Ind. Eng. Chem. Res. 1991,30, 2133-2137 Voogd, P.; Scholten, J. J. F.; Van Bekkum, H. Use of the t-Plot-De Boer Method in Pore Volume Determinations of ZSM-5 type Zeolites. Colloids Surf. 1991,55, 163-171. Yamagishi, K.; Namba, S.;Yashima, T. Preparation and Acidic Properties of Aluminated ZSM-5 Zeolites. J. Catal. 1990, 121, 47-55. Yaehima, T.; Yamagishi, K.; Namba, S.; Nakata, S.; Asaoka, S.
2133
Alumination of ZSM-5 Type Zeolite with AlC&. In Innovation in Zeolite Materials Science; Grobet, P. J., Mortier, W.J., Vansant, E. F., Schulz-Ekloff, G., Eds.; Elsevier: Amsterdam, 1987; pp
175-182.
Received for review October 12, 1990 Accepted May 13, 1991
Hydrotreatment of Irati Shale Oil: Behavior of the Aromatic Fraction Julio C. Afonso and Martin Schmal* Federal University of Rio de Janeiro, COPPEIEQIUFRJ, C.P. 68502, 21945 Rio de Janeiro, Brazil
Jari N. Cardoso Institute of ChemistrylUFRJ, Centro de Tecnologia, bloco A, sala A-603, 21910 Rio de Janeiro, Brazil
Roger Frety Znstitut de Recherche5 sur la Catalyse, CNRS, 2, Avenue Albert Einstein, 69626 Villeurbanne Cedex, France
This work presents the chemical transformations that occur in the aromatic fraction of Irati shale oil under rather drastic hydrotreating conditions, at 400 "C and 125 atm, using a commercial Ni-Mo/A1203 catalyst in sulfided form. The aromatic fraction was analyzed before and after reaction by gas chromatography/mass spectrometry. Several compounds were identified by using this method. The main reactions are the partial hydrogenation of the aromatic rings forming hydroaromatic compounds and the cracking of the lateral alkyl chains. Hydrotreatment leads to a more complex aromatic fraction due to the formation of new compounds.
Introduction Natural shale does not contain an appreciable concentration of aromatic hydrocarbons. Nevertheless, during the pyrolysis of shale, they are formed due to several reactions of the kerogen (cracking, condensation, aromatization, cocking, etc. (Loureiro and Costa Neto, 1982)). By increasing the temperature of pyrolysis the aromatization is favored because, under these conditions, the aromatic compounds are thermodynamically more stable than the nonaromaticones (Loureiro and Costa Neto, 1982;Uden, 1981). From the pyrolysis of shale, a great variety of compounds was obtained, from simple benzene to polyaromatics with four or five condensed rings (Uden, 1981; Hertz et al., 1980;Radke and Welte, 1981). Small lateral alkyl chains (methyl or ethyl) attached to aromatic rings were often found. The aromatic fraction of Irati shale oil was already characterized by Loureiro and Costa Neto (1982). The common alkylbenzenes were identified, but many other compounds involving several families of aromatics and hydroaromatics were not fully characterized. Data of literature indicate that under hydrotreating conditions, the conversion of aromatic model compounds (Sapre and Gates, 1981,1982)or shale oil (Harvey et al., 1986)leads to the formation of hydroaromatic compounds because they are thermodynamicallymore stable under these conditions. Miki et al. (1983)have shown that the partial saturation of aromatic hydrocarbons is a catalytic reaction and diminishes carbonization and coking on the catalysts, although it implies a higher hydrogen consumption. Temperature favors the condensation and aromatization reactions with formation of compounds with three or more condensed rings, as well as more complex compounds, which, by deposition, deactivate the catalyst. The alkyl chains are thermally or catalytically cracked (cracking or hydrocracking). The rupture of the saturated ring of hy-
droaromatic compounds, like indans and tetralins, occurs in the presence of a catalyst and under high hydrogen pressure. Although the basic reactions during hydrotreatment of shale oil are the partial saturation and the cracking of lateral alkyl chains, literature data also show (Harvey et al., 1986) the occurrence of other reactions during this process (isomerization, aromatization, cyclization). This fact leads to a very complex behavior of several classes of compounds, which are involved in various reactions, some being formed and others being destroyed. Our objective is to analyze the aromatic fraction of Irati shale oil before and after hydrotreatment in order to identify the main chemical compounds, either destroyed or formed, and the corresponding reactions.
Experimental Section 1. Materials. A commercial Ni-Mo/A1203 catalyst (Shell 324;2.7% NiO, 13.2% MOO,; 157 m2/g;0.48 cm3/g) was used. The oil was derived from pyrolysis of Irati shale (Sao Mateus do Sul,Parana, Petrosix Process); the main properties are: final boiling point, 485 OC; density, 0.95 g/cm3; viscosity, 95 cP; percentage of sulfur and nitrogen, 0.82% and 0.93%, respectively (w/w). 2. Hydrotreatment was performed in a three-phase fluidized-bed reactor. CS2 (1% w/w)was initially added in order to sulfide the catalyst (200"C, 100 atm, 9 h). The reaction conditions were temperature, 400 "C; total pressure, 125 atm; space velocity, 1 h-l; hydrogen/oil ratio, 600/1. After the steady state was reached, samples were collected at regular inte~als,centrifuged to eliminate solid particles, and kept in the dark at low temperature. The experiments were repeated once more, under the same conditions and with a new catalyst. We obtained the same level of conversion and the same product distribution, which was analyzed in terms of residual nitrogen and sulfur contents and hydrocarbon distribution as well as the physical properties of the treated oil (Souza et al., 1985).
0SSS-5SS5/9~/2630-2133$02.50/00 1991 American Chemical Society
2134 Ind. Eng. Chem. Res., Vol. 30, No. 9,1991 Table I. Families of Aromatic and Hydroaromatic Compounds MW from fragmentono. of compounds Brcompound natural oil treated oil 92 toluene 1 1 4 4 106 C2-alkylbenzene I 6 120 C3-alkylbenzene 134 C4-alkylbenzene 9 12 13 7 148-218 C5-C10-alkylbenzene naphthalene 128 1 1 142 methylnaphthalene 2 2 dimethylnaphthalene 156 5 6 C3-alkylnaphthalene 170 8 10 C4-alkylnaphthalene 184 13 13 phenanthrene 178 1 1 192 methylphenanthrene/anthracene 5 5 206 dimethylphenanthrene/anthracene 6 9 220 C3-alkylphenanthrene/anthracene 3 6 234 C4-alkylphenanthrene/anthracene 4 248 C5-alkylphenanthrene/anthracene 1 202 pyrene/fluoranthene 2 216 methylpyrene/ fluoranthene 3 chrysene 228 1 indan 118 1 1 methylindan/tetralin 132 3 5 146 dimethylindan/methyltetralin 7 11 160 C3-alkylindan/dimethyltetralin 5 9 174 C4-alkylindan/C3-alkyltetralin 10 12 188 C5-alkylindan/C4-alkyltetralin 4 6 194 methyldihydrophenanthrene/anthracene 2 4 196 methyltetrahydrophenanthrene/anthracene 3 6 208 dimethyldihydrophenanthrene/anthracene 3 210 dimethyltetrahydrophenanthrene/anthracene I 222 C3-alkyldihydrophenanthrene/anthracene 3 224 C3-alkyltetrahydrophenanthrene/anthracene 3 236 C4-alkyldihydrophenanthrene/anthracene 1 C4-alkyltetrahydrophenanthrene/anthracene 238 2 indene 116 1 1 methylindene 130 4 3 144 dimethylindene 4 C3-alkylindene 158 5
Details of the three-phase fluidized-bed reactor and the apparatus are given elsewhere (Souza et al., 1985,Silva and Schmal, 1989). 3. Separation of the Aromatic Fraction. The shale oil before and after hydrotreatment was fractionated in order to obtain the aromatic fraction. The separation process of McCarthy and Duthie (1962)was employed. The oil sample (1g in 1 mL of CH2C12)was first eluted over a column (25cm X 25 mm) of Si02/KOH (8/1w/w) with ether to eliminate acids, after which it was submitted to a thin-layer-chromatographicseparation @io2;Kiesegel 60-F254,Merck) with n-hexane. Phenanthrene (retention factor (RF)= 0.4)was used as a standard to separate the aromatic fraction (RFbetween 0.35 and 0.45). The whole oil was used for the determination of alkylbenzenes not found in the aromatic fractions. 4. Analysis. The aromatic fractions were analyzed by gas chromatography/mass spectrometry (HewletbPackard GC/MS Model 5987,coupled with an HP-1000 data system). A SE-54 capillary column (25-mi.d., 0.25rm) was used with the following conditions: carrier gas, N2 (60 cm/s); injector temperature, 260 OC; heating rate 4 OC/min (40-280 "C);electron energy, 70 eV. The samples were dissolved in CS2at the same concentration, and the volume injected was 1.0p L with a split ratio 1/20. The resulting spectra were compared to the HP-1000 data system (NBS file, 75000 compounds) and two atlases of spectra of model compounds (Stenhagem et al., 1969; Cornu and Massot, 1975). Injection of standards was made whenever possible (see Table 11). Some papers published previously the fragmentation rules for aromatic compounds (Budzikiewicz et al., 1964;Kinney et al., 1952);others
95 of content, % formation or natural oil treated oil removal 0.81 0.81 30 1.65 0.99 40 4.04 1.90 53 2.25 0.96 57 2.03 0.58 71 0.85 0.72 15 1.03 0.78 25 2.70 1.40 48 2.04 0.71 64 1.02 0.31 69
0.56
1.00
79
0
1.10
m
0.44 3.10 0.47 1.38 2.10 0.58
1.02 5.70 0.61 1.20 1.62 0.40
134 85 30 15 26 31
0.32 (dihydro) 0.28 (tetrahydro)
0.89
176
0.74
122
5.54
0.40
92
published the elution profile sequence of several aromatic hydrocarbons (Loureiro and Coeta Neto, 1982;Radke and Welte, 1981;Radke et ai., 1982). In addition, the boiling point (Weast, 1982)was correlated to the retention time as a tentative for the identification of some compounds.
Results and Discussion 1. Introduction. The data of the simulated distillations (ASTM 1160)of samples taken after 6 h or at the end of the hydroproceseing indicate that the liquid-phase composition did not present any significant alteration. For this reason, only the final sample was analyzed and compared to the natural oil to identify the transformatiom that occurred during hydroprocessing. Table I shows all the families present in the aromatic fraction, before and after hydrotreatment, including the number of isomers and the semiquantitative contents of the compounds (obtained from simple integration of the peak areas of the chromatograms). Benzene was probably lost in the vapor phase. It was impossible to determine the structural characterization of most compounds due to the large number of possible isomers, but the aUtylbenz8nea (C144)and all simple compounds grouped in other families were identified. Table 11presents all the compounds that were characterized. 2. Aromatic Ring Hydrogenation. This is the most characteristic reaction of hydrotreatment due to the presence of a great variety of hydroaromatic compounds after hydroprocessing. Nevertheless, with the exception of the alkylbenzenes, the complete hydrogenation of aromatic compounds to the corresponding cycloalkanes is not observed. 'H NMR data indicate a drop of 40% of the
Ind. Eng. Chem. Res., Vol. 30, No. 9, 1991 2135 Table 11. Identified Compounds in the Aromatic Fractions toluenea* 8ec-butylbenzene'r n-butylbenzene" ethylbenzene's o-xylenebd naphthalene"* m-xylene" 2-methylnaphthalene"" p-xylene" 1-methylnaphthalene"$ propylbenzeneca phenanthrene"* 1,2,3-trimethylbenzeneM 2-methylanthracenebsC 1,2,4-trimethylbenzeneW l-methylphenanthrenebpc 1,3,5-trimethylbenzeneW 2-methylphenanthreneb$ o-isopropyltoluene" 3-methylphenanthreneb* m-isopropyltoluene" 9-methylphenanthreneb$ p-isopropyltoluene" 1-methylindan'df 1-methyl-2-ethylbenzene" 2-methylindan'dJ 1-methyl-3-ethylbenzene" 3-methylindan'd 1-methyl-4-ethylbenzene" 4-methylindan'p 1,3-dimethyl-5-ethylbenzenecd tetralin"* 1,4-dimethyl-2-ethylbenzene'd indana* 1,3-dimethyl-4-ethylbenzenecd indenec 1,2-dimethyl-4-ethylbenzenecd pyreneCJ 1,2-dimethyl-3-ethylbenzenecd fluoranthenecf 1,3-dimethyl-2-ethylbenzenecgd chryseneCJ o-propyltoluenecJ
Winw
indam
3.6
4.0
4.4
4.6 i2
5:s i o
6.4
6.6 f.2 Retention Tinwfminl
Ibl
In)naity au 1200
600-
3.2
3.6
4.0
4.4
4.0
5.2 5.6
6.0
6.4
66 7.2 R o t n t h Tiinelmint
Figure 1. Mass fragmentogram (m/z 174) of C4-alkylindans and C3-alkyltetralins in the aromatic fraction of natural oil (a) and treated oil (b).
Identified through authentic standard. Identified in comparison with literature data (Loureiro and Costa Neto, 1982; Radke and Welte, 1981; Radke et al., 1982). CIdentifiedby mass spectral interpretation. Identified by boiling point-retention time correlation and/or calculation of the total number of possible isomers. eIdentified only in the fraction of natural oil. 'Identified only in the fraction of treated oil. Table 111. Alkylcyclohexanes and Alkylbenzenes in the Irati Shale Oil content, W compound natural oil treated oil alkylbenzenes 10.84 5.24 alkylcyclohexanes 1.66 7.06 total 12.50 12.30
proton attached to the aromatic ring, confirming the partial hydrogenation of aromatic rings. The higher stability of the hydroaromatic compounds, as compared to the corresponding cycloalkanes, is in good agreement with data in the literature (Sapre and Gates, 1981,1982; Harvey et al., 1986). One of these reactions is the hydrogenation of alkylbenzenes to alkylcyclohexanes. The results are presented in Table 111. Noteworthy is the increase of the number of alkylcyclohexanesafter hydrotreatment. In the natural oil, only the methyl and two dimethylcyclohexanes are detected whereas in the treated oil, the amounts of methyl-, dimethyl-, and C3-alkylcyclohexanes (trimethyl and methylethyl) are improved. Measurable amounts of ethyl-, n-propyl-, and C4-alkylcyclohexanes (dimethylethyl, tetramethyl, and methylisopropyl) are also observed. In some alkylcyclohexanes (dimethyl and trimethyl) both cis and trans isomers are formed, which is usual in this reaction (Burwell, 1969). Figure 1shows one typical fragmentogram ( m / z 174) of alkylidans and tetralins. In this fragmentogram (as well as in those corresponding to molecular weights 146, 160, and 188)the right-hand side region is enhanced after hydrotreatment with the formation of other peaks representing new products. The boiling point (Weast, 1982)retention time correlation allows estimation that the alkylindans elute before the isomeric alkyltetralins (see Figure 1). Thus, this figure indicates the conversion of alkylnaphthalenes to alkyltetralins. Table I shows not only an important formation of hydroaromatic condensed-three-ringhydrocarbons (dihydro and tetrahydro), but also the formation of new compounds. Consideringthe hydrogenation of the corresponding aro-
Figure 2. Hydrogenation of alkylphenanthrenes(and anthracenes).
matic molecules (see Figure 2), the first step is probably the hydrogenation of the more reactive central ring (Morrison and Boyd, 19731,resulting then in the formation of a dihydroaromatic compound. This is the l,4-hydrogenation type. Nevertheless, as the hydrogenation of a second ring is not observed (formation of an octahydroaromatic compound), the formation of the tetrahydroaromatic compounds could be attributed to the migration of the double bonds to the central ring; the direct hydrogenation of a lateral ring (Lemberton et al., 1989) is also another possibility (Figure 2). 3. Cracking of Lateral Alkyl Chains. This is another important reaction in hydrotreatment. Table I indicates an increase of the elimination of the alkylbenzenes with the increase of the molecular weight and the length of the chain. This suggests cracking of long lateral chains of such compounds with formation of low-molecular homologues. There is also other evidence for this reaction: n-propylbenzene disappears after hydrotreatment but the amount of n-propylcyclohexane is very small, implying cracking of the propyl group. The amounts of the three isopropyltoluenes are strongly diminished but that of the isopropylmethylcyclohexanes is extremely small, indicating cracking of the isopropyl group. Table I also shows an increase of the removal of alkylnaphthalenes, indans, and tetralins with the increase of the molecular weight. Figure 1 is quite clear: the lefthand-side region is less intense after hydrotreatment, probably indicating cracking of the CCalkylindans with formation of lower molecular weight compounds; on the other hand, the region on the right shows some peaks that are diminished, suggesting the same reaction for C3-alkyltetralins. Some alkylnaphthalene profiles are also modified: several C4dkylnaphthalenes practically disappear after hydrotreatment. Thus,the longer alkyl chains
2136 Ind. Eng. Chem. Res., Vol. 30,No. 9, 1991
(retentian tin#,min I Figure 3. (top) Mass fragmentogram (m/z 202) of fluoranthene and pyrene in the aromatic fraction of natural oil (left) and treated oil (right). (bottom) Mass fragmentogram ( m / z 216) of methylfluoranthene and methylpyrene in the aromatic fraction of natural oil (left) and treated
oil (right).
of these compouhds can be cracked to form lower molecular weight homologues. Data in Table I do not permit characterization of cracking of lateral chains for the three-ringcompounds due to the fast rate of formation. 4. Aromatization. Table I shows that the amounts of the three- and four-ring aromatic compounds rise sharply, indicating formation during hydrotreatment. Such a conclusion can also be drawn from Figure 3. The question is which compounds are the precursors. It is not possible to give an unambiguous explanation, but two possibilities are considered: 1. Natural oil contains amounts up to 2.4% w/w hopanes and steranes, polycycloalkanes, which are almost eliminated (90%)after hydrotreatment, but the expected reaction products were not found. 2. Some alkylnaphthalenes, alkylindans, and alkyltetralins could condense themselves to give three-ring compounds or even more complex products. These considerations are based on the stability of aromatic and hydroaromatic compounds when compared to the polycycloalkanes under hydrotreating conditions and on the fact that the mass balance of tetralins, indans, indenes, and naphthalenes is far from being satisfied (see below). One explanation is that these precursors are strongly adsorbed on spent catalyst. After hydrotreatment, the catalyst was submitted to Soxhlet extraction with n-hexane (24 h) and benzene (24 h). The precursors mentioned above, the three- and four-ring aromatic hydrocarbons, as well as other compounds still more complex (including polymeric ones), are present here, which correspond roughly to 10 w t % of the catalyst. According to literature (Appleby et al., 1962;Silva and Schmal, 1989), compounds with two or more aromatic rings, especially anthracenes and phenanthrenes, are among the main coke producers. These observations suggest that aromatization and condensation reactions occur mainly over the catalyst. 5. Other Reactions. 5.1. Conversion of Indenes. Probably the most important reaction is the hydrogenation of the double bond, with conversion to the corresponding indans. Nevertheless, if the conversion of alkylcyclopentadienes and alkenes is complete (loo%), that of indenes is rather limited, 92%, probably due to steric effects
I
4
(0-pmpyl t d m )
Figure 4. Rupture of the saturated ring of akylindana and tetralins.
and/or to the conjugation of the double bond with the aromatic ring. 5.2, Opening of Saturated Rings. The data in Table I allow the calculation of the total amount (wt %) of indenes, indans, tetralins, and naphthalenes before and after hydrotreatment. The obtained values are 21.1 and 15.8%, respectively. Thus, mass balance indicates the existence of other reactions whose compounds are consumed. One piece of evidence for new reactions is the appearance of three new alkylbenzenes in the hydrotreated oil: sec-butylbenzene, o-propyltoluene, and n-butylbenzene. The presence of these compounds can be explained by the rupture of the saturated ring of alkylindans and tetralins, as shown in Figure 4. These results agree with the data of Miki et al. (1983),suggesting that this reaction appears under high hydrogen pressure and on the surface of the catalyst, as in the present case. 5.3. Cyclization/Condensation. Another possibility to explain the disappearance of alkylindans, tetralins, naphthalenes, and indenes is the cyclization/condensation of some of these compounds to form compounds of three or more condensed rings (aromatics and hydroaromatics). 5.4. Transalkylation. From the calculated relative proportions of the two methylnaphthalenes, before and after hydrotreatment, we observed that the @-isomer(2methyl) represents respectively 40 and 70% of the total amount of these compounds. The &position is thermo-
Ind. Eng. Chem. Res., Vol. 30, NO. 9, 1991 2137 dynamically favored under high temperature (Morrison and Boyd, 1973). Thus, we can explain it by the alkyl chains in the a-position, which are more easily removed than those in @-position,and/or a migration of the chain from the a- to the @-position,transalkylation. Harvey et al. (1986) observed this reaction in the hydrotreatment of Rundle shale oil in a continuous reactor with Mo-containing catalysts. Conclusions The aromatic fraction of Irati shale oil shows two principal reactions: hydrogenation of aromatic rings; cracking of lateral alkyl chains. However, there are also many secondary reactions: aromatization and the possible occurrence of cyclization/condensation and the rupture of saturated rings in other compounds like indans and tetralins; transalkylation and the hydrogenation of the double bond of indenes. Although the total amount of aromatic compounds decreases after hydrotreatment, the behavior of each family depends on its nature: Alkylbenzenes and alkylnaphthalenes are mainly consumed with formation of alkylcyclohexanes and alkyltetralins, respectively. Three and four-condensed-ring aromatic compounds are clearly formed by aromatization reactions during hydrotreatment. The amounts of the lower molecular weight alkylbenzenes and alkylnaphthalenes decrease in a lower proportion than those of the superior homologues (Table I). In the case of alkylindans and tetralins, the amounts of their lower molecular weight compounds even increase after hydrotreatment (beyond the cracking of high molecular weight homologues, there are other reactions, e.g., hydrogenation of indenes and alkylnaphthalenes). All the families mentioned above are largely predominant in the aromatic fraction (some 84% of the total). Thus,the global effect of hydrotreatment is to favor the formation of lighter compounds, but the inverse behavior is also possible as verified by the formation of three- and four-condensed-ring aromatic compounds. After hydrotreatment, the number of compounds is increased. Most of them have several small lateral alkyl chains. Thus, the utilization of the aromatic fraction of Irati shale oil for fine chemical purposes would need further simplification, like hydrodealkylation or vapor dealkylation. Acknowledgment We thank Ricardo B. Coelho, Heloisa Freitas, and Carlos Cesar for the analyses at the Institute of Chemistry of the Federal University of Rio de Janeiro, Brazil. This work was supported by CNPq, CAPES, and CENPES. Registry No. Ni, 7440-02-0; Mo, 7439-98-7; indene, 95-13-6; naphthalene, 91-20-3; phenanthrene, 85-01-8; methylindene, 29036-25-7;indan, 496-11-7; dimethylindene, 29348-63-8 chrysene, 218-01-9; aec-butylbenzene, 13598-8; 0-propyltoluene, 1074-17-5; n-butylbenzene, 104-51-8.
Literature Cited Appleby, W. G.; Gibson, J. W.; Good, G. M. Coke Formation in Catalytic Cracking. Znd. Eng. Chem. Process Des. Dev. 1962,1, 102-110. Budzikiewicz, H.; Djerassi, C.; Williams, D. H. Interpretation of Mass Spectra of Organic Compounds; Holden-Day: San Francisco, 1964; pp 162-167. Burwell Jr., R. L. Deuterium as a Tracer in Reactions of Hydrocarbons On Metallic Catalysts. Acc. Chem. Res. 1969,2,289-296. Cornu, A,; Massot, R. Compilation of Mass Spectral Data. Index de Spectres de Masse, 2nd ed.; Heyden & Sons LM. in Cooperation with SCM Publications: London, 1975; Vol. I and 11. Harvey, T. G.; Matheson, T. W.; Pratt, K. C.; Stanborough, M. S. Catalyst Performance in Continuous Hydrotreating of Rundle Shale-oil. Znd. Eng. Chem. Process Des. Deu. 1986,%, 521-527. Hertz, H. S.; Brown, J. M.; Cheder, S. N.; Guenther, F. R.; Hilpert, L. R.; May, W. E.; Parris, R. M.; Wise, S. A. Determination of Individual Organic Compounds In Shale-oil. Anal. Chem. 1980, 52, 1650-1657. Kmey, Jr., I. W.; Smith, J. R.; Ball, J. S. Identification of Thiophene and Benzene Homologs. Anal. Chem. 1952,24,1391-1396. Lemberton, J. L.; Touzeyidio, M.; Guisnet, M. Catalytic Hydroprocessing of Simulated Coal Tars I. Activity of a Sulphided Ni-Mo/Alz03 Catalyst for the Hydroconversion of Model Compounds. Appl. Catal. 1989,54,91-100. Loureiro, M. R. B.; Costa Neto, C. Hidrocarbonetos Aromaticos do Oleo de Pirolise do Xisto da Formacao Irati. An. Acod. Bras. Cienc. 1982, 54, 87-96. McCarthy, R. D.; Duthie, A. H. A Rapid Quantitative Method for the Separation of Free Fatty Acids From Other Lipids. J . Lipid Res. 1962,3,117-119. Miki, Y.; Yamadaya, S.; Oba, M.; Sugimoto, Y. Role of Catalyst in Hydrocracking of Heavy Oil. J. Catal. 1983,83,371-383. Morrison, R. T.; Boyd, R. N. Quimica Organica, 7th ed.; Fundacao Calouste-Gulbenkian: Lisboa, 1973; p 1172. Radke, M.; Welte, D. H. The Methylphenanthrene Index (MPI): A Maturity Parameter Based On Aromatic Hydrocarbons. In Adoances in Organic Geochemistry; Bjoroy, M., et d., Eds.; Wiley: Chicheater, 1981; pp 504-512. Radke, M.; Willisch, H.; Leythaeuser, D. Aromatic Components of Coal: Relation to Distribution Pattern to Rank. Geochem. Cosmochim. Acta 1982,46, 1831-1848. Sapre, A. V.; Gates, B. C. Hydrogenation of Aromatic Hydrocarbons Catalyzed by Sulfided Co-Mo/A120a. Reactivities and Reaction Networks. Znd. Eng. Chem. Process Des. Deu. 1981,20,68-73. Sapre, A. V.; Gates, B. C. Hydrogenation of Biphenyl Catalyzed by Sulfided Co-Mo/AlzOa. The Reaction Kinetics. Znd. Eng. Chem. Process Des. Dev. 1982,21, 86-94. Silva, M. I. P.; Schmal, M. DesativaGi5.o do Catalisador Ni-Mo Comercial no Hidrocraqueamento Seletivo de Oleo de Xisto ParaDiegel em Leito Trifhico. Fifth Brazilian Symposium on Catalysis, Sept 13-15, 1989, Guarujl-SP; Instituto Brasileiro de Petrbleo: Rio de Janeiro, 1989; pp 286-295. Souza, 9. L. M2; Silva, M. I. P.; Schmal, M. Hidrotratamento Catalitico de Oleo de Xisto em Leito Fluidizado Trifhico. Third Brazilian Symposium on Catalysis, Aug 21-23,1985, SalvadorBA; Instituto Brasileiro de Petr6leo: Rio de Janeiro, 1985; pp 209-223. Stenhagem, E.; Abrahmson, S.; McLafferty, E. W. Atlas of Mass Spectral Data; Interscience Wiley: London, 1969; Vol. I and 11. Uden, P. C. Liquid Chromatographic Class Separation and High Resolution Gas Chromatography of Shale-oil Polar Compounde. Prepr. Pap.-Am. Chem. SOC.,Dio. Fuel Chem. 1981,26,82-88. Weast, R. C. CRC Handbook of Chemistry and Physics, 63rd ed.; CRC Press: Boca Raton, FL, 1982; pp C344, C345, C531.
Received for reuiew September 4, 1990 Accepted April 17, 1991
