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APRIL. 1935
.
INDUSTRIAL AYD ENGINEERING CHEMISTRY
Acknowledgment The coal analyses were made by H. M. Cooper of the U.S. Bureau of Mines, and the agglutinating value and Fischer low-temperature tests were carried out under the direction of SV.!A. Se1vig:of the U. S.Bureau of Mines.
Literature Cited (1) Bauni, K., and Heuser, P., Gliickauf, 66, 1497-1602, 1538-44 (1930); Fuel, 10, 51-64 (1931). (2) Beet, A. E., Ibid., 3, 390-2 (1924). (3) Boosere, M. de, Ibid., 5 , 532-7 (1926). (4) Cockrsm, C.. and Wheeler, R. V., Ibid., 6, 423-8 (1927). ( 5 ) Fieldner, 9.C., Davis, J. D., Thiessen, R., K e s t e r , E. B., and Selvig, W.A., Bur. Mines, Bull. 344 (1931). (5A) Fieldner, A. C., Davis, J. D., Thiessen, R . , Kester, E. B., Selvig, W. A., Reynolds, D. 1., Jung, F. W., and Sprunk, G. C., Bur. Mines, Tech. P a p e r 542 (1932'1.
i;1
(6) Finn, C. P., Trans. Inst. Mining Engrs. (London), 80, 283-306 i1930-3 1). (7) Lehmann, K., and Hoffman, E., Brennstof-Chem., 13, 21-9 (1932). (8) Lehniann, K., and Hoffman, E., Gluckauf, 68, 793-800 (1932). (9) Rlttnlelster, %-., 64, 624-37 (1928), (10) Seyler, C. A , Brit. Dept. Sci. Ind. Research, P h u s . Chem. Survey .Vutl. Coal Resources, 16 (4pri1, 1929). (11) Sinnatt, F. S., Trans. Inst. Mining Engrs., 62, 156-79 (192122)
(12) Thiessen, R., Ill. State Geol. Survey, Coijp. Mining Series Bull. 33, 58-89 (1930). (13) Thiessen, R., Trans. d m . Inst. Mininy .Vet. Engrs., 88, 644-72 (1930). (14) Wandless, -1. AT., and Macrae, J. C., Fuel, 13, 4-15 (1934). (15) Wigginton, R., Ihid., 5, 476-8 (1926). RECEIVEDNovember 20, 1934. Presented before the Division of Gas and Fuel Chemistry a t the 88th Jleeting of t h e American Chemical Society. Cleveland, Ohio, September 10 to 14, 1934. Published b y permission of the Director, U. S.Bureau of Mines. ( N o t subject t o copyright.)
The Cooking Process VIII. s. I.
Volatile Organic Acids by the Saponification of Aspen Wood'
ARONOVSKY AND ROSS AIKES GOItTNER. Minnesota Agricultural Experiment Station, St. Paul, Slinn.
Aspen sawdust was cooked with sodium carbonate for 2 hours a t 170' C. The ratio of wood to liquor and the concentration of the salt in the liquor were varied. The yields of residual woods and total organic matter in the residual liquors were obtained. The volatile organic acids were recovered from the black liquors by distillation with phosphoric acid and neutralized with barium hydroxide. The yields varied from 4.6 to 7.0 per cent of the oven-dry wood calculated as acetic acid. A decrease in the concentration of sodium
Ederer (G), llelander and \f-allin ( I s ) ,and Rawling (16) have been granted patents on the production and recovery of acetic acid a i a by-product of the pulo and other woJd-usine: ind u s t r i e s . Mullin-and Hunter (14) give a good review of the manufacture of acetic acid froin wood. Previous data obtained here ( 2 ) s u g g e s t e d that t h e v o l a t i l e acids mere formed by the saponification of acetyl groups attached to cellula+ and lignin r e d u e > . If that is the niechaniam of the process, lower concentrations of qodiuin carbonate should give equally good yields of volatile acids, since the time and temp e r a t u r e d i d not have Courtesg, S o r t h u e s t P a p e r C o m p a n y much effect on the quantiPORTION OF BEATER ROOMS H O ~ I YBEATERS G FII,I,ED~5 ITH STOCK ties of acids formed. It I'ulp laps in extreme left foreground w a s t h e r e f o r e decided
PREVI( )US paper ( 2 ) ~ l i o ~ v ethat d T.G to 11.4 per cent volatile organic acids (calculated as acetic), based on the ox-en-dry weight of aspen sawdust used, were o b t a i n e d by cooking w i t h a q u e o u s s o d i u m carbonate solutions. These quantities of volatile acids were much larger than mere expected. The literature on the p r o d u c t i o n of volatile organic acids is too voluminous t o b e included in this paper. H o w e v e r , s o m e of the pertinent literature dealing with this problem is summarized in Table I. Higgin ( I O ) , Rinman ( I C ) ,
QA
' P r e v i o u s p a p e r s iri thiseries o E a r t i c 1 e B appeared i n IXDC8TRIAL
AKD IcSGIXEERISO
CREVISTRY in 1930, 1933, aiid 1934.
carbonate gave a slight decrease in the yields of volatile acids, while varying the wood-to-water ratio, within the limit* given in this paper, had no appreciable effect. The production of volatile organic acids from wood in these experiments is therefore attributed to saponification. The coefficient of distribution of these acids between water and ether showed that only acetic and formic acids were present. The ratio of formic to acetic acid varied from 1 5 . 9 to 1:9.4.
to run a series of cooks using lower concentrations of sodium carbonate and also higher ratios of wood to water. The ratio of wood to water, 3:100, used in this work up to the present time was considered too low to be of commercial importance. TABLE I. SUMMARY O F THE LITERATURE Cit,atinn
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INDUSTRIAL AND ENGINEERING CHEMISTRY
452
Wood Hardwoods Pine Hardwood 1 1
Source or Treatment Destructive distn. Fusion wjth KOH Fusion with NaOH Sulfite black liquor Sulfite black liquor
Aspen Pine Aspen Norway spruce
Volatile Acidsa
4-770 acetic 18-28% acetjc 17-2070 acetic 2-9 g./l. formic and acetic 2.6-4.2% acetic and 0.04-0.09W formic NaOH black liquor 4.5% acetic 3% acetic and 3% formic NaOH black liquor 2 0 7 NaOH a t 170" C. 6.8-9.8% acetic '-
N a 6 H black liquor
Norway apruce Above black liquor heated with NaOH 1 hr. a t 360" C. (7) Aspen NaOH black liquor heated to 350' C. a t 200 a t m . for 15 min. with NaOH Basis, original wood. (6)
acetic and 2.0% formic
7.2%
9.3% acetic
mometer and separatory funnel and connected to a condenser. Fifty cubic centimeters of phosphoric acid (specific gravity 1.7) were added and the mixture was distilled until about 150 cc. were left in the flask. Water (150 cc.) was then added through the funnel to the solution in the flask, keeping the level in the flask constant. Distillation was continued until about 75 to 100 cc. were left in the flask. A few drops of phenolphthalein were added to the distillate. Then a solution of barium hydroxide was added until a pink color was obtained. The solution was thoroughly mixed by shaking and was allowed to stand. Carbon dioxide gas was then passed slowly into the solution which waa constantly stirred until there was no further change in color. The resulting solutions from all of the cooks had a color ranging from yellow to orange. The solution was distilled to about 200 cc., the resulting liquid was shaken with decolorizing carbon and filtered, and the carbonate-free filtrate was evaporated to dryness at 105' C. The dried residue was weighed and ground in a mortar. Samples were then taken for the determination of barium aa barium sulfate. The molecular weight of the product waa calculated from the barium content. On assuming that only the acetic and formic salts of barium were present in this product, the percentage of each acid was calculated. The data on these cooks are given in Tables I1 to IV, inclusive.
Residual Woods
Experimental Procedure Six sets of cooks, in duplicate, were run with sodium carbonate a t 100 pounds per square inch (7 kg. per sq. cm.) pressure (170" C.) for 2 hours. In the first three sets the quantity of salt was kept constant while the ratio of wood to water was raised from 3:lOO to 9:lOO; in the other sets the ratio was kept a t 3:100, and the amount of salt was varied from 5 to 15 per cent of the weight of the wood. The cooking procedure was the same as that outlined in the previous papers (2). After washing the residual woods, they were dried and weighed, and the residual liquors were evaporated in vacuo to about 900 cc. and then diluted to 1liter in volumetric flasks. Aliquots (25 cc.) of these liquors were used in the determination of total organic matter. The remainder of the liquor was poured into a 3-liter round-bottomed flask fitted with a ther-
The residual woods of cooks 46 and 47 were somewhat darker than those of cooks 31, 44, and 45, which, in turn, were darker than those of cooks 48 and 49 (Table 11). The residues from cooks 50, 51, 52, and 53 were darker than that from 44, while those from cooks 54 and 55 were lighter in color. There was not much difference in pliability of the wood, except perhaps that from cooks 48 and 49 which appeared slightly harder than the others. Increasing the concentration of the salt tended to lighten the color. The percentage yield of residual wood increased with a decrease in the concentration of sodium carbonate. In the cooks where the ratio of wood to water was greater than 3:100,
WOODS AND TOTALORQANIC MATTERIN RESIDUAL LIQUORS TABLE 11. YIELDS O F RESIDUAL NarCOa Used
0
Cook No.
Weight, grams
oven-dry wood
31 44 45
18.0 18.0 18.0
20.0 20.0 20.0
Weight0 of Wood Used Gram; 100 100 100
46 47
18.0 18.0
10.0 10.0
48 49
18.0 18.0
50 51
13.5 13.5
52 53
% of
Yield Residual Wood % of ori inal Weight, oven-& grams wood
Ratio of Wood to Water
Organic Matter in Liquor % of ori inal Weight, oven-fry gram8 wood
Material Not. Accounted For in This Table % of Weight, oven-dry grams wood
3:lOO 3:lOO 3:lOO
63.6 64.2 63.9
70.8 71.4 71.1
18.5 19.1 19.0
20.6 21.2 21.2
7.7 6.6 7.0
8.6 7.4 7.7
200 200
6:100 6:IOO
137.9 137.4
76.7 76.4
29.5 30.0
16.4 16.7
12.4 12.4
6.9 6.9
300 300
9:100 9:100
215.2 215.6
79.8 79.9
36.1 36.4
13.4 13.5
18.4 17.7
6.8 6.6
15.0 15.0
100 100
3:lOO 3:lOO
65.4 65.0
72.7 72.3
18.2 18.4
20.2 20.5
6.3 6.5
7.1 7.2
9.0 9.0
10.0 10.0
100 100
3:lOO 3:lOO
67.2 67.6
74.8 75.2
16.1 18.1
17.9 17.9
6.6 6.2
7.3 6.9
4.5 54 55 4.5 89.8% oven-dry.
5.0 5.0
100 100
3:lOO 3:lOO
68.7 69.0
76.4 76.8
14.6 14.4
16.3 16.1
6.6 6.5
7.3 7.1
6.67 6.67
VOL.4TILE ACIDSWITH BARIUMHYDROXIDE TABLE111. YIELDS O F BaRz OBTAINED BY NEUTRALIZINQ
31 44 46
NaCOs Used % of oven-dry wood 20.0 18.0 20.0 18.0 18.0 20.0
46 47
18.0 18.0
10.0
48 49 50 51
18.0 18.0 13.5 13.5
Cook No.
Weight, grams
Weighta of Wood Used, Grams
Ratio of Wood to Water
B a in BaRz,
%
Mol. Weight of BaRn, Grams
Acid H R as Combined in BaRr, Grama
-Yield Weight, grams 6.8b
100 100 100
3:lOO 3:lOO 3 :100
li:6 10.6c
54:ia 54.47
252.2
116.8
6.3 4.9c
10.0
200 200
6:lOO 6:100
23.1 23.9
54.72 54.62
251.1 251.6
115.7 116.2
6.67 6.67 15.0 15.0
300 300
9 :100 9:lOO 3:lOO 3:lOO
30.2 30.4 13.3 13.6
54.46 54.59 54.80 54.66
252.3 251.7 250.7 251.4
12.4 12.3 9.1 8.9
54.47 54.78 54.42 54.59
100 100
9.0 9.0
10.0 10.0
100 100
3:lOO 3 : 100
4.5 54 55 4.5 a 89.8% oven-dry.
5.0 5.0
100 100
3:lOO 3 : 100
52 53
Yield BaRn Gram:
of Acid HR% Of % of organic dry oven-dry matter wood
36.7'~ 33.0 25.8'
7.6) 7.0 5.50
10.6 11.0
36.0 36.9
116.9 116.3 115.3 116.0
14.0 14.1 6.1 6.3
38.7 38.6 33.6 34.1
5.9 6.1 5.2 5.2
252 2 250.8
116.8 115.4
5.7 5.7
35.7 35.2
6.4 6.3
252.5 251.7
117.1 116.3
4.2 4.1
28.8
4.7 4.6
262:2
:
iiir:s
b T h e yield of acid in cook 31 was calculated from the titration with NaOH, as acetic acid. c The low vield of BaR, obtained in this cook &as due t o a partial decomposition brought about by excess heat.
28.8
6.8
7.0
INDUSTRIAL AND ENGINEERING CHEMISTRY
APRIL, 1935
453
ROOMFOR PREPARING
COOKINGLIQUORS FOR ALKALINEPULPS (A paper mill contains more industrial ohemioal equipment t h a n simply digesters and paper machines.)
Courtesu, Northwest Paper Company
the increase in yield was larger than can be accounted for by the decreased concentration of the soda.
Total Organic Matter in Residual Liquors The liquors were reddish black except for those of cooks 48, 49, 54,and 55 which were orange-red and clear when hot, and tan to brown-orange and turbid when cold. The liquors of the other cooks had very little sediment even when cold. ,411 were slightly alkaline to litmus paper. The yields of total organic matter in the liquors are given in Table 11. Although larger quantities of organic matter were found in the residual liquors of cooks 46, 47, 48, and 49, the data show that the percentage yields on the basis of the original wood were lower with the increasing ratio of wood to water. The quantities of organic matter obtained in the cooks, where the concentration of sodium carbonate was less than 15 per cent, approached that found in cooking with water only (I), under the same conditions of time, temperature, and wood-to-water ratio. The material not accounted for in the analysis-gases, volatile oils, etc.-was remarkTABLE IV.
ably constant under the various conditions used in this series of cooks. This result shows that either the time or temperature of cooking, or both, is the controlling factor in breaking up the woody material into gaseous products, when the sodium carbonate used is less than 20 per cent of the weight of the wood. The data in the previous report showed that, on increasing the sodium carbonate from 20 to 40 per cent, an increase in the destruction of the constituents of the wood occurred.
Volatile Acids in Residual Liquors The yields of the volatile acids obtained as the barium salts are shown in Table 111. The molecular weights of these salts calculated from the barium content approach closely the molecular weight of barium acetate. The data in Table I11 show that 115.3 to 117.1 grams is the weight of a monoatomic acid (HR) combining with 1 gram atomic weight of barium. If the acid were acetic, this weight would be 120.0 grams. The yields of volatile acids in this series were somewhat
DISTRIBDTION OF FORMIC ASD ACETICACIDSIN BaR2 OBTAINED FROY THE VARIOUSCOOKS -Acetic
Acid-
-Formic
Acid-
Weight, grams 0.6 0.5
organic matter 3.3 2.5
% of oven-dry original wood 0.7 0.5
Ratio of Formic t o Acetic Acids 1:9.1 1:9.2
11.26 11.25
Weight, grams 5.7 4.4"
organic matter 29.7 23.20
% of oven-dry original wood 6.3 4.95
85.00 86.60
15.00 13.50
9.2 9.7
31.3 32.4
5.1 5.4
1.4 1.3
4.7 4.4
0.8 0.7
1:6.6 1:7.4
252.3 251.7
89.00 87. 00
11.00 13.00
12.6 12.4
35.0 34.1
4.7 4.6
1.3 1.6
3.7 4.4
0.5 0.6
1:9.4 1:7.8
13.3 13.6
251.4 250'7
83.50 86.00
16.50 14.00
5.2 5.5
28.7 29.9
5.8 6.1
0.9 0.8
4.9 4.2
1.0 0.9
1:5.9 1:7.1
12.4 12.3
252.2 250.8
88.75 83.75
11.25 16.25
5.2 4.8
32.2 30.1
5.8 5.4
0.6 0.8
3.5
5.0
0.6 0.9
1:g.o 1:6.0
54 9.1 262.5 90.50 55 8.9 251.7 87.00 Partial decomposition due t o excess heat.
9.50 13.00
3.9 3.6
26.4 25.2
4.3 4.1
0.5 0.5
3.5 3.3
0.6 0.5
1:7.6 1:7.7
No. 44 45
Weight BaRs, Grams 13.6 10.6"
Mol. Weight BaRz Grad8 262.2 252.2
Barium Acetate in BaRz,
Barium Formate in BaRz,
88.75 88.75
46 47
23.1 23.9
251.1 251.6
48 49
30.2 30.4
50 51 52 63
Cook
%
%
% of
% ' of
,
454
IhDUSTRIAL A\ D ENGINEERING CHEMISTRY
lower than were expected from the earlier data (2). In the latter case, however, the quantities of acids were measured by titration with standard alkali, whereas in this series of cooks the number of manipulations and the adsorption of some of the salt by the decolorizing carbon probably tended to give somewhat low yields. It appears that the increase in the ratio of wood to water does not have much effect on the yields of volatile acids, but that the latter decreases somewhat with a decrease in the concentration of soda. The mechanism of the reaction is probably saponification, but there must be enough soda present, above that necessary to take care of other nonvolatile acidic products, to insure complete saponification of all of the acetyl groups present in the wood. Table I11 shows that 15 per cent sodium carbonate gave practically the same yield of volatile acids as 20 per cent, the other conditions being constant. In order to determine whether other volatile acids besides formic and acetic acids had been formed, the coefficient of distribution of the mixture of acids between water and ethyl ether was determined. Runs were made a t room temperature on pure acetic acid, on pure formic acid, on a mixture of approximately 90 per cent acetic and 10 per cent formic acids, and on the mixture of acids obtained in this series of cooks. All experiments were conducted a t approximately equivalent acid concentrations. The coefficient, of distribution found were: acetic acid, 0.4634; formic acid, 0.3750; mixture of acetic (90 per cent) and formic (10 per cent) acids, 0.4405; acids obtained from the sodium carbonate cooks, 0.4514. These data indicated that the volatile acids obtained from this series of cooks consisted almost exclusively of formic and acetic acids. Assuming that only formic and acetic acid5 mere present, a graph was constructed from which, if the barium content of the mixture were known, the percentage of each of the3e acids in any mixture of the barium salts could be ascertained. The data based on these calculations are &own in Table IV.
VOL. 27. NO. 4
The actual yields of acetic acid are naturally lower than those shown for HR in Table 111, but they are all about equal to those obtained in destructive distillation. The ratio of formic to acetic acids is not very constant, varying from 1:5.9 to 1:9.4. Similar ratios were obtained by Honig (11) for the volatile acids of a sulfite cook.
Literature Cited Aronovsky, S. I., and Gortner, R. A., IND.ENQ.CHEM.,22, 264 (1930). Ibid., 22, 941 (1930). Croas, C. F., Bevan, E. J., and Isaac, J. F. V., J . SOC.Chem. Ind., 11, 966-9 (1892). Ederer, J., German Patent 273,036 (April 23, 1913). Griffin, M. L., J. Am. Chern. Soc., 24, 235-8 (1902). HBgglund, E., Cellulosechern., 5, 81-7 (1924). HRgglund, E., Pappers- Travariitid. Finland, No. 1, 508-15, 569-76 (1931). Hilgglund, E., and Bjorkmann, C. G., Svensk Kem. Tid.,36, 133-55 (1924). Hawley, L. F., “Wood Distillation,” New York, Chemical Catalog Co., 1923. Higgin, W. H., British Patent 13,409 (Aug. 8, 1891). Honig, M., C h e m - Z t g . , 36, 889-90 (1912). Mahood, S. A., and Cable, D. E., J. IND.ENG. CHEM.,11, 651-5 (1919). Melander, K. H. A, and Wallin, J. H., Swedish Patent 62,831 (April 27, 1927). Mullin, C. E., and Hunter, H. L., Cellulose, 1, 84-9, 138-41, 183-7, 215-18, 235-8, 258-60, 287-91 (1930). Rawling, F. G., U. S.Patent 1,681,684 (Aug. 21, 1928). Rinman, E . L., German Patent 244,816 (Feb. 10,1911). Rinman, E. I,., Papier-Fabr., 10, 39, 101 (1912). Wells, S. D., Grabow, R. H., Staidl, J. A., and Bray, M. W., Paper Trade J . , 76, No. 24, 49-55 (1923). RECEIVED December 10, 1934. Presented before the Division of Celluloae Chemistry at t h e 88th Meeting of the American Chemical Society, Cleveland, Ohio, September 10 t o 14, 1934. Published with the permission of the director as Paper No. 1300, Journal Series, Minnesota Agricultural Experiment Station. S. I. Aronovsky is the Cloquet Wood Products Fellow, University of Minnesota; the fellowship was established by the Northwent Paper Company of Cloquet, Minn.
DHYIXGAND REROLLING OPERATIONSIN MANUFACTURE OF CASEIN-COATED PAPER This paper is used for magazines that require an extra quality paper and those that tint their illustrations.
