1
an (WECUnit Processes Review
Thermal and Cata Decomposition of Hy rocarbons by A. J. deRosset and C. V. Berger, Universal Oil Products Co., Des Plaines, Ill. Naphthalene from the hydrodealkylation of petroleum stocks reaches commercial market
XE
MOST SIGNIFICANT industrial development has been the commercialization of hydrodealkylation of alkyl aromatics to produce benzene and naphthalene. Several processes have been announced, and one, Hydeal, is in commercial operation i n several locations for the production of benzene and naphthalene. This technique provides a new source of these basic aromatics i n high purity for the growing petrochemical industry. T h e hydrocracking a r t continues to be active for the production of motor fuels as well. Low methane yield in this process was exemplified by the "paring" reaction of hexamethylbenzene, which yielded Cq to Cg isoparaffins on catalytic hydrogenolysis. T h e California Institute of Technology ballistic piston was applied for the first time to hydrocarbon research and decomposed hexane a t pressures u p to 115,000 p.s.i.g. Significant review articles appearing during the period covered (approximately April 1960 through February 1961) included a summary of patent literature ( 9 A ) .
Thermal Decomposition
Industrial. Hydrogenated thermal tar has been shown to be a suitable hydrogen donor in the thermal hydrocracking of crude residua ( 7 4 A ) . It is claimed that such stocks are more effective than Tetralin, per unit of available hydrogen, in the case of hydrogen transfer to the acceptor. These donors were as equally effective as Tetralin in inhibiting gas and coke formation. T h e complete decomposition of paraffins and naphthenes over fluidized coke in the presence of hydrogen results mainly in the formation of light gases, although some aromatics are formed (78A). Partial conversion of the parent hydrocarbon, such as cyclohexane, also shows significant yields of intermediates, such as rnethylcyclopentane. 680
Continuous hydrocracking of crude oil in the absence of catalysts results in substantial production of light paraffins and lower boiling aromatics (23A). At the most severe conditions of residence time, pressure, and temperature, the gaseous products are rich in methane and the liquid rich i n benzene. Economic factors in the choice of feed stock for the production of acetylene by partial oxidation were considered ( 75A). I t is contended that although lighter feed stocks (methane) are cheaper than heavier feeds (propane) on a n equivalent acetylene basis, oxygen consumption and plant costs work i n reverse and must be taken into consideration. A redesigned fluid coking unit is said to result in lower construction and operating costs (20A). T h e improvements have resulted from commercial experience. Research. Gas chromatography has revealed a rich pattern of pyrolysis products in some classical thermal decompositions. Nineteen different aromatic compounds were identified from heating acetylene a t 700' C . (7A). Aromatization of 1,3-butadiene a t 550" and 700' C. (8A) yielded 34 species. At the lower temperature these comprised cyclohexenes, cyclohexadienes, and predominatly Cg aromatics. At the higher temperature, aromatization was complete and yielded benzene, toluene, and polycyclics. The postulated intermediate, 4-vinylcyclohexene, gave a pyrolysis pattern similar to that of 1,3-butadiene. T h e thermal decomposition of 1,5-hexadiene (79A) and of 2-methyl-1,5hexadiene ( I 7A) yielded allylic free radicals. T h e former compound gave Cs and Cc cyclo-olefins and benzene with a n activation energy of 31.3 kcal. per mole. This value was suggested by Szwarc in 1949 for the dissociation energy of the central C-C bond in diallyl but rejected as improbably low. Dissociation of the alkadiene yielded 1,5-hexavia diene and 2,5-dimethyl-1,5-hexadiene a scrambling of allyl and P-methallyl radicals. This reaction proved re-
INDUSTRIAL AND ENGINEERING CHEMISTRY
versible. Bromine impurity sensitizcd cyclization of the alkadienes. T h e diacetylene 1,6-heptadiyne supported a n autodecomposition flame when pyrolyzed under oxygen-free conditions. Polymerization is a primary process, followed by craeking of a cyclic intermediate (IOA). Fast flow low pressure pyrolysis experiments on alkylbenzenes and diarylmethanes by Errede (5A) yielded benchscale quantities of reactive intermediates and final products. Disappearance of the primary products, benzyl radical and p-xylylene, trapped a t -78" C., could be followed by iodometric titration ( 6 A ) . Products of toluene pyrolysis, a t 970' C., 0.5 mm. of H g pressure, and 2 milliseconds residence time, included benzene and xylene from disproportionation, and a nonvolatile fraction comprising bibcnzyl, diarylmethane, and anthracene. A 14% conversion of p-xylylene a t slightly more severe conditions gave principally p-xylylene polymers, including the cyclo-, di-, tri-, and tetramers together lvith small amounts of diaryl compounds and anthracene. Benzene (26A) heated to 1200' C. in helium for 4 milliseconds gave acetylene and diacetylene. Apparently the primary reaction was ring ruptured to give a n unstable six-carbon chain which immediately dissociated to two- and fourcarbon fragments. Triphenylmethane (72A) was pyrolyzed a t 700 O C.: 3 mm. of Hg, and 0.5-second contact time to yield benzene and hydrogen in a n unexpectedly high 7.5 to 1 ratio. Phenanthrene (7324) gave three icomeric biphenanthrenes and two dibenzylperylenes. The unusual hydrocarbon bicyclo[2,2,2]-2,5,7-octatriene (called "barrel ene" on account of its barrel-shaped electron cloud) thermally decomposcd a t 350' C. to benzene and acetylene ( 3 0 A ) . The relative ease of decomposition suggests that it is not stabilized by electron dislocation energy. X number of authors (2A, ~ ? A :7r1, 2Z4. 27A, 2QA) have investigated the ring
opening of cyclopropane and cyclobutane to test Slater's theory of gaseous unimolecular reactions. Linear hydrocarbon polymers thermally decompose in a random fashion which leads to first-order kinetics. For example, linear polyethylene vaporized a t 400' C. on a spring balance showed a predicted maximum in vaporization rate at 20y0conversion ( 2 8 A ) . Systematic deviation from random theory occurred with increased branching. The thermal degradation of poly-p-xylylene followed first-order random cleavage kinetics with an activation energ) of 58 kcal. per mole (27A). The polymer prepared by pyrolysis of p-xylene decomposed at 335' C. over 10 times faster than one prepared by Hoffmann degradation of p-methylbenzyltrimethylammonium chloride. The shock tube technique was exploited for obtaining information on thermal decomposition a t high temperature and short contact time. Skinner (25A) showed that ethylene, at 0.5% concentration in argon, decomposed to acetylene and hydrogen by a first-order molecular mechanism. The low activation energy of 46 kcal. per mole rules out formation of free radical intermediates. Ethane (24A) decomposed via methyl radicals with an activation energy of 79.3 kcal. per mole. This compares with 83 kcal. calculated for C-C bond dissociation energy in ethane from Errede's (4A) correlation and with 86 kcal. reported in this review last year. The theoretical possibility of duplicating the conditions of the shock tube on a continuous basis was investigated by Miller (77A), who concluded that energy transfer requirements were prohibitively high. A new technique applied for the first time to thermal decomposition of hydrocarbons was the ballistic piston a t the California Institute of Technology (76A), with which n-hexane was decomposed a t pressures up to 115,000 p.s.i.g. The most striking effect was the low activation energy, 8.4 kcal. per mole, observed.
Catalytic Cracking Industrial. A hydrogenation technique, called the H-Oil process, in which an ebullient bed of catalyst is employed, has been developed. Application of the process to desulfurization (6B) as well as to the hydrocracking of residua ( 7 8 ) was disclosed. The catalyst is suspended in an expanded volume in liquid oil by means of process hydrogen fed up-flow through the reactor. The upward passage of liquid serves also to create turbulence. Recycle of liquid product is employed to control temperature rise. I t is claimed that the advantages of the process include effective temperature control, efficient reactor volume utilization, and low catalyst consumption rates.
For handling heavy stocks, the reactor section is divided into two separate series cracking zones containing catalyst, in each of which a separate internal recycle is employed to improve catalyst utilization. I t is anticipated that the API gravity of the product would be from 15 to 20 units lighter than the charge. A conversion of GO to 80% below the initial boiling point of the feed is normally expected. Operation on de-asphalted gas oils was also discussed. The reactions of some classes of hydrocarbons in the Isocracking process result in some unusual products (33B). For example, C ~ to O C I methylbenzenes ~ dealkylate predominantly to Ce and C9 aromatics, but without the formation of methane. Most of the dealkylated fragments appear as Ca, C4, and CS paraffins. I n an analogous fashion, CII to C14 monocyclic naphthenes (CS and C8 ring) are reduced in molecular weight to Cs and Cs, again with the formation of Cd and Cb fragments. Unlike aromatics, however, C3 is only a minor product; and furthermore, the ratio of is0 to normal in the C4 and CS fragments is much higher than in the case of the aromatics. Naphthalenes undergo half hydrogenation to Tetralins which open up in the saturate ring to alkylbenzenes. These may, in turn, dealkylate. The economic aspects of this process have been covered in a separate article (34B). European practice in the hydrocracking of asphaltic crudes has been described (40B). The hydrocracking step employs a paste catalyst, a brown coal semicoke impregnated with FeS04 and NaOH. After a partial condensation of heavy residua, desulfurization of the vaporized cracked product is effected. I n a typical example it is reported that a crude having a gravity of 0.947 and containing 3.2% sulfur and 14.3y0 Conradson carbon is convertible to 75% gasoline and light gas oil when consuming only 1.9% hydrogen. Statistical distributions of various properties of equilibrium cracking catalysts frdm commercial fluid catalytic cracking units have been reported (3B, 44B). The surface area and activity appear to follow the normal distribution law, while the concentration of the contaminants follows a log-normal distribution. Curves are presented which summarize the data conveniently. The merits and the problems of various catalyst compositions have also received attention (29B). Crocoll and Jaquay ( 7 7 4 72B) considered both the chemical and physical aspects as well as the mechanical factors that contribute to rate of catalytic cracking and product distribution. The presentation is a concise summing up of knowledge on the subject. Comparable articles (228, 23B) on the mechanical design of moving bed catalytic cracking units have also appeared. Useful material on the effect
of feed stock composition (35B) and also on mechanical design (5B) has also been published. Several articles describing the advantages in product quality and the economic consequences of hydrodesulfurizing of catalytic cracking feed stocks have appeared (24B, 36B, 42B). Research. A novel reaction called "paring" (37B) occurs when hexamethylbenzene is hydrocracked. The methyl groups build up side chains of four carbon atoms or longer by a ring expansion and contraction mechanism. Hydrocracked products are C4 to C8 isoparaffins and the stripped rings. Naphthenic carbonium ions are less favored as possible intermediates than dienyl carbonium ions, since naphthenes were not prominent in the product. Hydrogenolysis of tetramethylcyclopentane over platinum-alumina at 350' C. broke the ring to give a spectrum of isoparaffins
(78B). A novel application of an old reaction was the hydrogenolysis of high boiling polyphenyls to give diphenyl (43B). Object was to reclaim nuclear reactor coolant, polymerized under influence of heat and radiation. Methane cracked catalytically over alumina, as shown by the drop in activation energy from 87 kcal. per mole for the thermal reaction to 68 kcal. per mole (7SB). Over molybdenum films, methane dissociated to hydrogen and adsorbed methylene radicals (SB), Bond (4B) hydrocracked propane and methylcyclopropane over iridium and platinum a t temperatures as low as 15' C. I t is considered that polymerization precedes cracking in carbonium ioncatalyzed decomposition of hydrocarbons and that this is the route of coke formation. Tertiary paraffins (32B) are most vulnerable to degradation in acid-catalyzed isomerization because of the ease with which they form carbonium ions to react with olefins. Kemball ( 2 7 8 ) , after a careful study of cyclopentene cracking over silica-alumina, concluded that polymerization and rapid rearrangement to a six-member system would account for the C 4 to CI and C3 to C a ratios much greater than unity. Naphthenic, olefinic, and aromatic bicyclics were obtained by Topchiev (38B) by cracking cyclohexene over silica-alumina. The aromatics are probably the principal precursors of coke via dehydrogenation and hydrogen exchange ( 2 0 8 ) . However. aromatic structure affects coke-forming tendency. For example, anthracene was a much worse coke former than phenanthrene and chrysene more so than pyrene (78). Carbon-14 tracer studies with Cp-labelled n-decane (45B) suggested that details of coke-forming mechanism were different at 850' F. than at 950' F., since at the lower temperature relatively little activity was found in the catalyst deposit. '
VOL. 53,
NO. 8
AUGUST 1961
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ank-4
Unit Processes Review
Coke formation is substantially suppressed in hydrocracking, and conversion a t a given temperature is greater. Archibald ( 2 8 ) attributes the first to effective removal of olefins by hydrogenation a n d the latter to a longer residence time a t the higher pressure used and absence of catalyst fouling. Coonradt (?OB) found a considerable variation of catalyst activity and selectivity when the type and amount of hydrogen active promoter were changed. Catalyst fouling involves both acid and hydrogen activity. Pretreatment to remove nitrogen and sulfur improved activity, selectivity, and catalyst life. Decomposition rates of tert-but)-lbenzene (25B) and 2,3-dimethylbutane (27B) were used to measure the catalytic activity of a variety of commercial cracking catalysts. In both reactions, the activation energy was constant, independent of catalytic activity. Differences in activity were reflected in the pre-exponentia1 factor of the Arrhenius rate expression, a quantity associated with the surface area or the number of active sites per gram of catalyst. .4ctivation energy measurements in cumena cracking were cited by Topchieva to support the view that above 450" C. the kinetics enter a regime of diffusion control where catalyst pore size is important (39B). Formic acid decomposition served as another reaction for evaluating cracking catalyst activity (76B). Development of methods for determining the quantity and strength of acidity on catalysts continued (8B, ?3B, 77B, 46B). Cracking activity, which may be due to a very few strong sites, does not always correlate with acidity measurements, nor are these measurements carried out a t cracking temperatures. Nevertheless, they appear to be a significant property of the catalyst. Optical spectra of molecules adsorbed on cracking. catalyst affords a clue to the nature of the adsorbing sites (28B, 30B, 37B). The "boron n u m b x , " obtained by measurement of isotopically exchangable boron in the catalyst after treatment with diborane, is considered a measure of the number of hydroxyls in silicaalumina which are attached to aluminum (47B). Kovel composites exhibiting cracking activity included Be-Ti, Si-Ga, Si-Th, and Ge-AI (74B). High surface area Alp04 gels were made by treating a solution of AlC1, and HsP04 with liquid ethylene oxide (26B). T h e pure gel and its composite with 11yo silica were considerably more active than commercial cracking catalyst and gave the same product distribution. Donaldson (75B) found high-alumina synthetic catalyst to withstand vanadium poisoning better than low alumina catalyst.
682
Catalytic Reforming
cyclopentane (4C) and substituted cyclopentanes from cyclo-octane via the 1-5 bridged intermediate (5C).
A yield octane number correlation for platinum catalyst reforming has appeared (6C). The correlation allows Literature Cited prediction of the yield of debutanized gasoline for a given octane number, Thermal Decomposition leaded or clear, when feed properties are (1A) Badger, G. M., Lewis, G. E., Napier, I. M.: J . Chem. Soc. 1960, p. 2825. defined. Feed stock properties consid(2.4) Butler, J. N., Kistiakowsky, G. B., ered significant were research octane J . Am. Chem. Soc. 82, 759 (1960). number and mid-boiling point. I t is (3A) Chesick, J. P., Zbid., 82, 3277 (1960), claimed that the accuracy of the correla(44) Errede, L. 4.,J . Phys. Chem. 64, 1031 (1960). tion is within "2 clear octane numbers. (5-4) Errede, L. .4., Cassidy, J. P., J. T h e factors to be considered i n maxiAm. Chem. Sac. 82,3653 (1960). mizing aromatic production from plati(6A) Errede, L. -4.> Cassidy, J. P., J. num reforming (77C) and in removal of Org. Chem. 24,1890 (1959). (7A) Flowers, M. C., Frey, H. M., J . feed contaminants have been published Chem. Soc. 1960, p. 2758. (7C). An excellent discussion of plati(8.4) Gil-Av, E., J . Chem. Eng. Data 5 , num reforming catalysts was given by 98 (1960). Connor (3C). (9A) Heinemann, H., Lefrancois, P. A., World Petrol. 31, No. 8, 76 (1960). The alumina support contributes (10A) Henderson, U. V., J. Pliys. Chem. acidity to the dual functioning platinum, 65,309 (1961). chromia, and molybclena reforming (11A) Huntsman, W. D., J. Am. Chem. catalysts. Pines and his students (7CSac. 82,6389 (1960). (12A) Janz, G. J., DeCrescente, M. A., 9C) evaluated the acidity of aluminas by a J . Phys. Chem. 64,829 (1960). series of test reactions, principally the (13A) Lang, K. F., Bufflieb, H., Kalowy, isomerization of cyclic and branched J., Ber. 93,303 (1960). olefins. Aluminas precipitated from (14A) Langer, A. W., Stewart. J., othrrs, IND.ENG.CIICM. 53,27 (1961). aluminate solutions failed to promote (15A) Lockwood, D. C., Petrol. RGner these isomerizations and ivere classed as 39, No. 11,223 (1960). basic. Aluminas precipitated from the (16A) Longwell, P. A., Sage, B. H., nitrate or derived from aluminum isoJ . Cliem. Eng. Data 5, 322 (1960). (17A) Miller, I . , F., Uniu. Microjilms propoxide were effective and \\-ere (Ann Arbor, Mich.) L. C. No. Mic-60classed as acidic. Impregnation of acidic 2594; Dissertation Abstr. 21, 325 (1960). alumina with N a O H reduced the total (18.4) Owens, P. J . , Long, R., Garner, number of acid sites without affecting the F. H., I N D . ENG.CHEM. 53, 10 (1961). (19A) Ruzicka, D. J.: Can. J . Chem. 38, distribution of acid strengths. Impreg(20A) 827 (1960). Saxton, A. L., Wcinberg, H. N., nation with NaCl poisoned the strong sites selectively and changed the distribuWright, R. O., Petrol. Rejiner 39, No. tion as well as the number of sites. 5, 157 (1960). (21.4) Schaefgen, J. R., J . Polymer Sci. Molybdena impregnated on acidic and (22A) 41,133 Schlag, (1959). E. W., Rabinovitch, B. S., basic aluminas was used to aromatize n-octane. Ratio of xylene isomers proJ . Am. Chem. Sac. 82, 5996 (1960). duced tended toward the theoretical (23.4) Schultz, E. B., Jr., Mechales, N., Linden, H. R . , 1x0. ENG. CHEW52, equilibrium as acidity of the base in580 (1960). creased. Labelled 1,2-dimethyl-lG I 4 (24A) Skinner, G. B., Ball, W. E., J . cyclohexane aromatized over a catalyst Phys. Chem. 64,1025 (1960). of moderate acidity gave xylenes with (25A) Skinner, G. B., Sokolski, E. M., Zbid., 64, 1028 (1960). the preponderance of activity in the side (26A) Slysh, R . S.: Um'c~. Microjlms chain. (Ann Arbor, Mich.) L. C. No. MicAromatization of 1,l-dimethylcyclo60-2174; Dissertation Abstr. 21, 144 (1960). hexane involves either removal of a gem(27A) Thiele, E., M'ilson, D. W., J . Phys. methyl group to give toluene or its transClzem. 64,473 (1960). (2S.A) Wall; L. A,, Straus, S., J . Poiym~r fer to another position on the ring, in Sci.44, 313 (1960). which case xylenes are made. Chromia (29A) Wibery, K. B., Bartley, W. J., on basic alumina favored the first course J . Am. Chem. Soc. 82,6375 (1960). exclusively, while on a n acid support it (30A) Zimmerman, H. E., Paufler, K. M., Zbid.; 82, 1515 (1960). gave a preponderance of xylenes. Labelled 2,2-dimethy1-4-methyl-Cl4Catalytic Cracking pentane was dehydrocyclized by Can(1B) Appleby, W. G., Gibson, J. W., nings (2C)over chromia-alumina to make Good, G. M., Division of Petroleum a mechanistic study of the reaction. Chcmistry, 138th Meeting, ACS, New York, September 1960. Chromia-alumina (70C) catalyzed for(2B) Archibald, R. C.: Greensfelder, B. S., mation of phenanthrene in 80% yield others, IND.E N G . CHEM. 52, 745 (1960). from /3-butylnaphthalene. (3B) Blazek, J. J., Macke, F. H., PetroT h e low temperature (300" C.) platichem. Engr. 32,No. 13, C-30 (1960). (4B) Bond, G. C., Newham, J., Trans. num-charcoal-catalyzed Ce cyclization Faraday Soc. 56,1501 (1960). reaction, currently under investigation (5B) Chatman, W. C., Wei Chen, C., by Soviet researchers, yielded the biAtkins, G. T., Petrochem. Engr. 32, cyclic compound pentalane from propylNo. 12, C-37 (1960).
INDUSTRIAL AND ENGINEERING CHEMISTRY
(6B) Chervenak, M . C., Johanson, E. S., others, OilGasJ. 58,No. 35, 80 (1960). (7BI Chervenak. M . C.. Johnson. C. A.. ' &human, S. 'C., Petrh. ReJiner '39, No: 10,151 (1960). (8B) Clark, R . O., Anal. Chim. Acfa 23, 189 (1960). (9B) Coekeibergs, R., Decot, J., others, 2nd Intl. Congr. on Catalysis, Paris, July 1960. (10B) Coonradt, H. L., Ciapetta, F. G., others, Division of Petroleum Chemistry, 138th Meeting, ACS, New York, September 1960. (11B) Crocoll, J. F., Jaquay, R. D., Petrochem. Engr. 32,No. 12, C-24 (1960). (12B Zbid., No. 13, C-26. (13B] D anforth, J. D., 2nd Intl. Congr. on Catalysis, Paris, July 1960. (14B) Danforth, J. D., Meents, M., Scott, F., Division of Petroleum Chemistry, 138th Meeting, ACS, New York, September 1960. (15B) Donaldson, R . E., Rice, T., Murphy, J. R., Zbid. (16B) Fisher, J. B., Sebba, F., 2nd Intl. Congr. on Catalysis, Paris, July 1960. (17B) Fripiat, J. J., Vancompernolle, G., Servais, A., Bull. SOC. chim. France 1960, p. 250. (18B) Gault, F. G., Germain; J. E., 2nd Intl. Congr. on Catalysis, Paris, July -1960. (19B) Germain, E., Fremaux, J., Ponsolle, L., Bull. soc. chim. France 1959, p. 1371. (20B) Gladrow, E. M., Kimberlin, C. N., Division of Petroleum Chemistry, 138th Meeting, ACS, New York, September 1960. (21B) Hall, W. K., Maclvcr, D. S., Weber. H. P., IND.ENG.CHEM.52,421 (1960).
(22B) Hoge, A. W., Ashwill, R. E., White, E. A,, Petrochem. Engr. 32, NO. 12,
j24B z ? Horne, B ~ ~W.~13,.A., C-32. ~ dMcKinney, ~.
J. D., Rice, T., Zbid., 32,No. 5, C-19 (1960). (25B) Johnson, M. F. L., Melik, J. S., Division of Petroleum Chemistry, 138th Meeting, ACS, New York, September 1960. (26B) Kearby, K., 2nd Intl. Congr. on Catalysis, Paris, July 1960. (27B) Kemball, C., Rooney, J. J., Proc. Royal Soc. (London) A257,132 (1960). (28B) Leftin, H. P., Hall, W. K., J . Phys. Chem. 64,383 (1960). (29B) Loper, B. H., DeBaun, R. M., Pettochem. Engr. 32; No. 13, C-20 (1960). (30B) Nicholson, D. E., Nature 186, 630 (1960). (31B) O'Kuda, M., Tachibana, T., Bull. Chem. SOC.Jafian 33,863 (1960). (32B) Schriescheim, A., Khoobiar, S. H., 2nd Intl. Congr. on Catalysis, Paris, July 1960. (33B) Scott, J. W., Mason, H. F., Kozlowski, R. H., Petrol. Refiner 39, No. 4, 155 (1960). (34B) Scott, J. W., Robbers, J. A., others, Petrol. Rejner 39,No. 5, 161 (1960). (35B) Service, W. J., Petrochem. Engr. 32, NO.12, (2-31 1960). (36B) Slyngstad, E., Lempert, F. L., m.,32, NO. 5, c - i 3 (1960). (37B) Sullivan, R. F., Egan, C. J., others, J . Am. Chem. Sod. 83,1156 (1961). (38B) Topchiev, A. V., Mamedaliev, G. M., others, Izvest. Akad. Nauk S.S.S.R. Odtel. Khim. Y Q U 1960, ~ p. 1084. (39B) Topchieva, K. U., Antipina, T. V., Shien, L. H., 2nd Intl. Congr. on Catalysis, Paris, July 1960.
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a I N THE WORKS
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(40B) Varga, J., Karolyi, J., others, Petrol. ReJner 39, No. 4, 182 (1960). (41B) Weiss, H. G., J . Am. Chem. SOG. 82,1262 (1960). (42B) Williams, C. C., Abbott, M. D., Petrochem. Engr. 32, No. 5, C-25 (1960). (43B) Wineman, R . J., Scola, C. A., Division of Petroleum Chemistry, 138th Meeting, ACS, New York, September 44B) World Petrol. 32, No. 2, 45 (1961). 45B) Wynnemer, D. * J., Division of Petroleum Chemistry, 138th Meeting, ACS, New York, September 1960. (46B) Zettlemoyer, A. C., Chessick, J. J., J . Phys. Chem. 64 1131 (1960). Catalytic Reforming (1C) -Blue, E. M.; Spurlock, B., Chem. Eng. Progr. 56, No. 4, 54 (1960). (2C) Cannings, F. R., Fisher, A., others, Chem. &? Znd. (London) 1960, p. 228. (3C) Connor, H., Zbid., 1960, p. 1454. (4C) Kazanski, B. A., Liberman, I. M.. others, Dokladv Akad. Nauk S.S.S.R. 133,364 (1960): (5C) Kazanski, B. A., Shokova, S. I., others, Zbid., 133, 1090 (1960). (6C Nelson, W. L., Oil Gas J . 59, No. 7, 84 (19611. (7C) Pine;, H., Benoy, G., J . Am. Chem. Sod. 82,2483 (1960). (8C) Pines, H., Chen, C., Ibid., 82, 3562 (1960). --, (9C) Piries, H., Haag, W. O., Zbid., 82, 2471 (1960). (1OC) Shuikin, N. I., Erivanskaya, L. A.3 'QUk Yang, A. H., Doklady Akad. S.S.S.R. 133,1125 (1960). (11C) Stewart, L. D., Lush, R . A*, Miller, J. H., Oil Gas J . 59, NO. 6, 110 (1961). \ - -
2%
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Manuscripts Accepted for Publication within the Next Three Issues of IIEC
Continuous Pilot Plant for the Manufacture of Phosphoric Acid
Pentane and Hexane Isomerization
D. W.
Leyshon and W . A. Lutz Dorr-Oliver, Inc., Stamford, Conn.
J. A. Rabo, P. E. Pickert, and R. 1. Mays Linde Ca., Tonawanda, N. Y.
Performance of low-grade phosphate rock can be tested in this facility. Data for design of commercial plants can be obtained
A new catalyst, palladium metal on a modified zeolite support, is used for isomerization in an intermediate temperature range. Yields are comparatively high, and feed pretreating costs relatively low
Pilot-Plant Production of Highly Concentrated Wet-Process Phosphoric Acid
W. C. Scott, G. G. Patterson, and H. W . Elder Tennessee Valley Authority, Wilson Dam, Ala.
A direct-fired unit concentrated merchant-grade acid to over 70% PsOs, part of which was i n the polyphosphate form. Product acid compared well with electric-furnace acid Direct-Fired Evaporators for Wet Process Phosphoric Acid W. 1. Weisman, Ozark-Mahoning Co., Tulsa, Okla.
I n many cases, direct-fired evaporators are the best choice of concentration equipment. Problems i n materials of construction of submerged combustion burners have recently been solved. Several satisfactory fume scrubbers are now available
Hydrocracking with Platinum-Acidic Oxide Catalysts
H. 1. Coonradt, F. G. Ciapetta, W . E. Garwood, W . and J. N. Miale Sacony Mobile Oil Co., Inc., Paulsboro,
K.
Leaman,
N. J.
A dual-functional hydrocracking catalyst, platinum on a solid mixed
oxide of high acidity, gives very high activity and selectivity. Both acidity and hydrogenation functions of the catalyst are described Metals Poison Cracklng Catalysts
R. E. Donaldson, T. Rice, and J. R. Murphy Gulf Research and Development Co., Pittsburgh, Pa.
Poisoning by vanadium and nickel was tested under conditions similar to commercial fluid cracking operations Knudsen Flow Diffusion in Porous Pellets
Catalyzed Combustion of Hydrocarbon Vapors at low Concentrations J. E. Johnson, J. G. Christian, and H. W. Carhart U. S. Naval Research Laboratory, Washington, D. C.
Hopcalite is an effective catalyst for certain hydrocarbon vapors i n the concentration range found i n air pollution. The effect of temperature on the reaction is reported
R. H. Villet and R. H. Wilhelm Princeton University, Princeton, N. J.
An experimental technique measures effective diffusion constants i n porous pellets. Equipment is sturdy, and method rapid. Statistical analysis is applied to diffusion of nitrogen and hydrogen through silicaalumina catalyst beads VOL. 53. NO. 8
AUGUST 1961
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