METHOD FOR MANUFACTURING A CATALYST SUITED FOR HYDROGENATION OF AROMATICS

Abstract: The present invention concerns a method for manufacturing such a heterogeneous catalyst suited for hydrogenation of aromatics which contains nickel bonded onto an aluminum oxide support. In the method a nickel-containing precursor is vaporized and introduced in gas phase into a reaction space where it is brought in contact with the aluminum oxide support material. According to the invention the nickel-containing precursor used is an organic nickel compound such as nickel acetylacetonate which is kept in a sufficiently high vapor pressure and allowed to interact with the support for a sufficiently long time to introduce the reagent in excess amounts relative to the number of bonding sites available on the support. The reaction temperature is approx. 190...220 C. The unreacted nickel compound is removed from the reaction space at the reaction temperature, and the product resulting from the interaction between the nickel compound and the support is treated at a temperature of 200...600 C to remove the organic parts of the nickel compound. The produced catalyst is treated with hydrogen at a temperature of 300...600 C to activate the catalyst. By cyclically repeating the above-described method steps 2...10 times, nickel-contained catalysts of good dispersion are attained in which the nickel content can be varied in the range 3...21 wt.% of the support weight. The catalysts have an excellent activity, particularly in a hydrogenation reaction of sulfur-free hydrocarbon feedstock.

Description: Method for manufacturing a catalyst suited for hydrogenation of aromatics The present invention concerns a method for manufacturing such a heterogeneous catalyst according to the preamble of claim 1 suited for hydrogenation of aromatics which contains nickel bonded onto a porous inorganic support such as alumina. Several oil-refining related processes such as hydrogenation, hydrogen cracking and methanation employ catalysts comprised of a support and nickel. Synthesis processes also use nickel catalysts. For instance, cyclohexane required for polyamide manufacture and other purposes is typically made through hydrogenation of benzene. Conventional heterogeneous hydrogenation catalysts incorporate a catalytically active component bonded onto a support material. The most common methods for bonding the active components onto the support are impregnation, precipitation and ion exchange techniques. The precursors hereby are compounds of the catalytically active component such as salts, for example, which are soluble in a suitable solvent such as water, alcohol or a hydrocarbon. Owing to these premises, a plurality of work steps have compulsory in conventional catalyst manufacturing methods. Among others, the following work steps have been required: Making a solution of the catalyst species or its precursor; treatment of the support with the solution; removal and recovery of unreacted suspension; catalyst wash, drying and calcining plus separate processing steps for the activation of the catalyst. Prior-art techniques involve multiple problems related, among other things, to the great number of processing steps and difficulties in a controlled manufacture of catalysts. Obviously, the use of solvents also brings about complications owing, for instance, to their interaction with the support material and the impurities they may contain. The art knows also other methods for manufacturing Ni-containing hydrogenation catalysts. Uemura et al. [Sekiyo Gakkaishi 32 (1989) 15-20 and J. Chem. Eng. Jpn 22 (1989), 48-54] have prepared an Ni/Al 2 O 3 catalyst starting from the vapor phase, whereby the precursor has been NiCl 2 which was vaporized at 1073 K ( = 800 °C) and allowed to react with alumina at 1013...1073 K (= 740...800 °C). During the reaction, NiCl 2 is condensed onto the alumina surface, the chloride is removed with the help of hydrogen and the nickel is reduced. The obtained Ni concentration is dependent on the used reaction time. In the catalyst manufactured according the above-described method disclosed by Uemura et al., nickel is poorly dispersed onto the support surface, forming clusters of 500...600 nm diameter onto the support surface. When compared with the bulk content of nickel, the formation of such large clusters causes an appreciable reduction of the active nickel area capable of catalytically interacting with the reactant vapor phase. It is an object of the present invention to overcome the drawbacks of the above- described conventional techniques and to achieve an entirely novel nickel catalyst for hydrogenation reactions. The invention is based on principle that nickel is deposited onto the support material surface from vapor phase containing a compound of sufficiently high vapor pressure. Such a compound employed in the invention is an organonickel compound. The reaction between the nickel compound and the support is carried out under conditions in which the nickel compound is chemisorbed on the surface bonding sites of the support. The support is heated to a temperature which is above the condensation temperature of the nickel compound employed, yet below the decomposition temperature of said compound. The vaporized nickel compound is offered in an excess ratio relative to the surface bonding sites available of the support surface, whereby the bonding process is controlled only by the qualitative properties of the surface bonding sites and the reagerit under the process conditions used. According to the above-described method, advantageous bonding sites on the support material surface will be saturated with nickel. More specifically, the catalyst in accordance with the invention is principally characterized by what is stated in the characterizing part of claim 1. By virtue of the method according to the present invention, it is possible to attain an improved distribution of the nickel species on the support material surface. It has been found that the size of the Ni particles remains very small even after repeated reaction cycles. Such a good dispersion of the metal species is achieved by way of the above-described saturation-controlled surface reactions which are described in greater detail in FI patent publication 84562 and FI patent application 913438. In saturation-controlled surface reactions, the metal compound to be bonded is introduced onto the support material surface at such a high temperature that chemisorption reactions alone are possible between the metal compound and the support. Herein, the number of bonding sites on the support has been regulated to a desired level by way of preheating, for example, prior to the actual reaction. The reagent is allowed to interact with the support until essentially all bonding sites capable of forming a bond have reacted. After this stage, any further prolonging of the reaction time or introduction of excess reactant onto the support surface has no contribution to the achieved metal species content. In this aspect the present method is thus entirely different from the method disclosed by Uemura et al. in which the metal species content is determined by the reaction time and reactant concentration. To obtain good dispersion, the use of a nickel compound of large molecular size is also presumed. Thence, the use of a nickel compound containing organic ligands results in an even distribution of the metal species on the support surface, since the reaction temperature employed does not permit physisorption, and therefore, the bonding of such a metal compound molecule onto a similar molecule is inhibited. It has been found that nickel deposited in accordance with the present method from the vapor phase of an organometallic compound onto a support forms a greater number of nucleation points on alumina than is possible by means of prior-art methods. Nucleation points in this context must be understood as separately located nickel atoms about which clusters are formed during the growth of the catalyst nickel content. The greater the number of nucleation points the better the dispersion and greater the surface area covered by the active species. At 10 wt. % nickel content, catalysts made according to the present method have only half the cluster size of that in conventionally manufactured catalysts. In a first advantageous embodiment of the present invention, the precursor employed is Ni-acetylacetonate [abbreviated as Ni(acac) 2 in the text below]. This molecule has a size which is large in relation to the density of bonding sites on the support surface. In a second advantageous embodiment of the invention, the pre¬ cursor employed is nickelocene (dicyclopentadienyl-nickel(-Q). Obviously, the invention can be implemented using other organic nickel compounds, provided that their organic parts are capable of inhibiting such a close deposition of two adjacent nickel atoms that they could form large-size clusters when bonding onto the support surface. Support materials onto which said nickel compound is deposited according to the invention are porous inorganic supports, advantageously aluminum or silicon oxides, or mixtures thereof. Also magnesium or titanium oxides, or mixtures thereof, or cogels formed with the above-mentioned inorganic supports may be used as support materials. The process conditions are set so as to prevent condensation of the Ni compound onto the support surface, but rather to favor the formation of a chemical bond with aluminum oxide, or alternatively, to evaporate away from the surface and find the closest free bonding sites on the surface. The operating temperature is advantageously in the range 50...300 °C. For Ni(acac) 2 , the advantageous temperature range is 190...220 °C, e.g., approx. 200 °C. Nickelocene is advantageously processed at approx. 100...250 °C. The reaction temperature can be set above the vaporization temperature of the compound. Thus, according to an alternative embodiment, the precursor (e.g., nickelocene) is evaporated at approx. 130...170 °C (e.g., at approx. 150 °C) and reacted with aluminum oxide at 100...300 °C, e.g., at approx. 180...220 °C (typically at approx. 200 °C). The reagent is introduced in an excess ratio relative to the number of bonding sites available on the support surface. The unreacted Ni reagent is purged from the reaction space with the help of an inert carrier gas at the reaction temperature employed. Then, a portion of the reagent adhering to the support remains bonded by the ligand to the nickel species. Removal of the ligand can be performed with the help of, e.g., water vapor or dry/moist air at a temperature above the reaction temperature. When Ni(acac) 2 is used as the reactant, the ligands are removed at approx. 200...600 °C, particularly advantageous at approx. 300... 500 °C. With nickelocene, the ligands are advantageously removed at approx. 200...400 °C. The Ni content of the catalyst can be increased stepwise by processing the catalyst through a greater number of Ni reagent/air reaction cycles. The annexed diagram shows how the nickel content increases with Ni(acac) 2 as the precursor from approx. 3 wt. % after one process cycle to over 21 wt. % after 10 process cycles. The number of reaction cycles can be easily implemented by introducing the Ni- containing compound, nitrogen and air into the reaction space in a cyclic sequence. After removal of ligands, the catalyst is activated with the help of conventional techniques by using hydrogen reduction of the nickel bonded onto the alumina surface at elevated temperature, advantageously at approx. 300...600 °C. All reaction steps can be carried out by simply opening and closing the gas line valves of the reaction vessel, whereby the support proper can be kept continuously in the same reaction space. This makes the catalyst manufacture simple, since use of any solvents is obviated and the support need not be transferred from the reaction space to a calcining oven or similar separate processing unit. According to an advantageous embodiment of the invention, a nickel-alumina catalyst suited for use in a hydrogenation reaction of sulfur-free hydrocarbon feedstock containing aromatics, in which catalyst the nickel content is approx. 3...21 wt. % . In test performed by the inventor, it has been found that over certain nickel content ranges doubling of the nickel content can even quadruple the catalyst activity (in particular when the nickel content is increased from 5 wt. % to 10 wt. %), giving a reason to define the preferred nickel content range according to the invention as 8...12 wt. %. To manufacture such a catalyst, only four or five reaction cycles are needed. Typical application examples of a catalyst obtained in accordance with the present invention are represented by hydrogenation reactions of benzene and toluene. The invention offers significant benefits. The catalyst according to the invention is particularly suited to the hydrogenation of aromatics in both liquid and gas phase conditions using sulfur-free feedstock. Namely, sulfur is a well-known catalyst poison for Ni-containing catalysts that by all means should be removed prior to hydrogenation. The activity of the novel catalysts in toluene conversion into methylcyclohexane has been superior in comparison with both catalysts made by impregnation for reference tests and three commercially available catalysts. The tests have been carried out in both differential and integral conditions, as well as in liquid and gas phases. The activity and stability of catalysts prepared from vapor phase in accordance with the invention have in all tests been at least equal and in multiple cases even distinctly better than the corresponding properties of conventionally manufactured and commercially available Ni/Al 2 O 3 catalysts. In kinetic comparison with a commercial catalyst grade it was found out that during the hydrogenation of toluene, interaction between the nickel species and the reactants (toluene and hydrogen) on the surface of a catalyst according to the invention, made from the vapor phase of the active species, is more favorable than on a commercial-grade catalyst in which toluene, for instance, forms a very strong bond with surface of the active species. Thus, the catalyst made from the vapor phase achieves improved reaction rates and higher conversions. With the help of different analysis methods (i.a., XRF, XRD, ESCA, SEM/EDS and LEIS), the nickel content was found satisfactory and the dispersion of the nickel species at least as good, in multiple cases even better, than in catalysts marketed commercially and manufactured by way of impregnation. Catalysts according to the invention also have a higher activity than other prior-art catalysts prepared from the gas phase, which property evidently can be traced to good dispersion of the active species. Manufacture of catalysts according to the invention is simpler than through conventional methods therein that a lower number of reaction steps is needed relative to prior-art methods and the different manufacturing steps are carried out sequentially in a single reaction space without using solvents. The concentration of the active species in the catalyst is controlled by the steric properties of the support surface and the reactant compounds employed, not by the concentrations used in the reaction space. By virtue of the invention, an improved method over prior-art techniques is achieved for controlling the nickel content in catalyst manufacture to a desired level by varying the number of cycles of the pretreatment/reaction sequences. The invention is next examined with the help of a few exemplifying embodiments. The diagram of the annexed drawing shows the Ni content in wt. % of a catalyst made according to the invention as a function of Ni(acac) 2 cycles employed. A detailed description of the diagram was given above. Example 1 Manufacture of catalysts according to the invention The support for the catalyst was aluminum oxide by AKZO under the trade name Alumina 000-1.5. The product was crushed and screened to particle size 0.15...0.3 mm. A 5...10 g aliquot of the support was used in each catalyst batch. After pretreatment at 800 °C the surface area of Al 2 O 3 was 152 m 2 /g. The surface area was determined using the multi-point BET method. The reagent used was Ni(acac) 2 , which is a commercially available compound. The vaporization temperature of this compound is 190...210 °C. The reagent was introduced onto the support in gas phase in excess ratio relative to the hydroxyl groups (surface bonding sites) available on the support surface. The number of hydroxyl groups in alumina has been theoretically determined by, i.a., Knozinger, H., Ratnasamy, P., Catal. Rev. Sci. Eng. j (1978) 31. According to tests performed by the inventor, complete saturation of alumina surface, that is, a nickel content of approx. 3 wt. % can be attained by using 1.5 mmol of the reagent Ni(acac) 2 . The catalysts were manufactured by placing the support in a static column through which the reagent vapor was routed from top downward. By using the reagent in 2-...3-fold excess amounts (approx. 3...4.5 mmol), the nickel content at the top of the column was assured to be equal to that of the column lower end, thus guaranteeing the saturation of the support surface. The catalysts listed in Table 1 were manufactured at a partial vacuum of 10...50 mbar, and the carrier gas was nitrogen. The basic structure of the apparatus employed in the manufacture is disclosed in FI patent publication 84562. The catalyst manufacture comprises five steps. During the first step the support material was heat-treated in an oven under air atmosphere (step A). This procedure removed physisorbed water and a portion of OH groups from the support surface. Next, any water physisorbed during possible storage of the support material was removed from the support in the reaction space under nitrogen atmosphere (step B). During the subsequent step the Al 2 O 3 support was treated with Ni(acac) 2 , whereby nickel was chemisorbed onto the aluminum oxide surface (step C). The posttreatment applied was purging with air which removed acac-ligands still left on the Ni species (step D). Moist air was used for air purging. As a final treatment the catalyst was purged with nitrogen (step E). Table 1 shows six exemplifying grades of Ni/Al 2 O 3 catalysts with temperatures and durations of the above-described manufacturing steps, as well as the numbers of cycles in the repetition of the above steps in the manufacture of each catalyst. The last column of table gives the nickel content of the manufactured catalyst in weight percent. The nickel content was determined using x-ray fluorescence and the carbon content by combustion (via determination of carbon dioxide). All catalysts listed in Table 1 had a carbon content below the detection threshold of 0.1 wt. % . Table 1. Manufacture of catalysts according to the invention. Several catalysts were made for the activity tests described below by bonding the nickel in above-described manner onto the surface of the aluminum oxide support. The Ni contents of the manufactured catalysts were in the range 3...21 wt. % . Catalyst #7 was prepared in the same fashion as Catalyst #2 with the exception that the number of process cycles was 2 and the ligands were removed by water vapor treatment. The nickel content of Catalyst #7 was 4.6 wt. % . Example 2a (reference) Manufacture of catalyst by impregnation method Reference catalysts were made using a conventional impregnation method in the following fashion: First, nickel nitrate was dissolved in water to an aqueous nickel nitrate solution. Next, dry impregnation was carried out until the entire volume of the solution was absorbed by the support material pores. The amount of nickel nitrate was approx. 0.12 g of Ni per 1 g of support. The support material was agitated by shaking during the impregnation step. Subsequently, the catalyst samples were dried at 120 °C for 12 h and heat-treated at 300 °C under oxidizing atmosphere. When the number of process cycles was varied from 1 to 3, the Ni contents of the catalyst samples were 5.4, 11.3 and 17.7 wt. %, respectively. Example 2b (reference) Reference catalyst samples were made using an impregnation method. First, Ni(acac) 2 was dissolved in tetrahydrofuran (THF) to obtain a solution (4.2 g Ni(acac) 2 per 10 ml THF). The dry-impregnation step was carried out until the entire volume of the solution was absorbed by the support material pores. The amount of the solution applied was approx. 0.5 ml per 1 g of support. The support material was agitated by shaking during the impregnation step. Subsequently, the catalyst samples were dried at 120 °C for 12 h and the (acac)-ligands were removed by heat-treatment for 4 h at 300 °C under oxidizing atmosphere. Using different numbers of process cycles (comprising impregnation, drying and oven- treatment), catalyst samples of varying Ni contents were made. E.g., for 1...3 process cycles, the Ni contents of the catalyst samples were 3.8, 7.5 and 10.9 wt. %, respectively. The carbon content (formed by possibly remaining ligands) in all catalyst samples was below the detection threshold and the nickel species were well dispersed in all catalysts as the catalysts were XRD amorphic (having a Ni compound particle size less than 20 A) with respect to Ni compounds. The above-described analysis results are proof of an extremely successful impregnation. At this stage, catalysts samples were made from the same Ni compound (Ni(acac) 2 ) onto identical alumina support by way of both dry impregnation and a method according to the invention directly from vapor phase. Activity comparison of the catalysts was performed in hydrogenation of toluene in gas phase at 175 °C using a molar ratio approx. 3.1 of H 2 to toluene and WHSV of approx. 90. The comparison was made between Catalyst # 1 (cf. Table 1), manufactured in the method according to the invention by cyclically introducing Ni(acac) 2 onto alumina substrate from vapor phase until an Ni content of 10.1 wt. % was attained, and a catalyst made in the above-described impregnation method by bonding Ni(acac) 2 from a solution onto identical alumina substrate as was used in the manufacture of Catalyst # 1. This impregnated catalyst (IMP / acac) had an Ni content of 10.9 wt. %. Results of activity comparison are as follows: Catalyst: Yield [g of product (methylcyclohexane)/g Ni /h] #1 235 IMP / acac 140 Obviously, the superiority of the catalyst made in the method according to the invention is definitely related to the manufacturing method. Example 3 Functional comparison of catalyst activities in gas phase This activity comparison was carried out using the catalyst samples made in Examples 1 and 2. Also three commercial-grade catalysts were tested. The function of the catalysts was compared both in gas-phase (at ambient pressure and 115...230 °C temperature) and liquid-phase (at 10 bar pressure and 120...220 °C temperature) hydrogenation of toluene in a minireactόr. A gas chromatograph was used for monitoring the reactions. The catalysts were activated with the help of hydrogen flow through the reactor simultaneously with the elevation of reactor temperature to optimal level. The activation of the commercial-grade catalysts was carried out in accordance with manufacturers' instructions. Impregnated catalysts and those manufactured from vapor phase were activated in optimal conditions for each catalyst. Subsequent to the activation of the catalysts, toluene was fed into the reactor and the test reaction was initiated. The first test was performed to compare the conversion efficiency of two catalysts (#1 and #4) made from vapor phase with that of a commercial-grade catalyst of approximately equivalent Ni content. The comparison was made in gas-phase test conditions at 175 °C temperature, a molar ratio of approx. 3.1 of H 2 to toluene and WHSV of approx. 90. Conversion in Table 2 refers to that relative portion of feedstock toluene expressed in wt. % which is converted in the reaction into products. Each test run was performed using 0.2 g of the catalyst. Column 3 of the table gives the yield of the desired product, methylcyclohexane (MECH). The result in this column is the amount of MECH in grams per hour divided relative to one gram of nickel. In all test runs the selectivity for the desired product was in excess of 99 % . Table 2. Catalyst activities as determined in gas phase Example 4 Comparison of catalyst activities in gas phase In the second test (cf. Table 3) one (#7) of the catalysts made according to the novel gas-phase method was compared with a commercial-grade catalyst and an impregnated catalyst (IMP) with 11.3 wt. %, manufactured according to Example 2a. All three catalysts were compared in gas-phase conditions at ambient pressure and 120...210 °C temperature. The amount of the commercial-grade catalyst was 0.03 g, while 0.30 g of catalysts A and IMP were used. The molar ratio of the feedstock hydrogen to toluene was approx. 7. Table 3 gives the results for comparison of both attained conversions and yields defined in the same fashion as in the above example. Table 3. Catalyst activities as determined in gas phase Example 5 Comparison of catalyst activities in liquid phase A commercial-grade catalyst (0.008 g) was compared with Catalyst A (0.038 g) in liquid-phase conditions (pressure = 10 bar, temperature 120...230 °C, = 7). The results of the comparison are given in Table 4 (using the same definitions as those for the tables above). Table 4. Catalyst activities as determined in liquid phase Example 6 Comparison of reaction rates available with different catalysts in gas phase The fourth test was performed to compare the reaction rates attainable with a commercial-grade catalyst (Commercial #3) and a novel catalyst (#2) made from vapor phase in differential conditions of gas phase at different temperatures. Table 5 gives the reaction rates at different temperatures as conversion rate of methylcyclohexane (MECH) per hour and gram of catalyst, and respectively, gram of Ni. The partial pressure ratio Pjc P to i ueoc was approx. 2,2. Table 5. Reaction rate in hydrogenation of toluene for different catalysts As is evident from the results above, the catalysts according to the invention in multiple cases provide superior activity over three commercial-grade catalysts and one impregnated reference catalyst manufactured by the inventor. Example 7 Manufacture of catalysts from nickelocene The support material of the catalyst here was same aluminum oxide as in Example 1. The support was pretreated at 800 °C. Water possibly physisorbed during storage into the Al 2 O 3 support was removed. The required heat treatment was carried out at 200 °C in a reaction space filled with nitrogen at a partial vacuum. The duration of the heat treatment was 3 h. The reagent used was commercial-grade nickelocene, Ni(C 5 Hj) 2 . Vaporization temperature of nickelocene in the catalysts of this example was 150 °C and the reaction temperature at which the nickel species were chemisorbed onto the Al 2 O 3 support was 200 °C. The reaction time was 4 h. The hydrocarbon ligands of nickelocene were removed with the help of moist air. The air treatment was carried out at 200 °C for 2 h and at 400 °C for 4 h. Finally the catalyst was purged with nitrogen at 400 °C for 1 h. Table 6 lists 3 catalysts manufactured in the above-described manner. The column "No. of repetition cycles" in the table indicates the number of repetition cycles for the above-mentioned nickelocene/air treatment steps. Catalysts #8, #9 and #10 had a carbon content which was below the detection threshold of less than 0.1 wt. % . Table 6. Catalysts made according to Example 7. Example 8 Activities of catalysts made from nickelocene The activities of the catalysts made according to Example 7 were compared with Catalysts #1 and #4 as well as the Commercial catalyst #1. The comparison was carried out in differential conditions, for hydrogenation of toluene, at approx. 4 % conversion at ambient pressure and 175 °C temperature. The molar ratio of H 2 to toluene in feedstock was approx. 2.5, corresponding to a thermodynamical equilibrium conversion of approx. 45 %. Table 7 gives the reaction rate of toluene after a 4-hour run (stabilized state) as the amount of produced methylcyclohexane per gram of catalyst and 1 h, as well as per gram of catalytic nickel and 1 h. The catalysts are rated in column 4 for functionality according to their catalytic performance and nickel content. Table 7. Reaction rate in hydrogenation of toluene for different catalysts As is evident from Table 7, catalyst described in Example 7 rate as excellent for their functionality. Thus, nickelcyclopentadienyl is well suited for use as the precursor in the manufacture of a hydrogenation catalyst.

Claims: Claims 1. Method for manufacturing such a heterogeneous catalyst suited for hydrogenation of aromatics which contains nickel bonded onto a porous inorganic support, in which method a nickel-containing precursor is vaporized and introduced in gas phase into a reaction space where it is brought in contact with the support material, characterized in that a) the nickel-containing precursor used is an organic nickel compound which is kept in a sufficiently high vapor pressure and allowed to interact with the support for a sufficiently long time to introduce the reagent in excess amounts relative to the number of bonding sites available on the support, b) the unreacted nickel compound is removed from the reaction space at the reaction temperature, c) the product resulting from the interaction between the nickel compound and the support is treated at a temperature of 200...600 °C to remove the organic parts of the nickel compound, after which d) the product is treated with hydrogen at a temperature of 300...600 °C to activate the catalyst. 2. A method as defined in claim 1, characterized in that nickel acetylacetonate is used as the nickel compound. 3. A method as defined in claim 1, characterized in that nickelocene [dicyclopentadienyl-nickel(II)] is used as the nickel compound. 4. A method as defined in claim 1, characterized in that the nickel compound is vaporized at a temperature of approx.100...250 °C and reacted with the support at a temperature of approx.100...300 °C. 5. A method as defined in any foregoing claim, characterized in that the nickel compound is reacted with the support at a temperature higher than that used for its vaporization. 6. A method as defined in claim 1, characterized in that the nickel compound is reacted with the support at a temperature of approx.190...220 °C. 7. A method as defined in claim 3, characterized in that the nickel compound is vaporized at a temperature of approx.130...170 °C and reacted with the support at a temperature of approx.180...220 °C. 8. A method as defined in any foregoing claim 1...7, characterized in that the support is aluminum oxide. 9. A method as defined in any foregoing claim, characterized in that the reaction is carried out in nitrogen atmosphere at a partial vacuum of approx. 20...50mbar. 10. A method as defined in any foregoing claim 1...9, characterized in that the organic parts of the nickel compound are removed with the help of a treatment carried out using dry or moist air, a mixture of oxygen and nitrogen or water vapor. 11. A method as defined in claim 1, characterized in that the organic parts of the nickel compound are removed with the help of a water vapor treatment carried out at a temperature of 200...500 °C. 12. A method as defined in claim 1, characterized in that the manufacturing steps a...d are cyclically repeated 2...10 times. 13. A method as defined in claim 8, characterized in that the aluminum oxide used as the support is pretreated at 600...900 °C for 4...20 h, advantageously for 6 h at 800 °C, prior to the reaction. 14. A catalyst, characterized by being manufactured through a method defined in any of claims 1...12. 15. Use of a catalyst defined in claim 14 in a hydrogenation reaction of an at least essentially sulfur-free hydrocarbon product. 16. Use as defined in claim 15, characterized in that the catalyst is used in the hydrogenation of benzene and toluene.

Inventors: LEHTOVIRTA ULLA, LINDBLAD MARINA, LINDFORS LARS PETER, LEHTOVIRTA, ULLA, LINDBLAD, MARINA, LINDFORS, LARS, PETER
Applicants: LEHTOVIRTA ULLA, LINDBLAD MARINA, LINDFORS LARS PETER, NESTE OY
Application year: 1993
Main classification: B01J37
IPC codes: B01J23, B01J37, C07C5