CATALYSTS FOR THE CONVERSION OF SYNTHESIS GAS TO ALCOHOLS

Abstract

A catalyst support for manufacturing a mixture of alcohols from synthesis gas comprises a combination of nickel, molybdenum, at least one metal selected from the group consisting of palladium, ruthenium, chromium, gold, zirconium, and aluminum, and at least one of an alkali metal or alkaline earth series metal as a promoter. The catalyst may be used in a process for converting synthesis gas wherein the primary product is a mixture of ethanol (EtOH), propanol (PrOH), and butanol (BuOH), optionally in conjunction with higher alcohols.

Claims

1. A process for producing one or more C.sub.2-C.sub.4 alcohols comprising: placing synthesis gas in contact with a catalyst under conditions sufficient to convert at least a portion of the synthesis gas to at least one of ethanol, propanol and butanol, wherein the catalyst comprises: nickel; molybdenum; at least one metal selected from a group consisting of palladium, ruthenium, chromium, gold, zirconium, and aluminum; a promoter comprising at least one of an alkali metal or alkaline earth metal; and a catalyst support selected from a group consisting of silica, alumina, magnesium oxide, and mixtures thereof.

2. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, further comprising: reducing the catalyst using a reducing agent prior to contact with the synthesis gas.

3. The process for producing C.sub.2-C.sub.4 alcohols according to claim 2, wherein the reducing agent comprises hydrogen.

4. The process for producing C.sub.2-C.sub.4 alcohols according to claim 2, wherein reducing the catalyst comprises using the reducing agent at a pressure between 0.10 MPa and 4.14 MPa.

5. The process for C.sub.2-C.sub.4 alcohols according to claim 4, wherein reducing the catalyst further comprises using the reducing agent at a temperature between 250 C. and 1200 C.

6. The process for C.sub.2-C.sub.4 alcohols according to claim 5, wherein reducing the catalyst further comprises using the reducing agent at a temperature between 330 C. and 700 C.

7. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, wherein at least a portion of the synthesis gas is converted to methanol.

8. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, wherein at least a portion of the synthesis gas is converted to acetaldehyde.

9. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, wherein the conditions include a minimum pressure of 500 psig (3.4 MPa).

10. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, wherein the conditions include a pressure of from 1,500 psig (10.3 MPa) to 4,000 psig (27.6 MPa).

11. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, wherein the conditions include a temperature of from 200 C. to 500 C.

12. The process for producing C.sub.2-C.sub.4 alcohols according to claim 1, further comprising recycling at least a portion of unconverted synthesis gas.

13. A process for producing one or more C.sub.2-C.sub.4 alcohols comprising: placing synthesis gas in contact with a catalyst at a minimum pressure of 500 psig (3.4 MPa) and a temperature of from 200 C. to 500 C. to convert at least a portion of the synthesis gas to at least one of ethanol, propanol and butanol, wherein the catalyst comprises: nickel; molybdenum; at least one metal selected from a group consisting of palladium, ruthenium, chromium, gold, zirconium, and aluminum; a promoter comprising at least one of an alkali metal or alkaline earth metal; and a catalyst support selected from a group consisting of silica, alumina, magnesium oxide, and mixtures thereof.

14. The process for producing C.sub.2-C.sub.4 alcohols according to claim 13, further comprising: reducing the catalyst using a reducing agent prior to contact with the synthesis gas.

15. The process for producing C.sub.2-C.sub.4 alcohols according to claim 13, wherein at least a portion of the synthesis gas is converted to methanol.

Description

EXAMPLE 1

[0030] Combine 180 milligrams (mg) gold(III) chloride hydrate (HAuCl.sub.4.Math.3H.sub.2O) with 3 grams (g) silica gel (SiO.sub.2) and 0.75 milliliters (mL) water. Heat the mixture at 70 C. for 1.5 hours under vacuum, allowing the water to evaporate to dryness. Cool the catalyst to ambient temperature. Add 67 mg nickel(II) nitrate hexahydrate (Ni(NO.sub.3).sub.2.Math.6H.sub.2O) in 0.75 mL H.sub.2O to the mixture. Heat the mixture at 70 C. for 1.5 hours under vacuum. Cool the catalyst to ambient temperature. Add 92 mg chromium(III) nitrate nonahydrate (Cr(NO.sub.3).sub.3.Math.9H.sub.2O) in 0.75 mL H.sub.2O to the mixture. Heat the mixture at 70 C. for 1.5 hours under vacuum. Cool the catalyst to ambient temperature. Add 45 mg ammonium molybdate tetrahydrate ((NH.sub.4).sub.6Mo.sub.7O.sub.24.Math.4H.sub.2O) in 0.75 mL H.sub.2O to the mixture. Heat the mixture at 70 C. for 1.5 hours under vacuum. Cool the catalyst to ambient temperature. Add 148 mg cesium nitrate (CsNO.sub.3) in 0.75 mL of H.sub.2O to the mixture. Heat for 2 hours at 70 C. under vacuum, then increase the heat in static air with a 10 C. per minute heating rate until the temperatures reaches 120 C. and hold for 1 hour. Heat to 210 C. with a 10 C. per minute heating rate and hold for 1 hour. Finally, heat to 350 C. with a 10 C. per minute heating rate and hold for 1 hour. Cool the finished catalyst to ambient temperature.

[0031] Load 0.2 mL of this catalyst into a -inch (0.635 cm) stainless steel tubular reactor. Reduce the catalyst in-situ with flowing H.sub.2 gas at 330 C. for 150 minutes. Heat the reactor and its contents to the temperature stated in Table I using an electric furnace. Use premixed H.sub.2 and CO to pressurize the interior of the reactor to the pressure stated in Table I. The feed gas mixture contains H.sub.2 and CO at the ratios stated in Table I. Pass the feed gas mixture at the stated GHSVs through the reactor to yield a reaction product. Pass the reaction product through a pressure letdown valve and flow past a gas chromatograph (GC) sampling point into a cooled condenser. Collect and analyze both gaseous and liquid products from the condenser. GC analysis of reaction products from the reaction chamber shows that MeOH, EtOH and other alcohols are present. Table I shows product content in terms of molar selectivity to ethanol, all alcohols (ROH selectivity), hydrocarbons and carbon dioxide together with reaction temperature and CO conversion. As used herein, MeOH/ROH means the fraction of alcohols that is attributed to methanol, on a molar basis by carbon atom.

TABLE-US-00001 TABLE 1 a b c d e Temperature ( C.) 270 300 320 340 360 Pressure (psig) 1500 1500 1500 1500 1500 H.sub.2/CO (molar ratio) 1 1 1 1 1 GHSV (hour.sup.1) 4500 4500 4500 4500 4500 CO Conversion 0.05 0.2 0.63 1.4 20.42 (wt %) Ethanol selectivity 0 10 12 11 10 (mole %) ROH selectivity 3 26 33 32 35 (mole %) MeOH/ROH n/a 0.73 0.48 0.47 0.4 (molar ratio) Selectivity to 39 31 25 29 30 hydrocarbons (mole %) Selectivity to CO.sub.2 58 42 41 39 40 (mole %)

EXAMPLE 2

[0032] Replicate Example 1, but use alpha-alumina (-Al.sub.2O.sub.3) instead of SiO.sub.2. Report results in Table 2.

TABLE-US-00002 TABLE 2 a b c d e Temperature ( C.) 270 300 320 340 360 Pressure (psig) 1500 1500 1500 1500 1500 H.sub.2/CO (molar ratio) 1 1 1 1 1 GHSV (hour.sup.1) 4500 4500 4500 4500 4500 CO Conversion 1 2.64 8.38 9.93 29.59 (wt %) Ethanol selectivity 16 19 19 10 7 (mole %) ROH selectivity 67 52 46 33 23 (mole %) MeOH/ROH 0.79 0.54 0.5 0.3 0.3 (molar ratio) Selectivity to 22 25 29 34 39 hydrocarbons (mole %) Selectivity to CO.sub.2 9 21 23 32 37 (mole %)

[0033] The data in Examples 1 and 2 show syngas conversion to alcohols even at relatively low pressures such as 500 psig (3.4 MPa) or less.