PROCESS FOR PRODUCING 1-(4-ISOBUTYLPHENYL)ETHANOL BY HYDROGENATION OF 1-(4-ISOBUTYL-PHENYL)ETHANONE IN THE PRESENCE OF A CATALYST COMPOSITION COMPRISING COPPER

Abstract

Described is a process for producing 1-(4-isobutylphenyl)ethanol by reacting 1-(4-isobutyl-phenyl)ethanone with hydrogen in the presence of a catalyst composition comprising cop-per and one or more metals other than copper, and a use of a respective composition and/or of a pre-composition, the pre-composition comprising a mixture of oxides of copper and oxides of one or more metals other than copper, in a catalytic hydrogenation process for producing 1-(4-isobutylphenyl)ethanol from 1-(4-isobutylphenyl)ethanone.

Claims

1. A process for producing 1-(4-isobutylphenyl)ethanol comprising S3) reacting 1-(4-isobutylphenyl)ethanone with hydrogen in the presence of a catalyst composition comprising copper and one or more metals other than copper, wherein the catalyst composition comprises the copper in a total amount in a range of from 30 mass-% to 98 mass-%, relative to a total mass of metals present in the catalyst composition.

2. The process according to claim 1, wherein the catalyst composition comprises the copper in a total amount in the range of from 45 mass-% to 98 mass-% relative to the total mass of metals present in the catalyst composition.

3. The process according to claim 1, wherein the catalyst composition comprises in addition to the copper: c2) a carrier component comprising one or more substance selected from the group consisting of aluminium, aluminium compounds, silicon, silicon compounds, zirconium, zirconium compounds, carbon, and carbon compounds, wherein a total amount of aluminium, silicon, zirconium and carbon in the catalyst composition, relative to the total mass of copper present in the catalyst composition, is in a range of from 2.5 mass-% to 60.0 mass-%; and/or c3) one or more metal different from the group consisting of copper, aluminium, and zirconium, wherein the total amount of the one or more metal different from the group consisting of copper, aluminium, and zirconium in the catalyst composition, relative to the total mass of metals present in the catalyst composition, is in the range of from 0.1 mass-% to 55.0 mass-%.

4. The process according to claim 1, wherein the catalyst composition comprises in addition to the copper: c2) a carrier component comprising one or more substance selected from the group consisting of aluminium, aluminium compounds, silicon and silicon compounds, wherein the total amount of aluminium and silicon in the catalyst composition, relative to the total mass of copper present in the catalyst composition, is in the range of from 3.0 mass-% to 35.0 mass-%; and/or c3) one or more selected from the group consisting of manganese and zinc, wherein the total amount of manganese and zinc in the catalyst composition, relative to the total mass of metals present in the catalyst composition, is in the range of from 0.5 mass-% to 35.0 mass-%; and optionally one or more metal selected from the group consisting of alkaline metals and alkaline earth metals, wherein the total amount of the one or more metal selected from the group consisting of alkaline metals and alkaline earth metals in the catalyst composition, relative to the total mass of metals present in the catalyst composition, is in the range of from 0.1 mass-% to 25.0 mass-%.

5. The process according to claim 1, wherein the catalyst composition comprises: c1) copper in a total amount in the range of from 60 mass-% to 95 mass-% relative to the total mass of metals present in the catalyst composition; c2) a carrier component comprising one or more substance selected from the group consisting of silicon and silicon compounds, wherein the total amount of silicon in the catalyst composition, relative to the total mass of copper present in the catalyst composition, is in the range of from 3.5 mass-% to 15.0 mass-%; and c3) manganese in a total amount in the range of from 0.5 mass-% to 20.0 mass-% relative to the total mass of metals present in the catalyst composition; and optionally one or more metal selected from the group consisting of sodium and calcium, wherein the total amount of the one or more metal selected from the group consisting of sodium and calcium in the catalyst composition, relative to the total mass of metals present in the catalyst composition, is in the range of from 4.5 mass-% to 15.0 mass-%, and wherein the added masses of components c1) and c3) present in the catalyst composition make up the total mass of metals present in the catalyst composition.

6. The process according to claim 1, wherein in the catalyst composition a molar ratio of: copper:nickel is >10; and/or copper:chromium is >10; and/or copper: ruthenium is >10; and/or copper: palladium is >10; and/or copper: graphite carbon is >50.

7. The process according to claim 1, wherein in the catalyst composition, a molar ratio of copper:aluminium is >10; and/or copper:zinc is >10, and/or the 1-(4-isobutylphenyl)ethanone present in step S3) comprises other organic and/or inorganic chemical compounds, selected from the group consisting of acetic acid, acetates, fluorides, chlorides; oxygen-containing compounds, ketones, aldehydes, esters, ethers, water; nitrogen-containing compounds, amines, amides, urea compounds, nitrates, nitrites, nitrosyl compounds; sulfur-containing compounds, thioles, thio ethers, sulfides, sulfates, and sulfones, in an amount of ≤10 mass-% relative to the total mass of the 1-(4-isobutylphenyl)ethanone and the other organic and/or inorganic chemical compounds.

8. according to claim 1 wherein the 1-(4-isobutylphenyl)ethanone is present in a liquid phase for at least a part of the process or process time of step S3), and/or 1-(4-isobutylphenyl)ethanone and/or 1-(4-isobutylphenyl)ethanol make up ≥90.0 vol.-% of the liquid phase in step S3).

9. The process according to claim 1, wherein the reacting in step S3) is carried out at least for a part of the process or process time: at a hydrogen pressure in the range of from 0.5 to 8.0 MPa; and/or at a molar ratio of hydrogen to the 1-(4-isobutylphenyl)ethanone which is present at the start of step S3) in a range of from 1 to 20; and/or at a temperature in a range of from 30° C. to 200° C.

10. The process according to claim 1, wherein the reacting in step S3) is carried out continuously for at least a part of the process or process time, optionally in one or more fixed-bed reactor and/or in two or more serially connected reactors comprising one or more main reactor, each comprising one or more recycle loops or one combined recycle loop, and one or more post-reactor, not comprising recycle loops, wherein a recycle ratio in the one or more recycle loops is in the range of from 0.1 to 20; and/or the catalyst composition comprises a fixed-bed catalyst or fixed-bed catalyst composition, and/or the catalyst load is in a range of from 0.1 kg [1-(4-isobutylphenyl) ethanone]/(kg catalyst composition*h) to 5.0 kg [1-(4-isobutylphenyl)ethanone]/(kg catalyst composition*h), where the kg [1-(4-isobutylphenyl)ethanone] is the total amount of 1-(4-isobutylphenyl)ethanone present at the start of the reaction; and/or 1-(4-isobutylphenyl)ethanone is continuously fed into or provided to reaction step S3) in an amount of ≤500 t/h.

11. The process according to claim 1, further comprising the following steps before step S3): S1) providing or preparing a pre-catalyst composition comprising a mixture of oxides of copper and oxides of one or more metal other than copper, wherein the pre-catalyst composition comprises the oxides of copper in a total amount in the range of from 30 mass-% to 90 mass-% relative to the total mass of the pre-catalyst composition; and S2) reacting the pre-catalyst composition from step S1) with hydrogen, preferably at a temperature in a range of from 120° C. to 230° C., such that the catalyst composition comprising copper and one or more metals other than copper used in step S3) results.

12. The process according to claim 11, wherein the pre-catalyst composition is present for at least a part of the process or process time as a formulation of solid particles and/or the reacting in step S2) is carried out for at least a part of the reaction or reaction time in the presence of a gaseous atmosphere comprising hydrogen gas and one or more other gases which are inert under the reaction conditions.

13. The process according to claim 11, wherein the pre-catalyst composition comprises in addition to the oxides of copper: p2) a carrier comprising one or more substance selected from the group consisting of carbon and oxides of aluminium, silicon, and zirconium, wherein the total amount of carbon and oxides of aluminium, silicon, and zirconium in the pre-catalyst composition, relative to the total mass of the pre-catalyst composition, is in a range of from 2.0 mass-% to 50 mass-%; and/or p3) oxides of one or more metal not selected from the group consisting of copper, aluminium, and zirconium, wherein a total amount of the oxides of one or more metals different from the group consisting of copper, aluminium, and zirconium in the pre-catalyst composition, relative to the total mass of the pre-catalyst composition, is in a range of from 0.1 mass-% to 55.0 mass-%.

14. A catalytic hydrogenation process comprising the use of a composition comprising copper and one or more metal other than copper, wherein the composition comprises the copper in a total amount in a range of from 30 mass-% to 98 mass-%, and/or a pre-composition comprising a mixture of oxides of copper and oxides of one or more metal other than copper, wherein the pre-composition comprises the oxides of copper in a total amount in a range of from 30 mass-% to 90 mass-%, for producing 1-(4-isobutylphenyl)ethanol from 1-(4-isobutylphenyl)ethanone,

15. The process according to claim 14, wherein the catalytic hydrogenation process is at least partly performed as a continuous hydrogenation process, and/or the composition is or comprises a fixed-bed catalyst or fixed-bed catalyst composition and/or the pre-composition is used or provided in a fixed-bed.

Description

EXAMPLES

[0254] The following examples are meant to further explain and illustrate the present invention without limiting its scope.

Example 1: Pre-Catalyst Compositions

[0255] The pre-catalyst compositions PCC1a, PCC1b, PCC2, PCC3, PCC4, PCC5, PCC6 and PCC7 shown in tables 1a to 1c below were obtained from commercial sources (BASF SE, Germany). Pre-catalyst composition “PCC-EX” in table 1c is a hypothetical pre-catalyst composition only used for demonstrating purposes in the calculation example below.

TABLE-US-00001 TABLE 1a Constituents of pre-catalyst compositions (mass-% of compositions) Composition: PCC1a PCC1b PCC5 Constituent [mass-%] of the pre-catalyst composition CuO 75.0 75.0 60.0 SiO.sub.2 12.0-17.0 12.0-17.0 17.5-22.0 MnO.sub.2 1.0-5.0 1.0-5.0 0 CaO and/or  5.0-10.0  5.0-10.0 20.0-24.0 MgO and/or Na.sub.2O Formulation Trilobed Trilobed Tablets extrudates extrudates Formulation 1.5 mm 3 mm 5 mm mean particle size

TABLE-US-00002 TABLE 1b Constituents of pre-catalyst compositions (mass-% of compositions) Composition: PCC2 PCC3 PCC4 PCC7 Constituent [mass-%] of the pre-catalyst composition CuO 70.0 60.0 55.0 67.0 Al.sub.2O.sub.3  3.0-10.0 27.0-32.0 42.0-45.0 26.0-30.0 MnO.sub.2 0  8.0-13.0 0 0 Composition: PCC2 PCC3 PCC4 PCC7 ZnO 20.0-25.0 0 0 0 CaO and/or 0 0 ≤1.0 0 MgO and/or Na.sub.2O La.sub.2O.sub.3 0 0 0 3.0-7.0 Formulation Tablets Tablets Tablets Tablets Formulation 1.5 mm 3 mm 3 mm 3 mm mean particle size

TABLE-US-00003 TABLE 1c Constituents of pre-catalyst compositions (mass-% of compositions) Composi- tion: PCC6 PCC-EX Constituent [mass-%] of the pre-catalyst composition CuO 45.0 75.0 SiO.sub.2 0 15.0 ZnO 0 5.0 Na.sub.2O 0 1.0 BaO  5.0-10.0 4.0 Cr.sub.2O.sub.3 40.0-45.0 0 Graphite 1.0-5.0 0 Formulation Tablets Tablets Formulation 3 mm 3 mm mean particle size

[0256] Composition PCC2 is e.g. commercially available from BASF SE under the trade name PURISTAR R3-30 T5X5; CuZn. Composition PCC3 is e.g. commercially available from BASF SE under the trade name Cu 0540 T (⅛)″. Composition PCC4 is e.g. commercially available from BASF SE under the trade name H3-82 T3X3. Composition PCC5 is e.g. commercially available from BASF SE. Composition PCC6 is e.g. commercially available from BASF SE under the trade name E 406T (⅛)″; CuCr. Composition PCC7 is e.g. commercially available from BASF SE under the trade name H9-66 T3X3 (⅛)″.

[0257] As reference, a commercially available nickel catalyst (Raney® nickel) was used.

[0258] For comparison, additional hydrogenation experiments were carried out using the following pre-catalyst compositions or catalyst compositions, respectively, not according to the invention:

[0259] 1) Pd/C (commercially available) and

[0260] 2) “NiO” (composition of “NiO” pre-catalyst composition: 16.7 mass-% CuO, 50.6 mass-% NiO, 1.5 mass-% MoO.sub.3, 31.0 mass-% ZrO.sub.2); the pre-catalyst composition “NiO” is per se known in the art. The catalytic hydrogenation reactions performed with this pre-catalyst composition were carried out according to procedures known in the art and similar to those described in this text (see examples 2 and 3).

Example 2: Activation of Pre-Catalyst Compositions to Catalyst Compositions (Steps S1) and S2))

[0261] A pre-catalyst composition as defined in tables 1a to 1c above was provided as fixed-bed catalyst under a nitrogen gas atmosphere (close to atmospheric pressure or at slight over pressure) and heated at a rate of 25° C./h to 50° C./h until the minimum activation temperature was reached. The minimum activation temperature (“T.sub.act”) applied in each case is shown in table 2 below.

[0262] The pre-catalyst composition was then activated by slow, stepwise addition of hydrogen gas until a concentration of 95 vol.-% of hydrogen (relative to the total volume of gases present) was achieved. The addition of hydrogen gas was controlled to limit the temperature increase over the reactor to 15° C. to 20° C. For the duration of the activation and reduction of the pre-catalyst composition the temperature was kept below the maximum temperature (“T.sub.max”) per pre-catalyst composition (applicable maximum temperatures per pre-catalyst composition are shown in table 2 below).

[0263] After the target concentration of hydrogen gas was reached and all exotherms had passed through the bed, the pre-catalyst composition was slowly heated to the respective hold temperature per pre-catalyst composition (“T.sub.hold”, see table 2 below for applicable hold temperatures per pre-catalyst compositions).

[0264] After this activation step, the resulting catalyst composition was cooled in a hydrogen atmosphere (as defined above) to a temperature of 100° C. or below, before it was used for the hydrogenation reaction (step S3)).

TABLE-US-00004 TABLE 2 Pre-catalyst composition activation processes and resulting catalyst compositions Resulting Pre-Catalyst T.sub.act T.sub.max T.sub.hold Catalyst Composition: [° C.] [° C.] [° C.] Composition: PCC1a 195 215 220 CC1a PCC1b 195 215 220 CC1b PCC2 195 215 220 CC2 PCC3 175 215 200 CC3 PCC5 195 215 220 CC5 PCC6 140 175 180 CC6

Calculation Examples

[0265] 1) Total Amount of Copper in a Catalyst Composition:

[0266] Below is provided an example for calculating the total amount of copper in an exemplary (hypothetical) catalyst composition as may be used in the process of the present invention, relative to the total mass of metals present in the catalyst composition, as the ratio of the mass of copper atoms present in the catalyst composition, divided by the total mass of metal atoms present in the catalyst composition, based on a hypothetical catalyst composition “CC-EX” (resulting from activation of a hypothetical pre-catalyst composition PCC-EX, see table 1c above):

[0267] Since catalyst composition “CC-EX” is hypothetically made from pre-catalyst composition “PCC-EX” (which contains 75 mass-% of CuO), its (relative) molar amount of copper is 0.942 mole/100 g of catalyst composition (calculated as [mass of CuO in 100 g of pre-catalyst composition]/[molar mass of CuO]=75 g/79.55 g/mol), corresponding to 59.68 g of copper/100 g of pre-catalyst composition.

[0268] Since the (molar) amounts of metals (metal atoms) do not change when preparing a catalyst composition from a pre-catalyst composition according to the process of the present invention, the above masses of metal atoms given for a particular pre-catalyst composition (e.g. PCC-EX) do also apply for the respective catalyst composition made from said particular pre-catalyst composition (e.g. CC-EX).

[0269] Analogous calculation as shown above give the following masses of metals (or metal atoms) per 100 g of catalyst composition CC-EX:

TABLE-US-00005 Copper: 59.68 g Zinc:  4.01 g Barium:  3.58 g Sodium:  0.74 g Sum: 68.01 g

[0270] The total amount of copper (or copper atoms) in catalyst composition CC-EX, relative to the total mass of metals (or metal atoms) present in the catalyst composition, is therefore 59.68 g/68.01 g=87.8 mass-%.

[0271] 2) Total amount of substances comprised by a carrier component (component c2)) of a catalyst composition:

[0272] Below is provided an example for calculating the total amount of aluminium, silicon, zirconium and carbon in a catalyst composition, relative to the total mass of copper present in the catalyst composition, as the ratio of the total mass of aluminium atoms, silicon atoms, zirconium atoms and carbon atoms present in the catalyst composition, divided by the total mass of copper atoms present in the catalyst composition, based on catalyst composition CC-EX:

[0273] The total mass of aluminium atoms, silicon atoms, zirconium atoms and carbon atoms present in 100 g of catalyst composition (according to calculation as set out in calculation example 1, above) CC-EX is 7.02 g (i.e. 7.02 g of silicon atoms, as no atoms of aluminium, zirconium or carbon/graphite are present in CC-EX).

[0274] The total amount of of aluminium, silicon, zirconium and carbon (respectively of their atoms) in catalyst composition CC-EX, relative to the total mass of copper (or copper atoms) present in the catalyst composition, is therefore 7.02 g/59.68 g=11.8 mass-%.

[0275] 3) Total amount of one or more metals not selected from the group consisting of copper, aluminium and zirconium (component c3)) of a catalyst composition:

[0276] Below is provided an example for calculating the total amount of one or more metals not selected from the group consisting of copper, aluminium and zirconium in a catalyst composition, relative to the total mass of metals present in the catalyst composition, as the ratio of the mass of atoms of the one or more metals not selected from the group consisting of copper, aluminium and zirconium present in the catalyst composition divided by the total mass of metal atoms present in the catalyst composition, based on catalyst composition CC-EX:

[0277] The total mass of the one or more metals (or metal atoms) not selected from the group consisting of copper, aluminium and zirconium present in the catalyst composition is the sum of the masses of zinc (atoms) plus barium (atoms) plus sodium (atoms) (per 100 g of composition CC-EX):

4.01 g+3.57 g+0.74 g=8.32 g

[0278] The total amount of one or more metals (or metal atoms) not selected from the group consisting of copper, aluminium and zirconium, in catalyst composition CC-EX, relative to the total mass of metals present in composition CC-EX, is therefore 8.32 g/68.01 g=12.2 mass-%.

[0279] A similar activation procedure as set out above was carried out with the NiO pre-catalyst composition and resulted in activated NiO catalyst compositions, as is known in the art.

[0280] In the reference pre-catalyst composition comprising Raney® nickel, the pre-catalyst composition was prepared in a usual manner known in the art, e.g. as disclosed in document EP 0 358 420 A2.

[0281] Pd/C was prepared for the reaction in a usual manner as is known in the art.

Example 3: Catalytic Hydrogenation of 1-(4-isobutylphenyl)ethanone with Catalyst Compositions in a Batch Process

[0282] A catalyst composition (for preparation see example 2 above, for applicable catalyst compositions used in this experiment see table 3 below) was added to an autoclave containing 1-(4-isobutylphenyl)ethanone, in an amount of 2 mass-% relative to the total mass of 1-(4-isobutylphenyl)ethanone present in the autoclave (mass calculation for the catalyst composition was based on the pre-catalyst composition used). The autoclave was pressurized with nitrogen gas to a pressure of 10 MPa and depressurized (to atmospheric pressure) again. This process was repeated 3 times. Then, the depressurized autoclave (flooded with nitrogen gas after the last depressurization) was pressurized with hydrogen gas to a pressure of 4.0 MPa and the reaction vessel of the autoclave was heated to a temperature of 100° C. under stirring for the hydrogenation process. The stirring was continued for 8 h before the autoclave was cooled to room temperature (20° C.) and depressurized to atmospheric pressure.

[0283] Catalyst compositions CC1a, CC2 and CC7 were prepared by the activation procedure as described in example 2 from pre-catalyst compositions PCCa1, PCC2 and PCC7, respectively.

[0284] After the hydrogenation process was completed, a sample of the final product was drawn from the reaction mixture and analyzed by gas chromatography. The area-% found for the product 1-(4-isobutylphenyl)ethanol was recorded and used for calculation of yield, selectivity for the main product 1-(4-isobutylphenyl)ethanol (shown in tables 3-8 as “selectivity for IBPE”), selectivity for the side product 1-ethyl-4-isobutylbenzene (shown in tables 3-8 as “selectivity for EIBB”) and conversion (as defined above). The resulting values are shown in table 3 below.

[0285] The reference hydrogenation process using Raney® nickel as catalyst composition was conducted in a manner as is known in the art, e.g. as disclosed in document EP 0 358 420 A2. The resulting values are also shown in table 3 below.

[0286] Further hydrogenation experiments were conducted with catalyst compositions as shown in table 3 below (NiO, Pd/C, see above). Hydrogenation with the NiO-catalyst was carried out under conditions equal to the conditions indicated in example 3 (above). Hydrogenation with the Pd/C catalyst was carried out in a usual manner as is known in the art. The respective results are also reported in table 3 below.

TABLE-US-00006 TABLE 3 Results of catalytic hydrogenation of 1-(4-isobutylphenyl) ethanone in a batch process Catalyst Selectivity for Selectivity for Conversion Yield Composition: IBPE [%] EIBB [%] [%] [%] CC1a >99.9 0 70 70 CC2 98 1.8 99 97 CC7 >99.9 0 55 55 Raney ®-nickel 90 9.5 98 88 (comparison) “NiO” 20 80 15 3 (comparison) Pd/C Rapid isomerization of starting compound (comparison) (e.g. into 3-isobutylacetophenone, 4-n- butylacetophenone, etc.)

[0287] From the results shown in table 3 above it can be seen that processes using comparative catalyst compositions “Pd/C” and “NiO” (both not according to the invention) were not suited for catalyzing the selective hydrogenation of 1-(4-isobutylphenyl)ethanone.

[0288] Processes using catalyst compositions (or pre-catalyst compositions, respectively) CC1a, CC2 and CC7 on the other hand were well suited to selectively hydrogenate 1-(4-isobutylphenyl)ethanone in a batch process with selectivities equal or higher than the reference process using Raney® nickel as catalyst composition, however, with varying degrees of conversion and yield.

[0289] As Raney® nickel is provided in powder form, it is not suited to be used in a fixed-bed reactor and thus not suited for use in a continuous catalytic hydrogenation process.

Example 4: Catalytic Hydrogenation of 1-(4-isobutylphenyl)ethanone with Catalyst Compositions in a Continuous Process

[0290] A continuous reactor (inner diameter: 8 mm, length: 1 m) equipped with a recycle-loop, a separator after the reactor and a heater for heating the starting compound (1-(4-isobutylphenyl)ethanone) was loaded with 30.0 g of a pre-catalyst composition (for applicable pre-catalyst compositions used in this experiment see tables 1a to 1c above and table 4 below).

[0291] The reactor system (reactor, recycle-loop, separator and heater) was flushed with nitrogen gas at room temperature (20° C.) and atmospheric pressure. Then, the pre-catalyst composition in the reactor was activated as described in example 2 above to result in the respective catalyst compositions as set out in table 2 above. When the activation process was completed, the reactor was pressurized with hydrogen gas to a pressure of 4.0 MPa and the temperature was raised to 120° C. When the target pressure and temperature were reached, the starting compound (1-(4-isobutylphenyl)ethanone) was fed into the reactor continuously at a rate of 5 g/h to 100 g/h.

[0292] During the hydrogenation experiment, samples were drawn from the reactor in regular intervals and analyzed by gas chromatography. The area-% found for the product 1-(4-isobutylphenyl)ethanol and for the side product 1-ethyl-4-isobutylbenzene in each case was recorded and used for calculation of yield, selectivity and conversion (see example 3, above). The resulting values are shown in table 4 below.

[0293] The recycle ratio was 4:1.

TABLE-US-00007 TABLE 4 Results of catalytic hydrogenation of 1-(4- isobutylphenyl)ethanone to 1-(4-iso-butylphenyl) ethanol in a continuous process Pre- Catalyst Catalyst Selectivity Selectivity Con- Compo- Compo- for IBPE for EIBB version Yield sition: sition: [%] [%] [%] [%] PCC1a CC1a >99.9 <0.1 98 98 PCC1b CC1b 99.7 0.2 95 95 PCC2 CC2 94 5.5 98 92 PCC3 CC3 99.7 0.2 92 92 PCC4 CC4 95 4.5 95 90 PCC5 CC5 98 1.5 82 80 PCC6 CC6 97 2.5 88 85

[0294] From the results shown in table 4 above it can be seen that all catalyst compositions (or pre-catalyst compositions, respectively) used were suited for catalyzing the hydrogenation of 1-(4-isobutylphenyl)ethanone in a continuous process with high selectivity (≥94%) and acceptable to high conversion to and yield of 1-(4-isobutylphenyl)ethanol. Highest selectivity at high conversion and yield was obtained when using catalyst compositions CC1a, CC1b and CC3, all comprising manganese oxide (as metal other than copper) and silicon or a silicon compound (from SiO.sub.2) or aluminium or an aluminium compound (from Al.sub.2O.sub.3) as substances of the carrier component. Best results in terms of selectivity, conversion and yield were obtained with catalyst compositions CC1a and CC1b with the results obtained with catalyst composition CC1a yet exceeding the results obtained with catalyst composition CC1b.

Example 5: Catalytic Hydrogenation of 1-(4-isobutylphenyl)ethanone in a Long-Term Continuous Process at Varying Temperature

[0295] A continuous reactor as described in example 4 above, but with the following modifications: [0296] inner diameter of reactor: 2.16 mm; length: 31 m [0297] after the separator, a second reactor (“post-reactor”) was positioned with the same dimensions as the first reactor;

[0298] was used for a long-term hydrogenation experiment. The continuous hydrogenation reaction was carried out as described in example 4 above with the pre-catalyst composition PCC1a (corresponding to catalyst composition CC1a, see example 4 and table 4 above), for a period of >8000 h.

[0299] The pre-catalyst composition was used in an amount (“pre-catalyst load”) of 1.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst*h) and this amount (or ratio) was held constant for the duration of the long-term hydrogenation experiment.

[0300] The hydrogen gas pressure applied was 3.5 MPa and was also held constant for the duration of the long-term hydrogenation experiment.

[0301] The temperature was varied during the hydrogenation process (step S3)) in a range from 30° C. to 200° C.

[0302] During the hydrogenation experiment, samples were drawn from the reactor in regular intervals and analyzed by gas chromatography as explained in example 4 above. The area-% found for the product 1-(4-isobutylphenyl)ethanol and for the side product 1-ethyl-4-isobutylbenzene in each case was recorded and used for calculation of selectivity and conversion (see example 3, above). The resulting values are shown in table 5 below.

[0303] The recycle ratio was 1:1.

TABLE-US-00008 TABLE 5 Results of catalytic hydrogenation of 1-(4-isobutylphenyl) ethanone in a long-term continuous process with pre-catalyst composition PCC1a at constant pre-catalyst load (varying temperature) Temper- ature Selectivity for Selectivity for Conversion [° C.] IBPE [%] EIBB [%] [%] 30 100 0 12 60 100 0 95 100 100 0 99 120 99 0.7 99 150 96 3.8 98 200 81 18 94

[0304] From the results shown in table 5 it can be seen that best results of the process according to the invention in terms of combined optimized values for conversion and selectivity (for the main product 1-(4-isobutylphenyl)ethanol) of the process are obtained in the temperature range of from 50° C. to 200° C., preferably of from 90° C. to 150° C., more preferably of from 100° C. to 130° C. in step S3).

[0305] Below a temperature of 50° C., preferably of 90° C., more preferably of 100° C., conversion of the starting compound had not reached its maximum yet. Above a temperature of 200° C., preferably of 150° C., more preferably of 130° C., conversion of the starting compound was declining again from the range of optimal conversion.

Example 6: Catalytic Hydrogenation of 1-(4-isobutylphenyl)ethanone in a Long-Term Continuous Process at Varying Pressure

[0306] A continuous reactor as described in example 5 above was used for a long-term hydrogenation experiment. The continuous hydrogenation reaction was carried out as described in example 4 above with the pre-catalyst composition PCC1a (corresponding to catalyst composition CC1a, see example 4 and table 4 above), for a period of >8000 h.

[0307] The pre-catalyst composition was used in an amount (“pre-catalyst load”) of 2.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h) and this amount (or ratio) was held constant for the duration of the long-term hydrogenation experiment.

[0308] The temperature applied was set to 120° C. and was held constant for the duration of the long-term hydrogenation experiment.

[0309] The pressure was varied during the hydrogenation process (step S3)) in a range from 0.5 MPa to 10 MPa.

[0310] During the hydrogenation experiment, samples were drawn from the reactor in regular intervals and analyzed by gas chromatography as explained in example 4 above. The area-% found for the product 1-(4-isobutylphenyl)ethanol and for the side product 1-ethyl-4-isobutylbenzene in each case was recorded and used for calculation of selectivity and conversion (see example 3, above). The resulting values are shown in table 6 below.

[0311] The recycle ratio was 4:1.

TABLE-US-00009 TABLE 6 Results of catalytic hydrogenation of 1-(4-isobutylphenyl) ethanone in a long-term continuous process with pre- catalyst composition PCC1a at constant pre-catalyst load (varying hydrogen pressure) Hydrogen Selectivity for Selectivity for pressure IBPE EIBB Conversion [MPa] [%] [%] [%] 0.5 100 0 58 1.5 100 0 80 2.5 100 0 82 3.5 99 0.7 99 4.0 99 0.7 99 10.0 95 5 100

[0312] The results shown in table 6 illustrate that best results of the process according to the invention in terms of combined optimized values for conversion and selectivity (for the main product 1-(4-isobutylphenyl)ethanol) of the process are obtained in the pressure range of from 0.5 to 8.0 MPa, preferably of from 1.5 to 4.5 MPa and more preferably of from 2.5 to 4.25 MPa.

Example 7: Catalytic Hydrogenation of 1-(4-isobutylphenyl)ethanone in a Long-Term Continuous Process at Varying Pre-Catalyst Composition Load

[0313] A long-term hydrogenation experiment was carried out as described in example 5 above, with the following modifications in the reaction set-up:

[0314] The temperature applied during the hydrogenation process (step S3) was set to 120° C. and was held constant for the duration of the long-term hydrogenation experiment.

[0315] The amount (or ratio) of pre-catalyst composition PCC1a used in the long-term hydrogenation experiment (“pre-catalyst load”) was varied during the hydrogenation process (step S3)) in a range of from 1.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h) to 3.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h).

[0316] During the hydrogenation experiment, samples were drawn from the reactor in regular intervals and analyzed by gas chromatography as explained in example 4 above. The area-% found for the product 1-(4-isobutylphenyl)ethanol and for the side product 1-ethyl-4-isobutylbenzene in each case was recorded and used for calculation of selectivity and conversion (see example 3, above). The resulting values are shown in table 7 below.

[0317] The recycle ratio was 1:1.

TABLE-US-00010 TABLE 7 Results of catalytic hydrogenation of 1-(4-isobutylphenyl) ethanone in a long-term continuous process with pre- catalyst composition PCC1a at constant temperature (varying pre-catalyst composition load) Pre-catalyst load [kg[1-(4-isobutyl- phenyl)ethanone]/ Selectivity Selectivity (kg pre-catalyst for for Conversion composition*h) IBPE [%] EIBB [%] [%] 1.0 99 0.7 99 1.5 100 0 97 2.0 100 0 95 2.5 100 0 86 3.0 100 0 82

[0318] From the results shown in table 7 it can be seen that conducting a continuous process according to the invention with a total amount of pre-catalyst composition in the range of from 0.1 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h) to 5.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h), preferably of from 0.5 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h) to 3.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h), more preferably of from 1.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h) to 2.5 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h), where the kg [1-(4-isobutylphenyl)ethanone] is the amount of 1-(4-isobutylphenyl)ethanone present at the start of the reaction (step S2)) (“pre-catalyst load”) brought about the best results in terms of conversion to the main product.

[0319] In the further optimized range of pre-catalyst loads (as shown in table 7 above as a detailed view on the most preferred range of pre-catalyst amounts to be used), at pre-catalyst load rates below 1.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h), preferably below 1.25 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h), product selectivity had not reached its maximum value. At pre-catalyst load rates above 2.5 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst composition*h), preferably above 2.25 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst*h), conversion to the main product decreased from its maximum value.

Example 8: Catalytic Hydrogenation of 1-(4-isobutylphenyl)ethanone in a Long-Term Continuous Process at Varying Reaction Time

[0320] A long-term hydrogenation experiment was carried out as described in example 5 above, with the following modifications in the reaction set-up:

[0321] The temperature applied during the hydrogenation process (step S3) was set to 100° C. and was held constant for the duration of the long-term hydrogenation experiment.

[0322] The amount (or ratio) of pre-catalyst composition PCC1a used in the long-term hydrogenation experiment (“pre-catalyst load”) was held constant during the hydrogenation process (step S3)) at 1.0 kg [1-(4-isobutylphenyl)ethanone]/(kg pre-catalyst*h).

[0323] During the hydrogenation experiment, samples were drawn from the reactor in regular intervals and analyzed by gas chromatography as explained in example 4 above. The area-% found for the product 1-(4-isobutylphenyl)ethanol in each case was recorded and used for calculation of selectivity and conversion. The resulting values are shown in table 8 below.

TABLE-US-00011 TABLE 8 Results of catalytic hydrogenation of 1-(4-isobutylphenyl) ethanone in a long-term continuous process with pre- catalyst composition PCC1a at constant temperature (varying reaction time) Reaction time Selectivity Selectivity Con- (“time on stream”) for for version [h] IBPE [%] EIBB [%] [%] 50 99 0.7 99 1000 100 0 99 3000 100 0 99 5000 100 0 99 9500 100 0 99

[0324] From the results shown in table 8 it can be seen that a continuous process according to the invention with an optimized total amount of pre-catalyst composition and an optimized reaction temperature is suited for being conducted over extended time periods (>8000 h) without reduction in quality of the process parameters, in particular of selectivity and conversion of the hydrogenation process according to the invention. The process according to the present invention is therefore particularly suited for being conducted as a long-time, continuous industrial process.

Example 9: Preparation of Pre-Catalyst Compositions Suitable for Use in the Process of the Present Invention

[0325] Pre-catalyst compositions which are suitable for use in the process according to the present invention or in a preferred process according to the present invention as defined above (comprising pre-catalyst compositions of the type and of at least similar quality of performance in the process of the present invention as pre-catalyst compositions PCC1a and PCC1b with respect to beneficial selectivity, conversion and/or yield in the hydrogenation of 1-(4-isobutylphenyl)ethanone to 1-(4-isobutylphenyl)ethanol) having varying levels of copper oxide, sodium oxide and surface area were prepared as follows: copper oxide, clay, calcium hydroxide (lime), alkali metal source (sodium hydroxide), manganese oxide, and silica sol were mixed and kneaded. The mixture was then extruded with an extruder and dried at a temperature in the range of from 55° C. to 120° C. The extrudates were then calcined at a temperature in the range of from 450-600° C. to a desired surface area. The pre-catalyst compositions PCC8-1A to PCC8-1K had the properties outlined in Tables 9a to 9c, where “3F” means “3-fluted” or “tri-lobe”.

[0326] In tables 9a to 9c, the analysis for the mass percentages of the constituents CuO, SiO.sub.2, CaO, MnO.sub.2 and Na.sub.2O was conducted at a temperature of 650° C. in each case, as indicated in the tables.

TABLE-US-00012 TABLE 9a Properties of different pre-catalyst compositions after their preparation (1) Pre-Catalyst Com- PCC8- PCC8- PCC8- PCC8- position: 1A 1B 1C 1D Mass-% CuO at 74.1 74.1 74.1 74.1 650° C. Mass-% SiO.sub.2 at 13.2 13.2 13.2 13.2 650° C. Mass-% CaO at 5.7 5.7 5.7 5.7 650° C. Mass-% MnO.sub.2 at 0.9 0.9 0.9 0.9 650° C. Mass-% Na.sub.2O at 3.3 3.3 3.3 3.3 650° C. Size/shape (3F) 1/16” 1/16” 1/16” 1/16” BET surface area 46 52 35 20 [m.sup.2/g] Hg pore volume 0.40 0.39 0.38 0.32 [cm.sup.3/g] Average pore 344 303 442 631 diameter [Å] Packed bulk 0.95 0.94 0.97 1.08 density [g/cm.sup.3] Calcination 500 450 550 600 temperature [° C.]

TABLE-US-00013 TABLE 9b Properties of different pre-catalyst compositions after their preparation (2) Pre-Catalyst PCC8- PCC8- PCC8- PCC8- Composition: 1E 1F 1G 1H Mass-% CuO at 73.3 72.9 72.3 70.5 650° C. Mass-% SiO.sub.2 at 13.2 13.2 13.2 12.4 650° C. Mass-% Ca at 6.2 6.2 6.2 6.0 650° C. Mass-% MnO.sub.2 at 0.9 1.0 1.9 4.3 650° C. Mass-% Na.sub.2O at 3.3 3.3 3.2 3.3 650° C. Size/shape (3F) 1/16” 1/16” 1/16” 1/16” BET surface area 36 34 32 36 [m.sup.2/g] Hg pore volume 0.41 0.41 0.43 0.37 [cm.sup.3/g] Average pore 453 485 782 542 diameter [Å] Packed bulk den- 0.93 0.91 0.87 0.95 sity [g/cm.sup.3] Calcination 550 550 550 550 temperature [° C.]

TABLE-US-00014 TABLE 9c Properties of different pre-catalyst compositions after their preparation (3) Pre-Catalyst Com- PCC8- PCC8- PCC8- position: 1I 1J 1K Mass-% CuO at 74.1 74.2 73.8 650° C. Mass-% SiO.sub.2 at 13.5 13.2 13.9 650° C. Mass-% CaO at 6.3 5.9 6.4 650° C. Mass-% MnO.sub.2 at 0 1.9 1.1 650° C. Mass-% Na.sub.2O at 3.4 3.7 3.8 650° C. Size/shape (3F) 1/16” 1/16” 1/16” BET surface area 29 43 30 [m.sup.2/g] Hg pore volume 0.36 0.38 0.38 [cm.sup.3/g] Average pore 713 401 440 diameter [Å] Packed bulk den- 0.95 0.93 0.99 sity [g/cm.sup.3] Calcination temper- 550 500 500-550 ature [° C.]

Example 10: X-Ray Diffraction Analysis of Pre-Catalyst Compositions

[0327] A PANalytical MPD X'Pert Pro diffraction system was used to collect data for exemplary pre-catalyst compositions PCC8-1A to PCC8-1D. Cu K.sub.α-radiation was used in the analysis with generator settings of 45 kV and 40 mA. The optical path consisted of a 1° divergence slit, 2° anti-scatter slit, the sample, and an X'Celerator position sensitive detector. Each pre-catalyst composition sample was first prepared by backpacking the sample into round mount. The data collection from the round mount covered a range from 10° to 90° 20 using a step scan with a step size of 0.017° 20 and a scan speed of 0.036° 20 per second. The X'Pert Pro HighScore program was used for phase identification analysis.

[0328] It was found in this experiment that monoclinic copper oxide (CuO; 00-048-1548) was the predominant phase for exemplary pre-catalyst compositions PCC8-1A to PCC8-1D. The copper oxide crystallite sizes for exemplary pre-catalyst compositions PCC8-1A to PCC8-1D are shown in table 10 below:

TABLE-US-00015 TABLE 10 Copper oxide crystallite sizes of pre-catalyst compositions Pre-Catalyst PCC8- PCC8- PCC8- PCC8- Composition: 1A 1B 1C 1D Copper oxide 81 ± 5 78 ± 5 83 ± 5 160 ± 5 crystallite size [Å]

[0329] It was further found that orthorhombic sodium silicate (Na.sub.2SiO.sub.3; 04-008-2078) is present as a minor phase with its strongest reflection (020) matching up at 29° 20. Hexagonal silica (SiO.sub.2; 01-075-3165) was observed around 27° 20. The full listing of 2θ peaks is: 26.7°, 29.6°, 35.5°, 38.7°, 58.9°, 53.4°, 68.2°, 61.6°, 66.3°, 68.0°, 72.3°, 75.1°, and 82.9°.