Radiator Anti freeze Materials Identification in Used Crankcase Oils HARRY LEVIN, KARL UHRIG, AND ERVIN STEHR The Texas Company, Beacon, N. Y.
A method is described for the identificatrap, and has been consistently detectable. The residue left in t h e regarding tiOn Of antifreeze materials in automobile flask is tested for calcium chloride. motor oils increase, largely becrankcase oils where they occasionally find Substituting direct extraction with water for the distillation cause of the accidental introduct i o n i n t o t h e c r a n k c a s e of their way from radiators in winter service. procedure as the means of obtaining the antifreeze liquids usually liquids used in the cooling sysIt has been satisfactorily applied for the tem of the automobile rather detection of calcium chloride, glycerol, excessive in resulted dilutions, annoying and emulsions, conditions than any inherent fault of the ethylene and methyl, ethyl, and which caused glycerol to interfere with the glycol test. The distillaoil. Such liquids frequently isopropyl alcohols. tion appears essential in the presconsist of water and added antience of glycerol, to preclude i t freeze materials. Since the from giving the glycol test. water which is found in a crankcase may have accumulated b y condensation or because of a leak in the cooling system, Detection of Calcium Chloride merely identifying the water does not locate the engine conTo the flask containing the cool distillation residue add a few dition to be rectified. If the radiator antifreeze material milliliters of distilled wa,ter, shake thoroughly, and allow to settle can be identified in the crankcase liquid it tells the automoin a separatory funnel. Withdraw the aqueous layer through a wet filter pa er and test one portion of it in the usual manner for tive engineer that the cooling system needs overhauling. If chloride wit! silver nitrate solution, and another portion for no radiator liquid is present in the crankcase water, it may calcium with ammoniacal ammonium oxalate. mean that the crankcase is operating at too low a temperature or that better crankcase ventilation should be provided. Detection of Antifreeze Liquids Among substances found by the authors in used lubricating GLYCEROL. Glycerol may be suspected if during the oils taken from the crankcases of cars experiencing trouble primary distillation the glass parts in the vapor space do not were methyl, ethyl, and isopropyl alcohols, glycerol, ethylene drain cleanly after one hour. For the detection of glycerol glycol, and calcium chloride. Each of these substances has the method is essentially t h a t of Mulliken (6),involving the likewise been found in radiator antifreeze solutions recomdehydration of the alcohol with the formation of acrolein. mended to automobile users. Obviously, none can be conThe use of the smaller apparatus reduced the dead air space sidered a proper substitute for lubricating oil. and increased the sensitivity of the test. The method to be described has been found satisfactory for the detection of these antifreeze materials in used oils or Reagents. Potassium bisulfate powder and concentrated deposits taken from automobiIe crankcases. By means of it hydrochloric acid. Schiff reagent, prepared by dissolving 0.2 gram of rosaniline as little as 0.2 per cent by volume of each liquid and 0.03 per hydrochloride in 120 ml. of hot water. Cool, adding 2 grams of cent b y weight of calcium chloride in the oil has been defianhydrous sodium sulfite dissolved in 20 ml. of water, following nitely detected. The presence of a n y one compound alone did with 2 ml. of concentrated hydrochloric acid, and then diluting not cause a positive result to be obtained for any of the with water to 200 ml. The reagent is kept in a glass-stoppered bottle (amber colored). others nor did the simultaneous presence of all compounds Procedure. Place 1.0 ml. of the aqueous trap rinsings on a interfere with the detection of any one. Since slight amounts watch glass and heat it on a slow steam bath to evaporate the of the lower alcohols can conceivably result b y oxidation water. Absorb the residue left on the watch glass with about 0.5 through normal use of the lubricating oil or engine fuel, y m of powdered potassium bisulfate and transfer it to a 5-ml. ask. Attach the delivery tube and place its end under the suruncertain tests for them should be considered negative. face of 0.5 ml. of distilled water in a small test tube (75 X 10 mm.) cooled by an ice-water bath (Figure 1, B). Heat the flask with a Separation of Liquids and Calcium Chloride flame, gently until frothing ceases and the mass fuses, and then more vigorously for a few minutes, including about three fourths A well-mixed sample of the oil or deposit taken from the autoof the neck as well as the bulb. mobile crankcase is placed in a 500-ml. round-bottomed flask Remove the delivery tube, being careful to allow its liquid conwith 100 ml. of volatile petroleum solvent (commercial isooctane, tents to run into the test tube. To this solution add 1 ml. of 39 cents per gallon) and a few glass beads to prevent bumping. Schiff reagent, stopper, and shake well. A deep purple color will The apparatus is then assembled, heat applied, and the aqueous soon appear on standing and persist for many hours if glycerol distillate collected for one hour. The general procedure is was present, After standing for 24 hours the addition of an equal otherwise similar to the A. S. T. M. method (1) for water in pevolume of concentrated hydrochloric acid causes the color to betroleum products. The glass apparatus (Figure l, A ) has intercome a yellow-brown; if 2 ml. of this latter solution are then changeable ground joints. The s ecial trap, which has a capacity diluted to 30 ml. by slowly adding water, the color changes of 25 ml., was furnished on order Ey the Ace Glass Co., Inc., Vinethrough green to blue or violet-blue. land, N. J. The sample taken should be large enough to yield a t least 3 ml. This test was effective on the distillate obtained from oil of aqueous distillate. If the water content of the sample be very low, it is advisable to add 3.0 ml. of water to the sample before it is containing less than 0.2 per cent of glycerol. distilled, rather than use more than a 100-ml. sample. ETHYLENE GLYCOL.The presence of ethylene glycol is A t the end of one hour of distillation the heating is discontinued shown b y the presence of oxalic acid after oxidation with and the aqueous distillate is promptly withdrawn and retained for nitric acid (4, 8). subsequent testing for methyl, ethyl, and isopropyl alcohols and ethylene glycol. When the apparatus has cooled the hydroReagents. Concentrated nitric acid, concentrated ammonium carbon distillate is withdrawn and discarded. The tra is then hydroxide, and 10 per cent aqueous solution of calcium chloride. rinsed with 3 ml. of distilled water and the test for gkcerol is Procedure. Into a test tube (22 X 200 mm.) introduce 0.5 ml. subse uently made on these rinsings. The bulk of the glycerol of the aqueous distillate and 3 ml. of distilled water. Keep the that %stills under these conditions adheres to the walls of the URIKG the winter season
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MARCH 15, 1939
ANALYTICAL EDITION
test tube in a boiling water bath until the volume of solution has been reduced to 2 ml.; then add 2 ml. of concentrated nitric acid, transfer the solution to a 25-1111. Erlenmeyer flask, and boil it gently for 5 minutes but do not evaporate to dryness. The sample will give off brown fumes. Cool in ice and make alkaline by cautiously adding concentrated ammonium hydroxide from a dropper. Upon addition of the calcium chloride reagent, white calcium oxalate will be precipitated if ethylene glycol was present. This test worked satisfactorily on the distillate obtained from oil containing as little as 0.1 per cent of ethylene glycol.
General Test for Methyl, Ethyl, and Isopropyl Alcohols The presence of the volatile alcohols, methyl, ethyl, and isopropyl, is shown b y a general test. If the result be positive, a separate test for each alcohol is made by the specific methods which follow. A positive result b y this general test is not final proof that a volatile alcohol is present because there are other substances which give the same reaction. However, a negative result indicates the absence of methyl, ethyl, and isopropyl alcohols. Rosenheim (7) used a solution of ammonium thiocyanate in acetone or ethyl alcohol for the detection of cobalt salts. It
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was expected that an aqueous solution of ammonium thiocyanate containing a cobalt salt would give the same reaction upon the addition of alcohol, b u t the authors found that a high concentration of ethyl alcohol (50 per cent minimum) was required t o produce the color change, and they therefore developed the following scheme which permits the detection in low concentrations: REAGENTS.Anhydrous sodium carbonate. Cobaltous nitrate-ammonium thiocyanate reagent, prepared by dissolving 0.5 gram of cobaltous nitrate in 25 ml. of distilled water and adding it to a solution of 5 grams of ammonium thiocyanate in 25 ml. of distilled water. PROCEDURE. Dip a piece of filter paper into the cobaltous nitrate-ammonium thiocyanate reagent. Place it between two pieces of dry filter aper and cut off a strip 10 cm. long and just wide enough to fit tEe 2.5-mm. bore of the reflux tube (Figure 1, C). Remove the outside ieces of paper and place the test strip in the reflux tube so that t i e bottom edge of the paper is about 4 cm. above the lower end of the tube. When properly prepared the test strip is pink in color. It should not be allowed to dry completely because this alone may cause it to turn blue. Fill the small 1.5-ml. flask three-quarters full with anhydrous sodium carbonate (about 1 gram) and allow 0.5 ml. of the aqueous distillate to drop on the dry salt. Attach the reflux tube containing the test strip and put the flask on an electric plate which is already hot. Use an improvised wire tripod to hold the flask upright on a piece of asbestos with a hole in its center (Figure 1, C). Observe the test strip as the vapors rise slowly in the reflux tube. In the presence of a low-boiling alcohol the test s t r h will turn greenish blue as the first ring of rising vapors contacts it. The color disappears as the vapors containing large amounts of water reach the strip. Regulate heating so that vapors do not accumulate in the reflux tube and fill its bore with condensate, because this will frequently be too low in alcohol content to give the test which requires a rather high concentration. The appropriate concentration is present in the first vapor ring, thou h not always in the condensed 1iqui8.
C
The general volatile alcohol test gave positive results in aqueous distillates containing as little as 2 per cent of methyl, and 1 per cent of ethyl or isopropyl alcohols, equivalent to less than 0.1 per cent on the basis of the sample of crankcase oil. If a positive test is obtained, the following specific tests are used.
Methyl Alcohol I
f A
w
D
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FIGURE 1. DIAGRAMOF APPARATUS A . Apparatus for separating liquid antifreeze compounds from oil sample B. Apparatus for dehydration of glycerol and collection of acrolein C. Apparatus used to detect presence of volatile alcohols D,E . Apparatus for identification of isopropyl alcohol. D,, Setup for digesting oxidation mixture, and E , Equipment for removing acetone produced by oxidation
For the identification of methyl alcohol, a modification of the method of Georgia and Morales (3) proved satisfactory. Glycerol and glycol, however, interfere and must be removed b y distillation if found b y the previous tests. If neither glycerol nor glycol be present, the first distillation step described below is omitted and two 0.25-ml. portions of t h e aqueous distillate are used for the test instead of the 0.5-ml. portions specified in the procedure. REAGENTS.Ethyl alcohol solution, 5 per cent aqueous. Permanganate reagent, prepared by dissolving 3 grams of potassium per-
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INDUSTRIAL AND ENGINEERING CHEMISTRY
manganate and 15 ml. of 85 per cent phosphoric acid in water and making up to 100 ml. Oxalic acid reagent, pre ared by dissolving 5 grams of oxalic acid in 100 ml. of dilute sulruric acid (1to I). Schiff reagent (as used for glycerol test above), pyrogallol, and concentrated sulfuric acid. PROCEDURE. I n a 15-ml. long-necked flask place 0.5 ml. of the a ueous distillate, 2 ml. of distilled water, and 1 or 2 pieces of Aqundum to prevent bumping. Attach a delivery tube and very slowly distill off 1 ml. of liquid, collecting it in a IO-ml. graduate immersed in an ice-water bath. Divide this distillate into two equal parts and make the test for methyl alcohol in the following manner : Place 5 ml. of the ethyl alcohol reagent in each of two test tubes. Add one portion of the distillate to the first test tube only, and 2 ml. of the permanganate reagent to each test tube. Stopper and shake thoroughly; then allow to stand for 10 minutes. Add 2 ml. of the oxalic acid reagent to each tube, mix again, and let stand until colorless. Add the second portion of distillate to the second test tube and add to each test tube 5 ml. of the Schiff reagent. Shake well, then allow to stand. A violet or blue color in the first tube and the absence of such color in the second test tube after standing 0.5 hour indicate the presence of methanol. If both tubes are colorless, methanol is absent. If the second tube develops a blue or violet color, a new portion of the distillate should be treated to remove interfering aldehydes. To do this, introduce into a clean 15-ml. flask a solution of 0.2 gram of pyrogallol in 4 ml. of water, 0.5 ml. of distillate, and 1ml. of concentrated sulfuric acid. Sto per and shake the flask. then the mixture is pink, aldehyde allow it to stand for 10 minutes. is still present and more pyrogallol must be added to remove it. If the pink color is absent, distill off 2 ml. and test this distillate for methanol, using I-ml. portions instead of the usual 0.5-ml.
8
This test was satisfactory in an aqueous distillate containing 1 per cent of methanol, equivalent to less than 0.1 per cent on the basis of the crankcase oil.
Ethyl and Isopropyl Alcohols These alcohols are detected b y identifying the products which they form upon oxidation under controlled conditions. The isopropyl alcohol is oxidized t o acetone, which is detected essentially b y the method of Rae (6). T h e ethyl alcohol is oxidized to acetic acid and this is detected by a modification of the method of D e Vito (9).
ISOPROPYL ALCOHOL.Reagents. Chromic acid solution. To 10 grams of chromium trioxide dissolved in 100 ml. of water slowly add, while stirring, 15 m1. of concentrated sulfuric acid. Sodium nitroprusside solution. Add 5 ml. of aqueous 25 per cent sodium nitroprusside solution to 20 ml. of ammonium chloride solution containing 4 grams of ammonium chloride. This rea ent should be freshly prepared. Zoncentrated ammonium hydroxide. Procedure. Into a 25-ml. flask introduce 10 ml. of chromic acid solution and a few pieces of Alundum to revent bumping. Cool the flask in an ice-water bath, add 0.25 m!l of the sample to be tested, and attach a long reflux tube to the neck of the flask (Figure 1, D). Remove from the bath and allow the flask to stand at room temperature for 5 minutes. Then heat gently for 5 minutes, re lace the reflux tube with a delivery tube (Figure 1, E ) , and final& collect 0.5 ml. of distillate and to this apply the following test for acetone (6), the oxidation product of isopropyl alcohol : Test for Acetone. To 0.5 ml. of the sam le in a small test tube (10 x 75 mm.), add an equal volume o f sodium nitroprusside solution and mix thoroughly. Carefully overlay this mixture with about 1 ml. of concentrated ammonium hydroxide solution. A deep purple coloration appearing a t the interface between the two liquid layers within 10 minutes shows the presence of acetone. ETHYLALCOHOL.Reagents. Chromic acid solution, prepared by dissolving 30 grams of chromic anhydride in 100 ml. of water and addin while stirring 40 ml. of concentrated sulfuric acid. Sodium%ydroxide solution, 0.1 N in water. Dilute nitric acid, 1volume of nitric acid to 9 volumes of water. Lanthanum nitrate solution, 5 per cent in water. Iodine solution, 0.1 N in aqueous 10 per cent potassium iodide. Concentrated ammonium hydroxide. Procedure. Into a test tube (22 X 100 mm.) introduce 5 ml. of chromic acid solution and 5 ml. of water. Bubble air through the liquid at a fairly rapid rate (45 liters per hour) and immerse the test tube in an ice-water bath. When the temperature drops to
VOL. 11, NO. 3
10” C. or less, add to this solution 0.25 ml. of the sample at such a rate that the heat of reaction will not cause the temperature to rise above 30” C. After the reaction slows down and the temperature be ins to drop, replace the ice bath by a warm water bath. Keep tke temperature in the test tube at 35’ * 2” C. for 25 minutes, after which raise it to 60” * 2” C. for a final 10-minute period. Five minutes after the 60’ temperature has been reached, add 5 cc. more of chromic acid solution, taking care that the temperature remains within the required limits. After the final heating sto the stream of air, transfer the solution to a 50-ml. distilling &sk, and add 10 ml. of water to it, together with a few pieces of Alundum to prevent bumping. Heat the flask and collect the distillate in a long-necked flask (25 ml.) immersed in a beaker of ice and water. Continue the distillation until crystals appear in the distilling flask. Make the distillate alkaline with 0.1 N sodium hydroxide solution and evaporate to dryness on the steam bath in a 50-ml. beaker. Dissolve the residue in 1 ml. of water, add dilute nitric acid until the solution is decidedly acid, then divide this solution into 2 parts. Transfer one 0.5-ml. portion to a small test tube and test for acetic acid, the oxidation product of ethyl alcohol. Dilute the other portion with 2 volumes of water and test 0.5 ml. of this solution for acetic acid in the same manner, for confirmation. Test f o r Acetic Acid (2). Introduce 0.5 ml. of the solution into a 10 X 75 mm. test tube and add an equal volume of lanthanum nitrate solution, Then add a drop of 0.1 N iodine solution and thorou hly mix the contents of the test tube. Carefully overlay this sofution with about 1 ml. of concentrated ammonium hydroxide and allow to stand for 10 minutes. A deep blue or purple colored precipitate at the junction of the two liquids shows the presence of acetic acid.
The tests for methyl, ethyl, and isopropyl alcohols and glycerol can be applied directly to any combination of these substances as a general analytical scheme. The presence of water or ethylene glycol does not interfere. In an isolated case the authors found a sugar solution (apparently from use as a radiator antifreeze) in an automobile crankcase. Because it was an isolated case it does not seem necessary to include the method for its identification in this scheme.
Literature Cited (1) A. S. T. M. designation D-95-30, A. S. T. M. Standards on Petroleum Products and Lubricants, p. 345, 1937. (2) De Vito, G., Ann. chim. applicata,23,56 (1933). (3) Georgia, F.R., and Morales, R., IND. ENG.CEEM.,18, 304 (1926). (4) Middhton, A. W., Analyst, 59, 522 (1934). (5) Mulliken, S. P., “Identification of Pure Organic Compounds,” Vol. I, p. 169, New York, John Wiley & Sons, 1904. (6) Rae, J., Pharm. J., 116, 630 (1926). (7) Rosenheim, A.,and Cohn, R., Ber., 33,1113 (1900). (8)Rosenthaler, L., “Der Naohweis organischer Verbindungen,” p. 104, Stuttgart, Ferdinand Enke, 1926. RECEIVED March 19, 1938.
HELIVMAND HYDROGEN COMPRESSORS
