A CATALYST FOR CONVERTING SYNTHESIS GAS TO ALCOHOLS

Abstract

A catalyst for converting a synthesis gas, said catalyst comprising a first catalyst component and a second catalyst component, wherein the first catalyst component comprises, supported on a first porous oxidic substrate, Rh, Mn, an alkali metal M and Fe, and wherein the second catalyst component comprises, supported on a second porous oxidic support material, Cu and a transition metal other than Cu.

Claims

1.-20. (canceled)

21. A catalyst for converting a synthesis gas, said catalyst comprising a first catalyst component and a second catalyst component, wherein the first catalyst component comprises, supported on a first porous oxidic substrate, Rh, Mn, an alkali metal M and Fe, and wherein the second catalyst component comprises, supported on a second porous oxidic support material, Cu and a transition metal other than Cu.

22. The catalyst of claim 21, wherein in the first catalyst component, the molar ratio of Rh, calculated as elemental Rh, relative to Mn, calculated as elemental Mn, is in the range of from 0.1 to 10; the molar ratio of Rh, calculated as elemental Rh, relative to Fe, calculated as elemental Fe, is in the range of from 0.1 to 10; and the molar ratio of Rh calculated as elemental Rh, relative to the alkali metal M, calculated as elemental M, is in the range of from 0.1 to 5.

23. The catalyst of claim 21, wherein the alkali metal M comprised in the first catalyst component is one or more of Na, Li, K, Rb, Cs.

24. The catalyst of claim 21, wherein at least 99 weight-% of the first catalyst component consist of Rh, Mn, the alkali metal M, Fe, O, and the first porous oxidic substrate.

25. The catalyst of claim 21, wherein the first porous oxidic substrate comprises silica, zirconia, titania, alumina, a mixture of two or more of silica, zirconia, titania, and alumina, or a mixed oxide of two or more of silicon, zirconium, titanium, and aluminum, wherein in the first catalyst component, the weight ratio of Rh, calculated as elemental Rh, relative to the first porous oxidic substrate is in the range of from 0.001:1 to 4.000:1.

26. The catalyst of claim 21, wherein the first catalyst component has a BET specific surface area in the range of from 250 to 500 m.sup.2/g, a total intrusion volume in the range of from 0.1 to 5 mL/g, and an average pore diameter in the range of from 0.001 to 0.5 micrometer.

27. The catalyst of claim 21, wherein in the second catalyst component, the transition metal other than Cu is one or more of Cr and Zn, wherein the molar ratio of Cu, calculated as elemental Cu, relative to the transition metal other than Cu, calculated as elemental metal, is in the range of from 0.1 to 5.

28. The catalyst of claim 21, wherein at least 99 weight-% of the second catalyst component consist of Cu, the transition metal other than Cu, O, and the second porous oxidic substrate.

29. The catalyst of claim 21, wherein the second porous oxidic substrate comprises silica, zirconia, titania, alumina, a mixture of two or more of silica, zirconia, titania, and alumina, or a mixed oxide of two or more of silicon, zirconium, titanium, and aluminum, wherein the weight ratio of Cu, calculated as elemental Cu, relative to the second porous oxidic substrate is in the range of from 0.001 to 0.5.

30. The catalyst of claim 21, wherein the second catalyst component has a BET specific surface area in the range of from 100 to 500 m.sup.2/g, a total intrusion volume in the range of from 0.1 to 10 mL/g, and an average pore diameter in the range of from 0.001 to 5 micrometer.

31. The catalyst of claim 21, wherein the weight ratio of the first catalyst component relative to the second catalyst component is in the range of from 1 to 10.

32. The catalyst of claim 21, wherein at least 99 weight-% of the catalyst consist of the first catalyst component and the second catalyst component.

33. A reactor tube for converting a synthesis gas, comprising a catalyst bed which comprises the catalyst of claim 21.

34. The rector tube of claim 33, being vertically arranged, comprising two or more catalyst bed zones, wherein a first catalyst bed zone is arranged on top of a second catalyst bed zone, wherein the first catalyst bed zone comprises the catalyst, and wherein the second catalyst bed zone comprises the second catalyst component.

35. The reactor tube of claim 34, wherein the volume of the first catalyst bed zone relative to the volume of the second catalyst bed zone is in the range of from 0 to 100.

36. A method for converting a synthesis gas comprising hydrogen and carbon monoxide to one or more alcohols, comprising utilizing the catalyst according to claim 21.

37. A process for converting a synthesis gas comprising hydrogen and carbon monoxide to one or more of methanol and ethanol, said process comprising (i) providing a gas stream which comprises a synthesis gas stream comprising hydrogen and carbon monoxide; (ii) providing the catalyst according to claim 21; (iii) bringing the gas stream provided in (i) in contact with the catalyst provided in (ii), obtaining a reaction mixture stream comprising one or more of methanol and ethanol.

38. The process of claim 37, wherein prior to (iii), the catalyst provided in (i) is reduced, wherein reducing the catalyst comprises bringing the catalyst in contact with a gas stream comprising hydrogen.

39. A process for preparing the catalyst according to claim 21, comprising (a) providing the first catalyst component; (b) providing the second catalyst component; (c) mixing the first catalyst component provided in (a) and the second catalyst component provided in (b).

40. The process of claim 39, wherein providing the first catalyst component according to (a) comprises preparing the first catalyst component by a method comprising (a.1) providing a source of the first porous oxidic substrate; (a.2) providing a source of Rh, a source of Mn, a source of the alkali metal, and a source of Fe; (a.3) impregnating the source of the first porous oxidic substrate obtained from (a.1) with the sources provided in (a.2); (a.4) calcining the impregnated source of the first porous oxidic substrate, and wherein providing the second catalyst component according to (b) comprises preparing the second catalyst component by a method comprising (b.1) providing a source of the second porous oxidic substrate; (b.2) providing a source of Cu, a source of the transition metal other than Cu; (b.3) impregnating the source of the second porous oxidic substrate obtained from (a.1) with the sources provided in (a.2); (b.4) calcining the impregnated source of the second porous oxidic substrate.

Description

EXAMPLES

Reference Example 1: Determination of Characteristics of Materials

Reference Example 1.1: Determination of the BET Specific Surface Area

[0217] The BET specific surface area was determined via nitrogen physisorption at 77 K according to the method disclosed in DIN 66131.

Reference Example 1.2: Determination of the Total Intrusion Volume

[0218] The total intrusion volume was determined by Hg-porosimetry at 59.9 psi (pounds per square inch) according to DIN 66133. It is 1.6825 mL/g for the first catalyst component according to Example 1.1 and 1.0150 mL/g for the second catalyst component according to Example 1.2.

Reference Example 1.3: Determination of the Average Pore Diameter

[0219] The average pore diameter was determined by Hg-porosimetry according to DIN 66133. It is 0.01881 micrometer the first catalyst component according to Example 1.1 and 0.02109 micrometer for the second catalyst component according to Example 1.2.

Reference Example 2: Determination of Selectivities and Yields

[0220] The selectivity with respect to a given compound A, S(A), was determined via GC chromatography analysis.

[0221] In particular, the selectivity S(A) was calculated according to following formula:

S(A)/%=[Y(A)/X(CO)]*100

[0222] Y(A) is the yield with respect to the compound A and X is the conversion of carbon monoxide.

[0223] Conversion X(CO)

[0224] The conversion X(CO) in % is defined as

X(CO)/%=[(R.sub.mol(CO in)−R.sub.mol(CO))/R.sub.mol(CO in)]*100

[0225] For a given reaction tube, the (inlet) molar flow rate R.sub.mol(CO in) is defined as

R.sub.mol(CO in)/(mol/h)=F(CO)/V

wherein

[0226] F(CO)/(I/h) is the flow rate of carbon monoxide into the reaction tube;

[0227] V/(I/mol) is the mole volume.

[0228] Further, the (outlet) molar flow rate R.sub.mol(CO) is defined as

R.sub.mol(CO)/(mol/h)=R.sub.C(CO)/(M(C)*N.sub.C(CO))

wherein the carbon flow rate R.sub.C(CO) in (g(C)/h) is defined as

R.sub.C(CO)/(g(C)/h)=(F(CO)/R(CO))*F

[0229] wherein

[0230] F(CO) is the peak area of the compound CO measured via gas chromatography,

[0231] R(CO) is the response factor obtained from gas chromatography calibration,

[0232] F is the measured flow rate of the gas phase; and

[0233] wherein

[0234] M(C) is the molecular weight of C;

[0235] N.sub.C(CO) is the number of carbon atoms of CO, i.e. N.sub.C(CO)=1.

[0236] Yield Y(A)

[0237] The yield Y(A) in % is defined as

Y(A)/%=(R.sub.C(A)/R.sub.C(CO in))*100

[0238] The (outlet) carbon flow rate R.sub.C(A) in g(C)/h is defined as

R.sub.C(A)/(g(C)/h)=(F(A)/R(A))*F

[0239] wherein

[0240] F(A) is the peak area of the compound A measured via gas chromatography,

[0241] R(A) is the response factor obtained from gas chromatography calibration,

[0242] F is the measured flow rate of the gas phase.

[0243] The (inlet) flow rate R.sub.C(CO in) in g(C)/h is defined as

R.sub.C(CO in)/g(C)/h=R.sub.mol(CO in)*M(C)*N.sub.C(CO)

[0244] wherein

[0245] R.sub.mol(CO in) is as defined above,

[0246] M(C) is as defined above;

[0247] N.sub.C(CO) is the number of carbon atoms of compound CO, i.e. N.sub.C(CO)=1.

Example 1: Preparation of the Catalyst of the Invention

Example 1.1: Preparation of the First Catalytic Component

[0248] A colloidal silica gel (Davisil® 636 from Sigma-Aldrich, powder, having a particle size in the range of from 250 to 300 micrometer, a purity of at least 99%, an average pore diameter of 60 Angstrom, a total intrusion volume of 0.75 mL/g, and BET specific surface area of 515 m.sup.2/g) was calcined for 6 hours at 550° C. in a muffle furnace to obtain a BET surface area of 546 m.sup.2/g. An aqueous solution containing 5.79 g rhodium nitrate solution (10.09 weight-% Rh), 0.58 g manganese nitrate tetrahydrate (Mn(NO.sub.3).sub.2 4H.sub.2O), 0.76 g iron nitrate nonahydrate (Fe(NO.sub.3).sub.3 9H.sub.2O) and 0.60 g lithium nitrate was added dropwise to 20 g of the calcined silica gel. The impregnated support was then dried at 120° C. for 3 hours (heating rate: 3 K/min) and calcined in air at 200° C. for 3 hours in a muffle furnace (heating rate: 2 K/min).

Example 1.2: Preparation of the Second Catalytic Component

[0249] A colloidal silica gel (Davisil® 636 from Sigma-Aldrich) was calcined for 12 hours at 850° C. in a muffle furnace to obtain a BET specific surface area of 320 m.sup.2/g. An aqueous solution containing 3.75 g copper nitrate trihydrate (Cu(NO.sub.3).sub.2 3H.sub.2O) and 4.59 g zinc nitrate hexahydrate (Zn(NO.sub.3).sub.2 6H.sub.2O) was added dropwise to 20 g of the calcined Davisil®. The impregnated support was then dried at 110° C. for 3 hours (heating rate: 3 K/min) and calcined in air at 400° C. for 3 hours in a muffle furnace (heating rate: 2 K/min).

Comparative Example 1: Preparation of a Catalyst Having a Non-Inventive First Catalytic Component

[0250] A first catalyst component was prepared as follows: A colloidal silica gel (Davisil® 636 from Sigma-Aldrich) was calcined for 6 hours at 550° C. in a muffle furnace to obtain a BET specific surface area of 546 m.sup.2/g. An aqueous solution containing 11.66 g rhodium nitrate solution (10.09 weight-% Rh), 2.94 g manganese nitrate tetrahydrate (Mn(NO.sub.3).sub.2×4H.sub.2O) and 1.52 g iron nitrate nonahydrate (Fe(NO.sub.3).sub.3×9 H.sub.2O) was added dropwise to 40 g of the calcined Davisil®. The impregnated support was then dried at 120° C. for 3 hours (heating rate: 3 K/min) and calcined in air at 350° C. for 3 hours in a muffle furnace (heating rate: 2 K/min).

Comparative Example 2: Preparation of a Catalyst Having a Non-Inventive First Catalytic Component

[0251] According to the teaching of US 2015/0284306 A1, a first catalyst component was prepared as follows: A colloidal silica gel (Davisil® 636 from Sigma-Aldrich) was calcined for 12 hours at 725° C. in a muffle furnace to obtain a BET specific surface area of 451 m.sup.2/g. An aqueous solution containing 0.49 g of titanium(IV)bis(ammoniumlactato)dihydroxide solution (50 weight-% from Sigma-Aldrich) was added dropwise to 20 g of the calcined Davisil®. The impregnated support was then dried at 110° C. for 3 hours (heating rate: 3 K/min) and calcined at 450° C. for 3 hours in a muffle furnace (heating rate: 2 K/min). Subsequently, this intermediate was impregnated dropwise with a second aqueous solution, which contained 1.78 g rhodium chloride trihydrate (RhCl.sub.3 3H.sub.2O), 0.88 g manganese chloride tetrahydrate (MnCl.sub.2 4H.sub.2O) and 0.06 g lithium chloride (LiCl). The volume of both aqueous solutions equated to 100% water uptake. The impregnated support was then dried at 110° C. for 3 hours (heating rate: 3 K/min) and calcined under air at 450° C. for 3 hours in a rotary calciner (heating rate: 1 K/min).

[0252] The individual materials had the compositions as shown in Table 1 below.

TABLE-US-00001 TABLE 1 Compositions of the prepared materials Catalyst component Rh/ Mn/ Fe/ Li/ Ti/ Cl/ Cu/ Zn/ BET/ wt-% wt-% wt-% wt-% wt-% wt-% wt-% wt-% m.sup.2/g Comparative 2.5 1.1 0 0.04 0.18 2.7 0 0 397 Example 1 Example 1.1 2.4 0.53 0.49 0.25 0 0 0 0 397 Comparative 2.5 1.1 0 0.04 0.18 2.7 0 0 397 Example 2 Example 1.2 0 0 0 0 0 0 3.8 4.1 247

Example 3: Catalytic Testing

Example 3.1: Catalyst Reaction in Single-Catalyst Bed Reactor

[0253] The reactions were performed in continuous flow a stainless steel reactor in the gas phase. The catalyst bed was not diluted with inert material. Particle fractions were used with a dimension of 250-315 micrometer. The catalyst particles were placed into the isothermal zone of the reactors. The non-isothermal zone of the reactor was filled with inert corundum (alpha-Al.sub.2O.sub.3). Three reaction temperatures were adjusted during the continuous experiment (260° C., 280° C., and 300° C.). The H.sub.2/CO ratio of the synthesis gas was varied between 5 and 2 for each reaction temperature, giving 6 parameter variations in total. The reaction pressure was kept constant at 54 bar(abs) for each experiment. The total mass (g) for each catalyst placed into the reactor was: [0254] 0.636 g of the first catalyst component of Comparative Example 2 (RhMnLiTiCl/SiO.sub.2) [0255] 0.578 g of the first catalyst component of Comparative Example 1 (RhMnFeCl/SiO.sub.2) [0256] 0.602 g of the first catalyst component of Example 1.1 (RhMnFeLi/SiO.sub.2)

[0257] Each catalyst was subjected to an in-situ reduction in H.sub.2 for 2 h at 310° C. prior to the reaction. Synthesis gas with CO and H.sub.2 contained 10 volume-% Ar as the internal standard for online gas chromatography (GC) analysis. Reaction was carried out with a gaseous hourly space velocity of 3750 h.sup.−1. Data were collected for at least 5 hours on stream. A summary of the reaction conditions and catalytic performance of the individual catalyst is given in Table 2. Selectivities are reported in carbon atom %, determined as described in Reference Example 2.

TABLE-US-00002 TABLE 2 Catalytic reaction in single-catalyst bed reactor Catalyst T/ H.sub.2/ X(CO)/ S_CO.sub.2/ S_MeOH/ S_EtOH/ S_CH.sub.4/ S_AA/ S_HAc/ ° C. CO .sup.a) % .sup.b) % .sup.c) % .sup.d) % .sup.e) % .sup.f) % .sup.g) % .sup.h) Comp. 260 5 28 3 6 30 53 0 1 Ex. 1 260 2 10 2 4 33 44 0 2 280 5 44 6 12 22 56 0 0 280 2 18 5 7 29 47 1 1 300 5 72 7 10 14 65 0 0 300 2 31 7 8 24 53 1 1 Ex. 1.1 260 5 14 24 15 31 21 0 0 260 2 5 20 6 31 22 0 3 280 5 35 28 9 26 28 1 0 280 2 13 24 5 25 24 2 3 300 5 75 29 5 21 37 2 0 300 2 28 30 3 20 30 2 1 Comp. 260 5 62 0 0 19 37 15 0 Ex. 2 260 2 19 0 0 8 25 25 0 280 5 91 1 1 24 54 3 0 280 2 35 1 0 11 33 20 0 300 5 89 3 1 24 61 1 1 300 2 41 3 1 17 40 15 0 .sup.a) molar ratio of hydrogen relative to oxygen in the synthesis gas stream .sup.b) conversion of carbon monoxide .sup.c) selectivity towards carbon dioxide .sup.d) selectivity towards methanol .sup.e) selectivity towards ethanol .sup.f) selectivity towards methane .sup.g) selectivity towards acetaldehyde .sup.h) selectivity towards acetic acid

Results of Example 3.1

[0258] As shown above, in Table 2, the inventive first catalyst component according to Example 1.1 exhibits a much better (much lower) selectivity with regard to the by-product acetaldehyde than the catalyst according to comparative example 2. In particular, for each temperature and for each ratio H.sub.2/CO in the feed stream, the inventive first catalyst component according to Example 1.1 exhibits a much better (much lower) selectivity with regard to the by-product methane than both the catalyst according to comparative example 1 and the catalyst according to compartitive example 2.

Example 3.2: Catalyst Reaction in Two-Catalyst Bed Reactor

[0259] The reactions were performed in the gas phase using 16-fold unit with stainless steel reactors. The catalyst bed was not diluted with inert material. Particle fractions were used with a dimension of 250-315 micrometer. The catalyst particles were placed into the isothermal zone of the reactors. The non-isothermal zone of the reactor was filled with inert corundum (alpha-Al.sub.2O.sub.3). The catalyst bed was designed so that a physical mixture of two catalysts is used: The synthesis gas meets at the entrance of the reactor initially a physical mixture of two catalyst particles, the first and the second catalyst components (CuZn/SiO.sub.2 catalyst component+Rh-based catalyst component), and then the partially converted gas meets catalyst particles which consist only of the second catalyst component (CuZn/SiO.sub.2 particles). Three reaction temperatures were varied during the continuous experiment (260° C., 280° C., and 300° C.). The H.sub.2/CO ratio of the synthesis gas was varied between 5 and 2 between each reaction temperature, giving 6 variations in total. The reaction pressure was kept constant at 54 bar(abs). The total mass (g) for each catalyst for the top two-catalyst bed was as following: [0260] top mixture: [0261] 0.348 g of the first component of Comparative Example 1 (RhMnLiTiCl/SiO.sub.2) [0262] 0.104 g of the second component of Example 1.2 (CuZn/SiO.sub.2) [0263] bottom mixture: [0264] 0.255 g of the second component of Example 1.2 (CuZn/SiO.sub.2) [0265] top mixture: [0266] 0.317 g of the first component of Comparative Example 2 (RhMnFeCl/SiO.sub.2) [0267] 0.105 g of the second component of Example 1.2 (CuZn/SiO.sub.2) [0268] bottom mixture: [0269] 0.253 g of the second component of Example 1.2 (CuZn/SiO.sub.2) [0270] top mixture: [0271] 0.334 g of the first component of Example 1.1 (RhMnFeLi/SiO.sub.2) [0272] 0.106 g of the second component of Example 1.2 (CuZn/SiO.sub.2) [0273] bottom mixture [0274] 0.256 g of the second component of Example 1.2 (CuZn/SiO.sub.2).

[0275] Each catalyst mixture was subjected to in-situ reduction in H.sub.2 for 2 h at 310° C. prior to reaction. Synthesis gas with CO and H.sub.2 contained 10 volume-% Ar as the internal standard for online gas chromatography (GC) analysis. Reaction was carried out under a gaseous hourly space velocity of 3750 h.sup.−1. Data were collected for at least 5 hours on stream. The reaction conditions and catalytic performance for each catalytic mixture are given in Table 3. Selectivities are reported in carbon atom %, determined as described in Reference Example 2.

TABLE-US-00003 TABLE 3 Catalytic reaction in two-catalyst bed reactor Catalyst T/ H.sub.2/ X(CO)/ S_CO.sub.2/ S_MeOH/ S_EtOH/ S_CH.sub.4/ S_AA/ S_HAc/ ° C. CO .sup.a) % .sup.b) % .sup.c) % .sup.d) % .sup.e) % .sup.f) % .sup.g) % .sup.h) Comp. 260 5 20 12 12 31 42 0 0 Ex. 1 260 2 7 13 8 38 34 0 0 and 280 5 29 9 16 23 49 0 0 Ex. 1.2 280 2 11 9 12 33 41 0 0 300 5 47 7 15 17 58 0 0 300 2 19 9 12 26 48 1 0 Ex. 1.1 260 5 10 23 30 32 13 0 0 and 260 2 4 28 21 33 13 0 0 Ex. 1.2 280 5 20 26 19 30 22 0 0 280 2 8 29 12 34 19 0 0 300 5 40 27 10 26 32 0 0 300 2 17 28 7 31 26 1 0 Comp. 260 5 13 0 0 39 31 0 3 Ex. 2 260 2 4 0 0 36 23 0 5 and 280 5 23 2 1 42 39 0 1 Ex. 1.2 280 2 9 3 1 42 27 0 2 300 5 38 3 2 36 50 0 0 300 2 17 4 2 41 36 1 1 .sup.a) molar ratio of hydrogen relative to oxygen in the synthesis gas stream .sup.b) conversion of carbon monoxide .sup.c) selectivity towards carbon dioxide .sup.d) selectivity towards methanol .sup.e) selectivity towards ethanol .sup.f) selectivity towards methane .sup.g) selectivity towards acetaldehyde .sup.h) selectivity towards acetic acid

Results of Example 3.2

[0276] As shown above, in Table 2, the catalyst comprising the inventive first and second catalyst components exhibits a much better (i.e. much lower) selectivity with regard to the by-product acetic acid than the catalyst according the comparative first compound of Example 2. In particular, for each temperature and for each ratio H.sub.2/CO in the feed stream, the catalyst comprising the inventive first and second catalyst components exhibits a much better (much lower) selectivity with regard to the by-product methane than the catalyst comprising the comparative first catalyst component of Comparative Example 1 as well as the catalyst comprising the comparative first catalyst component of Comparative Example 2.

CITED PRIOR ART

[0277] US 2015/0284306 A1