iodine-azide reaction after removal of carbon dioxide and hydrogen sulfide. Mixtures of monohydric phenols (C6C,) were analyzed by Adlard and Roberts (M)by silylation of the phenols before gas-liquid chromatography in a capillary column. Lindeman and Nicksic (88'5) suggested the characterization of individual alkylphenols by proton magnetic resonance after acetylation. C'rump (325) resolved mixtures of siinple alkylphenols from kerosine; the phenols, coupled as p-nitrophenylazo dyes, were separated by two-dinien iional chromatography on silica gel impregnated with sodium hydroxide. 3krynnikova and Matveeva (14 0 4 sepirated phenols by steam distillation and bromination; the end of bromination was determined amperometrically. Zubkova and eoworkers ( 1 6 3 4 used thin layer chromatography on alumina for the separation and identification of alkylphenols and aminophenols in mineral or synthetic oils. The determination of the phenols used as additives or solvents was the subject of several papers. Berthold and Drescher (14J) determined 2,6-ditert-butyl-p-cresol in turbine oils by infrared spectioscopy, measuring the intensity of the 1168 cm-' band of the hydroxyl group on the tertiary carbon atom. The same additive was determineti by Braithwaite and Penketh (SOJ) using a pr0ced.u-e involving preliminary separation by distillation with methand followed hy analysis based on colorimetry, infrared spectroscopy, or gas-liquid chromatography. Braithwaite, I'enketh, and Underwood ( d f J ) separated 2-methyl-6-tert-butyl-p-creso1 from gasoline by column chromatography, oxidized witl- potassium ferricyanide, coupled with diazotized p-nitroaniline, and determi led spectrophotometrically. In'kova and Piyunkina (6;J) described a method for the determination of phenol and alkylphenols in additiveir. Norikov and Vetchinkina (11OJ) separated various lerf-butylphenol additives gas chromatographically using; Apiezon N as the stationary liquid phase. Geller, Shevrhenko, and Rastorguev ( 5 0 4 suggested two methods for the determination of phenol and cresol used in solvent extractions; one method is based on removing the solvents from the oil with aqueous sodium carbonate and the other removes them with steam distillation; in both methods phenol and cresol concentration is determined colorimetrically. 3lixtures of petrcleum acids were separated by Bock and Behrends (17 4 by esterifying and t k en separating the methyl esters by dir,tillation and gas chromatography with polyethylene glycol and 2-ethylhexyl sebacate as the stationary phase. Jenkins (685) desrribed the determinrition of carboxylic
acids and esters in petroleum distillates and residues by infrared spectroscopy; this paper includes a survey of recent reports in which infrared spectroscopy was applied to petroleum. Hill and Hill (68J) separated mixtures of free aromatic acids by gas chromatography with hexameth y l d i s i l a z a n e - t r e a t e d Chromosorb W coated with 15y0 Carbowax 20M. Harlow and Morman (555) described automatic ion exclusion-partition chromatography for acids involving separation on a column of sulfonic acid exchange resin and continuous automatic titration to pH 8.5. The oxygen-containing compounds resulting from the pyrolysis of light oil weIe isolated and characterized by Shor, Chertkov, and Gol'din (1375) using chromatography on KSM silica gel. Keil and Rentrop ( 7 2 4 found that the chief products of mineral oil aging (acids, esters, lactones, and alcohols) could be determined by infrared spectroscopy; the undiluted oils, after removal of sludge, were examined in the regions 1700 to 1800 and 3100 to 3600 cm-l. Banerjee and Budke (65) extended a spectrophotometric method for the determination of peroxide for use with unsaturated compounds.
Metals in Oil H. A. Braier, Gulf Research & Development Co., Pittsburgh, Pa.
A
methods which recently have evolved, activation analysis and atomic absorption spectrometry are gaining popularity among analysts for the determination of a variety of chemical elements in petroleum and related materials. In the 3.25-year period covered by the last two reviews, only two papers in each one of the above-mentioned techniques were abstracted, while in the 2-year period covered by the present review, six papers dealing with atomic absorption and eight involving activation analysis were published. The following papers are arranged by analytical methods. Activation Analysis. Fast neutron activation associated with y-ray spectrometry and computer programming has been applied by Hull ( W K ) to the determination of nitrogen, phosphorus, chlorine, zinc, and barium in lubricating oils. The use of computer data reduction in neutron activation analysis has been described by Steele (44K). Oxygen in hydrocarbons and barium in lubricating oils were determined by Gibbons (13K) as examples of the application of 14-m.e.v. neutron generators inactivation analysis. Additives in lubricating oils have been indirectly measured by determining barium, phosphorus, iron, sulfur, and chlorine by fast MONG THE INSTRUMENTAL
neutron activation ( I d K ) . Phosphorus, sulfur, and zinc were also determined in motor oil additives by radioactivation analysis by Nagy and Saokolyi (36K). Nuclear reactor irradiation followed by chemical separation and y-ray spectrometry has been used by Malvano (SWK) to analyze crude oils, crude asphalts, and polyphenyls for traces of nickel and cobalt. A similar approach was successfully applied by Colombo et al. ( 7 K ) to the systematic analysis of 11 metals in petroleum products. Ten elements in the parts-permillion and parts-per-billion range were identified and measured in some Italian oils and asphalts by Ciuffolotti et al. ( 6 K ) using an elaborated reactor irradiation technique. Atomic Absorption Spectrometry. This analytical technique has been used to rapidly determine traces of iron, copper, and nickel in gas oil feedstocks ( 1 K ) ; and nickel, down to 0.05 parts per million in catalytic cracking feedstocks by Trent and Slavin (46K). Several problems affecting the evaluation of lead in gasolines, especially the chemical natuie of the lead standard, have been studied by Dragnall and West ( Q K ) . A procedure for atomic absorption determination of lead in gasoline has been described by which lead can be evaluated with an accuracy of about 1% of the amount present (47K). Atomic absorption spectrometiy was applied to the determination of wear metals in lubricating oils: copper, chromium, iron, lead, and silver in concentrations ranging from 0-100 ppm have been determined by Burrows et al. ( 5 K ) in used lubricating oils with good reproducibility and without interference problems, The rapid determination of iron, copper, silver, magnesium, chromium, tin, lead, and nickel in lubricating oils has been reported by Means and Ratcliff ( S S K ) . Finally a procedure has been described by Sprague and Slavin (43K) for the rapid analysis of used aircraft lubricab ing oils for nickel, chromium, lead, copper, silver, and magnesium, a t the rate of 14 seconds per sample per element, with a precision of about 5%. Emission Spectrometry. A technique was described by Kahonitz ( 2 6 K ) for emission spectrographic determination of a variety of metals in liquid mineral oil products, uring a rotating electrode. An indirect determination of vanadium and nirkel has been reported by Petho ( S 6 K ) in which a pair of graphite electrodes are immersed in the oil, and heated to 1000" C before being excited by a high tension spark. Nine elements, including nickel and vanadium] have been estimated in petroleum and bitumens by Berman ( s K )first combusting the sample with a buffer mix and then exciting the ashes in a .F-ampere d.c. arc. Determination of trace elements in crude oils has been achieved by VOL. 39, NO. 5, APRIL 1967
175 R
Korosteleva et al. (2°K) first transforming the oil into coke and then exciting it with a 20-ampere d.c. arc. Zinc, barium, and vanadium were estimated in petroleum products without preliminary ashing by Hauptman (19K),using copper electrodes. An apparatus that can be attached to any spectrograph and that permits the safe spark excitation of petroleum products and flammable liquids has been described by Buncak (SK). Crankcase oil contamination was studied by Sokolov (42K) who determined iron, lead copper, chromium, silicon, aluminum, and tin after ashing the samples and using nickel as internal standard. The analysis of diesel oil to determine metals worn away by friction from engine parts has been reported (4OK) using conventional sample handling and spectrographic techniques. To avoid sample ashing, a method has been described by Pforr et al. ( S 7 k ) for zinc and calcium in compounded motor oils in which the sample is sprayed into the spark gap by means of a rotating carbon disk. Wear metals-iron, aluminum, lead, copper, chromium, and silicon-were determined in locomotive diesel oils by Sokolov (4lK). Boron in heavy hydrocarbon mixtures has been measured by Giorgini (15K) with no previous ashing by diluting the sample in a graphite matrix. Nickel, copper, vanadium, and iron in the parts-per-billion range were determined in ashes from catalytic feedstocks by Hoggan et al. (21K),using cobalt as internal standard and a directreading spectrometer. A general computer program was developed by Tunnicliff and Wezl-Jer (48K),which calculates and reports results from the common matrix method of emission spectrographic analysis. X-Ray. A review covering problems encountered in x-ray analysis, with emphasis on applications t o mineral oil products, has been reported by Louis (29K). In this paper, x-ray tubes, crystal analyzers, collimators, and characteristics of crystals are critically discussed. Detection limits in mineral oils for elements of atomic numbers between 15 and 82, using x-ray emission analysis, have been described by Louis (SOK). For elements heavier than chlorine a detection limit below 1 ppm is possible, and between 1 and 3 ppm for sulfur and phosphorus. X-ray emission spectroscopy was applied by the same author (28K)to the determination of zinc, barium, calcium, chlorine, sulfur, and phosphorus in lubricating oils. A direct simple channel method for analyzing 0.2-10 ppm of nickel in catalytic cracking feedstocks, in about 23 minutes, with a standard deviation of 0.1 ppm and within 0.1 ppm agreement with chemical results has been reported by Gunn (17K). Calcium, barium, zinc, and lead were determined by 176 R
ANALYTICAL CHEMISTRY
Burke et al. (4K) using x-ray spectrography in lubricating oils, white oils, and gasolines. This technique uses a pellet of a suitable reference element in a conventional Phillips cup containing the sample. Catalytic cracking feedstocks have been analyzed by Rowe and Yates (S8K) using x-ray fluorescence to determine copper, iron, nickel, and vanadium; the samples are prepared by ashing with xylene sulfonic acid. A discussion on the application of x-ray fluorescence spectrometry LO the determination of barium, zinc, and calcium in lubricating oils and additives has been reported by Haycock (20K). An internal standard technique to eliminate inter-element effects is used. Miscellaneous. A procedure for ash determination in hydrocarbons that is faster than the ASTM ash analysis D482-63 has been described by Dubeau et al. ( 8 K ) . In this method the oil evaporation time is decreased from 90 to 9 minutes by using a slight vacuum. Zinc calcium, and bromine in unused lubricating oils have been selectively estimated by Fisher ( I f K ) using complexometric titration with EDTA in an alcoholic-hydrochloric acid extract of the sample. Several procedures for the complexometric determination of zinc and calcium in oils containing additives have been studied, although no satisfactory results were reported by Studeny ( 4 6 K ) . A gravimetric method by Muzychenko et al. ( S 4 K ) for the determination of carbonates in oil additives containing calcium or barium involves treating the samples with sulfuric acid and determining the liberated carbon dioxide. A chemical method for determining barium in lube oils additives concentrates has been extensively tested by several laboratories (10K). In this procedure (IP Inorganic Analysis Panel ST-G-3), which is simpler and more rapid than the I€'-110, the samples are treated with sulfuric and nitric acids and the barium is weighed as sulfate. Routine photometric analysis for the determination of zinc additives in unused lubricating oils has been carried out by Howard ( 2 2 K ) forming the zinc dithizonate complex in a carbon tetrachloride solution of the oil. A pulse polarographic determination of microgram amounts of nickel and vanadium in petroleum stocks has been reported by Gilbert ( 1 4 K ) which can be effected on a single polarogram in a short time, after chemically treating the samples. T'anadium contained in petroleum as a porphyrin complex was determined by Ishii ( 2 5 K ) using an a x . polarographic technique after extracting the vanadium with a KSCS-HTSOa solution. Simultaneous polarographic behavior of nickel, cobalt, iron, and manganese has been studied in mineral residues of crude oils and a simultaneous determination of nickel and cobalt in several Romanian
oils has been described by Serbanescu ( S 9 K ) . A review covering the subject of polarographic analysis has been wrib ten by Ishii (24K) containing 57 references. Potentiometric acid-base titration has been applied by Lyashenko et al. (S1K) to the determination of calcium salts in lubricant oil additives. Two analytical procedures have been described by Hammerich and Gonderman (18K) to analyze combustion residues from engines. In one of them, lead, barium, and silicon are gravimetrically determined after insolubilization with acids; iron, zinc manganese, molybdenum, copper, and phosphorus are spectrophotometrically determined and a potentiometric method is used for chlorine, bromine, and boron. In the other procedure by Grant (16K), silicon and aluminum are colorimetrically determined, calcium and magnesium by complexometric methods and chloride by potentiometric titration.
Catalysts Ralph 0 . Clark, Gulf Research & Development Co., Pittsburgh, Pa.
Acidity. The measurement of acid sites by the titration technique using a series of color indicators continues to be used as reported by Bertolachi (2L)and Hirschler (1SL). Spectral absorption and electron paramagnetic resonance measurements of anthracene adsorbed on silica-alumina catalysts have been employed by Karakchiev et al. (14L) to elucidate protonic and aprotonic acidities. The infrared spectrum of coordinately bonded pyridine has also been utilized by Basila et al. (1L) and by Parry (18L) to differentiate between the types of acid sites. The distribution of acid centers was reported by Strich and Becker (2OL)by potentiometric titration with potassium methoxide in a nonaqueous system. Metals. Emission spectroscopy was used by Biktirnirova and Baibazarov (SL) to determine sodium in catalysts, and copper and palladium in sediments and deposits. Townsend (2%) reported the application of a fusion-cast disk technique for analyzing catalysts by emission x-ray spectrography. A modification of the Sen titrimetric procedure for determining nickel has been reported by Danowski and Lewandowska (7L). Svajgl ( 2 f L ) devised a colorimetric and a titrimetric method for tracing vanadium in hydrogenation processes. Potentionietric titration with ceric sulfate has been employed by Giuffre and Cassani (IOL) to determine the V+2 and V+3 contents of catalysts prepared from vanadium trichloride and aluminum alkyls. And, a complexometric method for molybdenum was devised by Uvarova and Rik ( 2 4 5 ) .
