Hydrogenation catalyst and method for producing same

Abstract

A method for producing a shaped CuZn catalyst for hydrogenating organic compounds containing a carbonyl function. The shaped catalyst is suitable for hydrogenating aldehydes, ketones and also carboxylic acids and/or their esters, fatty acids and/or their esters, such as fatty acid methyl esters, to the corresponding alcohols, dicarboxylic anhydrides, such as maleic anhydride (MAn), or esters of diacids to dialcohols, such as butanediol. The present invention further relates to CuZn catalysts obtainable by the production method.

Claims

1. A process for producing a shaped tableted catalyst body, comprising the steps of: (a) carrying out a thermal treatment of a metal carbonate mixture by heating to a temperature in the range from 200 C. to 300 C. for a time of from 1 hour to 6 hours to give a thermally treated metal carbonate mixture having a carbonate content in the range from 2.7 to 14.0% by weight, and (b) tableting the thermally treated metal carbonate mixture obtained in step (a), wherein: the metal carbonate mixture is obtained by (i) combining a solution A and a solution B by simultaneous introduction into a joint vessel to form a precipitate 1 at a pH value in the range from 6.0 to 7.5, separating off the precipitate and drying the isolated precipitate by heating to a temperature in the range from 75 C. to 130 C., or (ii) mixing a precipitate 2, a precipitate 3 and optionally one or more precipitates 4, with the precipitates being dried by heating to a temperature in the range from 75 C. to 130 C. before mixing, after mixing or both; and: precipitate 2 is a copper carbonate-containing precipitate obtained by combining a solution C with a solution D by simultaneous introduction into a joint vessel at a pH value in the range from 6.0 to 7.5, precipitate 3 is a zinc carbonate-containing precipitate obtained by combining a solution E with a solution F by simultaneous introduction into a joint vessel at a pH value in the range from 6.0 to 7.5, precipitate 4 is a precipitate containing at least one metal carbonate different from copper carbonate and zinc carbonate and is obtained by combining at least one solution G with at least one solution H by simultaneous introduction into a joint vessel at a pH value in the range from 6.0 to 7.5; and solution A is obtained by dissolving a copper compound, a zinc compound and optionally one or more further metal compounds in a solvent, optionally with the aid of an acid or base, solutions B, D, F and H are identical or different and are obtained by dissolving a carbonate compound in a solvent, solution C is obtained by dissolving a copper compound in a solvent, optionally with the aid of an acid or base, solution E is obtained by dissolving a zinc compound in a solvent, optionally with the aid of an acid or base, and solution G is obtained by dissolving a metal compound which is not a copper or zinc compound in a solvent, optionally with the aid of an acid or base.

2. The process as claimed in claim 1, wherein the thermal treatment is carried out at a temperature in the range from 270 C. to 290 C. for a time of from 1.5 to 5 hours.

3. The process as claimed in claim 1, wherein the copper compound is selected from the group consisting of copper, copper oxide (Cu.sub.2O and/or CuO), copper nitrate, copper sulfate, copper carbonate, copper hydroxide carbonate, copper acetate, copper halides, Cu-ammine complexes and mixtures thereof.

4. The process as claimed in claim 1, wherein the zinc compound is selected from the group consisting of zinc nitrate, zinc sulfate, zinc chloride, zinc carbonate, zinc hydroxide, zinc sulfite, zinc acetate, zinc phosphate, zinc metal and ZnO and mixtures thereof.

5. The process as claimed in claim 1, wherein the metal compound, which is not a copper compound or zinc compound, is a compound selected from the group consisting of Al, Ti, Mn, Ni, Cr, Fe, Co, Mo, Ce and Zr and mixtures thereof.

6. The process as claimed in claim 1, wherein the carbonate compound is selected from the group consisting of alkali metal, alkaline earth metal and ammonium carbonates, alkali metal, alkaline earth metal and ammonium hydrogen carbonates and mixtures thereof.

7. The process as claimed in claim 1, wherein the thermally treated metal carbonate mixture contains 5% by weight or less, based on the total weight of the thermally treated metal carbonate mixture.

8. The process as claimed in claim 1, wherein a lubricant is added in an amount of from 0.1 to 5% by weight, based on the total weight of the composition to be tableted, to the thermally treated powder obtained from step (a) before tableting.

9. The process as claimed in claim 8, wherein the lubricant is added in an amount of from 0.5 to 5% by weight, based on the total weight of the composition to be tableted.

10. The process as claimed in claim 8, wherein the lubricant is graphite.

11. The process as claimed in claim 1, further comprising the step of: (c) reducing the shaped tableted catalyst body obtained from step (b) to give a reduced shaped catalyst body.

12. The process as claimed in claim 11, wherein reduction is effected by hydrogen.

13. The process as claimed in claim 11, wherein reduction is carried out at a temperature in the range from 150 C. to 400 C.

14. The process as claimed in claim 11, wherein reduction is carried out over a time of from 1 hour to 10 days.

15. The process as claimed in claim 11, wherein (a) the reduced shaped catalyst body is covered with a liquid with exclusion of air after reduction, or (b) a mixture of an oxygen-containing gas and an inert gas is supplied to the reduced shaped catalyst body with the concentration of oxygen in the mixture during introduction being from 0.001% by volume to 50% by volume.

16. A shaped tableted catalyst body obtained by a process as claimed in claim 1.

17. The shaped tableted catalyst body as claimed in claim 16, having a carbonate content in the range from 2.7 to 14.0% by weight.

18. A reduced shaped tableted catalyst body obtained by a process as claimed in claim 11, wherein the shaped tableted catalyst body obtained from step (b) has, before reduction, a carbonate content in the range from 2.7 to 14.0% by weight.

19. The reduced shaped tableted catalyst body as claimed in claim 18, whose Cu metal surface area is 19 m.sup.2/g or more, based on the total mass of the catalyst.

20. The shaped tableted catalyst body as claimed in claim 18, containing Cu(0) in a proportion in the range from 5 to 70% by weight, based on the shaped tableted catalyst body.

21. A method for hydrogenating an organic compound comprising the step of exposing the organic compound to a shaped tableted catalyst body as claimed in claim 16, during manufacture of the organic compound.

22. The method as claimed in claim 21 where the organic compound has at least one carbonyl group.

23. The method as claimed in claim 21, wherein the organic compound is selected from the group consisting of aldehydes, ketones and monocarboxylic, dicarboxylic and polycarboxylic acids and/or esters thereof.

24. A method for catalyzing a reaction comprising the step of exposing the reaction to a shaped tableted catalyst body as claimed in claim 16, wherein the reaction is selected from the group consisting of synthesis gas reactions, methanol syntheses, Fischer-Tropsch syntheses, pyridine syntheses, ester hydrogenolyses, amination reactions, N-alkylations, hydrogenations of nitriles, hydrogenation of esters, hydrogenation of diesters to diols, hydrogenation of sugars to polyols, alkylation of a phenol by means of an alcohol, amination of an alcohol, dehydrogenation of a primary alcohol to the aldehyde, dehydrogenation of a secondary alcohol to a ketone, dehydrogenation of alkanes to alkenes, dehydrogenation of cycloalkanes to aromatics, dehydrogenation of diols, hydrogenation of an aldehyde, hydrogenation of an amide, hydrogenation of a fatty acid, selective hydrogenation of a fat, selective hydrogenation of an oil, hydrogenation of a nitroaromatic hydrocarbon, hydrogenation of a ketone, hydrogenation of furfural and hydrogenation of carbon monoxide or carbon dioxide to form methanol.

Description

DESCRIPTION OF THE FIGURE

(1) FIG. 1 shows the dependence of the Cu metal surface area (in m.sup.2/g of sample) of the reduced catalysts on the carbonate content (in % by weight of carbonate) of the unreduced catalysts.

DETERMINATION OF PHYSICAL PARAMETERS

(2) The physical parameters described in the present patent application are, unless indicated otherwise, determined as follows:

(3) Conductivity is determined in accordance with DIN 38404, part 8.

(4) Lateral compressive strength is determined in accordance with DIN EN 1094-5.

(5) Residual loss on ignition is determined in accordance with DIN EN 196-2.

(6) Pore volume and pore radius distribution are determined by mercury intrusion in accordance with DIN 66133.

(7) Carbonate content is determined in accordance with DIN ISO 10693.

(8) Cu metal surface area is determined by N.sub.2O pulse chemisorption.

EXAMPLES

(9) The invention is illustrated with the aid of the following, nonlimiting examples. Even though these examples describe specific embodiments of the invention, they serve merely to illustrate the invention and should not be interpreted as restricting the invention in any way. As a person skilled in the art will know, numerous modifications can be made thereto without going outside the scope of the protection of the invention as defined by the accompanying claims.

Reference Example 1 (Production of the Uncalcined Material)

(10) The uncalcined material is produced by precipitation of the metal nitrates by means of sodium carbonate to form their carbonates, and the precipitate is subsequently filtered off, washed and spray-dried.

(11) Solution 1 is produced by dissolving 675 g of ZnO in 1636 g of HNO.sub.3 (65% strength) and subsequently adding 1020 g of Cu(NO.sub.3).sub.2.3H.sub.2O and 10 l of deionized water. Solution 2 is produced from 1333 g of Na.sub.2CO.sub.3 and 10 l of deionized water. The two solutions are heated to 70 C. and stirred. These are subsequently introduced into a precipitation vessel. The pH in the precipitation vessel is 6.8. The volume flows of solution 1 and 2 are set so that this pH is established. As soon as the two solutions have been used up, the precipitate formed is filtered off and washed with water. The filter cake is then resuspended in about 5 l of water and spray-dried. The resulting dried but still uncalcined pulverulent material is the starting material for the further preparations. The carbonate content of the uncalcined pulverulent material, determined in accordance with DIN ISO 10693, is 16.4% by weight.

Example 1 (Production of Catalyst 1)

(12) For the production of catalyst 1, 100 g of uncalcined material (produced as described in reference example 1) and 2 g of graphite are mixed and tableted to give shaped bodies having a diameter of around 3 mm and a height of about 3 mm. The carbonate content of catalyst 1, determined in accordance with DIN ISO 10693, is 16.1% by weight.

Example 2 (Production of Catalyst 2)

(13) Catalyst 2 is produced by thermally treating uncalcined material (produced as described in reference example 1) for 0.5 hour at 280 C. The carbonate content of this thermally treated powder, determined in accordance with DIN ISO 10693, is 15.4% by weight. 100 g of this thermally treated powder are subsequently mixed with 2 g of graphite and tableted to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 2, determined in accordance with DIN ISO 10693, is 15.1% by weight.

Example 3 (Production of Catalyst 3)

(14) Catalyst 3 is produced by thermally treating uncalcined material (produced as described in reference example 1) for 1.0 hour at 280 C. The carbonate content of this thermally treated powder, determined in accordance with DIN ISO 10693, is 12.3% by weight. 100 g of this thermally treated powder are subsequently mixed with 2 g of graphite and tableted to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 3, determined in accordance with DIN ISO 10693, is 12.1% by weight.

Example 4 (Production of Catalyst 4)

(15) Catalyst 4 is produced by thermally treating uncalcined material (produced as described in reference example 1) for 1.5 hours at 280 C. The carbonate content of this thermally treated powder, determined in accordance with DIN ISO 10693, is 7.7% by weight. 100 g of this thermally treated powder are subsequently mixed with 2 g of graphite and tableted to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 4, determined in accordance with DIN ISO 10693, is 7.5% by weight.

Example 5 (Production of Catalyst 5)

(16) Catalyst 5 is produced by thermally treating uncalcined material (produced as described in reference example 1) for 3 hours at 280 C. The carbonate content of this thermally treated powder, determined in accordance with DIN ISO 10693, is 5.7% by weight. 100 g of this thermally treated powder are subsequently mixed with 2 g of graphite and tableted to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 5, determined in accordance with DIN ISO 10693, is 5.6% by weight.

Example 6 (Production of Catalyst 6)

(17) Catalyst 6 is produced by thermally treating uncalcined material (produced as described in reference example 1) for 4.5 hours at 280 C. The carbonate content of this thermally treated powder, determined in accordance with DIN ISO 10693, is 3.2% by weight. 100 g of this thermally treated powder are subsequently mixed with 2 g of graphite and tableted to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 6, determined in accordance with DIN ISO 10693, is 3.1% by weight.

Example 7 (Production of Catalyst 7)

(18) Catalyst 7 is produced by thermally treating uncalcined material (produced as described in reference example 1) for 6 hours at 280 C. The carbonate content of this thermally treated powder, determined in accordance with DIN ISO 10693, is 2.2% by weight. 100 g of this thermally treated powder are subsequently mixed with 2 g of graphite and tableted to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 7, determined in accordance with DIN ISO 10693, is 2.2% by weight.

Reference Example 2 (Production of Material Calcined at 325 C.)

(19) Calcined material is produced by calcining uncalcined material (produced as described in reference example 1) at 325 C. for 2 hours in a convection oven. The carbonate content of the calcined material, determined in accordance with DIN ISO 10693, is 4.9% by weight.

Example 8 (Production of Catalyst 8)

(20) Catalyst 8 is produced by mixing 15 g of the uncalcined material (produced as described in reference example 1) with 85 g of the powder calcined at 325 C. (produced as described in reference example 2) and 2 g of graphite and tableting the mixture to give shaped bodies having a diameter of about 3 mm and a height of about 3 mm. The carbonate content of catalyst 8, determined in accordance with DIN ISO 10693, is 6.5% by weight.

(21) Comparative Catalyst

(22) A catalyst containing 26% by weight of Cu and 53% by weight of Zn serves as comparative catalyst. The carbonate content, determined in accordance with DIN ISO 10693, is 2.5% by weight. The comparative catalyst is in the form of pellets having a diameter of about 3 mm and a height of about 3 mm and has a pore volume of 210 mm.sup.3/g and a Cu metal surface area of 12.8 m.sup.2/g.

Example 9 (Activity Measurements)

(23) The activity of the catalysts is examined for the hydrogenation of methyl ester of fatty acid (FAME). An electrically heated fixed-bed reactor having a reactor volume of 25 ml is used for this purpose. Methyl laurate (C12-methyl ester) is used for the test. The reaction product formed is analyzed by gas chromatography to evaluate the ester conversion and the selectivity to the fatty alcohol and the formation of by-products. The conversion is calculated from the molar amount of ester used and the molar amount of ester which remains in the product.

(24) For the analysis by gas chromatography, 6.0000 g of the product formed are mixed with 0.2000 g of 5-nonanol (internal standard). The sample is subsequently analyzed twice using a gas chromatograph.

(25) Equipment Used:

(26) GC: Agilent 7890A with FID

(27) Column: ZB-1, 60 m0.25 mm from Phenomenex

(28) Software: EZ Chrom Elite Version 3.3.2 SP1

(29) Test conditions in the hydrogenation of methyl laurate: Reaction temperature: 180 C. Pressure: 280 bar GHSV (H.sub.2): 20 000 h.sup.1 LHSV (ester): 1.4 h.sup.1

(30) Table 1 shows the results for the catalysts described as values for the conversions of C12-methyl ester at 180 C. The improved activity of the catalysts according to the invention compared to the comparative catalyst can clearly be seen.

(31) TABLE-US-00001 TABLE 1 Conversions of C12-methyl ester at 180 C. Conversion of C12-methyl Catalyst ester at 180 C. [%] Catalyst 1 68.0 Catalyst 2 74.1 Catalyst 3 77.8 Catalyst 4 80.0 Catalyst 5 80.5 Catalyst 6 78.5 Catalyst 7 72.0 Catalyst 8 79.3 Comparative catalyst 70.2

(32) Determination of the Cu Metal Surface Area

(33) The Cu metal surface area of the catalysts is determined according to the principle of N.sub.2O decomposition:
2Cu+N.sub.2O.fwdarw.Cu.sub.2O+N.sub.2

(34) For this purpose, the sample is reduced by means of hydrogen (activation gas 5% of H.sub.2 in He) at 240 C. in a TRACE GC ULTRA reduction oven (from Brechbhler) for 16 hours. The sample is subsequently transferred into the TPDRO 1100 series instrument from Thermo Electron, flushed with He and the N.sub.2O pulse chemisorptions is started. The Cu metal surface area is calculated from the amount of N.sub.2 formed in He, which is determined by means of a thermal conductivity detector.

(35) Table 2 shows the values of the carbonate content of the shaped catalyst before reduction and the Cu metal surface area.

(36) TABLE-US-00002 TABLE 2 Carbonate content and Cu metal surface areas Carbonate content Cu metal surface area [% by weight] [m.sup.2/g of catalyst] Catalyst 1 16.1 18.2 Catalyst 2 15.1 19.6 Catalyst 3 12.1 21.2 Catalyst 4 7.5 23.1 Catalyst 5 5.6 23.7 Catalyst 6 3.1 23.0 Catalyst 7 2.2 20.1 Catalyst 8 6.5 21.8 Comparative catalyst 2.5 12.8

(37) The analytical data show that the carbonate content of the catalysts varies as a function of the duration of the thermal treatment. The carbonate content correlates with the Cu metal surface area of the reduced catalysts. A proportion of carbonate in the range from 3.1 to 12.1% by weight gives a relatively high Cu metal surface area of more than 21 m.sup.2 per gram of catalyst. The improvement in the activity in the hydrogenation test is coupled thereto.

(38) It can be seen from Table 1 that the catalysts produced according to the invention display a significantly increased conversion of methyl laurate compared to the comparative catalyst.

(39) In summary, it can thus be stated that an improvement in the economics, in particular an increase in the conversion into the target product, is achieved by the catalyst according to the invention.