSIS
Vol.
13,
No.
I
WOOD MEAL AND UNTREATED WHITE PINE SAWDUST Methyl Pento- Penfo---Solubility of Sample inMethyl sanin s a n i n ReCellu- CelluCold Hot 1 Per cent Acetic Pento- Pento- CelluCrude ducing Acid san san lose lose lose Lignin Fiber sugars Ash Moisture Water Water Ether NaOH Unhydrolyzed dust 80-100 6 . 0 0 8.81 10.23 4.13 23.16 . . . . 56 31-56 00 31 45 i .’% 9 .‘io 2 , 3 7 56 . ‘ a 4 7 .‘50 8 . 0 0 i .‘8J (30 :65) 6 3 : si None 0 . 8 2 mesh 6.46 8.70 10.08 4.11 22.86 . . . . . . . . . . . . . . . . . . . . . . . . . .... 0.80 8.75 10.15 4.12 23.01 . . . . . . . . . . . . 56.61 Average.. ............... 6 . 2 3 . . . . . . . . .... 0.81 Unhydrolyzed dust through 6 . 3 8 9.21 10.78 4.88 25.39 53.76 32.15 1.52 o.’dil d:a8 i:ai 100-mesh ....................... 54.45 (30.50) 60.81 None 6.39 9.23 10.95 4.84 25.76 ............ ..... . . . . . . . . . . . . . . . . . . 1 .so Average.. 6.39 9.22 10.87 4.86 25.57 54.11 . . . . . . . . ..... . . . . . 1.51 Unground wood meal through 4 . 1 5 30.17 30.64 3.94 43.24 . . . . . . . . . . . . 36.01 . . . . . . . . 37.21 . . . . . . . . . . 4.94 100-mesh 0.78 4 . 3 8 2.15 35.97 . . . . . . . . (29.62) 4 6 . 8 8 17.47 .... 4.09 30.59 30.69 3.77 42.59 ............ ........ 4.92 30.66 3.85 Average . . . . . . . . . . . . . . . . . 4 . 1 2 30.38 42.92 35.99 . . . . . . . . ..... 4.93 Ground wood meal through 3 . 6 4 31.11 28.23 3.80 40.23 37.77 . . . . . . . . 39.36 . . . . . 3.35 0.65 4.66 i:50 100-mesh ....................... 38.03 (31.46) 49.31 16.20 4.11 27.55 28.39 4.06 39.04 ..... . . . . . ..... 3.27 29.33 28.31 3.93 39.64 ............ Average . . . . . . . . . . . . . . . . . 3 . 8 8 37.90 ..... . . . . . 3.31 Ground wood meal through 5 . 3 8 ................... 37.46 . . . . . . . . ..... ..... ..... 80-100 mesh ....................... . . . . 37.23 ........ ..... ....................... 2.83 3.83 Average . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 This value is undoubtedly somewhat low since the condenser was accidentally removed before the flask had sufficiently cooled. OP
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..... . . . . .
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........ ........
.
.....
..... . . . . ..... ..... ...................................
soluble materials have been greatly increased by the hydrolysis, while the ether-soluble remains about the same. I n comparing the yield of pentosans from the original wood and from the completed stock food, i t will be seen t h a t considerable difference exists. Since the yield of finished stock food is about g o t o 94 per cent of the original wood, the pentosan yield from the stock food amounts t o about 4.05 and 4.43 per cent, respectively, when calculated upon the dry weight of the original wood. I n other words, about 45.4 per cent of t h e , original pentosan remains in the finished product. This difference is best accounted for by assuming a partial conversion of the pentoses liberated by hydrolysis into volatile acids and furfura1.l Such an assumption is necessary t o account for the volatile acid formed in the condensed blow-off and centrifuged liquor. Although but little difference is apparent in the quantity of acetic acid obtained by the acid hydrolysis of the original wood and treated wood, too much confidence should not be placed in the quant i t y of acetic acid obtained from the stock food, since there is a possibility t h a t a portion of this was liberated from the calcium salts formed during neutralization. The methyl pentosans in the wood are almost unaffected by the digestion with sulfuric acid. The average yield of cellulose in both samples of the original wood is 55.79 per cent, while the average yield from the stock food is 37.08 per cent. When the cellulose from the latter is recalculated upon the original dry weight of the wood the average yield is 34.11 per cent. This indicates a loss of 21.68per cent of cellulose from which 15.5 per cent of total reducing sugars were produced. The latter value, which is also calculated from the original dry weight of the wood, shows a yield of sugar corresponding t o 71.5 per cent of the theoretical, assuming t h a t all of the cellulose t h a t is removed goes t o form reducing sugar. The calculation is a t best an approximation, since the complexity of the cellulose molecule, and hence the number of molecules of water entering into the reaction, is not known. LIGNIN D E T E R N I N A T I O N
The method used for the lignin determination was 1
Kressman’s unpublished bulletin.
....
.....
..... ..... .....
.....
............
....
.
I
.
.
.....
....
..... .....
t h a t described by Mahood and Cable,l except t h a t a 16-hr. digestion with 7 2 per cent sulfuric acid was used, ,since in a more recent study these authors found the longer period more desirable. The lignin determination is of interest, since i t shows t h a t the total quantity of lignin contained in the wood is not appreciably altered. The values contained in parenthesis are the ash-free values calculated from the dry weight of the original wood and indicate t h a t no change has occurred in what is ordinarily considered as the lignin complex. This is of great interest since heretofore the assumption has always been made t h a t a large portion of the lignin was removed. DETERMINATION O F
a-,/?-,A N D
7-CELLULOSE
The determination of a-,p-, and r-cellulose2 was carried out as follows: About z g. of cellulose obtained by the chlorination method were thoroughly mixed with 2 0 cc. of 17.5 per cent sodium hydroxide and allowed t o stand for exactly 30 min. a t room temperature. The mercerized fiber was then treated with 2 0 cc. of water, thoroughly stirred, and filtered on a n alundum crucible with the use of strong suction. The a-cellulose which remained in the crucible was washed with I O cc. portions of cold water until the filtrate showed no alkaline reaction. It was then treated with hot I O per cent acetic acid, washed six or eight times with hot water, dried a t 1 0 5 ’ C., and weighed. The alkaline filtrate was made distinctly acid with concentrated acetic acid, which caused the 8-cellulose t o separate in a finely divided condition, and the brownish color of the liquor t o become lighter. To coagulate the suspended material, the solution was heated in a water bath until the particles settled and the solution became clear. The /%cellulose was then filtered on an alundum crucible, washed six or eight times with hot water, dried a t 10j O , and weighed. The portion of the cellulose permanently dissolved was y-cellulose. No difficulty was experienced in the determination of a-,8-, and y-cellulcse in the cellulose obtained from 1
P a p e r , 26, No. 24.
Ik12p . 23; Cross and Bevan, “Paper Making,” 1916, p. 9 7 ; Schwalbe, “Chemie der Cellulose,” 1911, p . 637. a Cross and Bevan, “Researches on Cellulose,” 1906-10, Vol.
Jan., 1921
T H E J O U R N A L O F I N D U S T R I A L A N D EAVGIN E E RI N G C H E iMIS T R Y
the unhydrolyzed sawdust, except in one or two cases where the filtration was slow, owing t o the porosity of t h e crucible. T h e results in Table V were obtained using the original untreated sawdust. TABLE V-PER
CENT a-,8-, A N D
?-CELLULOSE IN CELLULOSE PROM ORIGINAL WHITE PINESAWDUST Cellulose Sample Obtained from a-Cellulose @-Cellulose 7-Cellulose Unhydrolyzed dust through 80-100 mesh... 57.36 19.61 23.03 Mixing cellulose obtained from unhydrolyzed sawdust, 80-100 mesh, and unhydrolyzed sawdust through 55.85 lOO-mesh, respectively. ., , 29.42 14.75
........................
..... ...
I n the case of cellulose obtained from the hydrolyzed wood, considerable difficulty was encountered, owing t o its character after treatment with the alkali. I n all cases i t was impossible t o filter in the 3 0 min. prescribed by the method, so t h a t the action of the alkali continued in some cases for 8 or I O hrs. This difficulty could not be overcome, and no definite analysis could be made. The cellulose, upon treatment with alkali ( 1 7 . 5 per cent), became semitransparent and had the appearance of collodion. T h a t portion t h a t could be drawn through the crucible reprecipitated upon mild dilution with water. This precipitate coagulated upon warming, and i t behaved and looked very much like the usual pcellulose. The coagulated precipitate was filtered on a n alundum crucible with suction, and the filtrate acidified with strong acetic acid, with the result t h a t no further precipitate was obtained. Because of the difficulties outlined above, no analytical data on the CY-, p-, and 7-cellulose from the cellulose from hydrolyzed wood are contained in this paper. It is hoped t h a t further investigations mill clarify this point. I n one case the alkali-treated cellulose from hydrolyzed wood was strongly diluted with water. The fine white precipitate was warmed, and the coagulated material filtered, washed, and dried. It had the semitransparent appearance of dried collodion and amounted t o 96 per cent of t h e original sample. Because of its peculiar properties i t is apparently a product intermediate between a- and P-cellulose. Since i t is partially soluble in alkali i t may be concluded t h a t it is more easily digested in t h e alkaline intestinal tract t h a n the true a-cellulose, especially in t h e presence of enzymes present in the intestines. METHOD F O R C R U D E FIBER D E T E R M I N A T I O S
The crude fiber was determined b y the method outlined in Bureau of Chemistry Bulletin 107, page j 6 , with minor modifications. I t is briefly as follows: Two grams of the sample are extracted with ether for 4 or The excess of ether is removed by suction and the material dried t o constant weight. It is then treated with z o o cc. of boiling 1.25 per cent sulfuric acid, and boiled under a reflux condenser for 30 min. After filtering with suction on an alundum crucible it is washed with hot water and treated with z o o cc. of boiling 1.25 per cent sodium hydroxide solution. After boiling for another 30 min. under a reflux condenser it is rapidly filtered with suction through an alundum crucible and washed with hot water until free from alkali. After drying to constant weight it is incinerated in an electric muffle a t 700' to 800' C. The loss on incineration is considered t o be crude fiber. 5 hrs. in a Soxhlet extractor.
6j .
I t is interesting t o note t h a t the crude fiber has been reduced from 14 t o 1 5 per cent. Another interesting feature is the fact t h a t the sum of the cellulose and lignin is greater t h a n the quantity of crude fiber. This indicates t h a t a t least a portion of either t h e cellulose or lignin, or perhaps some of each, is removedl b y successive treatments with dilute acid and alkali.
sU M MA R Y I-A method for the preparation of a stock food from white pine sawdust is described. n-Leaching experiments carried out on the digested dust indicate t h a t five complete washings with a quantity of water equivalent t o the weight of t h e wood are necessary t o remove the sulfuric acid. The sugars were found t o leach with somewhat more difficulty t h a n the acid. 3-It is pointed out t h a t the sugars contained in the moist product are not appreciably affected by drying a t temperatures ranging from 7 j 0 t o 8 5 ' C. While some decrease is noted in total reducing sugars, the loss is apparently due t o the removal of volatile reducing substances. 4-A complete analysis is given for eastern white pine sawdust, and for the product obtained from the same after digesting with dilute acid under pressure. Attention is directed t o the changes resulting from this treatment. 5-The cellulose obtained from the digested wood differs from t h a t from the original wood in its behavior toward alkali. I n the former practically all of the cellulose is converted into a viscous semitransparent mass by 1 7 . j per cent sodium hydroxide, while in the latter over 50 per cent is unaffected. T H E EFFECT OF CONCENTRATION OF CHROME LIQUOR UPON T H E ADSORPTION O F ITS CONSTITUENTS BY HIDE SUBSTANCE' By Arthur W. Thomas and Margaret W. Kelly CHBMICAL LABORATORIES, COLUMBIA UNIVERSITY, NEW YORE. N. Y .
The concentration factor in the combination of hide substance with chromic oxide and sulfuric acid in chrome liquor has previously been reported by Miss M. E. Baldwim2 She studied the adsorption from various liquors containing 0.038 t o 6.640 g. of chromic oxide per I O O cc. of liquor, and found t h a t the adsorption reached a maximum a t concentrations of 1.5 t o 2.0 g. of chromic oxide per I O O cc., beyond which concentration the adsorption by the hide substance decreased. Results obtained by J. A. Wilson and E. A. Galluns in their investigation of the retardation of chrome tanning by neutral salts, led them t o believe t h a t , had Miss Baldwin's liquors been carried t o higher concentrations (to about 1 2 g. of chromic oxide per I O O cc.), a minimum point might have been obtained beyond which increasing concentration would have caused 1 Presented before the Leather Chemistry Division a t the 60th Meeting of the American Chemical Society, Chicago, Ill., September 6 t o 10, 1920. 2 J . Am. Leather Chem. Assoc.. 14 (19191, 433. s I b i d . , 15 (1920). 273.
