FI90632C - Process for the preparation of a catalyst for the hydrogenation of aromatics - Google Patents

Description

90632

A process for the preparation of a catalyst for the hydrogenation of aromatics

The present invention relates to a process for preparing a heterogeneous catalyst for the hydrogenation of aromatics according to the preamble of claim 1, which contains nickel attached to a porous inorganic support such as aluminum.

Many oil refining processes, such as hydrogenation, hydrocracking and methanation, use catalysts consisting of a support and nickel. Nickel catalysts are also used on the synthesis side. For example, cyclohexane, which is needed e.g. polyamide, is often obtained by hydrogenation of benzene.

Conventional heterogeneous hydrogenation catalysts contain a catalytically active component added to the surface of the support. The most common methods for attaching active components to the surface of a carrier are absorption, precipitation, and ion exchange. The starting materials are then compounds of the active component, for example salts which are soluble in a suitable solvent such as water, alcohol or hydrocarbon. Traditional methods of preparing catalysts are necessarily multi-step. The required steps are 20 mm. preparation of a solution from the catalyst component or its precursor, treatment of the support with the solution, removal and recovery of the unreacted solution, washing, drying and calcination, and previous treatments to activate the catalyst.

The prior art involves several problems due to e.g. due to the large number of preparation steps in '25 and the difficulty of producing catalysts in a controlled manner. Naturally, the use of solvents is also a disadvantage, e.g. due to their interaction with the applicant and the impurities they contain.

Other methods for preparing Ni-containing hydrogenation catalysts are also known in the art. Uemura et al. [Sekiyo Gakkaishi £ 2 (1989) 15-20 and J. Chem. Eng. Jpn 22 (1989), 48-54] have prepared a Ni / ΑΙ, Ο gas phase catalyst using NiCl2 as a starting material, which has been vaporized at 1073 K (= 800 ° C) and reacted with alumina at 1013 to 1073 K (= 740-800 ° C). During the reaction, NiCl 2 is condensed on the surface of the alumina, the chloride is removed with hydrogen and the nickel is reduced. The Ni content depends on the reaction time used.

In the catalyst prepared by the above-mentioned method of Uemura et al., Nickel is poorly dispersed on the surface of the support, forming clusters of 500 to 600 nm in size. The formation of such large clusters significantly reduces the active surface area of nickel interacting with the gas phase relative to the bulk concentration.

The object of the present invention is to eliminate the disadvantages associated with the prior art and to provide a new nickel catalyst for hydrogenation reactions.

The invention is based on the idea that nickel is added to the surface of the support from the vapor phase in the form of a compound having a sufficiently high vapor pressure. As such a compound, an organonickel compound is used. The reaction between the nickel compound and the support follows conditions in which the nickel compound is chemisorbed at the surface bond sites of the support. The support is heated to a temperature higher than the condensation temperature of the nickel compound used but lower than the decomposition temperature of said compound. There is an excess of nickel compound vaporized relative to the surface binding sites, with binding being affected only by the qualitative properties of the surface binding sites and the reagent under the conditions used. As described above, the favorable bonding sites on the surface are impregnated with nickel.

More precisely, the invention is mainly characterized by it. which is set out in the characterizing part of claim 1.

"25"

The method according to the present invention provides a good nickel distribution on the surface. It has been found that the Ni particles are very small even after successive cycles of reaction. Tållaiseen hyvåån metallidispersioon pååståån kåyttamållå "weari described kyllåstyviå surface reactions, which are further described in GB Patent '30 Application Publication 84 562 and FI Patent Application 913438. Kyllåstyvisså surface reactions :: · kiinnitettåvåå metalliyhdistettå brought to the carrier surface as a high outside temperature is, that only the chemisorption of the metal compound and the support of the electoral law are possible. The binding sites of the carrier 3 90632 are then adjusted, e.g. by heating, to the desired level before the actual reaction. The reagent is allowed to interact with the carrier until substantially all of the sites capable of bond formation have reacted. Thereafter, prolonging the reaction time or applying an excess of reagent to the surface no longer increases the metal content. In this respect, the method thus clearly differs from the solution published by Uemura and colleagues, in which the metal content is a function of time and the amount of reagent.

A good dispersion also requires the use of a nickel compound of rather large molecular size. Thus, by using a nickel compound with organic ligands, the metal can be distributed evenly on the surface because the reaction temperature does not allow physical sorption and thus the attachment of a metal compound molecule on top of another similar molecule. It has been found that in the present process, the nickel introduced from the vapor phase organometallic compound onto the support forms more nucleation points on the aluminum than the prior art methods. Nucleation points refer to distinct nickel atoms around which clusters begin to form as the nickel content increases. The more nucleation points, the better the dispersion and the surface area of the active component. With a nickel content of 10% by weight, the size of the catalyst clusters prepared by the present process is only half the size of the known catalyst clusters.

In the present application, Ni-acetylacetonate [hereinafter also abbreviated as Ni (acac) 2] is used as an exemplary compound. The size of this molecule is large with respect to the density of surface binding sites. However, it is clear that other organic nickel compounds can be used in the invention, in which the organic parts are able to prevent the two nickel atoms from becoming so close together that they form large clusters when bound to the surface. An example is nickelocene (dicyclopentadienyl nickel (II)).

The carriers to which the nickel compound is added according to the invention are inorganic porous carriers, preferably aluminum or silicon oxides or mixtures thereof. Magnesium and titanium oxides or mixtures thereof or cogels formed with the aforementioned inorganic carriers can also be used.

The manufacturing conditions are chosen so that the Ni compound does not condense on the surface, but either forms a chemical bond with the alumina or vaporizes away from the surface S and retrieves the following free surface bonding sites. In the case of Ni (acac) 2, it is preferably carried out at a temperature of 190 to 220 ° C, e.g. .200 ° C. Nickelocene is preferably used at a temperature of about 121-250 ° C. The reagent is brought into contact with the carrier relative to the additional binding sites. The unreacted Ni reagent is flushed out of the reaction space with an inert carrier gas at the reaction temperature used. Some of the ligand remains attached to the nickel from the reagent attached to the support. The removal of the ligand can be carried out, for example, with steam or with dry or moist air at a temperature higher than the reaction temperature. Preferably, the ligands are removed at a temperature of about 200 to 600 ° C, particularly preferably about 300 to 500 ° C.

The Ni content in the catalyst can be increased stepwise by adding Ni reagent + air reaction cycles. The figure below shows how the nickel content for Ni (acac) 2 increases from about 4% by weight after one cycle to more than 20% by weight after 10 cycles. The addition of reaction cycles is easily accomplished by alternately introducing Ni compound, nitrogen and air into the reaction space.

'20:

After removal of the ligands, the catalyst is activated according to the prior art by reducing the nickel on the surface of the alumina with hydrogen gas at an elevated temperature, preferably at a temperature of about 300 to 600 ° C.

All reaction steps can be performed by opening and closing the gas valves in the reaction vessel. . the carrier itself can be kept in the same reaction space at all times. This simplifies the preparation because no solvents are needed and the support does not have to be transferred from the reaction space to the calcination furnace or the like.

According to a preferred embodiment of the invention, a nickel / alumina catalyst suitable for the hydrogenation reaction of an aromatized sulfur-free hydrocarbon feed having a nickel content of about 4 to 20% by weight is produced. We have found that although at certain nickel content intervals, doubling the nickel content even quadruples the activity of the catalyst (this is the case when increasing the nickel content from 5% to 10% by weight), which is why 8-12% by weight of the invention is considered to be particularly preferred. . Four to five reaction cycles are sufficient to provide such a catalyst.

5

As a typical example of the use of the catalyst to be obtained according to the invention, mention may be made of the hydrogenation reactions of benzene and toluene.

The invention provides considerable advantages. The catalyst according to the invention is particularly well suited for the hydrogenation of aromatics under both liquid and gas phase conditions in a sulfur-free feed. Sulfur is a known catalyst poison for Ni catalysts that should be removed before hydrogenation. The activity of the new catalysts in the conversion of toluene to methylcyclohexane has been superior to both the catalysts prepared by impregnation of the comparative experiments and the three commercial catalysts. Experiments have been performed under both differential and integral conditions, in the liquid and gas phases.

The activity and stability of the catalysts prepared from the vapor phase according to the invention have been at least at the same level and in many cases at a clearly higher level in all experiments than the corresponding properties of the prior art and commercial Ni / Al 2 O 3 catalysts. In a kinetic comparison with a commercial catalyst, it was found that in the hydrogenation of toluene on the surface of the catalyst according to the invention prepared from the vapor phase, the interaction between nickel and reactants (toluene and hydrogen) is more favorable than with a commercial catalyst with strong toluene binding. \ Paste the surface of the active species. Thus, with its own catalyst prepared from the vapor phase, better reaction rates and higher conversions are achieved.

25. . Using various analytical methods (including XRF, XRD, ESCA, SEM / EDS and LEIS), the amount of nickel was also found to be at a usable level and the dispersed minimum of nickel was as good and in many cases better than that of commercial and impregnated catalysts.

The catalysts according to the invention also have a higher activity than the previously known gas phase catalysts, which is apparently due to the good dispersion.

The preparation of the catalysts is simpler than the known methods in that the reaction steps are fewer than in the known methods and the various preparation steps are carried out without solvents in succession in the same reaction space. The concentration of active species in the catalyst is regulated by the surface of the support and the steric properties of the reaction compounds used, not the dosage used. The invention also makes it possible to better control the nickel content of the catalyst to be prepared to the desired level by means of pretreatments and repetition of reaction cycles.

10

The invention will now be examined in more detail with the aid of a few application examples.

The figure in the accompanying drawing shows the Ni content of the catalyst to be prepared as 15% by weight as a function of the number of Ni (acac) 2 cycles. The pattern was described in more detail above.

Example 1

Preparation of catalysts according to the invention. Aluminum oxide supplied by AKZO under the brand name was used as the catalyst support. Alumina 000-1.5. The product was crushed and screened to a grain size of 0.15 ... 0.3 mm. 5 to 10 g of support were used per catalyst. The surface area of Al 2 O 3 after pretreatment at 800 ° C was 152 m 2 / g. The area was determined by the nitrogen BET multipoint method.

: 25: The reagent was Ni (acac) 2, a commercially available substance. Its evaporation temperature was 190-210 ° C.

The reagent was introduced into the support in the gas phase in excess relative to the hydroxyl groups (surface bonding sites) on the surface of the support. The number of hydroxyl groups in alumina are: 3f0: theoretically determined e.g. Knozinger, H., Ratnasamy, P., Catal. Rev. Sci. Eng. 17 (1978) 31. Based on the experiments we performed, 1.5 mmol of reagent 7 90632 is required for the complete saturation of the aluminum surface, i.e. a nickel content of about 4% by weight.

Ni (acac) 2. The catalysts were prepared by arranging the support in a static column through which the reagent vapors were passed from top to bottom. Using a 2 to 3-fold excess (about 3 to 4.5 mmol) ensured that the nickel content was as high at the top of the statue as at the bottom, indicating that the surface of the support was saturated.

5

The catalysts shown in Table 1 have been prepared under reduced pressure, 5 to 30 mbar, and the carrier gas has been nitrogen. The basic structure of the device used in the preparation is described in FI patent publication 84562. There were five steps in the preparation of the catalyst. In the first step, the carrier was heat treated in an oven in an air atmosphere (step 10 A). Physically sorbed water and part of the surface OH groups were then removed. Thereafter, any water physically sorbed during storage of the support in the reaction space under reduced pressure under a nitrogen atmosphere was removed from the support (step B). In the next step, the Al 2 O 3 support was treated with Ni (acac) 2, whereby nickel was chemisorbed on the alumina surface (step C).

The post-treatment was followed by air purging to remove any acac ligands still attached to Ni (step D). Moist air was used for air rinsing. After work-up, the catalyst was purged with nitrogen (step E).

20. Table 1 shows, by way of example, six Ni / Al 2 O 3 catalysts, the temperatures and times of the aforementioned preparation steps, and the number of times the previous steps have been repeated in the preparation of the catalyst. The last column of the table shows the nickel content of the finished catalyst, expressed as a percentage by weight. The nickel content is determined by X-ray fluorescence and the carbon content by combustion (-25 carbon dioxide determination). The carbon contents of all the catalysts shown in Table 1 were below the limit of quantification, i.e. <0.1 wt%.

g 90632

Table 1. Preparation of catalysts according to the invention.

Kata- phase phase phase phase phase lyt ABCDEN Ni __ (° C / h) (° C / h) (° C / h) (° C / h) (° C / h) (pcs) (wt%) 1 800/6 190/3 190/2 200/2 400/1 4 10,1 ____ + 200/2 +400/3 ____ 5 2. 800/16 450/3 200/4 200/1 400/1 4 9 4 _____ + 400/3 ____ 3. 800/16 450/3 190/2 200/2 400/1 4 10.8 ____ + 200/2 +400/3 ____ 4. 800/16 190/3 190/1 200/2 400/1 10 20.7 ____ + 200/3 +400/3 ____ 5. 800/16 190/3 190/1 200/2 400/1 6 14.1 ____ + 200/3 +400/3 ____ 6. 800/16 450/3 190/2 200/2 400/1 2 5.9 + 200/2 +400/3 10

For the activity experiments presented below, several catalysts were prepared by attaching 15 nickel to the alumina surface as described above. The Ni contents of the finished catalysts were between 2 and 21% by weight. Catalyst 7 was prepared as Catalyst 2 with the difference that the number of cycles was 2 and the ligands were removed by steam treatment. The nickel content of the catalyst 7 was 4.6% by weight.

20:

Example 2a (comparison)

Preparation of catalysts by impregnation process

Reference catalysts were prepared by a conventional impregnation method as follows: First, nickel nitrate was dissolved in water to form a nickel nitrate / aqueous solution.

Dry impregnation was performed so that the solution was completely absorbed into the pores of the carrier. Nickel nitrate was used at about 0.12 g Ni / g carrier. The carrier was shaken: during absorption. The catalysts were then dried at 120 ° C for 12 hours and heated to 300 ° C in an oxidizing atmosphere. With a number of manufacturing cycles of 1 to 3, the Ni content was 5.4, 11.3 and 17.7% by weight.

Example 2b (comparison) 5

Reference catalysts were prepared by the impregnation method. First, Ni (acac) 2 was dissolved in tetrahydrofuran (THF) to form a solution (4.2 g Ni (acac) 2 per 10 ml THF). Dry impregnation was performed so that the solution was completely absorbed into the pores of the carrier. The solution was used 0.5 ml / vehicle g. During absorption, the carrier was shaken. The catalyst was then dried for 12 hours at 120 ° C at a temperature, after which the acac ligands were removed by treating the catalysts at 300 ° C for 4 hours in an oxidizing atmosphere. Depending on the number of production cycles (impregnation, drying and oven), catalysts with different Ni contents were prepared.

For example, with the number of cycles 1-3, the nickel content of the catalysts was 3.8, 7.5 and 10.9 wt%. The amount of carbon (possible ligand residues) was below the limit of quantification in all catalysts and nickel was very well dispersed in all catalysts because the catalysts were XRD-amorphous for Ni compounds (particle size of Ni compounds less than 20 Å). The analysis results mentioned above show that the impregnation was successful 2ft. very well. Thus, the catalysts had been prepared from the same Ni compound (NKacac®) using the same aluminum by dry impregnation and the vapor phase by the process of the invention.

Comparison of the activities of the catalysts in the hydrogenation of toluene in the gas phase at 25: 175 ° C with a molar ratio of H 2 / toluene to 3.1 and WHSV 9090 was compared. The catalyst ff 1 (see Table 1) prepared by introducing Ni (acac) 2 into aluminum from the vapor phase by the process of the invention and having a Ni content of 10.1% by weight to a catalyst prepared by impregnating, as mentioned above, a solution of Ni (acac) 2 in the same alumina used in the preparation of catalyst ff 1. The Ni content of the catalyst (IMP / acac) prepared by impregnation: 30 was 10.9% by weight.

"The results of the activity comparison were as follows: 10 90632

Catalyst: Yield (g of product (Methylcyclohexane / gN / h # 1 235 IMP / acac 140 5) It can thus be seen that the superiority of the catalyst prepared according to the invention is due precisely to the preparation process.

Example 3)

Comparison of catalyst activities in the gas phase

For the activity comparison, the catalysts prepared in Examples 1 and 2 were used. Three commercial catalysts were also tested in the comparisons. The catalysts were compared both in the gas phase (atmospheric pressure and 115-230 ° C) and in the liquid phase (10 bar and 120-220 ° C) for the hydrogenation of toluene in a minireactor. The reactions were monitored by gas chromatography.

The catalysts were activated by hydrogen flowing through the reactor while raising the reactor temperature to the optimum level. Activation of commercial catalysts was performed according to the manufacturer's instructions. The impregnated catalysts as well as the catalysts prepared from the vapor phase 20. were activated under optimal conditions. After the catalysts were activated, toluene was charged to the reactor and the test reaction began.

The first experiment compared two catalysts prepared from the vapor phase (1 and 4). . conversion to a commercial catalyst of the same order of magnitude as nickel. Comparison 25- was performed in the gas phase, at 175 ° C, with a molar ratio of H 2 / toluene of 33.1 and WHSV of 9090.

In Table 2, conversion refers to the amount by weight of toluene fed which is converted to products in the reaction. 0.2 g of kata-30 lys was used in each test run. The third column defines the yield of the desired product, methylcyclohexane (MECH). The figures in the column correspond to the MECH obtained per hour per gram of nickel. In all test times, the selectivity for the desired product was> 99%.

li 90632

Table 2. Catalyst activities determined from the gas phase

Catalyst Conversion (% by weight) g MECH / gNi / h_ 5 _J__28 ^ 0__249.5_ _4__30 ^ 5__132 ^ 6_

Commercial 19.6 105.6 10 Example 4

Comparison of catalyst activities in the gas phase

In another experiment (see Table 3), one catalyst (7) prepared by the new vapor phase method was compared to a commercial catalyst (IMP) prepared by impregnation according to Example 2a, which contained 11.3 wt% Ni. All three catalysts were compared under gas phase conditions at atmospheric pressure and temperatures of 120-210 ° C.

0.03 g of commercial catalyst and 0.30 g of A and IMP catalysts were used. The molar ratio between the introduced hydrogen gas and toluene was 7.7. Table 3 compares the conversion level and the yield determined in the same manner as in the previous example.

20 12 9 Π 6 3 2

Table 3. Catalyst activities determined from the gas phase

Catalyst Lamp state (° C) Conversion (% by weight) g MECH / gNi / h _7__140__107__747_ 5 _7__172__337__2447_ _7__206__207__14M_ IMP__140__47__127_ IMP__172__187__547_ IMP__206__127__

Commercial # 2 172 14.9 244.0

Commercial tt2 206 9.1 148.4 15 Example 5

Comparison of catalyst activities in the liquid phase

The commercial catalyst (0.008 g) was compared to catalyst A (0.038 g) under liquid phase conditions (pressure = 10 bar, temperature 120-730 ° C, nH 2 / nT-7). Table 4 shows the results of the 20th comparison (definitions are the same as in the previous tables).

Table 4. Liquid phase activities of catalysts 251 Catalyst Temperature (° C) Conversion (% by weight) g MECH / gNi / h 7__153__37__221.4_ _7 __ ^ 83__107__601.8_ _7__2311__ £ 7__2440_

Commercial # 1,153 2.2 164.0_ 39 · Commercial £ 1,183 8.4 631.7_

Commercial # 1,231 34.3 2565 13 90632

Example 6

Comparison of reaction rates achieved with catalysts in the gas phase

The fourth example compares the reaction rates achieved with a commercial (Commercial # 3) and a proprietary catalyst (2) prepared by vapor phase-5 under differential conditions in the gas phase, at different temperatures. Table 5 shows the reaction rates at different temperatures in terms of methylcyclohexane (MECH) per hour and grams of catalyst / nickel. The partial pressure ratio pH? / P1rh, rTTli was -2.2.

10 Table 5. Reaction rate of toluene hydrogenation with different catalysts

BasBBSssasssassss = ssssa ssssaBBs ^: ^ p ^^ BSSs Bass saBsss ^ ^ = aB = i ^ B8SBSs

Catalyst Lamp state (° C) r = [gMECH / gkll / h] r = [g ^ »/ gNi / h] 2,151 3.86 38.3 2,171 6.82 67.5 2,184 6.63 65.7 15 Commercial # 3,151 4.43 7.4

Commercial # 2,170 4.61 7.7

Commercial # 3,191 2.74 4.6: 20. As can be seen from the results, the catalysts according to the invention often achieve superior activity over three commercial and in-house impregnated reference catalysts.

14 90632

Example 7

Manufacture of nickelocene catalysts

The same alumina as in Example 1 was used as the catalyst support. The support 5 had been pretreated at 800 ° C.

Any water physically sorbed during storage of the Al 2 O 3 support was removed. The lamp treatment was performed at 200 ° C in a reaction space under reduced pressure and a nitrogen atmosphere. The lamp treatment lasted 3 hours.

10

The reagent was a commercially available nickelocene, Ni (C5H5) 2. The evaporation temperature of nickelocene in the catalysts of this example was 150 ° C and the reaction temperature in which nickel was chemisorbed on the surface of the Al 2 O 3 support was 200 ° C. The reaction time was 4 hours. Nickelocene hydrocarbon ligands were removed with moist air. Air treatment was performed at 200 at 15 ° C for 2 hours and at 400 ° C for 4 hours. Finally, the catalyst was purged with nitrogen at 400 ° C for one hour.

Table 6 shows 3 catalysts prepared as mentioned above. The figure in the "revolutions" column of the table shows how many times the nickelocene + air steps mentioned above have been repeated.The catalyst concentrations of catalysts 8, 9 and 10 were below the limit of determination, i.e. <0.1 wt%.

Table 6. Catalysts prepared according to Example 7.

25 catalyst Ni content revolutions (wt%) (pcs.) 8. 5.0 1 9. 10.9 2 10. 22.1 4 15 90 632

Example 8

Activities of Catalysts Prepared from Nickelocene The activity of the catalysts prepared according to Example 7 was compared to Catalysts 1 and 4 as well as Commercial Catalyst # 1. The comparison was performed under differential conditions, hydrogenation of toluene at a conversion level of 44% at atmospheric pressure and 175 ° C. The molar ratio of H2 / T in the feed was 2,52.5, which corresponds to a thermodynamic equilibrium conversion at tasolla45%. Table 7 shows the reaction rate of toluene hydrogenation after 4 hours 10 runs (stabilized state) in terms of methylcyclohexane produced per gram of catalyst and time as well as per gram of nickel and time. In the fourth column, the catalysts are ranked on the basis of both the amount of catalyst and the amount of nickel.

15 Table 7. Reaction rate of toluene hydrogenation with different catalysts

Kat. r = r = Functionality: [gMECH ^ Scat ^ h] [SmECH ^ 8νϊ ^] f (r cat), f (r Ni) 1 14 140 78, 76 4 17 80 94,43 ': 29 8 9 195 50, 105 9 14 135 78.73 10 19 85 106.46

Commercial # 1 14 85 78.46 -.25 As shown in Table 7, the catalysts shown in Example 7 are excellent in performance. Thus, nickel cyclopentadienyl is an excellent starting material for the preparation of a hydrogenation catalyst.

Claims (13)

A process for producing a heterogeneous catalyst for hydration of aromatic compounds containing nickel bound to an inorganic porous support, the process comprising evaporation of a nickel-containing starting substance and its conduction in a gas phase to a reaction chamber, the said substance. be contacted with the carrier, characterized by a) as a nickel-containing starting agent, an organic nickel compound is used, the spring vapor pressure is maintained so high and the spring interaction with the carrier may be so long that there is an excess of the reagents in relation to the carrier's binding sites; b) non-reacted nickel compound is removed from the reaction chamber at the reaction temperature; c) the product resulting from interaction between the nickel compound and the support is treated at a temperature of 200 to 600 ° C for the removal of the organic parts of the nickel compound and then d) the product is treated with wet at a temperature. of 300 to 600 ° C to activate the catalyst. Process according to claim 1, characterized in that nickel acetylacetonate is used as the nickel compound. 3. A process according to claim 2, characterized in that the nickel compound is reacted with the support at a temperature of 190 to 220 ° C. 25 4. A process according to claim 1, characterized in that nickelocene (dicyclopentadienyl-nickel (II)) is used as the nickel compound. Process according to claim 1, characterized in that alumina is used as a carrier. A process according to any one of the preceding claims, characterized by the reaction being carried out in a nitrogen atmosphere at a reduced pressure of about 20 to 50 mbar. A process according to any one of the preceding claims, characterized in that the organic parts of the nickel compound are removed by a water vapor treatment carried out at a temperature of 300 to 500 ° C. A process according to any one of claims 1-6, characterized in that the organic parts of the nickel compound are removed with the aid of a treatment carried out with dry or moist air, a mixture of oxygen and nitrogen or with steam. 10 Method according to claim 2, characterized in that the process steps a to d are repeated 2 to 10 times. Process according to claim 5, characterized in that the alumina used as carrier is pretreated at a temperature of 600 to 800 ° C for 4 to 20 hours, preferably 6 hours at 800 ° C prior to the reaction. 11. Catalyst, characterized in that it is produced by a process according to any one of claims 1 to 10. 20 The use of a catalyst according to claim 11 for hydration of a substantially sulfur-free hydrocarbon product. The use according to claim 12, characterized in that the catalyst is used in the hydrogenation of benzene and toluene.