Lubricants, Oils and Greases N. H. Fick Texaco Inc., Beacon, N. Y.
Oils. Recent progress in lubricant analysis was reviewed by Fujita (330). Solid-liquid chromatography was combined with infrared (IR) spectrometry by Munteanu and Halus ( 7 3 0 ) to determine dialkyldithiophosphate, sulfonate, phenoxide and methacrylic additives in lubricants. Studt and Hoffman (970) determined zinc dialkyldithiophosphates in lubricants by forming their ammonium salts and applying IR spectrometry for identification. Structure of the additives was determined by saponification and gas chromatographic analysis of the resulting alcohols. A critical review of metal dialkyldithiophosphate additives in lubricating oil, their analysis and chemical structure was given by Martin and Georges (720),and Versino et al. (1040)applied solid-liquid chromatography and IR spectrometry to the analysis of this type of oil additive. Altmann et al. ( 2 0 ) used IR spectrometry to determine phenolic anti-oxidant additives in lubricating oil and Kveder ( 6 0 0 ) identified additives in oils by IR spectrometry after separation by dialysis and column chromatography. Application of high performance liquid chromatography (HPLC) to the analysis of petroleum products was the subject of a paper by Amos ( 3 0 ) .Included were examples of analysis of synthetkester as well as hydrocarbon-based oils containing complex surfactant additive systems. Sinsel et al. (920) employed HPLC to analyze glyceride-based lubricants using AGI-X8 anion-exchange resin and Zorbax-Si1 packings. A review of techniques to modify the surface of chemically bonded stationary phases and their application to HPLC was given by Pryde (810). Proseus (800) discussed gel-permeation chromatography as a means of analyzing both hydrocarbon and ester-based oils and Vamos (1030) described a method using this technique to determine molecular weight distribution in polymethacrylate type additives. The molecular weight of each fraction separated over styrene-divinylbenzene copolymer beads is calculated from the viscosity of its benzene solution. Crump and Lynes ( 2 1 0 )used macroreticular ion-exchange resins (Amberlyst 15 and 29) for the analysis of new and used lubricating oils. A technique described by Leighton et al. ( 6 4 0 ) utilized thin layer, gel, and disk electrophoresis to separate various classes of polymer, sulfonate, salicylate, phenate, and dialkyldithiophosphate lube oil additives. Chromatographic separation at right angles provided a useful finger-printing method for identification of the additives. For the continuous separation of additives from base oils, Ono and Tanaka ( 7 7 0 )utilized a Soxhlet extractor with silica gel column chromatography. Kodama and Takai (570) studied the determination of phthalic acid esters in oils with column chromatography using several substrates. Florisil required the least elution time. A discussion of methods to determine surface active compounds in detergent automotive oils was given by Versino et al. (1050). Putinier et al. ( 8 2 0 ) developed a gas chromatography method to determine water and ethylene glycol in used crankcase oils. A copper column packed with Chromasorb 102 operated a t 150 "C with a thermal conductivity detector was utilized with acetone as internal standard. A gas chromatography profile analysis of polycyclic aromatic hydrocarbons in waxy distillates, raffinates, and lubricating oils was described by Grimmer and Boehnke (390).Lee et al. (630) performed the same analysis by first partitioning the engine oils between cyclohexane and nitromethane and analyzing the nitromethane extract by gas chromatography. Gas chromatography was also used by Jantzen ( 4 7 0 ) in the determination of phosphoric acid esters in gas turbine oils employing a thermionic detector specific for phosphorus. Thin-layer chromatography was utilized by several investigators to study zinc dialkyl/diaryldithiophosphate additive compounds. Marshall (710) developed the chromatogram on a silica gel la er, identified the additive by spraying with dithizone in 8C14, and determined zinc on the appropriate zone of silica gel removed by scraping. Cox ( 1 8 0 ) visualized 238R
ANALYTICAL CHEMISTRY, VOL. 49, NO. 5, APRIL 1977
the spots with a solution of PdC12 and made quantitative determination by use of a thin-layer densitometer. Lamotte and Auvray (50, 6 1 0 ) reported on thin-layer chromatographic techniques to determine dithiophosphate additives in unused motor oils and their degradation products in used oils, and Brook et al. ( 1 3 0 ) used a combination of column chromatography with thin-layer chromatography to analyze motor oils for zinc dialkyldithiophosphates,sulfonates, and phosphonates. A method for the rapid determination of lead in used engine oils was reported by Turina (1010) who utilized the fluorescent (PbC14)2- as means of detection and quantitation. A plication of mass spectrometric analysis to identify the alky components of zinc dialkyldithiophosphates was reported by Lesko et al. (650).Grimmer and Glaser (380) made mass spectrometric studies of polynuclear aromatic hydrocarbons (PNA) in lubricating oil fractions. The combination gas chromatographic/mass spectrometric isolation and identification followed the PNA enrichment procedure described in an earlier paper by Grimmer and Boehnke
P
(390).
The simultaneous determination of 15 different wear metals in lubricating oils by inductively-coupled plasma atomic emission spectrometry was described by Fassel et al. (290). Detection limits of 0.0003-0.3 ppm were reported. Johnson et al. (490) applied atomic fluorescence flame spectrometry to analysis of wear metals in jet engine oils. The undiluted sample is aspirated directly into the flame. Simultaneous determination of trace wear metals in used oils was studied by Jackson et al. ( 4 4 0 ) with atomic absorption (AA) spectrometry using a silicon target vidicon detector. A study of zinc determination in lube oils and additives by AA spectrometry reported by Lukasiewicz and Buell ( 6 8 0 ) showed that bulk effects of various additive components cannot always be eliminated by simple dilution. In a review of atomic absorption analysis, Jantzen ( 4 8 0 ) covered the suitability of flameless AA spectrometry for the detection and determination of trace wear metals in used oils. Chuang and Winefordner (170) used a graphite rod atomizer with AA spectrometry to analyze jet engine oils for seven wear metals. Excellent precision and speed of measurement were reported. A multielement computer controlled rapid scan at,omic fluorescence spectrometer with a continuum source was described in a paper by Johnson et al. (500). Rapid scanning was achieved by use of programmed slewed-wavelength scanning. The simultaneous determination of barium, phosphorus, and oxygen in oil additives by neutron activation analysis was described by Kliment et al. (560). Landolt and Struckmeyer (620) also reported on a method to determine barium in petroleum products by neutron activation analysis. Plasma-jet direct current arc spectrometry for the determination of trace wear metals in oil was described by McElfresh and Parsons (690).The oil sample was force-fed into a helium arc and the spectrum recorded photographically. Felsen and Gilbert ( 3 0 0 )reported on a method to determine chlorinated solvent contaminants in hydraulic fluids. A low boiling fraction was vaporized and analyzed by IR spectrometry. A colorimetric method for detecting 1-100 pg of silicon in lube oils containing silicones was described by Kabrt (520). Farmer (280) developed a method to determine the amount of vegetable oil contaminants in lubricating oils used in seed processing equipment. Thermal methods of analysis were used by several investigators in studying oxidation characteristics of oils. Blaine ( 1 0 0 ) reviewed the use of differential scanning calorimetry (DSC). Noel and Cranton ( 7 4 0 ) and Trofimov et al. (1000) applied DSC to determining the effect of antioxidants on oil systems. Novoded et al. (760) and Cranton (200) studied the thermal stabilities of aromatic-naphthenic-paraffinic fractions of oil using DSC and differential thermal and thermogravimetric analysis. The relative inhibiting effects of the various structures were compared. Trofimov et al. ( 9 9 0 )determined the antioxidizing action of oil additives by measuring the amount of oxygen absorbed by the oil during oxidation in a thermostat. Oxygen and nitrogen were determined by gas chromatography and oxygen consumed was calculated from the altered oxygenhitrogen ratio. Berthold ( 8 0 ) presented a discussion of wear control with phosphorus-containing additives in engine oils and described thin-layer chromatography techniques employed to study the effects of acidic and basic additives and Total Base Number
on zinc dialkyldithiophosphate thermal decomposition. For determining engine oil consumption rate, Kawamoto et al. (530)developed a radiometric method wherein 35S is added to the engine oil in the form of oleic acid sulfide and detected in the exhaust gases. Shcherbinin et al. (910)studied changes in hydrocarbon group composition in engine oils after 120 hours service and related these compositional changes to physicochemical properties. Hydrocarbon group composition was determined by adsorption analysis using a 10/1 mixed silica gel/alumina adsorbent. A series of specially developed bench tests, described by DeJev and Brandone ( 2 3 0 ) ,was used to study the lubricating oil requirements of four-stroke motorcycle engines. Baber et al. ( 6 0 ) presented a paper describing an aircraft gas turbine engine deposit simulator test employing the No. 4-5 bearing compartment areas of a 557 turbine engine as the basic section of the simulator. Correlation was claimed with deposit ratings from full scale engine tests. The development of a lube oil oxidation and thickening bench test to simulate the ASTM Sequence I11 engine test was reported by Kuhn (590). Gergel and Riester's ( 3 7 0 )paper on diesel engine oil consumption studies reported on the use of a 425-hp turbocharged engine test and concluded that traditional properties, such as viscosity and volatility, do not completely account for variations in oil consumption. A paper chromatography procedure was developed by Freund et al. (320)to determine oil change intervals of diesel engine oil. Otte ( 7 8 0 )presented a paper which discussed prediction of gas engine failure based on carbon residue and insoluble levels, and quantity of oxidation and nitrogen fixation products in the oil obtained by infrared analysis. A continuous means to measure the air content of oil during engine operation by a new radioactive method was developed by Fock (310).Several investi ators gave -attention to low temperature pumpability s t u d e s of engine oils. Spohn and Stewart ( 9 5 0 )reported on use of a vacuum pipet rig to predict cold pumpability of oils in a V-8 engine after a 16-h cold soak. The results of a program conducted by ASTM D-2 using 13 reference oils in seven engines reported by McMillan et al. ( 7 0 0 ) indicated that the borderline pumping temperature and failure mode should be used as the basis for evaluating the ability of laboratory bench tests to predict low temperature engine oil pumpability. Methods to simulate high shear conditions in automotive lubrication were discussed in a paper by Jakobsen et al. (450). Talbot et al. ( 9 8 0 )developed an inexpensive electric motor driven air-cooled single cylinder engine test for the shear stability of multigrade oils. Gyer (400)reported on a rheology study of 12 ASTM ARO series reference oils using a diesel injector test apparatus to obtain high shear stress. The relationship between temporary and permanent viscosity loss with polymer type was discussed. The shear properties of thin solid organic films was the subject of a paper by Briscoe and Tabor (120).Jalrobsen and Winer ( 4 6 0 )discussed the high shear stress behavior of several different types of lubricants in a high pressure capillary tube viscometer. Busetto et al. ( 1 4 0 )employed a cylinder-piston type capillary viscometer to measure 210 O F (98.9 "C) viscosity of unigrade and multigrade engine oils to better simulate the high shear rates at engine operatin conditions. Rosenberg ( 8 5 0 ) developed an experimental technique using inductive transducers to measure thin films in the loaded region of journal bearings. Viscosity changes with time were determined on samples of single and multigrade oils from the bearing. A new calculating aid for viscosity index (VI) determinations, developed by Polinelli and del Ross ( 7 9 0 ) , utilized a viscosity-temperature chart, a goniometer, and nomograms to calculate VI and other VI-temperature-viscosity range relationships. A rheological study performed by Drenchev ( 2 6 0 )showed that when the viscosity of an engine oil a t low temperatures is to be found by extrapolation, the minimum actual viscosity should be used. Jones et al. ( 5 1 0 )used a capillary viscometer to measure viscosity of 13 mineral and synthetic oils as a function of temperature, pressure, and shear stress, and Hoette ( 4 1 0 ) tested 11 equations for their ability to represent extensive available data on viscosity dependence on temperature and pressure. Witt (1080)presented a paper which discussed the limits to which pressure, temperature and viscosity measurement can be used up to high pressures to predict effective viscosity. For the determination of the viscous desolidification point of wax-free lubricants, Gardos (360)developed a simple
device which requires only 6-16 drops of fluid and gives excellent correlation with the ASTM pour point procedure. Vamos (1020) presented a survey of micromethods for evaluation of lubricating oils. Physical methods of analysis to identify surface layers formed by organosulfur compounds in wear tests was the subject of a paper by Coy and Quinn (190).X-ray diffraction, electron probe microanalysis, and scanning electron and optical microscopy techniques combined with micro hardness testing were described and the effectiveness of several additive types were compared. Soul (940)presented a review covering the widespread use of the FZG rig test in lubricant specifications and its limitations and factors, including additive content and chemistry, affecting performance of oils in the test. The wear behavior of oils containing several additive types in the FZG spur gear machine was measured by Ruedinger ( 8 7 0 )with the aid of radionuclides. Examples of the high accuracy and greater sensitivity of this faster tracer method were given in comparison to gravimetric methods. Tracer techniques were also employed by Ivkovic and Lazic ( 4 3 0 ) to measure wear on mating surfaces in a gear test machine. Armstrong and Lindeman ( 4 0 ) described a versatile tester for friction, life, and wear on many types of lubricants under a variety of conditions. White (1070)reported on a versatile wear machine which simulates the contact conditions experienced in heavily loaded, slow speed gear systems. A new five-ball twin head machine for studying the effects of sliding and traction on the fatigue life of point contacts was described by Diaconescu et al. (240).Capone and Capone (150)carried out an investigation of thin oil films using a disk machine which employed combined rolling and sliding of the peripheries of two carbon steel disks, rotating against each other a t different angular velocities. The results, which correlated with the Falex machine, indicated that the critical temperature criterion is unsuitable for EP oils. The effect of rear axle lubricants on the fatigue life of tapered roller bearings was the subject of a paper by Kepple and Johnson (540).Rosenberg ( 8 6 0 ) presented a paper discussing the influence of polymer additives on performance of oils in a journal bearing test machine that applies a rotating load to the bearing. Several authors commented on separate aspects of a study of chemical effects of lubrication in the contact fatigue life of materials used in gears and rolling contact bearings. Howes et al. (420)reported on the apparatus and test conditions and design of the program, and Bhattacharyya et al. ( 9 0 ) presented a statistical analysis of the data including the predictive fatigue life equations which were developed. The differences observed between mineral oils and the synthetics were discussed by Littmann et al. ( 6 7 0 )who concluded that relative contact fatigue life for different lubricant chemistries should be evaluated at slip and stress levels of importance to the application. To establish a high pressure vane type hydraulic pump test facility that would duplicate the results obtained in the full scale F-38 pump test, Chirichella et al. (160) developed a less costly small scale simulated test using a modified F-5 pump. Results of tests with various lubricants were in good agreement with those obtained with the F-38. Agnesi et al. ( I D ) developed an improved hot wire transient measuring device to determine thermal conductivity of fluids. The dependence of thermal conductivity on molecular structure and viscosity was discussed. Becker ( 7 0 ) provided a discussion of scanning electron microscopy (SEM) including its principles of operation and its broad applications in the petroleum industry. Eyre and Dutta ( 2 7 0 ) presented a paper describing a technique for using an optical metallographic taper section through a wear surface, combined with the SEM, to examine simultaneously wear surface topography and substrate metallography. A review of the ferrographic technique, which provides data on the size distribution and types of particles present in a used oil, and Scott et al. (9OD)presented was given by Wescott (1060), a paper describing the use of this method to predict failure of lubricated surfaces and its possible use in correction of machine design. On the subject of metal working fluids, Rogers et al. (840) reported on a 12-week testing program to determine effectiveness of biocides. A laboratory procedure was compared with in-plant performance and found to give good correlation. For evaluating cutting oils, a drilling test used by Skells and Cohen ( 9 3 0 )employed a four-facet prismatic drill point to ANALYTICAL CHEMISTRY, VOL. 49, NO. 5, APRIL 1977
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measure tool wear as a function of drill speed. Kirk et al. (55D) studied grinding fluids by a modified pin-on-disk simulated test employing a hemispherical segment of a grinding wheel rubbing against steel. SEM and microprobe results from the simulated test and from actual grinding tests showed similarities in wear morphology. Raje (830)reported on development of methods for evaluating the performance of oils for traction drives and discussed various hypotheses concerning the relationshirJ of chemical comrJosition of fluids to their tractive capaciiy. The volatilitv of lubricating oils was studied bv RumDf (880)who devdoped relationshps between evapor&ion rite and atmospheric pressure, average boiling point and viscosity using the Noack (DIN 51 581) apparatus. Gardos (350)utilized a quartz-spring mass sorption microbalance in combination with an ultra high vacuum pump to measure evaporation rates of low volatility polymeric lubricating oils. Greases. Stanton (960)presented a paper covering research on analysis of greases by infrared spectrometry carried out by ASTM Technical Division G-IV-4. Of the three methods described for taking IR spectra, the slurry technique proved to be the most precise. Differential thermal, thermogravimetric, and IR analyses were used by Novoded and Bogdanov (750)to study the thermal oxidation stability of complex calcium greases. Thermal analysis was also used by Gar et al. (340)to determine the effect of base oil composition on thermal phase changes in lithium greases. In studying flow properties of greases at high temperatures, Komatsuzaki and Ito ( 5 8 0 ) found the apparent viscosity measured with a cylindrical rotational viscometer dropped sharply at a specific temperature for each grease-thickener combination. Dobson (250)made a correlation stud of grease flow properties using pipe, concentric cylinder, andlcone and plate viscometers. Culp et al. ( 2 2 0 )reported on a study of grease shear stability using extended shearing up to 96 h in the ASTM Roll Stability Tester and concluded the D 1831 2-h procedure is too short to give meaningful results. Lindeman and Polishuk (66D)reported on an investigation of the effect of internal radial clearances of 0.0003-0.0008 in. (0.008-0.02 mm) on grease life and torque in ball bearings. Equations for approximating the life of almost any long-life grease as a function of bearing temperature, bearing size, speed, load, and lease com osition were presented in a paper by Booser (1107. SchneiAr (890)presented a paper describing new test procedures for measuring water washoff resistance of greases used in extreme marine environments.
WaX D. R. Cushman and J. W. Schick Mobil Research and Development Corporation, Paulsboro, N.J.
T h e r m a l Conductivity. LeRoux, Smith et al. (9E)examined Fischer-Tropsch waxes, covering thermal conductivity at 20-130 "C, specific volume-temperature curves, average molecular masses, and clear points. The waxes were mainly C34-C150 n-paraffins. Chromatography. Four papers dealt with chromatographic analysis. Azizova et al. ( I E ) studied low-melting paraffins by gas-liquid chromatography. The concentration of n-paraffins increased with increasing melting point of the low-melting wax, and complex forming paraffinic-naphthenic fractions showed a high concentration of normal araffins. Zakupra and Kolosova (I3E)also used gas-liquicfchromatography to analyze high-molecular alkanes (to C51), obtaining more pronounced peak areas of individual compounds using calibration coefficients determined by adjusting conditions (time, temperature) and packing material to those used with model mixtures. Postnov et al. (IOE) calculated physicochemical properties of solid alkanes by programmed-temperature gas chromatography, with the aid of literature data on boiling point distribution and experimental retention temperatures. The calculated molecular weights and densities showed good agreement with standard values. Blau (3E)ap240R
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ANALYTICAL CHEMISTRY, VOL. 49, NO. 5, APRIL 1977
plied gas chromatography to the analysis of common waxes and wax mixtures, including paraffin and microcrystalline waxes. Spectrometry. Zmudzinska-Zurek (15E) used infrared spectroscopy to determine solid petroleum hydrocarbons in a slack wax fraction. Average number of methyl groups was verified, and n-alkane (from urea adduction) and isoparaffin concentrations were determined. Berthold and Staude (2E) also analyzed saturated hydrocarbon mixtures by infrared spectrometry to determine structural configurations of fractions from refined crude oil products such as n-paraffins, white oils, Vaseline, and microcrystalline wax. Zenker (14E)described an infrared method for control of paraffin wax oxidation in the presence of boric acid as a reaction control in production of alcohols from paraffins. He found a linear relation between absorption intensity of B-0 stretching vibration in the borate ester wax and the hydroxyl value of the hydrolysis product. Krivjansky et al. (BE)studied the purity of solid petroleum paraffin waxes and ceresins used in the food, cosmetic, and pharmaceutical industries, using UV spectrophotometry to determine aromatic and resinous content, and a combination of UV spectrometry and spectrofluorometry for content of aromatics having carcinogenic roperties. Concentrations as low as 1-10 pb were detected. ghiraishi and Takabatake (12E)also s t u i e d carcinogens in petroleum waxes and synthetic waxes by extraction of benzo[a]pyrene with dimethyl sulfoxide, clean-up of extract on a column of alumina, and determination by spectrofluorometry. Miscellaneous. Six papers covered subjects of general interest, or those which combined several analytical techniques. Ivanova et al. (6E)gave a review, with 33 references, on the chemical composition of peat waxes. Sekine (I1E)discussed low-temperature fluidity of waxy crudes and heavy (fuel) oils, covering changes in flow properties due to wax solidification, test methods, and preventive measures such as the use of additives. Zubarev and Nevolin (16E)studied the solubility of paraffin in etroleum. The amounts of paraffin crystallizing out of petroyeum products and crude oil and depositing on pipe walls while cooling and flowing through pipelines were determined from solubilit curves. Hanna and Mahmoudr(5E) reported on the distribution of n-paraffins in Marine Belayim wax distillate, using zeolite adsorption and gas chromatography. Fal'kovich et al. ( 4 E ) determined n- paraffins by contacting with calcium-A zeolite. Results were more accurate, with lower values than by contacting with urea. Zeolite adsorption data covered nine crudes (or mixtures). Data are also given on fractional crystallization with urea, followed by zeolite adsorption, showing the presence of branched chain and cyclic hydrocarbons. Kamita et al. (7E)made a structural analysis of liquid wax oxidates. Paraffin wax was air oxidized with catalyst and separated into liquid and solid oxidates. The liquid oxides were separated by saponification, extraction, and column chromatography. Each fraction was further characterized by gas chromatography and IR and NMR spectroscopy. Viscosity increased with increased ester content. Esters were mainly lactones and compounds with a t least two ester functions.
Asphalt James R. Couper Department of Chemical Engineering, University of Arkansas, Fayetteville, Ark. 7270 1
The majority of the research work performed during the past two years has been related to the composition of asphalt. The subheadings were arbitrarily selected to facilitate the readability and location of the information. Gel Permeation a n d Chromatography. Some type of preliminary separation of asphalt into its components is necessary prior to the use of a chromatographic separation. The initial separation usually involves a solvent separation or precipitation technique. The fractions obtained by the chromatographic methods may be further subjected to in-
