312
INDUSTRIAL AND E,VGIiWEERING CHEMISTRY
but does not attempt actually to duplicate the behavior of the oil in a “wet” turbine. Liquid water is not present, and, under these conditions, there seems to be practically no action of the acids on iron. There is no evidence of soap formation in the stability test and likewise in the turbine test runs neither oil showed a trace of ash after 7 months’ use. Acidity determinations are used as an index of the tendency of the oil to form soaps in the presence of water, and the assumption is explicitly made that the amount of soap formed will be proportional to the acid concentration. The turbine test runs therefore confirm the laboratory experiments as tests of the oxidizability of the oils. Unfortunately, no turbines which leak water were available for similar careful test runs. However, the evidence obtained from examination of used oils as well as laboratory experiments, in which it has been found that the acids formed by oxidation will attack iron in the presence of water, serves to indicate the validity of the above assumption. It might be proposed that the stability test be carried out with water as well as oil in the flask. However, in view of the recognized difficulty of obtaining satisfactory emulsion tests of oils under the simplest conditions, it hardly seems practicable to combine emulsion and oxidation tests. It is the belief of the writers that fundamental information on the rate of oxidation
VOl. 19, No. 2
of the oil, interpreted in terms of its effect on the behavior of the oil in the turbine, is the best means of evaluating turbine oils. Summary
The deterioration which turbine oils undergo in zervice is due to oxidation. Two types of oxidation products are formed: (1) asphaltic material, insoluble in the oil; ( 2 ) free acids, soluble in the oil. The latter, in the presence of water, form insoluble soaps in contact with metals such as iron and copper. A stability test has been developed in which moist oxygen is passed through the oil a t 100” C. in the presence of iron. Determinations of the acidity and demulsibility of samples taken periodically, along with the sludging time, serve as a measure of the degree of oxidation and its effect on turbine service. By comparative turbine test runs it has been established that this stability test substantially duplicates the behavior of oils in a dry turbine. Acknowledgment
The writers wish to acknowledge thanks for advice and suggestions to F. W. Sullivan, Jr., in whose department this work was carried out.
Acids in Automobile Crank Cases’ A Few Observations By A. F. Meston MOTOR IMPROVEMENTS. INC.,NEWARK, N. J,
An acid condition is always present in an automobile HE oil and vapors in cars were equipped with oil crank case. I t is shown that acids are present in the an automobile c r a n k filters. The gasoline used in lubricating oil, in the diluents in the oil, and in the case a r e always acid. the cars was, for the most. vapors escaping from the crank case. Some of the Corroded or “etched” wrist part, a n extensively adveracids are more soluble in water than in oil. Some of pins are occasionally found tised brand enjoying broad them are corrosive. Positive tests for naphthenic distribution. The oils used in automobile engines and acids are obtained with oils, diluents, and condensed are advertised as “100 per furnish striking evidence of water vapors. cent Pennsylvania.” It i s this acid condition. The The neutralization value of a crank-case oil apbelieved the conditions set seriousness of the condition parently reaches a maximum after the oil has been up by these oils and fuels. is apparently a matter of exin service for several hundred miles of car operation. were as favorable as those perience and of opinion. The The presence of sulfur is noted and data relating to under which the average car average car owner is blissits distribution in the various liquids and vapors are operates. No attempt was fully ignorant of its possipresented. made t o analyze the problems bilities and fortunately selthat sometimes arise when dom has reason to be otherwise. Superintendents in charge of fleets, who have noted blended fuels or special lubricants are used. Figure 1 shows graphically the increase in neutralization corrosion within the crank cases of their cars and trucks, have had considerable success in eliminating the trouble value or so-called “acidity” of the crank-case oil in a 1925 by providing crank-case ventilation. There is little in the model of a six-cylinder car, used by the owner in driving literature to show that the subject has been systematically about Kewark, N. J. The test started with new oil (desigstudied, but the efforts of automobile manufacturers to fur- nated as L-1) April 22, when the weather was quite cool, and nish ventilated crank cases indicate that they have appre- continued until August, a t which time very warm weather and unusually high humidity existed. No oil except samples ciated the advantages of this practice. The observations herein described were compiled, not for was removed during the test and make-up oil averaged 1 the purpose of explaining wrist-pin corrosion in particular, quart per 250 miles (1 liter per 380 km.). The acidity inbut to furnish additional information on the general subject creased quite evenly until a value of 0.35 mg. KOH per gram of of crank-case acidity, its extent and distribution. The data oil was reached, which appears to approximate an equilibrium were obtained from block test runs with a Chalmers Six value for this particular oil in this car. Figure 1 also shows engine and fromexperimental and routine runs of a number of the dilution present in the oil during the test. I n 400 miles the better known four-cylinder and six-cylinder cars. All (644 km.)the dilution reached an equilibrium for the operating conditions existing a t about 19 per cent. As the xeather 1 Received August 30, 1926. Presented before the Division of Pebecame warmer the dilution decreased, and throughout the troleum Chemistry a t the 72nd Meeting of the American Chemical Society, summer it remained quite constant, a t 8 per cent. The Philadelphia, P a , September 5 to 11, 1026
T
I,l7Di7STRIAL A-YD E~VGIIVEERI.\-G CHEMISTRY
February, 1927
tendency of the dilution to reach an equilibrium value has been studied by MacCoull,’~* and by Wilson and Wilkin.2 The factors controlling acidity are less easily analyzed than those controlling dilution, but there is a tendency for the acidity in crank-case oil to reach a condition of equilibrium. Table I gives the acidity values for various samples of oils withdrawn from automobile crank cases. It is significant t h a t in no instance did the value for acidity rise above 0.50 mg. KOH per gram of oil, nor did the oils in use several thousand miles have higher acidity values than those in use the customary 500 to 1000 miles (800 to 1600 km.). The various conditions under which engines operate will result in equilibrium being reached a t different neutralization values; but values over 0.60 mg. KOH are the exception rather than the rule for good quality, fat-free petroleum oils. An attempt was made to show that high acidity values accompanied high dilution, but the evidence is not conclusive. It must be remembered that in tvinter, when high dilution is prevalent, there is less road dust, to enter the oil and neutralize the acids present. From the tests on samples I,-23 and L-18, and other tests not listed, it does appear that the acidity of a used nil is reduced by driving off the diluent. Table I-New
and Used Motor Crank-Case Oils
DISTANCE SAMPLE
WITIIOUT
OIL
CHANGE
Miles
L-1 L-2 L-3 L-17 L-18 L-200 L-215 L-22a L-23“ L-30b L-32 L-33 L-34 L-36 L-37
x ~ ~ ~ , E & . c ,DILUTIONACIDITY
7c
by vol.
Querls “Penna.”
240 sec. at 100’ F. S e w oil ... 446 sec. a t 100° F. S e w oil “Penna.” 436 sec. at looo F. h-ew oil . .. 7 j 4 sec. at looo F. 1891 7 Feb. 27, 1926 32 9.5 2700 12 Aug. 11, 1926 L-17 with diluent removed 800 3 Feb. 6, 1926 5000 20 June 10, 1926 6 6000 24 Aug. 2, 1926 6 L-22 with diluent removed 42 0 Special 125 S e w oil
L-4 L-10
MA KE-UP OIL
L-32 with diluent removed 600 3 750 0 Jan. to Apr., 1926 L-36 with diluent removed
7.5
36
-;:2
.tfE. R ICOH/E. b y wt. 0.03 0.09 0.10 0.06 0.06 0.44 0.38 0.22 0.42 0.29 0.43 0.27 0.20 0.30 0.25 0.24 0.49 0.51
0.15
0.18
Table 11-Distillates SAMPLE
G-9 G-54 G-12 G-24 G-36 G-30a G-30b G-51 G-52 G-53 G-17 W-52 \T:-60
W-61 W-54 W-55
313 and Water from Crank Cases
PRODUCT
Motor gasoline-service station Condensed vapors f r o m starting burner Diluent from oil I,-12 Diluent f r o m oil L-23 From L-36. Titrated 4 months after removed From L-30. First 60 per cent of diluent From L-30. Last 40 per cent of diluent >fisc. diluents. From Sligh tests From crank-case oil rectifier From crank-case oil Diluent from L-17 Water removed with G-52 Condensed vapors from breather Condensed vapors from ventilator Condensed vapors from ventilator Condensed vapors from ventilator
ACIDITY
SULFUR
.Ilg. ROH/g. 0.01 0.09 0.20 0.27 0.60 0.60 0.85 0.30 0.43
cc
by wf. 0.08 0.10
0.27
. 0.13
1.16
2.48 1.26 1.63 11.5 5.25
0.005
A few determinations for total sulfur were made. The results are given in Tables I and 11. A sample of oil was removed from a light six roadster which had gone 15,000 miles (24,200 km.) without cleaning carbon or grinding valves. The oil had been circulated through a filter and had not been changed in 6000 miles (9660 km.). The dilution (6 per cent) was removed from the oil, after which the oil and diluent were tested for total sulfur. The new oil (L-3) and a commonly used gasoline (G-1) were also tested for total sulfur. The results indicated that the diluent remaining in the oil was the fraction containing the largest percentage of sulfur and that this percentage \vas appreciably higher than that contained in either the new oil or the gasoline. Considering, however, that perhaps 1.5 pounds (0.68 kg.) of sulfur had entered the carburetor with the more than 300 gallons (1135 liters) of gasoline used, and that 0.075 pound (34 grams) of sulfur had been introduced with the 7 gallons (26.5 liters) of lubricating oil, the sulfur in excess of what was originally in the new oil-this excess consisting of 0.003 pound (1.36 grams) in the oil and 0.001 pound (0.45 gram) in the diluent -was not a large amount.
a Samples taken progressively from same car using oil 1,-3 b Oil from a mixture of oil a n d diluent removed from crank case with special ventilator.
Table I1 gives the acidity values for motor gasoline, lubricant diluents, and various products of relatively low boiling points which pertain t o motor-car performance. When purchased, motor gasoline is practically neutral, but immediately it is subjected t o partial combustion or high temperatures an increase in acidity is noted. Sample G-54 was obtained by condensing the vapors removed from a partial combustion motor starter. I n this starting burner a small amount of gasoline undergoes partial combustion and is heated before it is drawn into the inlet manifold and mixed with the additional air necessary for complete combustion. I n general, the diluent distilled from crank-case oil has a higher acidity value than the oil from which it is taken. G-17 illustrates this relationship. Samples G-30a and G-30b would tend to show that different cuts removed in fractionally distilling off the diluent have the same acid value, but in several distillations various values were secured from the various cuts and no definite rule could be formulated. The amount of acid in water vapor removed from a crank case and condensed depends upon many factors, the rate at which it is removed and the temperature a t which i t is condensed being of importance. Sample W-60 was collected in a cold condenser in the laboratory. Samples W-54 and W-55 were collected in a bottle on the side of a car operating in warm weather.
* Numbers in text refer to bibliography
a t end of paper
TOTAL M / L € A G & OF CAR Figure I-Relation
of Acidity and Dilution to Mileage
Bjerregaard,3in his study of the sulfur content of the fractions distilled from various crude oils, found that the sulfur was widely distributed throughout the various fractions. An appreciable part of the total sulfur distilled over with the benzine, and when the benzine was fractionated a large part of the sulfur Kent over with the gasoline cut. From such data it can be inferred that the sulfur which enters an engine with the fuel will be widely distributed after the power stroke and mill be present, in part, in the exhaust gases, in the gases that “blow by” the pistons, and in the liquids that enter the crank case as mists and lubricant dilution. The advisability of removing the “blow by” gases before condensation of aqueous vapors containing sulfur compounds takes place
314
INDUSTRIAL A N D ENGINEERING CHEMISTRY
is evident. Evaporation of the diluent from the crank-case oil will also result in the removal of sulfur. According to Wood,4 many of the sulfur compounds found in naphthas are corrosive, especially if water is present, and a t elevated temperatures. Identification of Acids
No attempt was made to isolate and identify the acids present in automobile crank cases. Tests were made for the purpose of identifying the acids in a general way and to learn something of their characteristics. Used oil was neutralized with sodium hydroxide solution. The aqueous layer was removed and petroleum ether and copper sulfate crystals were added to it. A green copper salt of an organic acid was formed, and this left the water layer to enter and remain in the petroleum ether. Lewkowitschs gives this as a test for naphthenic acid. Similar results were obtained with diluents separated from crank-case oils. Less positive tests were obtained with water which had been removed as vapors from crank cases and condensed. Not all the green precipitate entered the petroleum ether; it appeared to be only slightly soluble in the water, but it did not quickly enter the ether as the material removed from the oils had done. The water had a greenish color, due to iron compounds, before the copper sulfate was added, and the tests were probably complicated by the presence of various salts. By neutralizing the used oils with lime, removing the soaps which formed and dissociating them with acid, viscous red liquids were obtained. Similar substances were removed from the diluent mixture, G-51. These red liquids were insoluble in water but soluble in alcohol. They were probably organic acids contaminated and colored with various hydrocarbons and sulfur compounds. Naphthenic acids are said to be colorless, or light yellow. Salathe6 separated naphthenic acid crystals from turbine oil sludge. Other investigators have obtained naphthenic acids from petroleum sludges as colorless oils. Samples of water, W-54 and W-55, were neutralized with 0.1 N KOH. A precipitate was obtained in each sample. The water was evaporated off on a water bath at temperatures below 180 F. (82 O C.). Sample W-55 gave a greenish soapy residue; sample W-54 gave a brownish soapy residue. Some crystals were found in the residues. Positive tests for calcium, magnesium, and iron were obtained. A portion of the residue was shaken with cold distilled water. A strong soapy foam was made. Some of sample W-54 was boiled for 2 hours with a piece of polished copper immersed in it. A green scum formed on the copper a t the water level. Pieces of polished brass, copper, and low-carbon steel (drawing stock) were left in W-60 for 3 weeks, the containers being shaken vigorously twice a day. The brass and copper showed negligible loss, but the steel, after cleaning, showed a 9.6 per cent loss. The greatest corrosion of the steel was just above the water level. Unfortunately, the brass and copper strips were totally submerged most of the time and a direct comparison could not be made. Water collected in a similar way etched polished wrist pins markedly after relatively short immersions. Water samples were tested with iodine (Lieben’s reaction) for acetaldehyde, but the odor of iodoform was not definitely recognized and no iodoform crystals were identified. Engler and Both' claim to have found butyric and other fatty acids, as well as naphthenic acids, in petroleum products. Not many of the acids found in petroleum oils have been identified, but as a group they resemble fatty acids in that the viscous acids of high molecular weight are oil-soluble and tend to concentrate in the high boiling point fractions of the oil, while the acids of low molecular weight are easily driven off with steam, and are found in the water and low
Vol. 19, No. 2
boiling point hydrocarbons. They will attack metals under certain conditions, and are capable of forming crystalline salts. The presence of sulfur is commonly observed* and probably plays an important part in many of the reactions, catalyticallyg~l0and otherwise. Van Brunt and Miller” state that sulfur acids are present in used crank-case oils, but give no data confirming this statement. The writer has seen no evidence of uncombined sulfur acids in these oils and believes that t h e small amounts taken up by the oils quickly combine with the suspended metals and bases in the oil, or combine with the unsaturated hydrocarbons present. In the present paper no conclusion is presented as to the relative bearing of sulfur compounds and oxidized hydrocarbons upon such problems as crank-case corrosion. When considering corrosion, attention should be directed to all
msrtLLArE
COLLECTED,
c,c
Figure 2-Measurement of Crank-Case Dilution, Capillary Funnel Method
water-soluble acids, especially those which reach the crank case as vapors and which may condense within the crank case upon cooling. Some of the high molecular weight oilsoluble acids are being investigated for lubricating properties. The presence of iron was shown in the water layers from crank cases, indicating some corrosion. Ash from samples of used oil showed the presence of iron oxide. Test Methods
The acidity values, or, more correctly, the neutralization values, were determined by titrating with 0.1 N KOH, using phenolphthalein as indicator, in accordance with A. S. T. M. Test Method D47-21. It is not conceded that this method gives reproducible results with dirty oils except when used under identical conditions, as when the titrations are made in the same laboratory by the same person. Check tests giving results within 5 per cent are usually considered satisfactory. Sulfur determinations were made with the calorimeter bomb method by a commercial testing laboratory. The high dilution values-those obtained in the early spring-were obtained by the capillary funnel method of the Bureau of Standards,12 commonly known as the Sligh test.
February, 1927
I i D U S T R I d L AND E-VGINEERING CHE-VISTRY
These values are now considered by the writer to be from 2 to 4 per cent high. I n the later tests, a modification of the Sligh test was used which consisted in conduching the test under reduced pressure. The collecting graduate and capillary funnel mere placed within a wide-mouthed bottle, which was closed with a flat brass plate with ground joint. The exit of the condenser projected through the brass plate and the condensate was delivered to the capillary funnel in the usual manner. The bottle was connected to a laboratory (water-operated) air pump and an absolute pressure of 45 to 55 mm. mercury was maintained throughout the apparatus during distillation. The capillary tube furnishes a ready means of reading the diluent end point, and distillation a t low pressures makes for accuracy because the fractions are closely defined.’3 The oil and diluent are not cracked during the test and can be used subsequently in other tests. Figure 2 gives graphically the results obtained a t
315
atmospheric pressure and a t reduced pressure with samples of the same oil. Bibliography 1-MacCoull, Lubricafion, 10, No. 6, 66 (1924). 2-Wilson and Wilkin, J . Soc. Auromoliue Eng., 18, 163 (1926). 3-Bjerregaard, Ind. Eng. Chem., 17, 142 (1925). 4-Wood, Sheely, and Trusty, Ibid., 17, 798 (1925). 5--lewkowitsch, “Chemical Technology and Analysis of Oils, Fats, and Waxes,” Vol. 111. 6--Salathe, Ind. Eng Chem.. 17, 414 (1925). 7-Engler a n d Boch, Chem.-Ztg., 16, 592 (1892). 8-Mabery and Smith, A m . Chem. J . , 13, 232 (1891); hlaberp. J . SOL. Chem. Ind., 19, 505 (1900). 9-Waters, Bur. Standards, Tech. P a p e r 4 ; J . Ind. Eng. Clrem.. 3, 812 (1911). l@-James, Chem. EZ M e t . Eng., 26, 209 (1922). 11-Van Brunt and Miller, I n d . Eng. Chern., 17, 416 (1925). 12-Bur. Standards, L e f f e v Circ. 200 (June 15, 1926). la-Ibid., Circ., “hleasurement of Crankcase Dilution, 1-acuum Distillation Transition M e t h o d , ” (January 26, 1925).
An Outline of the Law of Chemical Patents’ By E d w a r d Thomas 165 BROADWAY, NEW Yon=, N. Y.
(Confinucd from January issue)
Prior P u b l i c a t i o n s as Anticipations Prior publications have a n especial importance in connection with chemical patents. The vast journal literature of chemistry is well indexed and describes hundreds of thousands of chemical experiments and factory operations, where the literature of mechanics is poorly indexed and, moreover, describes relatively few machines and factory equipments. I t is necessary therefore t o indicate how the Courts interpret prior publications. INTERPRETING PRIORPcBLIcATIoN-In a suit on a patent covering the bleaching of flour one Court said: When it is sought to ascertain the state of the a r t by means of prior patents, nothing can be used except what is disclosed on the face of those patents. Such patents cannot be reconstructed in the light of the invention in suit, and then used as a part of the prior art. * * * Prior patents are a part of the prior art only by what they disclose upon their face. If they are carried into effect in the industrial world, what is learned from that experience also becomes a part of the prior art. An expert, however, cannot take a process patent, which has never been applied industrially, and work the process in his laboratory, and discover therefrom something which is not disclosed on the face of the patent, and then transfer t h a t experience back t o the time of the patent, and make it a part of the prior a r t for the purpose of defeating a meritorious invention. Naylor v. Alsop Process Co., 168 Fed. at 920. This doctrine was applied by Judge Colt in one of t h e suits on the Schultz process of chrome tanning: With the Schultz process before him, i t may be possible for a skilled expert to tan a skin by following what he believes t o be a liberal construction of the Francillon specification * * * The question is, assuming the Schultz process did not exist, does Francillon disclose a tanning process and by following literally his instructions, have you solved the problem of a practical and commercial method of chrome tanning? Tannage Patent Co. o. Donallan, 93 Fed. a t 820, 821.
Moore’s experiment * * * was published in a well-known technical magazine * * * It was a t most only a laboratory experiment without practical and commercial fruit * * * Such disclosures do not enrich the a r t in the sense required for a n anticipation * * * Abel’s salt * * * does not appear t o have ever been used in practice * * * i t was not merely a tentative experiment * * * It was fully described and published in well-known medical journals, and the disclosure would have answered the claims of a patent * * * It was published as a direction for all who wanted to use it, unlike Moore’s vague disclosures, which were meant rather for investigators * * * In view of such publications, Takamine cannot claim to have been the first. Parke-Davis and Co. v . H. K. Mulford Co., 189 Fed. at 108, 110.
ERRONEOUS PRIOR PUBLICATIONS-Judge Coxe sustained a patent on a dye in the face of many publications alleged t o anticipate it. As to one he said: A description which is insufficient t o support a patent can hardly be relied on as a n anticipation. In each instance the same precision is required * * * We have then a prior publication which purports to give a formula for producing a n insoluble compound and which omits one of the most important steps, leaving a blank where proportions should be stated with accuracy. Can it be, t h a t such a publication anticipates a patent for a soluble compound which gives with minute details all the steps necessary to accomplish t h a t result? * * * The question is, what does the prior publication say? Not what it might have said or what i t should have said. Badische Anilin and Soda Fabrik v. Kalle, 94 Fed. at 167, 168. SUGGESTIONS I N PRIOR PUBLICATIONS-Judge Mayer has pointed out under what conditions t h e suggestions of prior writers are t o be regarded as anticipations. I n a suit on a wireless telegraph patent applied for in 1901 he said:
It is extremely important to think, if possible, as of 1901. In this case, t h a t is a troublesome task, because of the extraordinary progress in this a r t since then, and the consequent difficulty of discarding from consideration many items of afteracquired knowledge. It is also necessary in this case not t o accord undue importance t o isolated suggestions in scientific papers and discussions. Such suggestions are not infrequently PRIOR LABORATORY EXPERIMEXTS DESCRIBEDIN PUBLICA- controlling in a well-developed and well-understood a r t where TIOh-S-In the exceedingly interesting decision on the adrenalin skilled men can readily appreciate the disclosure. In the infancy of a new, and, at the time, little understood art, however, the patents, Judge Learned Hand found the journal account of alleged prior a r t necessary to negative invention must be clear prior experiments by one Moore were insufficient to constitute and doubts * * * resolved in favor of the inventor. Kintner v. a n anticipation, but the account of other experiments by a chem- Atlantic Communication Co., 249 Fed. a t 77, 7 8 . ist, Abel, were sufficient to anticipate certain phases of the Suggestions in a prior patent are no more persuasive than invention, he said : if found in other literature. In a suit on a patent covering a celluloid fabric, Judge Coxe said: Received June 28. 1926.
