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Vol. 43, No. 12
bromophenacyl ester was prepared by the procedure given by corresponding diary1 derivatives, they were not analyzed. The nltro alcohols synthesized were: l-p-chlorophenyI-2-nitro-l- Shriner and Fuson (9). It melted at 224" C.; the literature melting point is 225' C. (IO). propanol; 1-p-chlorophenyl-2-nitro-1-butanol; l-p-chlorophenylThe ether solution of p-chlorobenzoic acid was evaporated and Znitro-I-pentanol; l-p-chlorophenyl-3-methyl-2-nitro-l-butanol; the acid twice recrystallized from an ethanol-water mixture. It melted a t 240' C.; the literature melting point is 242' C. (IO). p-chlorophenyl-( 1-nitro)cyclopentylmethanol ; p-chlorophenyl(I-nitro)cyclohexylmethanol ; 2-nitro-l-p-tolyl-l-butanol ; 2methyl-2-nitro-I-p-tolyl-1-propanol; 2-nitro-1-p-tolyl-1 -pentanol; ACKNOWLEDGMENT 2-methyl-2-nitro-1-p-tolyl-1-butanol; 3-methyl-2-nitro-l-p-tolylThe Commercial Solvents Corp. and the Purdue Research 1-butanol; and (1-nitro)cyclohexyl-p-tolylmethanol. Foundation furnished the funds required for these rcsrarcshes. PROOF OF POSITIONS OF RINGCHLORINE ATOMSIN 1,l-BIs-p hIicroanalyses were by Louis Roth and Harry Galbraith of the CHLOROPHENYL-2-NITROPROPAXE. 1,I- Bis-p-chlorophenyl-2Department of Chemistry, Purdue University. nitropropane was converted to the corresponding ketone by the The paper contains material froin the doctoral thwes of ht. B. action of dilute sulfuric acid on its alkaline solution. Oxidation Neher and R. T. Blickenstaff. of the ketone with chromium trioxide gave p,p'-dichlorobenzophenone, identified by mixed melting point with an authentic sample (1). LITERATURE CITED PROOF O F STRUCTURE OF l-p-CHLOROPHEI\TYL2-~;ITRO-1-pTOLYLPROPAKE. 1-p-Chlorophenyl-2-nitro-I-p-tolylpropane ( 10
grams) was added to a solution of potassium permanganate (40 grams) in water (600 ml.) containing sodium hydroxide (1 gram). The mixture was refluxed until the urple color of the potassium permanganate was discharged (15 !ours). The solution Wac: filtered to remove the solid manganese dioxide and unreacted 1p-chlorophenyl-2-nitro-I-p-tolylpropane.The resulting clear solution was acidified, and the precipitated acids (supposedly p chlorobenzoic and terephthalic) were removed by suction filtration. The mixture of acids was then continuously extracted with diethyl ether in a Soxhlet-type extractor for 8 hours. p-Chlorobenzoic acid, being ether-soluble, was removed by the extraction, leaving the terephthalic acid as an insoluble residue. The residue was recrystallized from absolute ethanol twice, after which it melted a t 298" to 300" C. with sublimation; literature (9) gives sublimation as taking place at 300" C. The p-
(1) Boeseken and Cohen, Chem. Zentr., 1915, I, 1376. ( 2 ) Bruson, H. A . , and Reiner, T. W., J . Am. Ciiem. Soc., 65, 23
(1943). (3) Drake, N. L.. ed., "Organic Syntheses," 1'01. 21, p. 15, S e w
York, John Wiley B: Sons, 1911. R.,and Seiferle, E. J., J . &on. Entomol., 40, 736-41 (1947). ( 5 ) Kamlet, J., U. S. Patent 2,151,517 (March 21, 1939). ( 6 ) Lipp, P., Ann., 449, 15, 1926. (7) Miiller, P., U. S. Patent 2,397,802(.4pril 2, 1946). (8) Rupe, H., and Gisiger, F., Helv. Chim. Acta, 8, 341 (1925). (9) Shriner and Fuson, "Identification of Organic Compounds," 2nd ed., p. 164, S e w York, John Wiley & Sons, 1944. (10) Ibid., p . 184. (11) Siegle, L. W,, and Hass, H. B., ISD. E m . CHEY.,31, 648 ( I % % ) . (12) Tindall, J. B., U. S.Patent 2,397,384(March 26, 1946). (4) Frear, D. E.
RECEIVED February 3, 1921.
Corrosion Resistance of Lirconium EFFECT OF OXYGEN, NITROGEN, CARBON, AND HAFNIUM ROBERT J. BRU31BAtTGH Research & Decetopment Laboratories, Foote Mineral Co., Berwyn, Pa. U n t i l recently all zirconium metal contained from 2 to
3% hafnium as impurity. Now commercial amounts of the metal are being produced which contain less than 0.1% hafnium. In previous reports on corrosion resistance of zirconium metal, investigators made no determinations of oxygen, nitrogen, or carbon content of metal being tested. In this paper are reported results of investigation of effects of small amounts of oxygen, nitrogen, carbon, and
c
OMMERCIAL production of very pure, low hafniumcontaining zirconium metal has been achieved. This has resulted in a growing interest in the chemical and physical properties of such metal. As specifications for metals, potentially useful in construction of nuclear furnaces and other special equipment, become more rigorous, lcnowledge of effects of impurities on such metals becomes increasingly important. Although corrosion data on zirconium metal had previously been reported by other investigators (1-4) no determinations of oxygen, nitrogen, and carbon had been made on the samples used. It was the purpose of this investigation to determine the effects of small amounts of oxygen, nitrogen, carbon, and hafnium content on the chemical corrosion resistance of zirconium metal. Limited tests were also carried out with titanium metal for comparison.
hafnium on corrosion resistance of zirconium metal. Higher concentrations of these contaminants were not studied, as they would not ordinarily occur in commercial metal of this grade. Presence of any of these impurities results in lowering of corrosion resistance of zirconium. Essentially pure zirconium metal has been found to be extremely resistant to attack by fuming nitric acid.
The results on single tests of the specimens considered are presented to confirm present literature. All corrosion tests were conducted under quiescent conditions-i.e., without stirring or aeration of solutions, and a t a temperature of 35" C. %?th but one exception (for comparison purposes) all samples were prepared from special high purity ductile zirconium containing leos than 0.1% hafnium. Reagents used in these tests included solutions of varying concentrations of sodium hydroside, ammonium hydroxide, hydrochloric acid, sulfuric acid, and nitric acid, a5 well as mixtures of the acids. EXPERIMENTAL WORK
MATERIALS.All samples of low-hafnium zirconium, manufactured by Foote Mineral Co. using the .DeBoer process, used in this investigation mere prepared from a single lot of crystal bar.
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
TABLE I. OXYGEN, NITROGEN,AND CARBON ANALYSES Actual Compositionb, % Specimen" Oxygen Nitrogen Carbon 0.011 0.170 0.263 Zirconium arc-melted 0.007 0.000 0.416 Zirconium' cold-rolled 0.006 0.000 0.289 Zirconium' cold-rolled 0.008 0.022 0.286 Zirconium: 0.1% oxygen 0.014 0.000 a . 660 Zirconium, 0.3% oxygen 0.062 0.044 0.123 Zircon/um, 0.05% nitrogen 0.219 0.000 0.371 Zirconpm, 0.28% nitrogen 0.009 0.000 0.122 Zirconium. 0.1% carbon 0.009 0.077 0.234 Zirconium; 0.3% carbon 0,022 0.071 0.000 Standard zirconiumc 0.053 0.006 Titanium by DeBoer process 0.283 0.012 Titanium: by magnesium reduction a Intended composition or physical tieatment. b Determined by analysis. All other zirconium specimens contained 0 Contained 2 to 3% hafnium. less than 0.1% hafnium.
Specimens were prepared directly from crystal bar which had been cold-rolled, unsheathed. Sheathed zirconium alloy samples were rolled a t 400' C. Magnesium-reduced titanium, su plied by Remington Arms Co., was melted in a graphite crucibE, by high frequency heating in an argon atmos here, then hot- and cold-rolled into 0.025inch sheet, and finajfSyannealed a t 1300' F. A sample of titanium crystal bar, manufactured by New Jersey Zinc Co. using the DeBoer process, was vacuum arc-melted under purified argon in a water-cooled copper crucible and coldrolled to a 0.025-inch sheet. Since preparation of samples entirely free of oxygen, nitrogen, and carbon was not practical, tests were made on Sam les of metal to which additional amounts of these elements had t e e n added. Alloys were prepared by adding master alloys of oxygen or nitrogen and zirconium or lampblack to the zirconium melt. Actual composition of the alloys thereby obtained were determined by chemical analyses. APPARATUS AND PROCEDURE. The apparatus consisted of 250ml. Erlenmeyer flasks partially immersed in a constant temperature water bath maintained at a temperature of 35" f 1" C. All specimens were supported in these flasks by a hooked glass rod held in position by a stopper of inert material. Preparation of samples consisted of milling 0.025-inch sheet to 1-inch squares, drilling a a/a2-inchhole for support, numbering with a scriber, surfacing with crocus cloth, degreasing with pumice powder, rinsing in distilled water, washing in 50% alcohol50% ether solution, drying under vacuum, and weighing to an accuracy of 0.1 mg. Specimens were then immersed completely
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in 175 ml. of corrosive media and were studied for a period of 2 weeks under quiescent conditions. After removal from the corrosive media, specimens were rinsed in distilled water, washed in 50% alcohol-50% ether solution, dried under vacuum, and weighed.
ANALYTICAL DATA. Results of spectrographic analyses of all zirconium samples used in this investigation showed that combined impurities of aluminum, magnesium, iron, titanium, nickel, calcium, and copper totaled less than 0.1% by weight. Spectrographic analysis also indicated that metallic impurities in magnesium-reduced titanium and in titanium produced by the DeBoer process were virtually the same-about 0.12% total. The greater cold ductility of the iodide metal can be attributed to its lower oxide, nitride, and carbon content, Average results of oxygen, nitrogen, and carbon analyses are listed in Table I. Analysis of magnesium-reduced titanium, submitted by Remington Arms Co., indicated carbon content to have been 0.12 to 0.21%. Oxygen and nitrogen contents were estimated to have been from a few hundredths to a few tenths per cent, respectively. CALCULATIONS. Corrosion values in milligrams per square decimeter per day are converted to inches per year by multipIying the former value by the factor 0.001437/d, where d is the density of the metal or alloy. Densities of zirconium and titanium used in the calculations are 6.50 and 4.64 grams per ml., respectively. RESULTS AND DISCUSSION
Corrosion results, summarized in Table 11, are expressed in both milligrams per square decimeter per day and inches per year. With but few exceptions, the results, where applicable, are in close agreement with those previously reported in the literature (f-d), Since there is only a slight variation in corrosion resistance of arc-melted, cold-rolled zirconium when compared to that of zirconium cold-rolled directly from crystal bar, it is concluded that the arc melting of zirconium in an atmosphere of argon does not affect its corrosion resistance. The presence of more than one contaminant in any specimen tends to obscure athe effect of a single contaminant upon the corrosion resistance of the specimen. However, it was felt that sufficient evidence was obtained to indicate the relative effects
TABLE 11. CORROSION RESULTS Solution Sulfuric acid concd. sulfuric acid: 19% Hydrochloric acid coned. Hydrochloric acid: 10% Nitric acid concd. Nitric acid' 10% Sodium hyhroxide 50% Sodium hydroxide' 10% Sodium chloride, Hydrochloric acid-nitric acid, 1:l Hydrochloric acid-sulfuric aci,d, 1:l Sulfuric acid-nitric acid. 1:1 Nitric acid, fuming Ammonia, 29.6%"
Solution Sulfuric acid concd. Sulfuric acid' 10% Hydrochlorid acid concd. Hydrochloric acid: 10% Nitric acid concd. Nitric acid' 10% Sodium hykroxide 5 0 7 Sodium hydroxide: 10% Sodium chloride, 20% Hydrochloric acid-nitric acid, 1:1 Hydrochloric acid-sulfuric acid, 1:l Sulfuric acid-nitric acid, 1:l Nitric acid, fuming Ammonia, 29.6%" a At room temperature.
Low-Hafnium Zirconium ( 0 . 0 5 % Nitrogen)Corrosion Mg./sq. dm./day Inch/year Soluble Gained 0.4 mg. 0.021 94 Gained 0 5 mg. Gained 0 4 mg. Gained 0.2 mg. Gained 0 1 mg. Gained 1 0 mg. Gained 0.8 mg. Slowly attacked 0,000046 0 21 0.16 705 Gained 12 1 mg. 0.000025 0 11
524 1.0 Soluble 0.78 0.83 0.39 0.11
Low-Hafnium Zirconium (0.3% Carbon) Corrosion Mg./sq. dm./day Inchhear Soluble Gained 0.4 mg. 0.24 1069 Gained 0.4 mg. Gained 0.3 mg. Gained 0.1 mg. Gained 0.4 mg. Gained 0.5 mg. Gained 0 . 5 mg. Slowly attacked 0.000016 0.07 0.15 670 Gained 10.3 mg Gained 0.5 mg.
Magnesium-Reduced Titanium Corrosion Mg./sq. Inch/ dm./day year 0.13 0.17 418 0.019 0.00032 60.6 Soluble 0.0095 0,00025 30.7 0.00019 0,00026 0.61 0,000034 0,00012 0.11 0.000035 No change 0.33 0.00011 0.28 0,000086 0.74 0,00024 0.025 78 11 0.0035 0.18 0.000056 0.11 0.000025
Low-Hafnium Zirconium (0.2870 Nitrogen) Corrosion Mg./sq. Inch/ dm./day year Soluble 0 000036 0.17 1339 0.3 0 000097 0.44 0.055 0 000012 No change 0.28 0 000061 Gained 0.6 mg. Gained 0.5 mg. Slowly attacked Gained 1 . 9 mg. 0 010 45,2 Gained 5 6 mg. Gained 0.2 mg.
Standard-Hafnium Ziroonium Corrosion Mg./sq. dm./day Inch/year Soluble 0.5 0.00011 107 0.024 0.28 0.000061 11 0.0025 0 22 0.00006 0 44 0.0001 0 22 0.00005 0 11 0.000025 Slowly attacked 0.22 0.00005 1113 0.25 Gained 59.7 mg. Gained 0 4 nig.
Soluble Gained 0 1 mg. 83 0 017 0 056 0 000013 0 22 0.00005 Gained 0 2 mg. 0 11 0 000025 No change Gained 0 1 mg Slowly attacked 0 99 0 00022 554 0 12 Gained 3 9 mg. 0 39 0.00009
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of increasing the amounts of various contaminants. For these reasons, although no definite numerical relationship between concentration of contaminant and its effect upon corrosion rate was established, it was concluded that addition of small amounts of oxygen, nitrogen, or carbon to zirconium results in only slight lowering of the corrosion resistance of the metal to most media. In the case of hydrochloric acid, however, the effect was quite pronounced. In general, increasing the concentration of the alloying element in zirconium results in a lowering of the corrosion resistance of alloy to the common chemical reagents studied. Nitrogen increases susceptibility of zirconium to corrosion more than equal amounts of oxygen or carbon. Since some segregation was present, especially in the carbon alloys, comparisons of corrosion rates were made on basis of nominal, rather than analytically determined, compositions. Standard zirconium, containing 2 to 3% hafnium, was found to be less resistant to chemical attack a t 35' C. than low-hafnium zirconium, containing less than 0.1% hafnium. Zirconium and its alloys appeared to be resistant to attack by both 10% sulfuric acid solution and 10% hydrochloric acid, but were readily dissolved by concentrated sulfuric acid. As reported by Taylor ( 4 ) , zirconium was found to be superior to titanium in its corrosion resistance. This superiority was particularly noticeable in hydrochloric acid solutions. An outstanding property of zirconium metal, as determined in this investigation, is its resistance to attack by fuming nitric acid. In most cases a slight gain of weight of samples was noted when zirconium and its alloys were treated with fuming nitric acid. This gain in weight was always accompanied by a pronounced blackening of the surface, probably caused by formation of a thin film of zirconium oxides. Samples of zirconium, autogenously welded in an atmosphere of argon, also were equally resistant to action of fuming nitric acid. Zirconium and its alloys were also resistant to both dilute and concentrated nitric acids. A 1 to 1 hydrochloric acid-nitric acid mixture and a 1 to 1 sulfuric acid-nitric acid mixture appeared to attack zirconium
Vol. 43, No. 12
and its alloys, although somewhat slowly in some instances. However, the 1 to 1 hydrochloric acid-sulfuric acid mixture caused only slight corrosion. SUMMARY
Chemical corrosion resistance of single specimens of zirconium metal, zirconium alloys, and titanium metal were studied. Where applicable, results obtained are in agreement with those previously reported. Vacuum-arc melting of zirconium metal prior to cold rolling does not materially affect its corrosion resistance, Standard grade zirconium, usually containing about 2.5% hafnium, is less resistant to corrosion than low-hafnium zirconium. Corrosion resistance of zirconium is slightly superior to that of titanium in most media and quite superior in dilute sulfuric acid and in both dilute and concentrated hydrochloric acid. Addition of small percentages of oxygen, nitrogen, and carbon results in a slight decrease in corrosion resistance of lowhafnium zirconium, with the effect being most pronounced in concentrated hydrochloric acid solutions. With the exception of concentrated hydrochloric acid solutions, these zirconium alloys will be acceptable as materials of construction in all media in which zirconium sheet itself is acceptable. Nitrogen alloys of zirconium are less resistant than either carbon or oxygen alloys. In general, increasing the concentration of the alloying material results in a decrease in the corrosion resistance of the alloy. Zirconium and its alloys showed excellent resistance to fuming nitric acid, indicating possible new commercial applications. Zirconium, autogenouslr welded in argon, was equal to zirconium sheet in corrosion resistance. LITERATURE CITED
(1) Gee, E. A , Golden, L. B., and Lusby, W. E., Jr., IND.ENQ. CHEW,41, 1668 (1949). (2) Jaffee, R. I., J . Metals, 1, No. 7, 6 (1949). (3) Muterials & Methods, 32, No. 4, 63 (1950). (4) Taylor, Donald F., J . Metals, 42, 639 (1950). RECEIVED March 14, 1951.
Catalytic Air Oxidation of Aromatics to Phthalic Anhydride J
CORLISS R. IiINNEY AND IRVIKG PINCUS' The Pennsylvania State College, State College, Pa. T h e increased demand for phthalic anhydride in recent years has induced manufacturers to look for additional sources of raw material from which it may be made. For this reason, the possibilities of producing this substance by the catalytic air oxidation of certain higher aromatics and coal tar fractions have been surveyed. From a 200' to 235' C. crude coal tar fraction, 759%yields of high quality phthalic anhydride were produced using a silica-based vanadium pentoxide catalyst. Pure methylnaphthalenes and a methylnaphthalene coal tar cut (235' to 270" C.) gave 28 to 40% yields, apparently free from methyl derivatives. Using an alumina-based catalyst, anthracene and phenanthrene yielded close to 50 and 35%, respectively. A sample of "anthracene salts" gave 24%. 1
Present address, Great Lakes Carbon Corp., Morton Grove, Ill.
Although yields are not so high as with pure naphthalene, phthalic anhydride of satisfactory quality can be produced from other raw material.
T
HE rapidly expanding demand for phthalicanhydride makes desirable increasing supplies of raw material from which it may be manufactured. Production from naphthalene is limited by the availability of this hydrocarbon from tar distillation and, to augment this supply, production from o-xylene obtained from petroleum has recently begun (6). Since patent claims have been made that phthalic anhydride appears in the products of the catalytic air oxidation of methylnaphthalene and phenanthrene ( d ) , a survey of the possibilities of producing phthalic anhydride from certain higher aromatics and coal tar fractions has been made. A list of substances and fractions oxidized appears in Table I. The materials were selected primarily on the basis of
