Document EqYORRNQM1nV4bkw95pYpBdg

768 INDUSTRIAL AND ENGINEERING CHEMISTRY Vol. 22, No. 7 hours. On the basis of 10 per cent fiber, this represents S.O kilowatt per ton of fiber per 24 hours, leaving a power consumption charge able against pulp pro duction of 13.3 kilo watts per ton fiber per 24 hours. This figure, however, should be further reduced; as the energy expended in grinding is not dis sipated but is recovered as heat, as the mixture of pulp and juice be comes heated in the grinding operation. Since the juice must be heated in any case, the heat absorbed by the juice represents useful work, so that the new power chargeable against board is only the energy lost in transforming the electrical energy through mechanical energy into heat plus the subsequent loss by radia tion. Even without taking the saving in steam for heating into consideration, the figure of 13.3 kilowatts per ton of fiber per 24 hours compares very favorably with the 37 to 45 kilowatts per ton of pulp per 24 hours in grinding wood for similar grades of wallboard. Since the refining and beating costs are practically the same, these power consumptions in grinding form a good index for the comparison of cost in the use of wood and Vazcane pulp for board manu facture. Properties of Board The insulating board produced from Vazcane pulp has proved to be equal to the best, and superior to most of the insulating boards on the market. In appear ance the board is very uniform, with a fine mat surface. Strength equal to that of current boards is attained with a less dense board. The decreased density gives a board of de creased thermal con ductivity over current boards. The semi-commer cial plant has proved so well the merit of the Vazcane process that plans are under way for the erec tion of commercial-size plants in several sugar-producing countries. Literature Cited (1} Babcock & Wilcox Co., "Steam, Its Generation and Use," 36th ed,, p. 247. (2) Kerr, Keats* Mechanical Engineers* Pocketbook, 8th ed., p. 810. (3) Manufacture of Pulp and Paper, Vol. Ill, Sect. 3, p. 86. (4) West, Paper Trade J., 19, No. 21, 52 (1920). Studies in the Drying Oils XIII--Changes in Linseed Oil, Lipase, and Other Constituents of the Flaxseed as It Matures (1929)1 E. R. Theis, J. S. Long, and G. F. Beal2 Le h ig h Un iv e r s it y , Be t h l e h e m, Pa . N A previous paper (S) Rapid formation of oil in the early stages of growth of string. Each seed in every I data were given show ing some progressive flaxseed is accompanied by marked decrease in the ac tivity of the enzymes present and by desaturation of sample is therefore the age specified. The writers felt changes in the constituents the first formed glycerides. Analysis of the oil in terms justified in making analyses of flaxseed during the grow of the four groups of fundamental acids shows a higher of the oil samples extracted ing season. The presence percentage of oleic acid in oil from the 1929 northwest by means of ether from the of the enzyme lipase in flax crop than'is normal for northwest oil. -- seeds. Even with the elabo seed was proved. The flax rate scheme of tagging plant flowers over a period of 10 or 12 days. The samples each flower there are some slight fluctuations in the figures. collected in 1928, at definite intervals, represented an average This probably comes from variations in soil and depth of of ages within this variation. The writers did not, there planting. fore, feel justified in making complete analysis of these ex tracted oils. In the case of the 1929 St. Paul samples herein described, each individual flower was tagged with pieces of colored Also the weather of the past year was abnormal. The early part was favorable and the fields both at St. Paul, Minn., and at Bethlehem, Pa., got an.early start. At St. Paul, however, and throughout the Northwest in general, the latter half of the season was abnormally hot and dry 1 Received April 15,1930. Presented before the Division of Paint and Varnish Chemistry at the 79th Meeting of the American Chemical Society, Atlanta, Ga., April 7 to 11,1930. and undoubtedly checked the normal growth of the plant, which was distinctly not the case at Bethlehem. At Bethle hem the nights were cool, whereas in the Northwest this was July, 1930 INDUSTRIAL AND ENGINEERING CHEMISTRY 769 Table I--Changes in Constituents of Oil during Maturation of Flaxseed Time af t er Fl o w e r in g Days On, Per cent IODINE No. On, Th io c yanat e No. On, Sa t d . Ac id s Per cent Ol e ic Ac id Per cent Lin o l eic Ac id Per cent Lin o BBKIC Ac id Per cent Ne u t r a l iz a t io n Un - No. SAPONIFI- Sa t d . St e a r ic ARLE Ac id s Ac id Per cent Per cent Pa l mit ic Ac id Per cent Sa p o n if ic a t io n Va l u e Hb j c a BROMIDE No. 10 12 13 2i!7 14 28.51 15 28.44 16 28.55 IT 30.55 18 37.77 20 37.94 22 37.50 23 37.07 24 37.46 25 37.67 27 37.33 28 37.72 29 36.04 33 36.17 34 37.40 37 37.85 39 37.31 40 35.30 23 33.89 23* 31.18 30 34.33 37 34.89 44 36.83 49 37.53 13S.3 149.5 169.6 169.6 163.8 158.8 161.0 169.1 169.4 176.2 170.5 174.2 175.0 171.2 175.7 162.3 178.8 174.0 175.6 170.3 163.9 173.9 188.7 178.5 182.9 190.7 189.0 90.8 97.9 101.5 104.4 101.0 99.7 100.4 108.0 107.6 108.3 109.2 109.5 109.3 106.6 107.3 103.5 111.2 107.1 108.9 108.3 104.5 12.5 10.4 10.1 10.0 10.0* 10.5 10.1 8.8 8.8 7.1 9.0 7.8 9.1 6.7 7.5 8.1 6.3 7.8 7.0 7.5 7.0 109.8 116.3 114.9 114.4 117.8 114.9 4.75 5.34 5.65 5.45 5.40 5.58 32.6 30.0 22.9 14.5 17.4 21.2 19.9 20.6 19.7 14.5 20.2 17.5 15.1 18.7 13.5 23.9 18,0 14.9 15.9 20.8 24.4 21.1 n.o 20,7 15.5 10.4 9.0 n o r t h w es t o il s 37.4 36.1 39.7 44.8 45.8 42,7 43.9 37.0 38.3 46.2 35.6 40.4 40.5 44.8 47.5 40.3 41.1 45.7 44.3 39.0 40.9 17.5 23.5 27.3-. 30.7 26.825.6 26.1 33.6 33.2 32.2 35.2 34.3 35.3 29.8 31.5 27.7 34.6 31,6 32.8 32.7 27.7 2.52 2.32 3.52 2.86 1*3 1.57 1.02 1.08 1.76 2.4 1.69 2.3 0.94 1.39 PENNSYLVANIA OIL 42.5 44.0 35.1 41.5 42.8 47.4 31.6 39.7 38.5 37.6 41.4 38.0 1.23 1.6 1.84 1.31 1.43 .,. 202.5 201.0 > 20^1 isilo 204.7 .. 204.9 201.7 203.0 202.0 197.5 201.7 205.0 206.1 202.7 197.8 200.1 199.1 198,2 198.1. 198.5 7.4 8.0 5.71 6*9 5.97 6'.02 5.3 5.3 6.2 6.3 6.28 4.3 4,45 5.1 \ l 2.7 2.0 3*. 07 0*2 2.98 s`.io 1.4 2.2 1.9 1.51 2.7 3.00 1.9 196 '.5 205.8 199.9 196'5 198.6 204.4 204.2 201.0 205.6 205.1 205.3 201.3 204.1 203! 2 206.2 205.5 Ac id Va l u e 4.75 4.5 5.1 5.2 5.1 5.3 0 0.8 0.6 0.3 0.3 0.3 1.64 1.71 1.70 1.22 1.96 2.08 32.4 41.4 36.8 35.2 47.8 41.3 ' . Estimated; sample too small for determination. 6 Picked from prematurely ripe 9pot in field. not generally the case. In the previous paper (8) it was mentioned'that in the laboratory the enzymes worked best at moderate temperatures and with ample moisture. The hot, dry conditions at St. Paul are manifested by lack of further increase in Unsaturation after 22 days and by a low degree of unsaturation of the oil from even the last seed samples. The iodine numbers are very low for North American seed. As shown by Table I, the percentage of oleic acid is much higher than normal. The data on the St. Paul samples serve, therefore, as criteria for an abnormal year and explain many of the abnormalities which are at present being en countered with the 1929 crop of northwest oil. The Bethle hem samples, on the other hand, matured more slowly and the iodine number rose to 190.7, with a corresponding low content of saturated acids and oleic acid. Protective coat ing films made from 1929 crop North American oil are likely to be soft, unless steps are taken to compensate for the higher content of oleic acid in the oil glycerides. Method The seed samples taken at frequent intervals at the Farm School of the University of Minnesota, and at weekly in tervals at Bethlehem, were treated as previously described (S). The following method was used to separate the constitu ents of the lipid material from the flaxseed samples and to get the data given in Table I, from which the percentages of the various constituent acids were calculated. After the determination of the iodine and thiocyanate () numbers, the oil was saponified with 0.5 N alcoholic potas sium hydroxide and the resulting solution titrated to de termine the saponification number. The alcohol was then evaporated and the resulting soap solution extracted with ether in order to determine the percentage of unsaponifiable matter. Hydrochloric acid (12 N) was added to liberate the fatty acids, which were washed with water until the washings were neutral to methyl orange. The ether solution of the fatty acids was filtered through a dry filter to remove traces of water and the ether then evaporated. The saturated acids were next precipitated by the Twitchell {J,) method on one portion of these. The hexabromide number was de termined on another portion. The saturated acids obtained from the Twitchell method were dissolved in alcohol and titrated with 0.1 N potassium hydroxide with phenolphthalein as indicator and the neutralization value thus determined. From this number the percentage stearic and palmitic acids was obtained. In many cases the original sample weighed only 2 or 3 grams. As before stated, the percentage of stearic acid (designated S) was directly determined. The percentages of oleic acid (0), linoleic acid (L), and linolenic acid (Le) were calculated from the iodine number (I.N.) and thiocyanate number (T.N.) with the aid of the following relationships: O + h + Le = 100 - S O + 2L + 3Le = = 1.154 I.N, O + h + 2be = 1^00 TggN = 1.154 T.N. Lin s e e d Oil N. W. Raw 1924 1927 1928 1929 1929 8. A. Alkali-refined N. W< Alkali-refined Calcutta raw 1929 S. A. raw Io d in e No. Oi l 188.0 184.1 185.0 180.5 179.9 182.9 185.2 181.4 - 178.2 Th io c yanat e No. Oi l 117.2 113.5 117.7 112.8 113.1 113.5 115.2 113.8 112.1 Table II--Composition of Linseed Oil Sa t d . Ac id s Per cent Ol e ic Ac id Per cent Lin o LSIC Ac id Per cent Lin o l en ic Ac id Per cent Nb u t r a l iz a - TJN- TION No. SAPONIPI- Sa t d . St e a r ic ABLE Ac id s Ac id Per cent Per cent Pa l mit ic Ac id . Per cent Ac id Va l u e Hs x a BROKIDS No. 4.8 13.3 41.6 40.3 198.2 4.5 5.4 13.2 45.0 36.4 197.5 5.4 6.9 16.4 35.9 41.8 1.36 199.2 5.3 7.9 14.2 40.4 37.8 1.83 198.7 7.2 6.8 16.0 39.7 37.6 1.44 201.4 5.4 9.0 10.8 40.1 40.1 0.96 202.0 6.9 6.5 12.7 41.3 39.6 1.22 201.8 5.1 9.3 12.7 37.4 40.6 1.17 201.2 7.5 9.0 14.5 37.9 38.6 1.43 203.2 6.5 0.3 0 ,, 0.6 2.86 40.8 0.4 1.89 37.2 1.4 2.28 37.0 2.1 0.36 40.3 1.4 0,32 37.4 1.8 2.02 41.2 2.5 40.0 770 INDUSTRIAL AND ENGINEERING CHEMISTRY Vol. 22, No. 7 These relationships are based on data obtained by Kaufmann and Keller (S); that each molecule of oleic acid adds 1 mole cule of (SCN)a, 1 molecule of linoleic acid adds 1(SCN)2, and 1 molecule of linolenic acid adds 2(SCN)2. The figure 86.65 is the average of the three factors 86.06,86.66, and 87.20, which, when multiplied across by 1, 2, and 3, respectively, give the iodine numbers of the individual glycerides which add up to the iodine number of the oil. Thiocyanate num bers are also expressed as milligrams of iodine per gram of oil. Kaufmann and Keller also show more exact and com plicated forms of these equations, but point out that the errors involved in the methods are greater than those entailed in using the equations with the average factor 86.65. The presence of lipase in the flaxseed and its progressive change during the growing season were confirmed for nine teen samples, by determining the rate of hydrolysis of eight different esters. Table HI--Decrease la Enzymatic Activity during Maturation BBTstaHSU Sa mp i.e s a Sr. Pa c e Sa mp l e s Time . aft$r 'Isoamyl flowering acetate Ethyl acetate Time after Tri- Methyl flowering acetin propionate Days- Cc. Cc. , Days Cc. Cc. 10 0.6 0.76 18 0;5 0.70 23 0.4 0.70 30 0.3 . 0.65 16 4.0 1.8 18 3.8 1.4 20 3.\25 1.25 21 3;2 33 3.2 l'.0 37 3.2 1.0 38 3'.2 0.9 39 3.2 0.9 40 3.2 0.9 o 0.1 normal alkali used in both cases. The change in enzymatic activity during maturation was determined by a study of . the hydrolysis of eight esters. The technic followed was precisely that previously described (S). The esters used were triacetin, methyl propionate, methyl benzoate, butyl acetate, methyl acetate, ethyl ace tate, isoamyl acetate, and isobutyl acetate. In all cases the enzymes in the seed caused hydrolysis of the esters and the enzymatic activity decreased .as maturation of the seed pro gressed, Data for four typical esters are given in Table III. Three of these are plotted in Figures 1 and 2. Discussion of Results The enzymatic activity of the seeds decreases during matu ration. This is in agreement with the writers' results on the 1928 crop. Further, as indicated by the curves, the enzymatic activity decreases as the percentage of oil in creases. There is marked decrease in enzymatic activity right after the big jump in oil formation 17 days after flowering. Appar ently the enzymatic activity is spent in synthesis of fatty acids and glycerol into oil. When the curves are inspected together, it is observed that as the degree of unsaturation increases the percentages of linoleic and linolenic increase and those of oleic and stearic decrease. This suggests that as the seeds mature desatura tion proceeds through the stages stearic, oleic, linoleic, to linolenic. Similar desaturation occurs in animal life. The percentage of saturated acids agrees with previous data in the literature. It is, however, likely that this is low. Bertram's method (1) yields a precipitate with a low iodine number and gives results 2 per cent higher for saturated acids. If this method had been employed, the percentage of oleic would have been decreased by 2 per cent. However, even on this basis the percentage of oleic acid in the St. Paul 1929 samples is higher than in previous years and higher than most of the data reported in the literature. Acknowledgment The help given by A. C, Arny, of the University of Min nesota, in raising the flax and obtaining the samples for this investigation is gratefully acknowledged. July, 1930 ; IND USTB1AL AND ENGINEERING CHEMISTRY The work is part of, the' research program on drying oils of Archer-Daniels-Midland Company and William 0. Good rich Company, and affiliated companies. Acknowledgment is due these companies for permission to publish the re sults. Literature Cited Cl) Bertram, Chem. Weckblai, 24, 226 (1927).' (2) Kaufmann and Keller, Z. ajtgciv. Chem., 42, 73 (1029). (3) Xheis, Long, and Brown, In d . En g . Ch b m., 21, 1244 (1929). (4) Twttchell, Ibid,, 13, 806 (1921), , 771 Vapor Pressure and Heat of Vaporization1 P. G. Nutting > IT. S. Ge o l o g ic a l Sosvav, Wa s h in g t o n , D. C. WING doubtless to its industrial importance in plant so that log T -f a = log T/A, etc. The derivative of Equa O design, a number of papers on the vapor pressure and tion 4 is also dimensionless and very simple. latent heats -of liquids, have recently appeared in In d u s t r ia l a n d En g in e e r in g Ch e mis t r y (3, S, 4) Diihring's rule 1ms found wide application in the calculation of d log p _ log p + b diogr iogr+o ,, . vapor pressures beyond the observed range, and recently Values of the constants a, 6, and c for water, carbon tetra Schultz (5) has developed a relation of similar form between chloride, and toluene are tabulated below. All three are nega the molal*entropies of two liquids, yielding heats of vapori tive in. each case and all are referred to natural logarithms. zation and critical temperatures. A great many other em The pressure units are indicated, as are also the tempera^ pirical relations have been suggested, ranging from Trouton's tures used in determining the constants. simple ML = 21 Tb to the complicated formula of Cederberg. Any new formula must be both simple and exact to be use ful. Thermodynamics leads no further than the exact relation Ct): ( dE/dm \ d log p . .. Water Water Carbon tetrachloride Toluene Constants of (log T 4- a) (loft p + b) = C Tf a b 0. 50,100 mm. -4.19916 -29.73019 100,200,300 atm. -4.43978' -19.76527 100,180,260 mm. -4.19173, -17.39190 110,214,320 atm. -4.54285 -15.77465 c -39.78249 -29,28810 -28.95958 -22.19930 \dW/dm)T d log T U' Pressures calculatedfrom Equation 4 using these constants between internal thermal energy, E, mechanical work, W, and vapor pressure, p. E is here identified with the internal latent heat, W with external latent heat, and p with pressure of saturated vapor. While Equation 1 cannot be solved in general terms, it is well adapted to the calculation of E when p is known through a range of temperatures. Another advantage is that it is dimensionless and therefore inde pendent of the units employed. dW/dm is known exactly, if concentrations of vapor and liquid are known, from the Clapeyron equation: dW RT fCv ,\ calories dm ~ M \Ci / gram 1; A check of the combination of Equations 1 and 2 in the form are in excellent agreement with those observed and will even stand for considerable extrapolation. Relation between Heat of Vaporization and Temperature The other new formula is a relation between heat of vapori zation and temperature, namely: L = A(TC - D or log L = log A + n log (Te -- T) (6) latent heat proportional to a power of the temperature meas ured down from the critical temperature. There is a rational basis for this formula, since internal latent heat represents work done on a liquid by the cohesive force within it and Tc -- T represents an energy deficit from a temperature, r L " r U +, r L. = RT d log p w ^/ C,, - 1,J\ calories (3) with numerical data shows that it does give results as certain as the data, as it should. In setting up empirical relations between L, p, and T for practical work, the forms of Equations 1 and 3 indicate the paramount importance of a relation between p and T which shall make d -log p/d log T simple. Most such relations previously suggested are parabolic in form, exceedingly cumbersome to use, and afflicted with troublesome dimen sions. The approximate energy line obtained by plotting log p against 1/T is nearly straight but not so convenient as the more curved line given by the plot of log p against log T. This can be very accurately represented by the hyperbola Tc, at which th^ cohesive force is zero. The constant n is about Vs for latent heats and 2/ for surface tensions as might be anticipated. For carbon tetrachloride L -- 6.128 (T. -- T)B-m holds very well from 0 C. to the critical temperature 283.1. For water, L = 8.2674 {Tc -- T)0-8357. For ethyl alcohol, n = 0.36; for C02, n = 0.424; for S02, n = 0.64. The linear relation indicated by Equation 6 is shown to hold very well in all the cases tried. Log surface tension plotted against log L is also a perfectly straight line for water, the only liquid for which a range of data are available. Critical temperatures may be calculated by Equation 6, but probably more easily by the Schultz formula relating differences in molal entropies. Literature Cited (log T + a) (log p + b) = C (4) which is dimensionless throughout, since the constant a is the (negative) log of a temperature and b the log of a pressure i Received April 16. 1930. Published by permission of the Director, U. S. Geological Survey. (1) Bridgman, "Thermodynamic Formulas," p. 20. (2) Cox, In d . En g . Ch b m., 16, 592 (1923). (3) Davis, Ibid., 17,735 (1925); 22,380(1930). (4) Krase and Goodman, Ibid., 22, 13 (1930). (5) Schultz, Ibid., 21, 667 (1929). (6) White, Ibid., 22, 230 (1930).