INDUSTRIAL AND ENGINEERING CHEMISTRY
March 1949
ucts were similarly reduced arid reoxidized. Thiosulfate derivatives cross-linked with formaldehyde withstood this reducing treatment for 100 hours without losing their fibrous form. The washed yarns did give a positive sodium nitroprusside test, a n indication t h a t not all the sulfur cross links contained methylene bridges. LITERATURE CITED
Bloomfield, G. F., J . Polymer Sci., 1,312-17 (1946). Borglin, J. N., U. S. Patent 2,392,359 (Jan. 8, 1946). Broderick, A. E., Ibid., 2,329,741 (Sept. 21, 1943). Bunte, H., Ber., 7,646-8 (1874). Coolidge, C., and Reese, J. S.,U. 8. Patent 2,375,838 (May 15, 1945).
Cramer, F. B., and Purves, C. B., J . Am. Chem. SOC.,61,3458-62 (1939).
Dillenius, H., Jentgen’s Kunstseide u. Zellwolle, 24, 520-33 (1942).
Farmer, E. H., and Shipley, F. W., J . Polymer Sci., 1, 293-304 (1946).
Gardner, T. S., and Purves, C. B., J . A m . Chem. SOC.,64, 153942 (1942).
Harris, M., Mirell, L. R., and Fourt, L., J . Research Natl. Bur. Standards, 29,73-86 (1942). Helferich, B., and Gnuchtel, A., Ber., 74B,1035-9 (1941). Hess, K., and Stenael, H., Ibid., 68,981-9 (1935). Heuser, E., Paper Trade J., 122, No. 3 , 4 3 (1946). Hull, C. M., Olsen, S. R., and France, W. G., IND. ENG.CHEM., 38,1282-8 (1946). Izard, E. F., U. 8.Patents 2,418,938-40 (April 15, 1947).
621
Irard, E. F., and Howk, B. W., Ibid., 2,418,941 (April 15, 1947).
Malm, C. J., and Clarke, H. T., J . Am. Chem. SOC.,51, 275 (1929).
Maxwell, R. W., U. S.Patent 2,373,135 (April 10, 1945). Morner, K. A. H., 2.phvsiol. Chem., 28, 594-615 (1899). Monorieff, R. W., and Bates, H., Ibid., 2,372,386 (March 27, 1945).
Morgan, P. W., U. 9. Patent, 2,418,942 (April 15, 1947). Muller, A., and Wilhelms, A., Ber., 74B, 698-705 (1941). Naylor, R. F., J . Polymer Sci., 1, 305-11 (1946). Oldham, J. W. H., and Rutherford, J. K., J . Am. Chem. SOC.,54, 366-78 (1932).
Olsen, 5 . R., Hull, C. M., and France, W. G., IND. ENG.CHEM., 38,1273-82 (1946).
Patterson, W. I., Geiger, W. B., Mirell, L. R., and Harris, M., J . Research Natl. BUT.Standards, 27, 89-103 (1941) ; Geiger, N. B., Kobayashi, F. F., and Harris, M., Ibid., 29, 381-9 (1942).
Raymond, A. L., in H.Gilman’s “Organic Chemistry,” 2nd ed., Vol. 11, p. 1612, New York, John Wiley & Sons, 1943. Rudy, H., Cellulosechem., 13, 49-58 (1932). Stoner, G. G., and Dougherty, A., J . A m . Chem. Sac., 63, 987-8 (1941).
Urquhart, G. G., Gates, J. W.,,?., and Connor, R., in N. L. Drake’s “Organic Syntheses, Vol. 21, p. 36, New York, John Wiley & Sons, 1941. Westlake, H. E., Jr., Chem. Rev., 39,230 (1946). RECEIVED December 8, 1947. Presented before the Division of Cellulose Chemistry a t the 111th Meeting of the AMERICAN CHEMICAL SOCIETY, Atlantic City, N. J.
Pure Hydrocarbons from Petroleum COMPOSITION OF C, FRACTION OF CATALYTIC GASOLINE JOHN GRISWOLD‘ AND J. E. WALICEY2 University of Texas, Austin, Tex.
A
hexane-hexene fraction from a Thermofor catalytic gasoline was separated into paraffinic and olefinic portions by the Distex operation. The two portions were analyzed by fractional distillation with refractive indexes, aniline points, bromine numbers, and specific dispersions on the small cuts. The percentages of &%dimethylbutane and of n-hexane were small, but the ratios of other isomeric hexanes corresponded approximately to equilibrium at the cracking temperature. Although a complete analysis as percentage of each individual hexene was not obtainable, many of the known isomers were present.
cal plates. On the other hand, chemical utilization does not require in all cases a material consisting of a single pure isomer. This investigation was undertaken t o shed light o n the hexenes which can be made available from the abundant supply of catalytic gasoline by application of the Distex operation. Laboratory studies showed t h a t activity coefficients for olefins are substantially the same as those for naphthenes of the same molecular weight wheri the solvent is aniline. Hence, the Distex operating conditions and type separation of paraffin-olefin mixtures are comparable to the same factors for paraffin-naphthene separation. EQUIPMENT AND ANALYTICAL T E S T S
T
H E bulk of synthetic aliphatic chemicals is made from olefins, and at least one concern manufactures a variety of products from pentenes. As yet there is no corresponding utilization of the hexenes. This is in part due t o the relative numbers of individual compounds and the difficulty of separating mixtures of CSisomers as compared t o mixtures of Cg isomers. There are three pentanes and six pentenes with two pairs of pentenes boiling 1O C. apart. There are five hexanes, and seventeen noncyclic hexenes have been reported. Most of the latter fall into narrow boiling groups, whose complete resolution by fractionation would require a column containing several hundred theoreti1
Present address, Illinois Institute of Technology, Chicago 16, Ill. Richmond, Calif.
* Present address, California Research Corporation,
The development of the Distex pilot plant and its application t o the separation of paraffin-naphthene-aromatic hydrocarbons in straight-run fractions have been reported (6, 7 , 8). For the present work, the apparatus described ( 6 ) was used with the addition of a Brown Instrument Company 12-point temperature recorder (Figure 1). Analytical distillations were made with t h e 11-mm. diameter Podbielniak Heligrid column, and densities (dz5) were determined with the apparatus and techniques given in earlier articles. Aniline points were determined with 1 ml. each of sample and of aniline sealed into glass tubes which were suspended and rotated in a water bath. Refractive indexes (n%5 and were determined with B
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
622
Vol. 41, No. 3
catalytic hydrogenation, and the theoretical values for pure olefins. The average figure of 90% bromination by this method was used t o calculate unsaturation of the numerous small Sam les. Tffe glass analytical hydrogenator is shown in Figure 2. It was mounted on a pivoted wooden frame and linked to a gearmotor for agitation. Adams catalyst was used and the general technique of flushing the system, reducing the oxide, and adding the sample followed t h a t of Joohel (11). Hovvevcr, when methanol was used as solvent, the results were found to vary with proportions of solvent and sample. This is ascribed to the nonideality of methanol-hydrocarbon mixtures and its effect on the partial pressures (IO). This source of error may be avoided by use of a solvent that forms ideal solutions with paraffins and olefins When methylcyclopentane was used as solvent, hydrogenation proceeded more slowly, requiring 10 t o 22 hours for completion However, it gave consistent and more accurate values on known samples. Hence, methylcyclopentane was used in the hydrogenation tests PREPARATION AND SEP4RATION OF Ca FRACTIQS
Figure 1. Distex P i l o t P l a n t as Used for S e p a r a t i n g Catalytic Gasoline F r a c t i o n Bausch and Lomb precision oil refractometer, using sodium and filtered mercury vapor illuminators. The specific dispersion, S, was calculated:
s
= 104(~7g
-
n,25)/d:5
Most of the small samples contained only paraffins and olefins.
For mixtures of these, the value of the specific dispersion above t h a t for paraffins is proportional to the bromine number and to the olefin unsaturation (9). This affords a means of calculating the hexene content of the present samples. Average specific dispersions used for the sodium and mercury indexes a t 25" C. were 124 for paraffins and 161 for olefins. Bromine numbers were determined by the rapid titration method of Uhrig and Levin (It?). Lewis and Bradstreet (IS) developed a more accurate method by which bromine substitution (that occurs simultaneously with bromine addition t o olefins) may be determined. The results of the latter authors show t h a t even with large excesses of reagent, bromine addition t o the double bond of olefins is not quantitative. I n this work, bromine numbers by the rapid Uhrig and Levin method were consistently between 87% and 93% of the values determined by specific dispersion, by
A 55-gallon drum of the first 257, distilled from a debutanized Thermofor gasoline was supplied by the Gulf Oil Corporation. The cracking unit was on high butene operation, charging a 30.5' A.P.I. gas oil from mixed crude sources. The oil vapor entered the reactor a t a temperature of 950' F., and the catalyst entered at 980" F. The reactor pressure was 10 pounds per square inch gage. Inspection tests on the original stock are given in Table I(>\). An analytical distillation with refractive indexes and bromine numbers is given in Figure 3. This figure shows an extremely high concentration of pentenes, and a total olefin content (from the bromine number on the stock) of between 55Y0 and 60%. The hexenes are almost all in the 50 to 70% portion, boiling bptween 58' and 70 O C. T o obtain the hexane-hexene fraction, the stock was reduced and then rerun by continuous fractional distillation using the 150-plate Distex column with a reflux ratio (LID) of 20 t o 1 in both cases. Although it x a s intended t o make a 40% bottoms in the reducing operation, losses of the stock were high due to leaks in the lines and around the pumps; of 150 liters charged, a bottoms product of only 42 liters was recovered. This material was rerun for a cut point of 85% overhead, and 31 liters were recovered. Operating conditions and material balances for these rune are given in Table 11. Inspeclion tests on the resulting hexanehexene fraction arc given in Table 1(B) and a n analytical distillation i3 given in Figure 4 The bromine number is 30 unith
T A B L EI. A . Original
dz' Aniline points, O C . After removal of unsaturates Total hexenes calod. from bromine S o . Lewis and Bradstreet Uhrig a n d Levin From specific dispersions, 2.5" C. By hydrogenation A.S.T.M. distillations, ' F. Indicated b.p. 5% 10 20 30 40 50 60 70 80 90 95 E n d point Reo. Residue LOSS Q
Stock 0.6419 1,3740 46.0 .,
Bromine
No.
Y C
112 109
59 57
.
.
.. 95
idi
103 106
108
111 115 120 130 148 172 172 95.6 0.9 3.6
..
..
ISSPECTION TESTS B. HexaneHexene Fraction 0,6658 1.3846 48.4 72.3 Bromine No. 70 80 42 78 41 (143. 126In 51 45
..
C. Distex Paraffin Fraction 0.6570 I ,3733 67.9 72.5 Bromine KO.
yo
25
13 15
..
15
28 (129, 124)"
141 142 143 144 144 144 145 145 146 147 148 151 ?64 97 1
138 139 139 140 140 140 140 141 141 142 143 145 147 96.8
2
2.3
14
1.2
Values in parentheses are specific dispersions before and after removal of unsaturates.
D. Distex Olefin Fraction 0.6876 1.3065 25.4 69.0 Bromine No. 167 I52 (137, 12515
..
148 150 130 150 150 I50 161 151 151 152 154 168 160 97 1 2
% 83 80 89
RO
March 1949
INDUSTRIAL AND ENGINEERING CHEMISTRY
lower than that of the original stock. The bromine and specific dispersion values are in good MERCURY agreement with MANOMETER the value of 45% H E I G H T e e CM. hexenes d e t e r P Y R E X TUBE I S X 500 M U mined by hydrog e n a t i o n . The olefin content between B O " a n d 63" C. is low as PYREX might be expected STOPCOCK since the boiling 4MM. OBLIQUE-BORE point of only one hexene is within this range. The final operation was a Distex Figure 2 s e D a r a t i o n into paraffin and olefin fractions using aniline as solvent. A cut point of about 40% of the feed to bottoms was selected in preference to the entire olefin content of 45% in order to minimize paraffins left in the bottoms. A solvent concentration of 80 mole % aniline and a hydrocarbon reflux ratio (L/D) of 20 t o 1 were maintained a t the top of the column. Flooding of the column occurred when the feed was preheated, and much smoother operation ensued with cold feed. During the latter part of the run the feed was not preheated. Inspection tests on the paraffin and olefin fractions are given in Table I and analytical distillations are given in Figures 5 , 6, and 7. The paraffin portion contains about 15y0 hexenes, 250 mostly low-boiling isoPO0 mers except a small amount in the 63' to 68' C. range where the E concentration in the m 100.: feed is highest. The z olefin portion contains about 10% of saturated hydrocarbons, mostly methylcyclopentane. The bottoms analysis indicates a sharp separation according to type, and more of the olefins could have been recovered with a slightly higher percentage of the feed split to the bottoms. O E T A I L S OF A N A L Y T I C HYOROGENATOR
I
-
;-b
COMPOSITIONS OF DISTEX FRACTIONS AND TOTAL HEXENEHEXANE MATERIAL
Catalytic c r a c k i n g under operating conditions for gasoline manufacture produces mixtures containing chiefly isomeric p a r a f f i n s , n a p h t h e n e s , olefins, and aromatics. Isomerization between
623
cyclohexene and the methylcyclopentenes is reported to be rapid and in the total C6 range: paraffins and olefins should be present in about equal proportions ( I ? ) . The inspection tests of Table I establish the major constituents of the hexane-hexene fraction as paraffins and olefins and the unsaturation as about 50%. Within the boiling range of this material are also cyclopentane, methylcyclopentane, and some of the reported values for methylcyclopentenes (3) and hexadienes (9). Tests with chloromaleic anhydride did not appreciably lower the bromine numbers and the samples did not give colored precipitates with ammoniacal cuprous chloride; this indicated virtual absence of conjugated diolefins and of acetylenes in the present material. Benzene was undoubtedly present in the raw gasoline from which the present fraction was obtained. It forms nonideal solutions with nonaromatic hydrocarbons, azeotropes with n-hexane and other near-boiling compounds and probably exhibits amotropic behavior with paraffin mixtures boiling as low as 68' C. Its activity coefficients are lower in olefins than in paraffins, but
TABLE 11. CONTINUOUS DISTILLATIONS A. Reduction of Original Stock
Operating conditions Reflux ratio (L/D) 20 t o 1 Cut point, feed t o overhead, 70 69 Feed rate, ml./min. 20 Overhead takeoff rate, ml./min. 14 Column effectiveness. theoretical plates 60-70 Material balance % Liters Feed to column 151.3 100 Overhead product 49.9 33 Bottoms product 42.4 28 Loss 59.0 39 Length of run 124 hours
B. Rerun of Reduced Stock 20 to 1
85 (by volume) 15 13
60-70 Litera 41.5 30.9 6.7 3.9 50 hours
I
I
%
100
75 16 9
T H L O R C T I C A L .I N U M B C I S PCNTLNE
HLXLNC
za7* 1000
1
624
INDUSTRIAL AND ENGINEERING CHEMISTRY
HEXANE-HEXENE
1.41
Vol. 41, No. 3
FRACTION
1.40 1.39 1.38 1.37 1.36
Figure 4
(
150
"I
0
1.385 1.380 1.375 1.370 1.365 1.360 60
55 50
45
Figure 5
'since experimental activity coefficients of such mixtures have not been reported yet, the presence of benzene must be suspected in a paraffi-olefin petroleum fraction boiling above 68" or 70" C., especially one that has not been thoroughly fractionated.
The present stock was distilled batchwise from a catalytic gasoline t o an overhead temperature of about 75 O C., at which temperature the vapor will carry a certain amount of benzene. On the continuous rerun distillation, the top temperaturc ranged
INDUSTRIAL AND ENGINEERING CHEMISTRY
March 1949
625
150
ANALYTICAL DISTILLATION
100 50
0 L.42
L.41 L.40 1.39 1.38
1.37 65
60 55
50
Figure 6 Ib5
--
- - - - - - -- ---------- - I
Ieo
A V E R A G E SPCClflC DISPCRSION o r MEXCHLI I55
OF
OLEFINIC EXTRACT _
_
_
---
150.
_. 14$
~ 21
I- n E x
e N -E I '
20
L
I COYrOSlr L
\
15
I
I
I
I 14
I
1.41
1.40 1.30 1.38
-a-
PENTLHL
65
60
Figure 7
from 62" t o 64" C.; this eliminated practically all of the benzene from the overhead. Suppose, however, that the hexane-hexene fraction contained 0.5% benzene or 150 ml. in the 30 liters of hydrocarbon. The Distex operation would remove quantita-
tively the benzene from the paraffin fraction. The pilot plant contained about 10 liters of circulating aniline m solvent; this was redistilled before the Distex run. The top temperature of the solvent recovery column varied only from 65' to 66" C., and the
INDUSTRIAL A N D E N G I N E E R I N G C H E M I S T R Y
626
TABLB 111. COMPOSITION OF HEXANE-HCXENE FRACTIOV Literature B.P.,
c.
%,2-Dimethylbutane 2.3-Dimethylbutane 2-hlethylpentane 8-Methylpentane n-Hexane Cyclopentane Met hylcyclopentane 2-Methyl-2-butene 3 3-Dimethyl-1-butene 3lMethyl-I-pentene 4-Methyl-1-pentene trans-4-Me thyl-2-pent erie 2,3-Dimethyl-l-butene cis-4-SIethyl-2-penten~ 2-Nethyl-1-pentene 1-Hexene 2-Ethyl-1-butene 2-Met hyl-2-pentene cis-3-Hexene trans-3-3Iethyl-2-penten e trans-2-Hexene trans-3-Hexene cis-2-Hexene czs-3-Methyl-2-p~nterie Cyclo-olefin Cyclo-olefin (6)
49.74 57.99 60.27 63.28 68.74 49.26 71.81 38.45
Total Individuals to Total Distex Distex Olefin Distex Fraction Paraffin Fraction, Fraction, Bottoms, Vol. ci % 75 % i C n 0 0.5 1 .o 7.7 13.3 i.9 0.4 2.4 44.7 26.0 1.1 15.3 25.6 6 1.6 2.3 0 0 4.0 0.6 43 0.7 0.8 '1.1 6.7 86 3.5 0 .6 0 0 0.3 4.3
55 58.4 62.2 1 67.2 67.6 67.8 67.9 68.1 68 6 70.52 66-67 71
+
t' ,
1.8
30
3 .O
2.9
50
1 0
27.4
0.ii
11.1
96
18 6 b
9 5
100
4 1
0
0 0
2.6 4.3
100.0
3.0 11.80
100 100
1 1
1.9 ~~
___I
Total
3.2
100.0
100.0
a ;ipproximate composition, 2-methyl-I-pentene 2.170, I-hexene 4.2%, 2-ethyl-1-butene 5 . 5 % . b Major constituente, 2- and 3-hexenes.
Figure 6 is the analytical Mistillation of the olefin fractions t o establish boiling point and refractive index curves and bromine numbers. Figure 7 is a second distillation on the same material with fewer and largcr cuts takcn to obtain more material for aniline points, specific dispersions, and other tests. Aft,er obtaining specific dispersions, the high refractive index material from 19.2 t o 33.6% distilled (63.6" to 66.5" C.) was cornposited. Its aniline 'point of 19.0" C. is lower than tha,t, of any noncyclic olefin. I t s specific dispersion is 159 and its hydrogenation value gives 9670 hexene. The latter test,s indicate that not more than a trace of diolefin is present. The various constants of this fraction all become reconciled by the presence of a cyclo-olefin; amethylcyclopentene is considered to be the most probable. Egloff ( 3 ) has collected the available data on the methylcyclopentenes, and none are established with high precision. Reported boiling points of d- and of dl-l-methyl2-cyclopentene range from 66.5" t o 71 O C., and reported boiling points for I-met,hylcyclopentene-1 range from 72 t o 76 C. Reported refractive indexes of all methylcyclopentenes range from 1.425 to 1.45 at 16" C., and an approximate average for n2i is 1.42. The high refractive indexes and low aniline points shown in the section boiling above 71" C. in Figures 6 and 7 likewise are incongruent with any mixture of paraffins, noncyclic olefins, and niethylcyclopentane. Assuming that there was complete elimination of benzene from this material as discussed earlier and the absence of 3- and 4-member ring compounds, there appears to be a second and higher-boiling cyclo-olefin present. Thc amount of cyclo-olefin necessary t o reconcile the constants was estimated using a refractive index of 1.42 as for the methylcyclopentenes. Assunling the presence of two cyclo-olefins as noted, Figures 6 and 7 provide a partial analysis of the Distex hexene fraction. A calculated t,ot,al of 1O.4y0 of saturated hydrocarbons is in good agreement wit.h the hydrogenation value of QOOj, hexenes. The actual split of the hexane-hexene fraction in the Distex run was 57% overhead and 43% bottoms; this with the analyses of the two portions gives the composition of the combined materials reported in Table 111, The total hexene cont,ent, of 44.0y0compares well with the value of 4573, by hydrogenation. Compounds boiling belox 50" or above 70" 0. undoubtedly suffered disproportionately high losses in the preparat'ion and analyses of the fractions, and their percentages in Table TI1 are lower than for the C6material in the original gasoline. Otherwise Table 111 is believed t o be fairly accurate. The high-boiling group of olefins undoubtedly mould be completely retained in the bottoms with a split, of 2% more of the feed t o bot,toms in the Distex operation.
solvent would pick up and retain all but a trace of the benzene Finally, the analytical distillations of Figures 4 t o 7 were conducted with 200 ml. of hydrocarbon and 100 ml. of aniline charged t o the stillpot as bottoms. Anv benzene in the overhead of a n analytical distillation would be most noticeable in the data a t the tail end of Figures 6 and 7. It would cause the boiling point, refractive index, and refractivity intercept t o rise sharply and the aniline point t o fall sharply. None of these trends appeared, and in view of the foregoing, it is highly improbable that any benzene was present in the overhead material as plotted in Figures 5, 6, and 7, and on which the final analysis is based. Several different type- or proximate analyses of narrowboiling petroleum fractions have appeared in the literature. By combining certain tests and features of these with efficient analytical fractionations, the concentrations or percentages of a number of the individual compounds may be determined. The boiling point curves of the analytical distillations limit components t h a t may be present a t any given point in the distillate t o a few compounds. For close-boiling mixtures t h a t the DISTRIBUTION OF ISOMERS column mill not separatc sharply, a binary of two known comlnalysrs of the saturated portions of a number of petroleum pounds may be resolved by refractive index. A ternary mixture hexane fractions or concentrates have been reported. Several may be resolved by refractive index and bromine number or of these analyses and the present results, all reduced t o a basis of specific dispersion where one or two of the compounds are ole100yo hexanes, are given in Table IT along with the thermodyfins. For a multicomponent mixture of olefins with one or two namic equilibrium distribution for 980" F. The percentage of paraffins or naphthenes, the group percentages of each of the n-hexane in the catalytic samples and the percentage of 2,2-disecond and third types may be estimated as above by assigning methylbutane in all samples are lower than correspond to equilibaverage or group values of the properties to that portion of marium at the temperature of cracking. However, the ratio of 2- t o terial of the first type. 3-methglpentane and the ratio of the latter to 2,3-diniethylbutane Figure 5 , with a n average refractive index for the group of four approximat? thc ratios for thermodynamic equilibrium olefins boiling between 67.2" and 68.1 C. (obtained from Figure 6), provides the analysis of the paraffin fraction given in Table 111. The 5.5% lower TABLE 11'. DISTRIBUTION O F ISOMERIC HEXANES I N \'ARIOUS SAMPLES olefin content (Table I) as comEquilibrium Catalytic7--Straight-Runpared t o the hydrogenation a t 980° F. Present Houdry Houdry Thermal E. Tex. E. Tex. Conroe Okla. gas (16) Work (1) (1) ( 2 ) (1) (4) (4) (6) value of the material charged to the analytical column is d u e partly or entirely t o disloss of low.proDortionate boiling olefins.
--
3
Vol. 41, No. 3
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March 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
Although the thermodynamic equilibrium distribution of hexenes has been reported (12),the present d a t a are inadequate t o draw any particular conclusions regarding the relative abundance of isomers. ACKNOWLEDGMENT
L. 0. Crockett of the Gulf Oil Corporation supplied the Cg concentrate, and J. E. Walkey, coauthor of this paper, held a Gulf Oil Fellowship from November 1944 through July 1945. The University of Texas Research Institute sponsored the work by the purchase of equipment and by the award of a research assistantship to B. R. Randall, who was active in the work. Many hours of assistance particularly in the analytical distillations were given by H. H. Hurmence, R. H. Bowden, Junam Chew, M. E. Klecka, K. s. McMahon, and E. D. Soltes. BIBLIOGRAPHY
(14) (15) (16) (17)
627
Griswold, Andres, Van Berg, and Kasch, IND. ENG.CHEY.,38, 65 (1946). Griswold and Morris, Ibid., 40, 331 (1948). Griswold, Morris, and Van Berg, Ibid., 36, 1119 (1944). Griswold and Van Berg, Ibid., 38, 170 (1946). Grosse and Wackher, IND.ENG. CHEJI., ANAL.ED., 11, 614 (1939). Hurmence, H.H., private communication, January 1945. Joshel, L. M., IND. ENG.CHEM.,ANAL.ED., 15, 590 (1943). Kilpatrick, Prosen, Pitzer, and Rossini, presented before the Division of Petroleum Chemistry a t the 109th Meeting of the AMERICAN CHEMICAL SOCIETY, Atlantic City, N. J. Lewis and Bradstreet, IND.ENG. CHEM.,ANAL.ED., 16, 617 (1944). Natl. Bur. Standards, American Petroleum Institute, Research Project 44, tables 2a, 6a, 8a, June 30, 1945. Rossini, Prosen, and Pitzer, J. Research Natl. B u r . Standards, 27, 529 (1941). Uhrig and Levin, IND. ENG.CHEM.,ANAL.ED., 13, 90 (1941). Voge, Good, and Greensfelder, IND.ENG. CHEM.,38, 1033 (1946).
(1) Bates, Rose, Kurtz, and Mills, IND.ENG.CHEM.,34, 147 (1942).
(2) Egloff, G., “Physical Constants of Hydrocarbons,” Val. 1, pp. 307-11, New York, Reinhold Pub. Co., 1939. (3) Ibid., Vol. 11, pp. 306-7 (1940). (4) Forziati, Willingham, Mair, and Rossini, Proc. Am. Petroleum Inst., 24, 111, 34 (1943) ; Petroleum Refher, 22, 379 (1943).
RECEIVED October 8, 1946. Presented before the Division of Petroleum Chemistry, 113th Meeting of the AMERICANC H ~ M I C ASOCIETY, L Chioago, Ill. Earlier articles in this series appeared in Volumes 35, pp. 117, 247, a n d 854 (1943); 36, p. 1119 (1944); 38, pp. 65 and 170 (1946): end 40, p. 331 (1948) of this journal.
Fungicidal Treatments for Cork Gaskets SIGMUND BERK Pitman-Dunn Laboratory, Frankford Arsenal, Philadelphia, P a . Growth of four species of fungi on protein bonded cork may deteriorate gaskets. Seven fungicidal formulations applied to protein and resin bonded cork were evaluated on the basis of a number of criteria for moldproofing automotive gaskets. The treated gaskets were incubated in fruit jars, in a cycled tropical humidity chamber, and at a tropical testing station in the Panama Canal Zone. Fungus tests conducted on the treated gaskets conditioned at elevated temperatures and leached with water showed that an aqueous treatment of p-nitrophenol and a fuel oil treatment of p-nitrophenol plus paraffin wax retained
sufficient fungicide to inhibit mold growth. The fungicidally treated gaskets did not disintegrate when immersed in boiling water, hot motor oil, or gasoline. Corrosion studies on the treated gaskets were made by placing the cork gasket between metal strips of aluminum, steel, brass, and zinc plated steel and exposing to 100 YOrelative humidity. Patch tests with gaskets treated with p-nitrophenol in fuel oil showed that this treatment was satisfactory for normal handling. On the basis of all the tests conducted, a 2% aqueous treatment of p-nitrophenol is recommended for moldproofing automotive cork gaskets.
T
gaskets were made by industrial and governmental laboratories, the published literature on the subject is scant (1-8). I n the manufacture of paper and vegetable fiber gaskets, fungicides have for sometime been incorporated in the glue used as binders. Kimberly and Scribner (9) described the use of @naphthol in glue in paper to prevent mildew growth. Delmonte (6) cites the work done by the Forest Products Laboratory on the mold resistance of protein glues treated with chlorinated phenols and their sodium salts. I n a previous report (3) fungicides were evaluated primarily on their ability to impart uniform protection against fungus growth to glue-glycerol bonded cork. Seven fungicidal treatments t h a t showed promise in t h e previously reported results (3) were applied to both protein and resin bonded cork and appraised on the basis of the following criteria: mycological tests in the laboratory and field exposures in the tropics; resistance of the treated gaskets t o fungus attack after storage at elevated temperatures and after leaching by water; physical tests to determine if the fungicidal treatments deteriorated the gasket; corrosiveness of the treated gaskets to metals; and toxicity to personnc.1 on handling the fungicidally treated cork.
HE deterioration of textiles by microorganisms under
tropical conditions is a known phenomenon. However, few realize that other materials, such as cork gaskets, also are attacked by fungi. During the recent war, many recommendations were made as a solution to the problem of controlling mold growth o n cork composition gaskets. One method suggested was individual packaging, b u t this was abandoned because of the scarcity of packaging material. A second method tried was coating the cork composition with a number of fungicides t h a t had been found effecti-re as textile preservatives. Fungus resistance tests conducted on gaskets treated with t h e latter fungicides revealed t h a t most of them were ineffective in controlling mold growth on protein bonded cork composition ( 2 ) . Therefore, a search was made for more potent fungicides and the results of these tests have been reported ( 3 ) . Untreated protein bonded cork is a n excellent source of nutrients for many species of fungi. This source of nutrients for mold growth may be poisoned by a 10-minute immersion of the cork gasket in a number of fungicidal solutions previously reported ( 2 , s). Although many attempts to fungusproof cork
