viscosity of aqueous glycerol solutions

8/12/2019 Viscosity of Aqueous Glycerol Solutions

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September 1951 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 YRillman, G .W. age, B. H., and Lacey, W. S . 'ru.ns. Am. Inst.Bridgeman, 0. C., J . Ana. Chem. Soc. , 49, 1174-83 (1927).Farrington, P. S., and Sage, B. H. , INI).ENG.C H E ~ I . ,1, 1734-7Kay, 1%'. B., b i d . , 30, 459--65 (193 8).Kuenen, J. P., Theorie der Verdamgfung und Verflllssigungvon Gemischen und der Fraktionierten Destillat ion, Leip-

zig, J. 8 arth, 1906.

M e t . E n g r s . , 174, 13-24 (1948).

(1949).

Lewis, G. N., J . A7n. C h e m . Soc., 30, 668-83 (1908).Lu, H., Newitt, D. M., and Ruhemann, M., Pro c . R o y . SOCMarchman, H., Prengle, H. W.,r., and Motard, R. L., IND.McMillan, W. A., Cole, H. A., and Ritchie, -4. ., IWD.NG.Prengle, H. W., Jr. , and Marchman, H., IND. NG.C H E M . , 2,

(London), SeriesA, No. 975, 178, 506-24 (194 1).ENG. HEM., 1, 2658-60 (1949).CHEM.,NAL.ED.,8, 105-7 (1936).2371-4 (1950).

(16) Reamer, H. H., Olds, R. H., Sage, 13. H.. and Lacey, W(17) Reamer, H. H., and Sage, B. H., Volumetric and PhasI b i d . , 36, 956-S(1944).havior of the Prouene-Prouane Svstem. to be Dublishe(18) Sage, B. H. , and Lacey, W: ., 7 ans. Am. Ins;. Mintnu(19) Ib i d . , 174, 102-20 (1948).(20) Sage, B. H., and Lacey, 11 . S . ND. KG. HEM., 0, 129

Engrs. , 136, 136-57 (1940).

(1948).(21) Sage, B. H., and Lacey, W. ., Thermodynamic Propof the Lighter Paraffin Hydrocarbons and Nitrogen, A1950.(22) Sage, B. H., and Lacey, W. N., P et ro l eum R e f i n e r , 29, (1950).(23) Vaughan, W. ., and Graves, S . K. , IXD.ENG.CHE1252-6 (1940).(24) Winkler, C. A., and Maass, O., Can . J . Research , 9,(1933).

RECEIVEDarch 6, 1951.

Viscosity of Glycerol and ItsdAqueous SoJ. B. SECUR AND HELEN E . OBERSTAK

Th e Miner Laboratories, C hicago 6 , I l l .Viscosity data for aqueous gl>cerol solutions in therange of 0" to 100" C . and 0 to 100% concentration havebeen reported by various auth ors, each working withinlimited temperature or conce ntration ranges. Differenttypes of viscometers were used. As a result there are gapsand inconsistencies n the data.

The viscosit? data reported here were obtained with asingle type of viscometer over the entire range of 0" to100' C . and 0 to 100% glycerol concentration.

The data will be useful in the design a nd use of glycerol-handling equipm ent. They also make it possible to useaqueous glycerol solutions s viscosity standards over awide range of viscosity and at temperatures from 0' tol o o a=

'SERE have been several studies of glycerol viscosity forlimited ranges of conceriti ations and temperature s. How-ever, there has been no extensive study of aqueous glycerol solu-

tions over 0 to 100 C. tem pera ture range using a single typ e ofviscometer. Herz and Wegner (12) measured the viscosity ofglycerol solutions of 10 to 92% concentration a t temperaturesFrom 10' to 80' C. Their results were published in te rms of bothrelative and absolute viscosity. Arch butt and Deelev (2) madecareful viscosity measurements of glycerol solutions a t 20' C.The capillary of their viscometer had a diameter of 0.6180 mm.and a length of 21.991 cm., with square ends. Th e hydros tatichead was increased by a supplementary tube attached to thecapillary when the more viscous solutions were used. Dark e andLewis (10)measured th e relative viscosity of glyceiol solutions of10 to 92% concentration a t 1' C . They did not record thespecific gravities of their solutions, nor did th ey s tat e how theviscosity measurements were made. They published their dat atogether with the relative viscosity data of Herz and Wegner tomake a comprehensive tabula tion. Cocks (9) combined otherpublished data with those published by Darke and Lewis andaddrd some original data obtained with a standard Redwood vis-cometer to make a compilation covering most of the points from1' to 100 C., and from 0 to 99% of glycerol. The da ta ar e givenin terms of poises. Ther e ar e a number of inconsistencies in theat)ovedata , particularly in the regwn of tempcratureq ahovc 70

C. Sheely (16), using a viscometer of the type describeBingham and Jackson 4),n which pressure on the liquicontrolled by a regulated air supply, made very careful mements of th e viscosity of glycerol solutions of 0 to 100% cotrat ions an d a t the temperatures of 20 , 22.5 , 25 , 27.5 30 C. Mtiller ( I C ) published viscosity values for water anconcentrations of glycerol at temperatures from 17 to 90 C

Vand Ill),using Ostwald viscometers, determined the visof glycerol solutions of 98.4 and 99.6% concentrations atemperatures from 80 to 167 6. Green and Pa rke 1 1 )ured the viscosities of glycerol solutions at temperatures0 to -40 C., within the limits of th e freezing points osolutions. Tam mann and Hesse (17) measured the viscos99.5% glycerol a t temper atures from -42' to -4.2 C.viscosity of pure glycerol a t pressures up to 12,000kg. per sqa t 30' C., was measured by Bridgman (6).

The present work was done to correct some inaccuracies previous data, to provide data where none were available, aprovide a series of consistent viscosity da ta all obtained wisame ty pe of viscometer, within t he limits of 0 to 100 C.,to 100% glycerol concentration.

GLYCEROL AND GLYCEROL SOLUTIONSA selected sample of C . P . glycerol was distilled from a

flask through a 25-cm. Vigreux column. Th e column wasnected to the flask with a standard-taper ground-glass The middle portion of the distillate, boiling point 1401 mm., weighing 4330 grams, xa s taken for use. Its spgravity a t 25/25' C. was 1.26192, which corresponds t o 99of glycerol by weight.

The glycerol-water solutions were prepared by mixing clated weights of glycerol and of distilled water which hadrecently boiled and cooled. Th e actual concentrations wetermined from their specific gravities a t 25/25' C. Two G25-ml. pycnometers were used. Dupli cate tests were madeeach solution, one test with each pycnometer. The equiglycerol concentrations were obtained from the da ta of Band Snoddy 5 ) . The maximum difference between dupdeterm inatio ns was equivalent to 0.08% glycerol. The avdifference was 0.04%. The concentrations of the solution


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2118 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 Y Vol. 43, N o . 9

TABLE. CALIBRATION OF VISCOMETERS A T 20" c.Vis-cometer Time, Solution Abaolute Kinematic ViscometerSolution No. Sec. Density Viscosity Viscosity Const.ant

Water 50 209.5 0.99824 1.0080 1.0068 0.00481G1 cerol, yogo.0260.0285.0785.0785.0796.0096.00

50100100200300300400

1946.3 1.15406 10.795622.3 1.15406 10.7955990.0 1.22223 110.04936.4 1.22223 110.04349.4 1.22223 110.041934 0 1.25109 623.50396.1 1.25109 623,50

9.35399.353990.03690.036Y0.0364118.37498.37

0 . i5030,09021 2660,2577

0.00, 10.20, 20.04, 29.96, 40.01, 49.93, 60.02, 60.97, 74.97, 79.99,85.07, 90.03, 92.09, 92.97, 94.96, 96.00, 96.99, 97.89, 98.86, and09.97%. The solutions with 50% or less of glycerol were storeda t 5" to 10 C. to prevent mold growth.

APPARATUSThe viscometers used were the No. 50, 100, 200, 300, and 400sizes of th e modified Ostwald viscometers described by Cannonand Fenske 7 , 8). Specifications and directions for use are alsogiven by the American Society for Testing Materials (ASTM) ( I ) .

The viscometer to be used for a test was selected so that theefflux time of the liquid would be a t least 200 seconds, and forconvenience, not over about 800 seconds. At temperaturesabove 60' or 70" C. evaporation of water from the solution in t heviscometer became appreciable. To reduce such evaporationan inverted U-tube was attached to th e two ends of th e viscom-eter v..-ithshortpieces of rubber tubing. Connected to the U-tubewere stopcocks arranged so that the solution could be blown intothe upper bulb of the viscometer preparatory to a test. Exce twhen th e solution was being transferred to t he upper bulb, t i esystem was kept closed. The internal pressure was the same asthe atmosphenc pressure, and the passa e between the ends ofthe viscometer was open. Even with &ese precautions therewas some slight loss of water from the solutions as vapor con-densed in the cooler art s of the tube above the thermost at bath.The amo unt of co nfen sate varied from a trace to perhaps twodrops when the more dilute solutions were heated to the highertemperatures. Because of this progressive loss of water, onlyfive individual readings were taken to obtain an average value insuch caaes.The thermostat could hold four viscometers, and it was fre-quently convenient to have several viscometers in operation a t onetime. The temperat ure was constant to =k0.05"below 60" C.Abovz 60 0 he constancy decreased, and at 90" to 100 C. wasf O . l .The thermometers used were calibrated by the U. S. Bureauof Standards . One, used from 0 to 60" C., had scale divisionsof 0.1 . The other, used from GO t o 100 C., had scale divisionsof 0.5 .The stop watches used were compared with an accurate pocketwatch (which had been checked against a chronometer) and thenecessary corrections applied to the average observed times.

For other solutions, ten readings were taken.

CALIBRATION OF THE VISCOMETERSWater was taken as the standard of reference, its absolute vis-

cosity a t 20" C. being 1.0050 centipoises (4 ) and its density0.99824. Using boiled, distilled water, the viscometer constantof the No. 50viscometer was determined with Equ ation 3.

1 )(2)

c = v/dt (3)

v kd or v ctdk = ct or c = k / l

where v = absolute viscosity in centipoises a t 20"C.k = kinematic viscosity in centistokes a t 20"C.= efflux time in seconds at 20" C.d = density of the liquid a t 20" C.c = viscometer constant at 20" C.Since the flow of water through the No. 100 viscometer was toorapid for accuracy, it was calibrated with a glycerol solution, theviscosity of which had been measured in the No. 50 viscometer,calculations being made with Equation 2. In a similar mannpr

the remaining viscoinetcrs acre calibrated R


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September 1951 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 Y

TABLE . VISCOSITY O F AQUEOUS GLYCEROLOLUTIONSGlycerol, - Temperature, C.

Viscosity, Centipoise*10 20 30 40 50 60 70 80 90 wt.0 1, 792 1. 308 1. 005 0. 8007 0. 6560 0.5494 0, 4688 0. 4061 0.3565 0.3165 10 2.44 1. 74 1. 31 1. 03 0. 826 0. 680 0. 575 0. 500 . . . . . .20 3. 44 2. 41 1. 76 1. 35 1. 07 0. 879 0. 731 0. 635 . . .

40 8. 25 5. 37 3. 72 2.72 2. 07 1. 62 1. 30 1. 09 0. 918 0. 763 50 14. 6 9. 01 6. 00 4. 21 3. 10 2. 37 1. 86 1. 53 1.25 1. 05 60 29. 9 17. 4 10. 8 7.19 5. 08 3. 76 2. 85 2. 29 1. 84 1. 52 65 45. 7 25. 3 15. 2 9. 85 6. 80 4.89 3. 66 2. 91 2.28 1. 86

30 5. 14 3. 49 2. 50 1. 87 1. 46 1. 16 0. 956 0.816 0:510 . . .

67 55. 5 29.9 17. 7 11. 3 7. 73 5.50 4. 09 3. 23 2. 50 2. 0370 76. 0 38. 8 22. 5 14. 1 9. 40 6. 61 4. 86 3. 78 2. 90 2. 34 75 132 65. 2 35 5 21. 2 13. 6 9. 25 6. 61 5. 01 3.80 3.00 80 255 116 60. 1 33. 9 20. 8 13. 6 9. 42 6. 94 5. 13 4. 03 85 540 223 109 58. 0 33. 5 21. 2 14. 2 10. 0 7. 28 5. 5290 1310 498 219 109 60. 0 35. 5 22. 5 15. 5 11. 0 7. 93 91 1590 592 259 126 68. 1 39. 8 25. 1 17. 1 11. 9 8. 62 92 1950 729 310 147 78. 3 44. 8 28. 0 19. 0 13. 1 9.46 93 2400 860 367 172 89.0 51. 5 31. 6 21. 2 14. 4 10. 3 94 2930 1040 437 202 105 58. 4 35. 4 23. 6 15. 8 11. 2 95 3690 1270 523 237 121 67. 0 39. 9 26. 4 17.5 12.4 96 4600 1585 624 281 142 77. 8 45. 4 29. 7 19. 6 13. 697 5770 1950 765 340 166 88. 9 51. 9 33. 6 21. 9 15.1 98 7370 2460 939 409 196 104 59. 8 38. 5 24. 8 17. 0 99 9420 3090 1150 500 235 122 69. 1 43. 6 27. 8 19. 0 100 12070 3900 1412 612 284 142 81. 3 50. 6 31. 9 21. 3

a Viscosity of water taken f rom Bingham and Jackson (4 ) .

Glyc-erol,%010203040560657075808590919293949596979899100

TABLEI . COMPARISONF VISCOSITY ATA temperature iritervnls of 10' C. Therefore.4rchbutt and p la t ed corrections for temperature cha0.1' or less would be cor rec t within th e l

experimental accuracy. A number of cor1. 005 0. 8007 1, 005 0.00 0. 800 0. 088 1. 005 0.00 were calculated for each of th e visco

1, 769 0. 51 1. 360 0. 74 1. 798 2. 16 Average values were then used in making2.50 1. 87 i:;;; :::: z: :: rections. These average values are given i6. 00 4. 21 6. 050 0. 83 4. 247 0. 88 5. 994 - 0. 10 I V The correct,ion is added with decreas

15. 54 2. 24 10. 02 1. 73 15. 26 0. 39 perature, subtracted with increased tempThe viscosities of solutions of even per ce

60. 1 33. 9 62. 00 3. 16 34. 92 3. 01 61. 27 1. 94 centration were calculated from the experdat a by interpolation, assuming logarith09 58. 0 112. 9 3. 58 60. 05 3. 54 112. 1219 109 234.6 7. 12 115.3 5. 77 233.15.82 275.9 crease of viscosity with concentra tion. The59 127 278. 4 7. 50 134. 4310 147 328. 4 5. 93 156.5 6. 46 326. 2367 172 387. 7 5. 65 182. 8 6. 28 386. 6 5. 35 change is actually greater than a logrtrithm457' 7 4' 74 212' o 4' 95 457'8 4' 76 tion. Therefore , if interpola tion is to be ma37 202523 237 545 4. 40 248. 8 4. 98 548. 0 4. 79

624 281 661 5. 93 296.7 5. 59 659. 3 more than abo ut 1% of glycerol con centra t765 340 805 5. 23 354. 0 4. 12 804. 1939 409 974 3. 73 424. 0 3. 67 997. 4 6. 22 preferable to plot accurately the known semilogarithmic coordinate paper which can

~ _ _iscosity, Centipoise6Sheely 16) Deeley 8 )Q Q_ _ ~ - ~uthorsZOOC. 30 Cr- 2 0 C. di8. 30' C . dig. 20 C. d%.

1. 311 0. 076 1. 024 - 0. 058 1.328 1. 37. 31 1.031. 76 1. 353. 72 2. 72

10. 96 1. 48 7. 312 1. 70 10, 791 - 0. 080. 8 7.1915. 2 9.8522. 5 14. 1 22. 94 1. 95 14. 32 1. 56 22. 63 0. 5835. 5 21.2 36. 46 2. 71 21. 68 2. 26 36. 63 3. 182. 846.45

1150 500 1197 4. 09 511. 0 2.20 . . . ...1412 612 1499 6.32 624. 0 1. 96 . . .MWSUREMENT O F VISCOSITY

When measuring the viscosities of the glycerol solutions, theviscometer to be used was selected so that the efflux time wouldbe at least 200 seconds. By this means the correction t o be ap-plied for the loss of kinetic energy was kept so low th at it could beomitt ed. Th e calculation of results was thereb y simplified andmade as described in ASTM D 44546T ( I ) , and also by Ruh,Walker, and Dean ( I @ , using Equation 1, given above. Theviscosities of the moet dilute solutions at the higher temperatureswere too low to be measured accurately.

The densities of glycerol solutions at 20" C. were calculatedfrom their specific gravities at 20/20 C. and th e density of w atera t 20' C. Densities of the glycerol solutions a t other than 20" C.were calculated wth the aid of the thermal expansion data ofGerlach as given by Lawrie 19).

When adjusting the thermostat to obtain a given t emperature ,i t was not practical to set i t precisely at the desired temperature,due to the design of the regulator. Divergence from desired tem-per ature did not exceed 0.1'. Th e observed times of efflux wereadjusted to correspond to the desired even temperature. Byplotting observed time for a given solution on a logarithmic scaleagainst temperature o n an arithmetic scale it was found tha t thed t i n g urve for each viscometer was nearly a straight line ovcr

to three significant figures and read the visfrom smoothly drawn curves. This latt erdure was used to obtain the viscositiw of

solutions of 65, 70 91, and 94% concentrations. Similaviscosities of 10% glycerol at 50, 60, and 70' C.,glycerol at 70" C., of 30%glycerol a t SO C., and 40% gly90' and 100' C. weie obtained by extrapolation of theComplete data are given in Table V.

The viscosity values obtained in th is work ar e believraccurate to a t least = t l t temperatures of 60 C. andAbove 60 C. the iiccuracy of temperature control and tctur e recording was less satisfactory. The evaporation ofrom the solutions introduced an error that incream1 wtemper ature. Therefore, th e accuracy of the data for thtemperatures varies from f 1 . 5 to 5~3.0%~he greaterbeing with the most dilute solutions at the highcst tctures..4comparison of th e viscosity values for 20' and 30'those of Sheely 16) or the same t empera tures and concen(see Table VI) shows the latter data to be consistently Th e differences range from a few t enth s of a per cent in theolutions to a maximum of 7.5%. Although there arevariations, there is nevertheleas a consistent difference bthe two seta of data which is probably to be ~ccaun tedordifferent types of visconietcrs used a n d the attendant corand calrulstions.


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2120 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 Y Vol. 43. N o. 9The viscosity data of Archbutt and Deeley (8) also are in

general higher than those reported in this paper, the greater dif-ferences being found with the more concentrated solutions. Aswith Sheelys dat a, th e type of viscometer used may explain themajor differences. Inte rpolated values to correspond with theglycerol concentrations used in this pape r ar e shown in TableVI.

Compared to the present d ata , the viscosities of glycerol solu-tions at 1C. as determined by Darke and Lewis IO) re muchtoo low. The differences are grea ter a t t he higher glycerol con-centrations, being 1.3% for 10% glycerol, and reaching a maxi-mum of 37.8% for 88% glycerol. Since Darke and Lewis pub-lished their data in conjunction with data of Hrrz and Wegner,it is assumed th at t he specific gravity tables of t he iatt er au thorswere used. Glycerol concentrations were recalculated with theBosart and Snoddy specific gravity tables when comparing theDarke and Lewis data with those of the present authors.

The viscosity d at a of H e r z and Wegner (II), ith th e glycerolconcentrations recalculated from th e Bo sart and Snoddy specificgravity tables, are in fair agreemerit with the present data at thelower solution concentrations and lower temperatures but other-wise show considerable irregularity, for the most part being toolow.

ACKNOWLEDGMENTThis work was sponsored by t he Association of American Soap

and Glycerine Producers, Inc., New York, N . Y.

LITERATURE CITEDAm. SOC. Testing Materials Standards, Vol. IIIA. TentativeArchbutt and Deeley, Lubrication and Lubricants, 5th ed.,Bates, F. ., and Associates, Natl. Bur. Standards, Circ. C44

Method D 44546T, p. 964-74,1946.p. 193,London, C. Griffin & Co., 1927.DD. 626.671 11942).Bi&ham,E. C., and Jackson, It. F., Bu l l . Bu r . S t a i i d u rd s , 14,

Bosart, L. W.,nd Snoddy, A. O., IND. ENG.CHEM., 9, 00-NO. 98, 9-86 (1917).10 (1927).Rridgman, P. W., P roc . Am. A c a d . A r t s Sci. 61, 7-99 (1926).Cannon, M. R., and Fenske, M. R., I n d . Eng. C h e m . , Anal.

Cannon, M. R., and Fenske, M . R., Oil Gus J . , 34, o . T. p.ocks, L. V., J . Soc. Chem I n d . , 48,279-80T (1929).Darke, W. F., and Lewis, E., Chemistrz/ & I n d u s t r y , 47, 107.7-02

Green, Edrnund, and Parke, J. P., . J . Sot. C he in . I t i d . , 58 19-20Hers, W. nd Wegner, A., Z. m d . Oj2-Fett-Ind., 45, 401-2Lawrie, J. W.,Glycerol and the Glycbls, p. 170,New T o r k ,Muller, Emma, Sitz . her . A k a d . Wiss. Wieti , Math.-nntia~i.Ruh, E. L., Walker, R. W., and Dean, E:. \V., nd. En g . C h c m . ,Sheely,M. L., IND.ENG.H E M . , ~ ~ ,060-4 (1932).Tamrnann, G., and Hesse, W., 2 n o rg . a l l ge m. C h e m. , 156, 18-Vand, Vladimir, Re se a rc h , 1,44-5 (1947).

E d . , 10,297-301 1938).45-46,48-49 April9, 936).

(1928).(1 39).(1925).The Chemical Catalog Co., 1928.Klasse A b L I I a , 133, 38-47 (1924).A n a l . Ed. 13, 46-9 (1941).57 (1926).

R E C E I V E D arch 18, 1849

Limits of Flammability of Paraffin-Hvdrocarbons in AirM . G. ZABETAKIS, G. S. SCOTT, AND G. W. JONES

U . S . Bureau of Mines , P i t t sburgh, Pa.

FLAMMABLE gaseous mixture is a mixture of gasesA hrough which flame can propagate. The flame is in-itia ted in the gaseous mixture by means of a n external sourcethat delivers energy t o the sys tem, composed of the gaseousmixture and its surroundings. A flammable gaseous mixturemay apparently or actually be rendered nonflammable by achange in one or more of the following items associated with th emixture or i ts surroundings:

( a ) Temperature( b ) Pressure(c) Ratio of combustible to oxygen( d ) Rat io of inert or other foreign gas to oxygen( e ) Characterist ics of the ignition sourcef ) Geometry and size of th e confining vessel( 9 ) Physical sta te an d surroundings of the gaseous miuture

Although a suit able change in one or more of the above itenis mayrender a flammable mixture nonflammable, the converse is notnecessarily true.

As in general only gaseous mixtures composed of one combus-tible an d air are considered in this investigation, item d is con-sta nt and will not be considered further. Furtherm ore, if all thcabove items are kept cons tant excc,pt c, which is varied by addingair, t he combustible content of th c flammable mis turc cvcintu:dlybecomes too low t o propagate flamv. If then a nuinb(1i.o f siini-lar tests are made in which e , f , and g are also varied (:~lth(~ughthe gaseous niixturo should roni:~inhoniogciicwus : I I I I

viscosity of aqueous glycerol solutions

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