November 1949
INDUSTRIAL AND ENGINEERING CHEMISTRY
LITERATURE CITED
(3) Buergef, M. J., Am. Mineral., 30, 551 (1945). (4) Ekwall, P., Kolloid-Z., 80, 77 (1937). ( 5 ) Ibid., 85, 16 (1938). (6) Ekwall, P., and Lindblad, L. G., Ibid., 94,4 2 (1941). (7) Jarisch, A., Arch. ges Physiol. (PjZilgera), 194, 337 (1932). (8) Kemp, A. R., and Straitiff, W. G., J . Phys. Chem., 4 4 , 7 8 8 (1940). (9) McBain, J. W., and Eaton, M., J . Chem. SOC.,1928,No. 2, p. 2166. (10) McBain, J. W., and Jenkins, W. J., Ibid., 121, 2325 (1922). (11) Matsumura, S., Kolloid-Z., 32, 173 (1923). (12) Merrill, R. C., and Getty, R., J . Phys. & Colloid Chem., 52, 167 (1948). (13) Neville, H. A., and Harris, M., Am. Dyestuff Reptr., 24, 200 (1935). (14) Powney, J., and Jordan, D. O., Trans. Faraday ~ o c . 34, , 363 (1938). (15) Putnam, W., and Neurath, H. J., J. Am. Chem. SOL, 66, 692, 1992 (1944). (16) Stauff, J., 2. physik. Chem., A183, 65 (1938). (17) Valko, E. I., Ann. N . Y . Acad. Sci., 46, 451 (1946). (18) Williams, R . C., J. Phys. Chem., 36, 3108 (1932).
(1) Altman, R. F. A., Arch. Rubbercult. Nederland.-Indi& 23, 239 (1939). (2) Anson, M. L., J . Gen. Physiol., 23, 239 (1939).
RECEIVEDNovember 16, 1948. Presented before the Meeting of t h e Division of Rubber Chemistry, AMERICAN CHEMICAL SOCIETY,Detroit, Mioh., 1948.
concentrations of oleate are employed, the effects of the two additives, salt or amino acid, are quite different. This irregularity has been attributed to the presence in the dilute solution of an acid soap whose stabilizing capacity is affected in a different manner by the two electrolytes. 3. The unique stabilizing power in latex of a stoichiometric acid sodium stearate formed in dilute solution has been observed. The compatibility of this compound and the corresponding acid sodium oleate with an amino acid to produce enhanced stabilizing power in latex emulsions has also been demonstrated. a .
c
2649
ACKNOWLEDGMENT
The author wishes to thank The Firestone Tire & Rubber Company for permission to publish these results and F. W. Stavely for his continued interest in the work. Thanks are also due A. J. Panella for preparing the samples tested and E. Glymph for the latex analysis given in Table I.
Promotion of Bitumen-Aggregate Adhesion by Chemical Means M. J. SNYDER
AND
A. E. PAVLISH
B a t t e l l e Memorial I n s t i t u t e , Columbus, Ohio
T h e adhesion of bitumen to road aggregate, particularly in the presence of water, is an important factor in the life of a bituminous road. Two general methods for improving the adhesion were studied. Chemical additions to the bitumen were more effective and economical than was treatment of the aggregate. Excellent bitumen treatments were developed which produced complete coating of hydrophilic aggregate by the bitumen and good resistance to water stripping. Amine hydrochlorides were the
most effective and economical of the additives studied. Treatment of aggregate with cupric chloride and a specific mixture of amine hydrochlorides, Emulsol 5049-W, produced an excellent affinity for bitumen. Other mixtures of amine hydrochlorides or amine salts were less effective. Treatment of the aggregate by deposition qf an insoluble, metallic-soap film on the surface yielded I erratic results and was not so satisfactory as the amine hydrochloride treatment of aggregate.
T
Numerous agents have been suggested for treatment of the aggregate (8, 11, 16, 17, 26, S1, SS, S4, 42) or for addition to the bitumen ( 2 , 4,9,10, 12-16, 18-80, 27-29, 52, 56-39, 43). Combinations of aggregate treatments and bitumen treatments have also been suggested (28, 24, g6, SO, 40). Bituminous emulsions have been used commercially to coat damp aggregate; both oil-in-water (7) and water-in-oil emulsions (S, 21) have been employed. Quartz, limestone, and blast-furnace slag aggregates, sized to pass a l/Anch screen and to be retained on a 4mesh screen, were used in the majority of tests. The sized aggregate was washed thoroughly with distilled water and stored in glass bottles until required. Samples of the wet aggregate weighing 500 or 900 grams were placed in a glass jar and the treating solutions added and mixed, in the case of aggregate treatments. In tests on treatment of the bitumen the treating agents were added to the bitumen in the glass jars and mixed by mechanical stirring, and the aggregate was added t o the bitumen. The bitumen used was
HE problem of the adhesion of bituminous coatings to
mineral aggregate is of prime importance in the service life of an asphalt roBd. A large percentage of failures occurring in bituminous pavements and surfaces are caused by displacement of the bituminous film from the aggregates by water, even though the aggregate was dry and well coated a t the time of construction. A dry aggregate is usually easily coated with bituminous material of the proper consistency. It is usually difficult or impossible to coat damp or wet aggregates unless oither the aggregate or the bituminous material has been chemically conditioned for this purpose, and it is sometimes advantageous economically to do this. There are two general chemical methods for improving the adhesion of bitumen to hydrophilic road aggregate. The aggregate surface may be modified so that the aggregate is preferentially wetted by bitumen rather than by water, or the bitumen may be modified so that i t will replace water from the surface of the aggregate. The requirements to obtain the desired wetting are well established (1, 6, W , 41 ).
2650
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 41, No. 11
TABLE I. TREATMENT OF AGGREGATE WITH METALLIC SOAPS Activator Kind
None Cupric Cupric Cupric Cupric
chloride chloride chloride chloride
None Cupric chloride Cupric chloride Cupric ahloride Cupric chloride Cupric chloride Cupria sulfate Cupric chloride Lead nitrate
Organic Addition
Molar strength
Molar strength
Kind
Type of Treatment
Coating Retention Amount of after Immersion Aggregate in Water for Coated, 70 24 Hr., %
Wet Quartz Aggregate
...
None ... 0.05 Sodium oleate 0.05 0.05 Sodium oleate 0.15 0.2 Sodium oleate 0.05 0.35 Sodium oleate f.05 Copper oleate deposited from kerosene solution
...
Two-solution, Two-solution, Two-solution, Two-solution,
immersion' immersion immersion immcrsion
Wet Limestone Aggregate None 6.2 Sodium oleate 0.05 Two-solution, immersion 0.35 Sodium oleate 0.05 Two-solution, immersion (2 5%) Two-solution, immersion 0.36 Sodium naphthenate 0.35 Sodium oleate 0.05 Excess activator, direct organic C 0.25 Sodium oleate 0.05 Excess activator, direct organic 0.25 Sodium oleate 0.06 Excess act,ivator, direct organic 0.15 Sodium oleate 0.05 Excess activator, direct organic 0.15 Sodium oleate 0.05 Excess activator, direct organic Copper oleate deposited from kerosene solution
... I
.
I
.
50 90
0
98 98 100
SO 80 20
50 90 98 98 95 95 85 98 98 100
50 70 70 90 90 0 90 85 60
9.. -R
0
n
0
Aggregate was immersed in activator solution drained immersed in organic solution drained and coated with bitumen. Aggregate was immersed i n E solution of copier oleate'in kerosene drained and coated with bitumen. Aggregate WES immersed in activator solution, drained, a small vdlume of brganic solution added (20 t o 30 cc. per 1000 grams of aggregate), and coated with bitumen. e
a cutback, RC-2, having the following partial analysis and properties: SDecific nravitv a t 26" C. Pinetratyon a t 25' C. (on residue), mm./lO sec. Bitumen (soluble i n CSz), % Organic insoluble, yo
Aeh % _-I..,
Ductifyty a t 25' C., cm. Furol viscosity a t 50' C., sec. Oliensis spot test Specific gravity of distillate Distillation b y Volume, Temp., C. To 170 190 225 260 315 360
%
... 10.5
18.5 22.0 24.0 25.5
0.942 91.0 99.60 0.17 n 79 l06T 308 Homogeneous 0.788
7%
Total
... 41
73 86 94 100
The jar containing the aggregate and bitumen then was stirred for 30 minutes on rolls rotating a t about 10 revolutions per minute, and the coated aggregate was transferred to wire trays 7 1 / 2 X 5'/2 X '/2 inch deep, The resistance of the coating to stripping then was determined b y immersing the mix in water at roam tempeiature. The percentage of aggregate coated was estimated visually before the trays were immersed in water and after 24 hours in water. Tests showed that immediate immersion of the coated aggregate in water was a much more severe test than allowing the coating to cure prior to immersion and might simulate the more severe conditions encountered in the field. All of the treating and mixing operations were conducted in a room maintained at 50'% relative humidity and a temperature of 80" F. AGGREGATE TREATMEKTS
Preliminary studies of the treatment of hydrophilic aggregate to improve its adhesion t o bitumen were concerned with the use of metallic soaps. Three methods of treatment were investigated: ( a ) the activator-soap treatment of McLeod ($55)in which the aggregate was first treated with a solution of a metallic salt, the excess liquid drained off, and then a solution of a fatty acid soap added to precipitate the metallic soap on the aggregate; ( b ) addition of a small volume of activator solution followed by addition of a small volume of soap solution without removal of any excess liquid; and ( c ) direct treatment of the aggregate with a solution of the metallic soap in a suitable solvent. The results of some of the representative metallic soap treatments are given in Table I.
The adhesion of bitumen for both wet quartz and wet limestone aggregate mas improved by deposition of metallic soaps on the surface of the aggregates. The mode of deposition of the soap film on the surface influenced the adhesion. Best results were obtained when the aggregate was immersed in an excess of the metallic salt solution, allowed to drain. and a small volume of the sodium soap solution added without draining. As was found by Swanson (SS), it was necessary to have sufficient excess solution to produce a colloidal sol of insoluble soap in addition to that formed on the aggregate in order to obtain good coating. The concentration of the activator solution was important; best results were obtained with copper chloride concentrations of 0.2 or 0.55 molar. Lead nitrate and copper chloride proved to be equally effective, but copper sulfate did not increase the adhesion when used with sodium oleate. Sodium oleate proved to bo more effective than other soaps such as sodium naphthenate. Deposition of the metallic soap directly on the aggregate from a nonaqueous solvent was not so effective as precipitation of the soap film by reaction. The surface of silica is made hydiophobic in froth flotation processes where silica is floated. The aliphatic amines and their salts are effective flotation agents for silica and were therefore investigated as agents for promoting the adhesion of hydrophilic aggregate to bitumen. The use of one of the quartz flotation agents, Emulsol 5049-W was studied thoroughly. Emulsol 5049-W is a mixture of the hydrochlorides of primary, straightchain, saturated amines obtained from the fatty acids of coconut oil, manufactured b y the Emulsol Corporation. The results of tests with this agent are given in Table 11. Emulsol 5049-W was effective in promoting the affinity of tho hydrophilic aggregates, quartz, limestone, and blast furnace slag, for bituminous materials. E rctrcatment of the wet aggregate with a solution of a copper salt, or incorporation of a copper salt in the Emulsol 5049-W solution, improved the results obtained with this agent. Copper salts were superior to lead, zinc, calcium, or ferric salts in promoting the affinity of aggregate for bitumen when used with the Emulsol 5049-W. Treatment of the wet aggregate with a solution 0.025 N in copper chloride, and containing 0.2 of Emulsol 5049-W, resulted in complete coating of the wet aggregate by bitumen and retention of 70Yo of the coating after immersion in water for 24 hours. This solution could be used three times without decrease in its cffectivcness, and exposure tests on aggregate treated with copper chloride and Emulsol 5049-W indicated that the effect of this treatment was not destroyed by weathering. Thus, the aggregate might
November 1949
2651
INDUSTRIAL AND ENGINEERING CHEMISTRY
WAIN LvlGTH OF AMINE HY[F1(IWLORICE
Figure 1. Effect of Chain Length i n Treatment of Aggregate w i t h A m i n e Hydrochlorides be treated in the quarry and stockpiled until required for road construction. The excellent results obtained with the mixture of amines led to investigation of specific amines in this mixture. Straightchain, saturated, primary amine hydrochlorides (obtained from the Emulsol Corporation and from Armour & Company, chemical division) having chain lengths of 6 to 18 carbon atoms were employed alone or in conjunction with copper salts. The effect of the chain length of the amine hydrochloride on the coating retention of wet aggregate treated with the amine hydrochlorides is shown in Figure 1. I n general, with quartz aggregate the coating retention increased as the chain length of the amine hydrochloride was increased; with limestone aggregate the retention increased markedly as the chain length was increased from 6 to 10 carbon atoms but did not change appreciably as the chain length was increased from 10 to 16 carbon atoms. The use of metallic salts with the amine hydrochlorides was detrimental with quartz aggregate and beneficial with limestone aggregate. The degree of acidification of the amine had a marked effect on the efficacy of the treatments. The presence of free hydrochloric acid in the amine hydrochloride solution was detrimental on quartz aggregate and slightly beneficial with limestone aggregate. The effect
of the presence of free amine in the amine hydrochloride solutions was erratic; with Bome amines the efficacy of the treatment was increased, and with other amines it was impaired. A limited study of treatment with amine acetates indicated that the amine acetates were more effective in promoting the affinity of wet aggregate for bitumen than were the hydrochlorides, Treatment with a 0.5% solution of the amine acetate was as effective as treatment with a 1.0% solution of the corresponding hydrochloride. The use of metallic salts with the amine acetates was detrimental. Treatment with aromatic amine hydrochlorides did not, in general, increase the affinity of road aggregate for bitumen. a-Naphthylamine hydrochloride improved the adhesion of bitumen on limestone aggregate but was ineffective on quartz aggregate. Approximately 75 of the numerous proprietary surface-active agents were investigated as agents for promoting the adhesion of bitumen t o aggregate. I n general, these agents were ineffective with or without copper salts. Those of the agents which were a t all effective were not effective for both quartz and limestone aggregates and would thus be restricted to treatment of one or the other of the aggregates. ADDITIONS T O THE BITUMEN
Treatment of the aggregate is not so practical as treatment of the bitumen in promoting the adhesion of the bitumen for road aggregate. The necessity of seeing that another material (the treating agent) is at a particular spot a t a particular time is a serious drawback in road construction. Large scale tests, conducted by the authors in cooperation with the Ohio State Highway Department, revealed that an aggregate treatment required more labor than that which might be expected with a bitumen treatment. Moreover, in cold weather, when a treatment would be most advantageous, the handling of large volumes of solution was difficult. Because of these practical disadvantages of aggregate treatments, the improvement of adhesion by chemical additions to the bitumen was studied thoroughly Emulsol 5049-W, which was effective in the treatment of aggregate, was found to promote the adhesion of bitumen for wet quartz and limestone when added to the bitumen. The addition of copper chloride in conjunction with Emulsol 5049-W produced a further increase in the adhesion. Other amine hydrochlorides
OF AGGREGATE WITH EMULSOL 5049-W TABLE 11. TREATMENT
Kind None None Cuoric chloride Cu'pric chloride Cupric sulfate Lead nitrate Zinc chloride Ferric chloride Calcium chloride Cupric chloride
None None Cupric chloride Cupric chloride Lead nitrate Zinc chloride Ferric chloride Calcium chloride Cupric chloride Cupric chloride
Molar Strength
... O:t)i5 0.05
0.05 0.05 0.05 0.05
0.05 0.05
... O:i)i5 0.05 0.05 0.05
0.05 0.05 0.05 0.05
Concn. of Emulsol 5049-W,
Treatment
%
None
0.5
0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Quarts Aggregate
Limestone Aggregate None 0.5 0.2 0.5
0.5 0.5 0.5 0.5
0.2 0.2
....
Excess * One-solution excessa One-solution excess Two-solution excess One-solution excess One-solution excess One-solution excess One-solution excess One-solution excess' treated aggregate weathered for 4 months0
Excess One-solution One-solution One-solution One-solution One-solution One-solution One-solution One-solution weathered
.... excess excess excess excess excess excess excess excess. treated aggregate for 5 Aonthsc
Amount of Aggregate Coated, % 50
100 100 100 100 100 100
Coating Retention after Immersion in Water for 24 Hr., %
0 30 70 80
70 20
100
15 0 20
100
85
m __
n 70 70 80
0
100 100 100 100 100
90 100 100
100
60 75 5
40 85 95
Blast-Furnace Slag Cupric chloride 0.25 0.75 One solution excess 100 80 a One solution containing both metallic salt and Emulsol 5049-W was used. .4n excess of solution was added, drained, and the aggregate coated with bitumen. b Separate solutions of the activator and organic agent were used. An excess of the solutions was added, drained, and t h e aggregate coated with bitumen. C Treated aggregate was stored on the roof at Battelle Memorial Institute. A total of 3.35 inches of rain fell during the 4-month period and 4.63 inches of rain fell during the 5-month period.
INDUSTRIAL AND ENGINEERING CHEMISTRY
2652
Vol. 41, No. 11
sebacic, phthalic, nitrobenzoic, sulfanilic, tridecanoic, pyromucic, TABLE 111. ADDITION OF AMINE~IYDROCHLORIDES TO BITUMEN and tartaric acids, also were ineffective. Copper amine compounds, prepared by reaction of an alcoholic solution of copper Bdditions to Bitumen _Coating Ketained chloride arid an alcoholic solution of an amine, markedly imAmine Hydrochloride after CUqllC Amount, A-gregate Immersion proved the adhesion of the bitumen for hydrophilic aggregate. chl.-. nrr- ri _P_ , hv e o a t e d , in Water for The use of the amine alone was more economical, however. The Kind wt. % by wt. % 24 Hr., % copper amine compounds were described and characterized Quarts Aggregate independently by Broome, Ralston, and Thornton (6). ... Emulsol 5049-Wa 0.2 100 50 Several typical surface-active agents mere employed as bitumen 0.34 Emulsol 5049-W 0.2 100 60 ... Emulsol 5049-W 0.4 100 90 additives. None of the agents promoted the adhesion of bitumen , , . Emulsol 5049-Yb 0.2 100 95 . .. A~1CL-Coco-C~ 0.4 100 50 for quartz aggregate, and only a few of the agents promoted the . Hexadecylamine hydrochloride5 0.4 100 7; affinity of bitumen for limestone aggregate. Treatment with . ,, Octadecylamine hydrochlorided 1.0 100 surface-active agents was more costly than the use of amines or Limestone Aggregate amine hydrochlorides , I .-a
.,,
0.34 .,.
.,. , . I
Emulsol 5049-W Emulsol 5049-IT Emulsol 5049-W Emulsol 6049-Y AMCL-Coco-C
0.4 0.4 1.0 0.2
1.0
100 100
100 100 100
55
80
90 95 85
Blest-Furnace Slage
. ,,
Emulsol 5049-Y
0.4
100
90
Gravell
.,,
Emulsol 5049-Y 1.0 100 95 A mixture of amine hydrochlorides having alkyl chain lengths corresponding t o those of the f a t t y acids in coconut oil marketed by Emulsol Corporation. b Commercial dodecylamine hydrochloride marketed by Emulsol Corporation. 6 A mixture of amine hydrochlorides having alkyl chain lengths corresponding t o those of the f a t t y acids in coconut oil. marketed by Armour &Company, chemical division. d Prepared from chemically pure amines supplied b y Armour B;: Company, chemical division. e Ohio State Highway Department No. 6 blast-furnace slag. f Obtained from the Ohio State Highway Department, Pickaway County division. a
also improved the adhesion when added to the bitumen. Dodecylamine hydrochloride, hexadecylamine hydrochloride, and SMCL-Coco-C (a mixture of amine hydrochlorides) were particularly effective. The use of metallic salts with the latter amine hydrochlorides did not improve the adhesion. The results of tests on the addition of amine hydrochlorides to bitumen are given in Table 111. Amines also were found to improve the adhesion of bitumen to wet aggregate. The chain length of the amine influenced the effectiveness, as is shown in Figure 2. I n general, the amines produced greater adhesion for quartz than for limestone aggregate. The use of metallic salts in conjunction with the amines was detrimental in most cases. Several organic copper compounds were tested. The copper soaps of stearic, oleic, palmitic, and linoleic acids did not increase the stripping resistance of bituminous coatings. Copper salts of organic acids, such as citric, hydroxybenzoic, lactic, maleic,
d 20
1
‘\lf I
I
1
~
I--
RESULTS
Treatment of road aggregate with cupric chloride and Emulsol 5049-W produced an excellent affinity for bitumen. Other amine hydrochlorides or mixtures of amine hydrochlorides, however, did not behave in the same manner, and the increased efficacy of the treatment with Emulsol 5049-W, brought about by the use of copper salts, was not characteristic of amine salts or mixtures of amine salts. Deposition of a continuous, water-insoluble, water-repelling coating of a metallic soap on the surface of the aggregate was difficult and the results obtained were erratic, Excellent bitumen treatments were developed which produced completo coating of hydrophilic aggregate by the bitumenand good resistance to water stripping. Of the additives studied, amine hydrochlorides were most effective and economical. Bitumen treatments were more economical and were more acceptable to highway engineers than were aggregate treatments. ACKNOWLEDGMENT
The permission of the Anaconda Copper Mining Company, the Kennecott Copper Corporation, and the Phelps Dodge Corporation to publish the results of this investigation is gratefully acknowledged. The authors wish to thank the Ohio State Highway Department, and particularly J. H. Goshorn, for cooperation and advice. LITERATURE CITED (1) Adam, N. K., “Physics and Chemistry of Surfaces,” p. 189, London, Oxford University Press (1941). (2) Agnew, R. J., U. S. Patent 2,430,546 (h’ov. 11, 1947). (3) Allen, W. A,, Ibid., 2,416,134 (Feb. 18, 1947). (4) Anderson, A. P., and Stross, F. H., Ibid., 2,427,488 (Sept. 16, 1947). ( 5 ) Rartell, F. E., and Osterhoff, H. J., Colloid Symposium Monograph, 5, 113 (1938). (6) Broome, F. K., Ralston, A. W., and Thornton, M. H., J . Am. Chem. SOC.,68, 67, 849 (1946). (7) Cole, W-. G., U. S. Patent 2,336,468 (Dec. 17, 1943). ( 8 ) Dahlberrr. A. B. C.. Ibid.. 2,192,284 (March 5. 1940). (9) Dohse, g . , and Spain, F., Ibid., 2,191,295 (Feb. 20, 1940). (10) French Patent 826,789 (April 8, 1938). (11) Ibid., 837,974 (Feb. 23, 1939). (12) Hemmer, L., Ibid., 832,683 (Sept. 30, 1928). (13) Hemmer, L., U. S. Patent 2,342,861 (Feb. 29, 1944). (14) Hersberger, A. B., and Gremski, F. C., Ibid., 2,430,815 (Nov. 11, 1947). (15) Holmes, A , , Ibid., 2,378,653 (May 8, 1945). (16) Johnson, J. M., Brit. Patent 469,202 (July 21, 1937). (17) Johnson, J. M., U. S. Patent 2,177,568 (Oct. 24, 1939). (18) Johnson, J. M., Ibid., 2,419,404 (ilpril 22, 1947). Ibid., 2,426,220 (Aug;.26, 1947). (19) Johnson, J. M., (20) Johnson, J. M . , and Brown, E. C., Ibid., 2,317,959 (April 27, 1943). (21) McCoy, P. E., Ibid., 2,313,759 (March 16, 1943). (22) Mack, C. J., IND. ENG.CHEM.,27, 1500 (1935). (23) Mack, C. J., J . SOC.Chern. I n d . , 60, 111 (1941). (24) Mack, C . J., U. S. Patent 2,283,937 (May 26, 1942). (25) McLeod, N. W., Can. Patent 417,776 (Jan. 18, 1944). (26) McLeod, N. W., Proc. Asphalt Paving Tech., 9, 1 (1937).
November 1949
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
(27) Mikeske, L. A,, Can. Patent 425,128 (Jan. 16, 1945). (28) Miner, C. S., Jr., Bryan, L. A,, Holysz, R. P., Jr., and Pedlow, G. W., Jr., IND.ENG.CHEM.,39, 1371 (1947). (29) Nicholson, V., Proc. Asphalt Paving Tech., 12, 9 (1940). (30) Roediger, J. C., U. S. Patent 2,332,260 (Oct. 19, 1943). (31) Saville, V. O., and Axon, E. O., Proc. Asphalt Paving Tech., 9, 86 (1937). (32) Suida, H., Jekel, O., and Haller, K., Asphalt u. Teer Strassenbautech., 39, 253 (1939). (33) Swanson, J. M., IND. ENG.CHEM., 36, 584 (1944). (34) Tremper, B., and Erwin, R.P,, Proc. Montana Natl. Bituminous Conf., 4, 102 (October 1938).
2653
(35) Tuaker, E. B., and Grubbs, H. M., U. S. Patent 2,276,436 (March 17,1942). (36) Ulrich, H., Plietz, E., rtndFerrares, O., Ibid., 2,351,241 (June 13, 1944). (37) Weetman, B., Ibid., 2,383,097 (Aug. 21, 1945). (38) Weetman, B., and Agnew, R. J., Ibid., 2,375,055 (May 1, 1945). (39) Whitacre, C. H., Ibid., 2,286,244 (June 16, 1942). (40) Williams, H. G., Brit. Patent 554,986 (July 28, 1943). (41) Winterkorn, H. F., Proc. Asphalt Paving Tech., 8, 79 (1936). (42) Winterkorn, H. F., Ibid., 9, 63 (1937). (43) Winterkorn, H. F., U. 8 . Patent 2,314,181 (March 16, 1943). RECEIVED January 14, 1949.
Equipment for Compressibility Measurements DATAONPROPANE B. J. CHERNEY', HENRY MARCHMAN, AND ROBERT YORK, J R . ~ Carnegie Institute of Technology, Pittsburgh 13, P a . Equipment is described for measuring pressure-volumetemperature characteristics of fluids from room temperature to 300" C. and from 10 to 220 atmospheres. The apparatus is suitable for measuring vapor pressures and critical properties as well as compressibilities. The limit of accuracy of the equipment is estimated to be 0.25%. This has been verified by measurements on propane, a material whose properties are well known. Some new data on propane are reported.
T
HIS institution started a program for determining thermodynamic properties of materials over a range of temperatures and pressures. Part of the basic data needed for this project is the complete and precise information on the volumetric behavior of the materials. The purpose of this paper is to describe the apparatus used in determining compressibilities. Measurements have been completed on several systems and are being prepared for publication. The apparatus for compressibility measurements of gases and liquids described here is a further development of the designs of Keyes ( 9 ) and Beattie (1). Essentially, the equipment consists of three main parts: A thermostated compressibility bomb whose effective volume can be varied by injecting or withdrawing mercury; a mercury compressor for the injecting or withdrawing of the mercury; and dead weight gage for determining the pressure on the sample. The equipment in its present form can be used for compressibility measurements at temperatures from 30' to 300' C. and a t pressure from 10 to 220 atmospheres. With minor modifications the pressure range can be appreciably extended. A schematic layout of the equipment is shown in Figure 1. In operation the bomb, 4,is directly connected to the mercury compressor, 18, and to one of the dead weight gages, 26 or 29. The gas sample to be investigated is confined by mercury in the bomb, 4. Mercury fills the portion of the bomb not occupied by the sample, the lines 5, 7, 13, 14, 17, and 21, the mercury compressor, 18, and the air trap, 16. I n the mercury U-tube, 22, there is a mercury-oil interface near the center of the right-hand le From this interface t o the oil injectors, 24, 31, the system is with heavy U.S.P. mineral oil. The parts filled with oil are the line, 23, the gages, 26 and 29, and the oil injectors, 24 and 31. Valves 2, 11, 25, and 30 are normally closed while valves 12, 15, and 20 are
. died
1 Present address, E. I. du Pont de Nemours & Company, Wilmington, Del. 3 Present address, Monsanto Chemical Company, St. Louis, Mo.
normally open. In addition, either valve 27 or 28 is opened to connect the desired pressure gage into the system. In addition to the parts shown in the schematic diagram, certain other equipment is necessary for the measurement of compressibilities. This equipment is described in detail later, but is listed here for reference: The charging system for purification of the sample and introducing it into the bomb; the thermostat and temperature regulating system for the compressibility bomb; the dual contact device in the U-tube for detecting the mercury oil interface; and the temperature measuring system for the bomb thermostat. COMPONENT PARTS O F APPARATUS
The manifold used for charging the sample is a piece of brass of square cross section into which four Hoke bellows valves have been soldered. There is a hole through the entire length which terminates in a standard superpressure connection for joining to the bomb charging valve. Two of the Hoke valves are provided with connectors for the weighing bombs, while the other two are connected to a vacuum gage and vacuum pump, respectively. The weighing bomb (Figure 2) is made of brass and is fitted with a Hoke bellows valve. Into the bellows valve is soldered a standard superpressure fitting of stainless steel. The compressibility bomb with its charging union is shown in Figure 3. The bomb was machined from a solid hexagon bar of American Iron & Steel Institute 410 stainless steel. The construction and closure are of standard high pressure designs, the details of which are apparent from the figure. The charging union is essentially the same design as that used by Beattie ( I ) except that a closure disk of annealed copper (0.002 inch thick) is used instead of gold. The actual determination of temperature on the international centigrade scale was accomplished by a platinum resistance thermometer which was calibrated, using standard methods, against the ice point, the steam point, and the sulfur boiling point. The thermometer used for this work was a four lead 25-ohm Leeds & Northrup (No. 8163) platinum resistance thermometer. The resistance of this thermometer was determined by a Leeds & Northrup-type G-1 Mueller bridge. The temperature of the sample is determined by measuring the temperature of an agitated oil bath which surrounds the compressibility bomb. After time
