&lay, 1934
INDUSTRIAL AND ENGINEERING CHEMISTRY
533
from the liquid portion of the culture, in a compact clot. Another isolated species of Oidium forms a thick ring which eventually breaks loose, the segments of "rope" remaining intact. The rest of the culture is highly viscous. This organism derelops slowly on potato-glucose agar with a restricted, raised, yellowish growth. Oidium also occurs in association with Monilia or Torula. A slimy species belonging t o the former genus and bearing a resemblance to Monilia candida also produced copious amounts of the mucilaginous mixture. An intimate association was discovered of this organism with the rope-forming Oidium referred to above. The growth consisted of elongated, rubbery, yellow bodies which, niicroscopically, revealed no features of structure that might assist in their identification. Such findings illustrate the complexity and heterogeneity of the microbiological formations which may occur under the varied environmental conditions found in pulp and paper mill\.
Uniform slime suspensions were obtained by agitation of the slime masses and the addition of a definite amount of water. Deposition of a quantity of this suspension upon a sheet-forming substratum, aided by the rapid withdrawal of water, resulted in coalescence of the slime particles and the production of a continuous, semi-transparent membrane of the type illustrated in Figure 1. I n order to give the sheet the necessary flexibility and resilience, the freshly prepared film was treated successively with glycerol solution and mineral oil, during steam-drying. ilt this stage in the process the membranes are capable of considerable stretch and may be manipulated to yield a high degree of transparency. Suitable finish can be produced by sizing or coating with resinous or waxy materials. The highly adhesive qualities of the slime particles and also of the freshly prepared film indicate their possible value as intermediary binding and cementing agents.
USEFULA P P L I C A T I OOF~ ;SLIME ~ SUSP~NSIONS Laboratory cultures were prepared in wide-mouthed, liter, Erlenmeyer flasks, each containing 200 cc. of medium. The slime growths may be gathered after short incubation intervals or allowed to increase, giving much larger yields. I n the latter case, clots weighing considerably over 100 grains were produced in 3 to 4 weeks. The moisture content of the slime clot is approximately 90 per cent.
LITERATURE CITED (1) Gesell, W. H., PaperInd., 14, 297 (1932); Schmid, W., Zellstofu. Papier, 10, 870 (1930); Pattillo, D. K., Pulp & Paper M a g . Can., 31, 551 (1931). (2) Sanborn, J. R., IND. ENG.CHEM.,25, 288 (1933); Science, 77, 290 (1933). (3) Sanborn, J. R., J . B a d , 23, 350 (1932). (4) Ibid.,26, 373 (1933). R ~ C E I V EDecember D 7, 1933.
Corrosion of Metals by Phenols F. H. RHODES,P. A. RIEDEL,AKD T-. K. HESDRICKS, Cornel1 University, Ithaca, N. Y MONG the organic compounds that are known to corrode steel and other metals are phenol and the cresols. The corrosion observed in stills and fractionating columns handling coal-tar oils is probably due, in part a t least, to the action of phenolic compounds on the metal. In the design of stills for the refining of phenol and cresols, the metal used in the construction of the condenser coils must resist the chemical action of the vapor and must not cause discoloration of the finished product. The corrosive action of tar acids on metal is also of importance in connection with the operation of the recently developed processes for the purification of petroleum oils by fractional extraction with cresol. But little information concerning the corrosion of metals by tar acids has been published. i\lIacleod, Chapman, and Wilson (1) found that cold cresylic acid attacks lead rapidly and is blackened by contact with nickel, has comparatively little action on tin or on copper, and corrodes aluminum and chrome steel only slightly. They report that hot cresylic acid acts rapidly on lead and aluminum, is darkened by nickel, and attacks copper and chrome steel only slowly. Inasmuch as they do not indicate the composition of the cresylic acid used, the areas of the test pieces of metal employed or the exact conditions under which the tests were made, their results have only qualitative significance. Seligman and Williams ( 2 ) found that aluminum is attacked rapidly by hot dry phenol or hot dry cresol, but that the pre3ence of a small amount of water inhibits the corrosion.
A
Zinc, commercial galvanizing spelter Nickel malleable ( 0 2 5 % Cu, 0.066% Mn, 0.59% Fe, 0.019% S, 0.21% Si, O'.OE% C ) Monel metal (29.9S%,Cu, 66.75% Ni, 1.61% Fe) Silver, pure electrolytic sheet High-carbon steel (1.4% C ) Low-carbon steel (0.2% C) Brass (64.15% Cu 35.3% Zn) High-chromium stekl (14.3% Cr, 0.12% C, 0.004% S, 0.006% P, 0.2% Si. 0.52y0 Mn) Chromium-nickel steel (17.9%Cr, 7.6% Ni, 0.15%, C, 0.006% S, 0.005% P, 0.24% Si, 0.48% M n )
The metals used in the present experiments were as follows:
The phenol and the cresols were prepared from material purchased as chemically pure and further purified by two distillations, in glass, through an efficient fractionating column. The purified materials were stored in sealed containers until used. In determining the rates of corrosion by dry tar acids at 25' C., a weighed and measured strip of the test metal was placed in a large test tube and covered with the melted acid. The tube was then closed with a stopper carrying a calcium chloride tube to exclude moisture and was allowed to stand in a thermostat a t 25" C. At the end of the test period the metal was removed, washed and dried, and reweighed. The experiments to determine rates of corrosion at this temperature were continued for about 100 days. In measuring the corrosion by wet acids at ordinary temperatures, the same general procedure was adopted, except that about 10 per cent of water was added to the acid and the tubes were closed with loosely fitting stoppers t o exclude dust. In measuring the rates of corrosion by the vapors of the tar acids at their boiling points, the measured and weighed test strip was placed in a bulb connected between a flask in which the tar acid was being boiled and a reflux condenser in which the vapor was being condensed. The apparatus was so designed that the metal was in contact only with the vapor and with the hot condensate that naturally condensed on the surface of the metal but was not washed by the stream of condensate from the reflux condenser.
Aluminum, commercial pure aluminum sheet Cop er, electrolytically refined annealed Leaf, chemical sheet, 99.8% phre
DRY TARACIDS. The rates of corrosion of the various metals by the dry tar acids a t 25' C. mere as follows:
EXPERIMENTAL WORK
INDUSTRIAL AND ENGINEERTNG
534 METAL
Phenol
Loss IN WEIQHT o-Cresol
m-Cresol
MR.per q.dm. per 94 hours
Aluminum
0.28 0.92 126 0.13 0.13 0.31 0.03 0.46 0.72 0.13 0.19 0.15
2Y Zinc
Nickel Monel metal Silver High-carbon steel Low-carbon steel Brssa High-chromium steel Chromium-nickel steel
0.115 1.7 66.5 0.26 0.05 0.08 0.08 0.04 0.26 0.20 0.21 0.16
0.06 1.0 78.6 0.15 0.01 0.05 0.04 0.04 0.10 0: 17 0.10
The phenol was discolored as follows: light pink by silver, zinc, and the high-chromium and chromium-nickel steels; red by aluminum and nickel; deep red by high-carbon and low-carbon steels and by monel metal; and black by copper, lead, and brass. A11 of the samples of o-cresol were red except those that had been in contact with lead, copper, carbon steels, and brass. The m-cresol that had stood over silver, nickel, aluminum, and monel metal was pale yellow; zinc, lead, and the various steels produced a darker yellow color, while the m-cresol that had been in contact with copper was dark red. WET TAR ACIDS. The corrosion by wet tar acids at 25’ C. was found to be as follows: -Lose Phenol
IN W E I Q ~ o-Cresol m-Cresol M R . per sa. dm. pw 84 houre 0.02 0.01 0.11 0.06 0.23 0.35 38.84 61.5 82.4 0.07 0.17 0.20 0.03 0.08 0.09 0.07 0.22 0.20 0.08 0.12 0.13 0.19 0.206 0.42 0.38 0.33 0.24 0.12 0.10 0.12 0.19 0.16 0.18 0.13 0.23 0.09
METAL Aluminum
:,9p”’
Zinc Nickel Monel metal Silver High-carbon steel Low-carbon steel Brass High-chromium ateel Chromium-nickel steel
The phenol was only slightly discolored by aluminum and by silver. Copper and lead turned the phenol black. I n all other cases the phenol, after standing in contact with the metal, was red. The o-cresol was black after contact with copper and lead; all other samples were red. Aluminum, silver, and nickel produced the least discoloration. Similar results were obtained with the m-cresol. DRYVAPORSOF TARACIDS. The corrosion by dry vapors a t the boiling point was found to be as follows: METAL Aluminum Copper Lead Zinc Nickel Monel metal Silver High-carbon steel Low-carbon steel Brass High-chromium steel Chromium-nickel ateel
c
Phenol
.... 2.1
Loss IN WEIQHT o-Cresol m-Cresol MR.per sa. dm. per 94 hours i:i2
...
.... 1.0
271 1.36
0.62 1.63 6.5 6.0 2.0 1.03 0.05
4.55 7.25 6.23 2.2 2.54 0.99
1156
1.01
... 18.6 ... ...
1.75 8.75
16.5
18.1 16.5 2.3 3.4 3.26
Aluminum waa attacked so rapidly by the dry vapor that in a comparatively short time the strip of test metal had disintegrated to a loose gray powder. On exposure to air, this material turned gray and gave a strong odor of phenol. The residue remaining in the flask used in the determination of the rate of corrosion of aluminum solidified on cooling to form a black pitchy maim The solidified material smelled strongly of diphenyl ether. Similar results were obtained in the experiments made with aluminum and the other tar acids. It appears that metallic aluminum reacts directly with the dry vapor of phenol or cresol to form aluminum phenolate or cresylate, and that, on heating, these salts decompose to form diphenyl ether or &cresyl ether. With lead, and also with zinc, the metal was also rapidly corroded and the surface of the test piece was coated with a
CHEMISTRY
Vol. 26, No. 5
white deposit. Samples of these white products of the corrosion reactions were removed, washed with ether, dried, and analyzed for lead and for zinc. The results were as follows.
-
-
Percentage of lead in product from Corrosion of lead by phenol Theoretical percentage of lead in lead phenolate 52.68 Percentage of sinc in product from corrosion of rinc by phenol Theoretical percentage of dnc in rinc phenolate = 25.99
0
Percentage of zinc in produqt from corrosion of zino by m-cresol Theoretical percentage of zinc in sinc cresylate 23.38
52.88
26.0
-
23.45
All of the tar acids that had been used in this series of tests were discolored to some extent. The least discoloration was produced by silver, the high-chromium steel, and the chromium-nickel steel. WET VAPORB OF TARACIDS. The corrosion by wet vapors at the boiling point was found to be as follows: LOSSI N WEIQHT PhenolMu. per 89.o-Cresol dm. p m 84 houram-Cresol
c
MBTAL Aluminum Cop er Leal Zinc Nickel Monel metal Silver High-carbon steel Low-carbon steel Bras8 High-chromium steel Chromium-nickel ateel
1.3 6.87 0.73 14.9 0.99 5.25 0.91 47.2 37.2 9.3 0.80 1.3
1.9 5.65 167 56.2 1.65 1.52 1.24 10.9 7.2 12.9 2.15 1.37
3.18 13.0 1650 282 0.85 3.02 3.28 62.8 28.3 14.8 0.73 0.74
All of the samples of tar acid that had been heated in contact with the metals were discolored to some extent. The discoloration was least with aluminum, silver, and the highchromium and chromium-nickel steels, and greatest with copper and the carbon steels. The presence of water greatly decreases the rate of attack of aluminum, zinc, and lead by the vapors of the tar acids. This may be due in part to the effect of the water in lowering the boiling points of the tar acids and thus decreasing the temperature of the vapors. I n the case of the aluminum, at least, the water has another and a more specific effect. The aluminum phenolate or cresylate formed by the direct action of the tar acid on the metal is decomposed by water with the formation of aluminum oxide, which is precipitated as a protective film on the surface of the metal.
CONCLUSION These results indicate that nickel or the chromium-nickel steels of the 18-8 type should be satisfactory for use in handling and condensing the vapors of phenol or the cresols. Lead is rapidly attacked by tar acids, and should not be used in handling these materials. The use of copper in phenol stills and containers for phenols a t ordinary temperatures should be avoided, both because the copper itself is attacked to a considerable extent and also because the products of the action of the tar acids on copper cause discoloration of the phenol or cresol. LITERATURE CITED (1) Macleod, Chapman, and Wilson, J . Sac. Chem. Id., 45, 401T (1926). (2) Seligman and Williams, Zbid.. 37, 159T (1916). RECEIIEDFebruary 2, 1934.
CORRECTION: In the paper, “Phosphate Fertilizers by Calcination Process,” by Reynolds, Jacob, and Rader, IND. ENQ.CHEM., 26, 406-12 (1934), two errors occurred on page 412. In Table XI1 the subheading for the fifth column should read “ F A FBI’ instead of “F FB.” Reference 49 under Literature Cited should read (‘,. . p . 411 . . .” instead of I ‘ . . . p. 50. . ..”
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