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I I\; D U S T R I A L A N D E N G I N E E R I N G C €I E M I S T R Y
COKCLUSIONS I n general, it appears for the present that beverage juice manufacturers marketing their products in glass containers should bear in mind the protecting influence of green on light deterioration. Some producers perhaps will not welcome green glass containers, as the clarity, color, and appeal to the eye of fruit juices is largely masked thereby. To those manufacturers the way is probably open for marketing in clear glass containers wrapped in one or another of the transparent green cellulose coverings that have recently come on the market. These coverings have the welcome feature that they are easily removed when a salesman desires to show a customer the true color of the juice without the necessity of opening the container. ACKNOWLEDGMENT The writer is indebted to the Corning Glass Works for furnishing data from which the transmission curves shown in Figure 2 were constructed.
Vol. 25, No. 8
LITERATURE C.TED (1) Bernoulli, A. L., and Cantieni, R., Helv. Chim. Acta., 15, 119-39 (1932). ( 2 ) Boutanc, A., and Bouchard, J., Compt. rend., 192, 95-7 (1931); Bull. SOC. chim., 51, 757-60 (1932). (3) Carpenter, D. C., Pederson, C. F., and Walsh, W. F., ISD. ENG. CHEM.,24, 1218 (1932). (4) Carpenter, D. C., and Walsh, W. F., Tu‘. Y. S t a t e Expt. Sta., Tech. Bull. 202 (1932). (5) Coe, M. R., and LeClerc, J. A, Cereal Chem., 9, 519-22 (1932). (6) Keeser, E . , Arch. e.zptl. Path. Pharmakol., 166, 624-33 (1932). (7) Leighton, P. A , , and Blacet, F. E., J. Am. Chern. Soc., 54, 316678 (1932). (8) Ludwig, F., and Ries, J., Schwei-.. med. Wochschr., 61, 324-31 (1931). (9) Pierce, W. C., and Morey, G., J . A m . Chem. SOC.,54, 467-72 (1932). (10) Serger, H., and Clarck, K., 2. Volkserndhr. Diatkost, 7, 22-4 (1932). (11) Shibata, Y., and Goda, S., Bull. Chem. SOC.Japan, 6 , 217-20 (1931). RECEIVED April 24, 1933
Gum Stability of Gasolines 11. Observed and True Oxygen Bomb Induction Periods J. W. RAMSAY AND H. S. DAVIS, Socony-Vacuum Corporation, Paulsboro, N. J. The rate of rise in temperature of gasoline durHAT t h e h e a t i n g - u p Two types of heating baths period during an oxygen w e r e used-a b o i l i n g w a t e r ing the heating-up period of oxygen bomb tests bomb induction test on bath s i m i l a r t o that r e c o m has been measured for bombs of several types, mended in the test of the Ethyl gasolines i n t r o d u c e s an unboth in oil baths and in water baths. Methods Gasoline Corporation, and also certainty in the measurement of correcting f o r this lag and data showing that an oil bath, which has already was early recognized ( 3 ) . It has the same true induction period was found in been described (4). not perhaps been equally recogThe t h r e e types of bombs nized that a slight variation in diferent bombs, although the apparent induction u s e d w e r e f i t t e d with ironthe final temperature can also periods were quite d i f f e r e d , are given. It is sugconstantan thermocouples (Figchange the value of the induction gested that either true indriction periods only be ure 1). The l e a d s w e r e r u n period. The induction periods, recorded or that the bomb testing outfit be rigidly through porcelain i n s u l a t o r s given in Part I of this series (J), standardized. into the bomb as shown. Inwere c o r r e c t e d ones. I n the stead of d r i l l i n g the head of meantime, Aldrich and Robie (1) The importance of knowing the lag both in the the Ethyl Gasoline C o r p o r a have also published a study of heating-up and cooling-down periods and also t i o n b o m b , t h e gage was rethe temperature rise of gasoline the exact value qf the final temperature is pointed moved and the leads run down s a m p l e s in brass bombs imout with reference to accelerated gum tests. through the st,em i n t h e head, mersed in an oil bath a t 100’ C. the &ge being placed on the and have used a similar method of correcting for the temperature lag. The bases for side arm of a pipe a t the top of the stem. the present authors’ corrections and the methods for their TABLE I. PHYSICAL CHARACTERISTICS O F O X Y G E N BOMBSUSED application are given in the present paper. IN TESTS The observed induction period may be defined as the time V. 0. E. G b elapsing between placing the bomb in the test bath and the V. 0 . a STEEL BOMB B R A ~BOXB S BOMB first perceptible drop in pressure. The pressure is allowed to Material Chrome-vanadium steel Yellow bras8 steel l/l thickness inch =/4 drop a t least 10 pounds before removing the bomb from the Wall Internal diamlter, inches 2 21/8 ‘Ig 11/a depth inches 9 9 111 / 1 bath, to make sure that the end of the induction period has Internal 65/lS Weight of bom’b, pounds 7 1/4 6”s 41/s Weight of cover, pounds 57/16 71/is been reached. Thickness of cover, inch 1 1 s/s The true induction period may be defined as the time that b Ethyl Gasoline Corporation. a Vacuum Oil Company. would elapse between placing the bomb in the test bath and the first perceptible drop in pressure if the gasoline sample The above arrangements made it possible to measure t h e were brought to the test bath temperature instantaneously. rate of temperature rise of a sample of gasoline under test Moreover, since the absolute value of the final temperature conditions of temperature and oxygen pressure. affects the induction period, it will be assumed here t h a t A 100-ml. sample of gasoline was measured into an 8-ounce true induction periods are measured a t 100 O C. oil sample bottle and the bottle introduced into the bomb. (Because of the smaller diameter of the Ethyl Gasoline CorporaEXPERIMENTAL PROCEDURE tion bomb, a 4-ounce bottle was used in that case.) The cover, The physical characteristics of oxygen bombs used in these with the thermocouple sealed in, was put on the bomb and made tight. The bomb was placed in the ice bath and charged with tests are given in Table I.
T
INDUSTRIAL AND ENGINEERING CHEMISTRY
August, 1933
120 pounds of oxygen. The thermocouple leads were attached to a potentiometer of the portable precision type. The bomb was allowed to cool in the usual manner and the inside temperat u r e r e c o r d e d . When the bomb had cooled to a point where the pressure recorder showed no further drop over a 5-minute interval, the pressure was adjusted to 100 * 2 pounds per square inch. A t e m p e r a t u r e r e a d i n g was then taken and the bomb transferred to a b a t h of b o i l i n g water or a constant-temperature oil bath. Temperature readings were taken every 5 minutes until the temperature of the gasoline D sample inside the bomb reached that of the heating bath.
P
The t i m e - t e m p e r a t u r e curves of the Vacuum Oil C o r n p a n y steel bomb in the oil and water baths, the brass bomb in the watw bath, and the Ethyl Gasoline Corporation bomb in its water bath, were determined. F i g u r e 2, the curve of the E t h y l Gasoline Corporation bomb, is given as a n example. Table I1 r e co r d s t 11 e time-temp e r a t u r e r e a d i n g s f o r t h e three types of bombs during the heating-up FIGURE 1. OXYGEN period in the different baths. When BOMB, SHOWING the oil b a t h w a s k e p t a t 100" C. THERMOCOUPLE IN (212" F.), the final bomb temperaPLACE ture was somewhat lower. This is A . Lead gasket B . Line to presprobably due to heat loss by radiasure recorder C. Needle valve tion. T a b l e I1 also s h o w s t h a t , D . Pressure union when t h e o i l b a t h was maintained E. Thermocouple F . Packing gland at approximately 100.8" C. (213.5" G . Leads t o potentiometer F.), the temperature of the gasoline s a m p l e i n s i d e the bomb was constant a t 100" C. (212" F.): DATAFOR BOMRSIN OIL AND TABLE 11. TIME-TEMPERATURE WATERBATHS V. 0. STEELBOMB V. 0. BRASEBOMB E. G. Boiling Cil bath Oil bath Boiling Oil bath BOMB water at at water at Boiling TIME bath 100' C. 100.8' C. bath 100' C. water Min. ' C. (7. C. c. c. O c. A-. 11 3.4 .. 2.3 3.2 3.4 0 4.0 24.0 47.7 65.2 77.2 85.0 90.4 94.0 96.4 98.2 99.3 100.0 100.2
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110
17.0 43.0 62.7 76.5 85.2 90.2 93.4 95.4 96.5 97.1 98:3 98:s
100:7
... ... ... ... ... ...
17.2 42.1 63.2 76.5 85.2 90.1 93.8 95.8 97.2 98.1 98.8 99.1 99.5
...
99:0
99.8 99.9
99:1
.. ..
100:o
99:1
...
... ... ...
25.4 47.1 62.2 73.2 81.2 86.8 90.8 93.6 95.4 96.8 98.5 99.2 99.8 100.0 100.2 100.4 100.5 100.6
17.0 38.6 54.9 66.8 75.4 81.9 86.0 89.3 91.3 92.8 94 0 94.7 95.5
...
...
...
...
TEMPERATURES Table I1 shows that, when bombs were heated in the boiling water baths, the final temperature was not 100" but 100.7" C. This superheating effect necessitated another correction t o arrive a t the true induction period at 100' C.: log
R-here Z
- bT
induction period, hours temp., " E(. a, b = conitants (Average value of b for seven gasolines was 0.0430.)
T
= =
= 0.043 X
0.7 = 0.030 = log 1.07
Accordingly, after correction for lag, the induction periods found in the boiling water baths (100.7' C.) were multiplied by 1.07 t o obtain the true induction periods a t 100" C. OF HEATING LAGCORRECTION READ TABLE111. CALCULATION FROM FIGURE 2
(Ethyl Gasoline Corporation bomb in boiling water) Av. TEMP.DCRISQ EQUIVALENT IN TERME ~ O - M I NINTERVAL . OF 100' c. TIMELAQ c. Minutes Minute9 32 0 10 1 9 79 93 5.5 4.5 1 98.5 9 100 10 0 Total lag 24.5
TABLE IV. APPLICATIONOF CORRECTION FACTORS TO ORSERVED INDCCTION PERIODS
C
lOgI = u
*
IIO0.7OC.
... ...
I n a former paper (4) i t was shown t h a t the data on induction periods, measured at different temperatures, could be related by the expression:
30 35 40 25
CORRECTION FOR DIFFERENCES IN FINAL BOMB
... ...
CORRECTIOY FOR LAG DURING HEATING-UP PERIOD
Minutes ~~
100:7
.. .. ..
2.7
V. 0. steel bomb in boiling water.. ............................ V. 0. steel bomb in oil bath (100.8' C.). ....................... V. 0. brass bomb In boiling water... .......................... E. G. bomb in boiling water., ................................
.I
96:s
=
This indicates t h a t the effective oxidation produced by any fixed period of heating (e. g., 10 minutes) increases about 2.7 times for each 10" C. This is shown graphically in Figure 3. From this curve the oxidation value of a 10-minute interval at any temperature in terms of its equivalent a t 100" C. can be read. For example, 10 minutes a t 90" C. are equivalent to 3.7 minutes a t 100" C. This curve was used in calculating corrections for heating lag of bombs. For example, the heating curve of Figure 2 was divided into 10-minute intervals, and the average temperature of each interval recorded. Then by using Figure 3, the equivalent of each of these intervals a t 100" C. was read. Table I11 gives the results from such a n analysis of the heating curves for the Ethyl Gasoline Corporation bomb. The difference between the time required to bring the sample to test bath temperature and the equivalent of this period a t 100" C. is taken as the lag of the bomb. The following lag corrections were determined for the bombs under test, the value being taken to the nearest 5 minutes:
SAMPLE
9s:2
97:2 10617
33.0 61 . O 78.0 87.5 93.2 96.5 98.5 99.6 100.2 100.7
T - 1 0 = 0.43 or log IIT IT
935
TYPEBOMB
HEATINQ BATH
V. 0. steel V. 0. steel v. 0.brass V. 0. brass V. 0. steel E. G. V. 0. steel V. 0. steel V. 0. brass V. 0. brass V. 0. steel V. 0. steel E. G.
Boiling water Boiling water Boiling water Boiling water Oil a t 100.8' C. Boiling water Boiling water Boiling water Boiling water Boiling water Oil a t 100.8O C. Oil, &t 100.8O C. Boiling water
IKDUCTION PERIOD Observed True Min. -%fin. 345 360 360 360 390 350 230 235 255 255 265 270 215
340 350 345 345 355 350 215 220 230 230 230 235 210
I n order to check these correction factors, two samples of gasoline were tested in each of the set-ups described here. The results of this series of tests are shown in Table IV. The observed induction periods of sample A range from 345 to 390 minutes, a spread of about 12 per cent. Those of sample C range from 215 t o 270 minutes, a spread of about
INDUSTRIAL AXD E N GINEERISG CHEMISTRY
936
21 per cent. When corrections are applied to obtain tiue induction periods, the values for sample A are from 340 to 355 minutes, a spread of only 4 per cent, and those of sample C from 215 to 235 minutes, a difference of about 10 per cent. These results indicate that the correction factors formulated are true within thelimits of experimental error. [Flood e t al. ( 3 ) stated in their work that the lag was taken as 15 minutes. As they used room temperature for charging the bomb, thiq would be in good agreement with the present work.]
Vol. 25. No. 8
As an additional illustration, the data on sample C (Table IV) may be considered. I n the case of the steel bomb heated in an oil bath, an observed induction period of 4 hours and
30 minutes mas obtained. Here little glass-dish gum mould be expected if the determination were made a t the end of 4 hours. However, in the case of Ethyl Gasoline Corporation bomb, which gave an observed induction period of 3 hours
DISCUSSION OF RESULTS I n work which involves the comparison of a number of samples of gasoline in a given bomb, correction factors are not of great importance. In this case only the relative valueare sought. However, if the oxygen-bomb induction period is to be made a quantitative figure, the method must be such t h a t a given gasoline will give the same definite value when tested by different laboratories. As stated before, this could be done by adopting a standard bomb and a standard procedure. This would inyolve considerable expense and new equipment a t many laboratories. On the other hand, by determining the correction for bomb3 by m e t h o d s described in this paper, concordant results may be o b t a i n e d on b o m b s of widely different physical characteristics. Such a move on the part of the : testing l a b o r a t o r i e s would iron W a out difficulties and c h a n g e t h e 2 status of the oxygen bomb from a 3 2 qualitative t o a q u a n t i t a t i v e c“ test. It w o u l d p e r m i t e a c h l a b o r a t o r y t o u s e i t s present equipment and formulate its own standard procedure. Although 0 IO 20 3 0 4 0 M in the present tests the bombs MINUTES w e r e f i l l e d a t ice temperature, FIGURE2. HEATING cURVE OF ETHYL GAS0any c o n v e n i e n t constant teniLINE c o R p o R A T I o N perature may be used, provided B o h r B I N B O I L I N G the c o r r e c t i o n s are determined WATER under the same conditions. The f o l l o w i n g results on a sample of aviation gasoline illustrate the value of bomb correction factors. The tests were i u n according to government procedure ( 2 ) . This specifies that the sample (200 ml.) be placed in a bomb and 100 pounds oxygen pressure applied a t room temperature. The bomb is then heated to 98-100” C . for 4 hours. The bomb is cooled and the sample remoTecl foi glass-dish gum determination. LABORATORY
GUM Mg./100 ml.
A B C
D
100 (4 checks) 20 (3 checks) 53 2
These erratic results were undoubtedly caused by differences in the heating lags of the various bombs. It has been shown t h a t during the induction period little gum is formed in the sample under test (1, 3, 4). The data on this particular sample of gasoline indicate that laboratory D used a bomb which did not come t o temperature as rapidly as others and the sample had not reached the end of the induction period. It must not be overlooked that oxidation and gum formation can also take place after the bomb has been removed from the bath. No data are available on the rate a t which the gasoline sample cools under these conditions. For some bombs such as the heavy one proposed by Ward ( 5 ) ,described below, i t must be rather slow.
gao +
/
1
1
‘
I
i ’ I
FIGURE3 . AVERAGEC H A N G E , IVVITH TEMPERATURE, OF EFFECTIVE 0x1D . ~ T I O X PRODUCED BY 10 - hl I N u T E H E A T I Y G P E R I O D A T ANY COZST.4NT TEMPERATURE Ratio, 2.7 times per 10’ C.
and 35 minutes on the same sample, an appreciable amount of gum would be expected a t the end of 4 hours, because the induction period has been exceeded by 25 minutes. The specification for such a test as the Proposed Federal Specification ( 2 ) should be more rigid in nature. Even the temperature range allowed (98” to 100” C.) can cause an error of 10 to 15 per cent in the induction period, The oxygen bomb proposed by Ward ( 5 ) is constructed of steel with a wall thickness of l l / l e inches, the total weight of the bomb being 75 pounds. The bomb is permanently installed in a steam-heated water bath. As the entire system, including the bath, must be cool when the bomb is charged, the time required t o raise such a mass of water and metal to 100” C. must be considerable. Ward states that ”the period of oxidation begins when the temperature of the gasoline has reached its maximum, as indicat’ed by the pressure recorded on the gage.” Such a statement is, of course, very much in error as is proved by the results given in the body of the present report. Oxidation occurs throughout the heating-up and cooling-down periods. The lag correction for such a system might be from 1 t o 2 hours. There seems no need for such a heavy bomb. It is recommended that all bomb results be given in terms of true induction periods. This will necessitate only the determination of the rates of temperature rise of each type of bomb under normal test conditions. It would involve very little work on the part of various laboratories and would put the oxygen bomb test on a quantitative basis.
LITERATURE CITED (1) hldrich, E . IT., and Robie, T i . P., S.A . E . Journal, 30, 198 (1932). (2) Bur. Standards, Proposed Revision of Federal Specification 2-d for Gasoline (Aviation, Domestic Grade) (3) Flood, D. T., Hladky, J. IT., and Edgar, Graham, paper presented before Petroleum Division at both Meeting of American Chemical Society, Cincinnati, Ohio, Sept. 8 to 12, 1930. (4)Ramsay, J. W., IND.EKG.CHEII.,24, 539-42 (1932). 1.5) Ward, B. P., Oil Gas J . , 31, KO.12, 16 (1932).
RECEIVEDJanuary 28, 1933. J. W. Ramsay’s present address is Cornell University, Ithaca, N. Y.
The heading for the third column i n Table I CORRECTION. appearing on page 623, IXDUSTRIAL AND ENGINEERINQ CHEMISTRY for June, 1933, in the article on “Poisonous Spray Residues on Vegetables,” by W. B. White, should read “Grain/lb.,” and n o t “Gramllb.” as printed.
