CATALYST CARRIER AND CATALYST COMPRISING SAME

Abstract

The present application relates to a catalyst carrier for use in the synthesis of dialkyl oxalates by gas-phase catalytic coupling of carbon monoxide comprising microscopic fine pores and one or more macroscopic large pores running through the catalyst carrier, wherein the ratio of the average pore diameter of each macroscopic large pore to the average diameter of the catalyst carrier is 0.2 or more. The present application also relates to a catalyst, comprising the catalyst carrier, an active component and an optional auxiliary, supported on the catalyst carrier. The catalyst according to the present invention not only catalyze effectively coupling of carbon monoxide in a gas phase to form dialkyl oxalate, but also improves heat dissipation, reduces pressure drop, reduces the amount applied of precious metal such as palladium, thereby reducing the use cost of the catalyst and production cost of dialkyl oxalate and then facilitating industrial mass production of dialkyl oxalate.

Claims

1. A catalyst carrier for use in the synthesis of dialkyl oxalates by gas-phase catalytic coupling of carbon monoxide comprising microscopic fine pores and one or more macroscopic large pores running through the catalyst carrier, wherein the ratio of the average pore diameter of each macroscopic large pore to the average diameter of the catalyst carrier is 0.2 or more.

2. The catalyst carrier of claim 1, wherein the catalyst carrier has one macroscopic large pore which runs through the catalyst carrier in the form of a straight line.

3. The catalyst carrier of claim 1, wherein the ratio of the average pore diameter of each macroscopic large pore to the average diameter of the catalyst carrier is from 0.5 to 0.8.

4. The catalyst carrier of claim 1, wherein the macroscopic large pore has a circular or elliptical cross-section.

5. The catalyst carrier of claim 1, wherein the catalyst carrier is spherical or ellipsoidal.

6. The catalyst carrier of claim 1, wherein the catalyst carrier has an average diameter of from 1 to 20 mm.

7. The catalyst carrier of claim 1, wherein the catalyst carrier is made of -alumina, alumina, silica, silicon carbide, diatomaceous earth, activated carbon, pumice, zeolites, molecular sieves, or titanium dioxide.

8. A catalyst for use in the synthesis of dialkyl oxalates by gas-phase catalytic coupling of carbon monoxide comprising a catalyst carrier, an active component and optionally an auxiliary, supported on the catalyst carrier, wherein the catalyst carrier comprising microscopic fine pores and one or more macroscopic large pores running through the catalyst carrier, wherein the ratio of the average pore diameter of each macroscopic large pore to the average diameter of the catalyst carrier is 0.2 or more.

9. The catalyst of claim 8, wherein the active component is palladium, platinum, ruthenium, rhodium and/or gold, and wherein the auxiliary is iron, nickel, cobalt, cerium, titanium and/or zirconium.

10. The catalyst of claim 8, wherein the active component is in an amount of from 0.1 to 10% by weight, and wherein the auxiliary is in an amount of from 0 to 5% by weight, based on the total weight of the catalyst.

11. The catalyst of claim 8, wherein the catalyst carrier has one macroscopic large pore which runs through the catalyst carrier in the form of a straight line.

12. The catalyst of claim 8, wherein the ratio of the average pore diameter of each macroscopic large pore to the average diameter of the catalyst carrier is from 0.5 to 0.8.

13. The catalyst of claim 8, wherein the macroscopic large pore has a circular or elliptical cross-section.

14. The catalyst of claim 8, wherein the catalyst carrier is spherical or ellipsoidal.

15. The catalyst of claim 8, wherein the catalyst carrier has an average diameter of from 1 to 20 mm.

16. The catalyst of claim 8, wherein the catalyst carrier is made of -alumina, -alumina, silica, silicon carbide, diatomaceous earth, activated carbon, pumice, zeolites, molecular sieves, or titanium dioxide.

17. The catalyst carrier of claim 7, wherein the catalyst carrier is made of -alumina.

18. The catalyst of claim 16, wherein the catalyst carrier is made of -alumina.

19. The catalyst carrier of claim 2, wherein the ratio of the average pore diameter of each macroscopic large pore to the average diameter of the catalyst carrier is from 0.5 to 0.8.

20. The catalyst carrier of claim 9, wherein the active component is in an amount of from 0.1 to 10% by weight, and wherein the auxiliary is in an amount of from 0 to 5% by weight, based on the total weight of the catalyst.

Description

EXAMPLES

[0053] Hereinafter, the present invention will be specifically described by referring to the examples, but the examples are not construed to limit the scope of the present invention.

[0054] The specific surface area is determined by the multipoint BET method. The water absorption rate is determined by the following method: 3 g of the carrier is weighed, and soaked in water of 90 C. for 1 hour, then taken out, dried with wiping and weighed. The water absorption rate of the carrier is calculated according to the following formula: W=(BG)/G100%, where W is the water absorption rate, G is the initial weight of the carrier, and B is the weight of the carrier after soaking in water for 1 hour. The amounts of palladium and iron loaded are determined by ICP atomic emission spectrometry, for example, by means of an inductively coupled plasma-atomic emission spectrometer. The time-space yield and selectivity of dimethyl oxalate are determined by gas chromatography analysis.

Example 1

Preparation of Catalyst Carrier

[0055] Pseudoboehmite having a purity of 99.99% and a specific surface area of 310 m.sup.2/g was wetted with an aqueous solution of 1 wt % nitric acid, kneaded and extruded into hollow cylinders having an inner diameter of 4.6 mm and an outer diameter of 6.5 mm. Next, the hollow cylinders were pelletized and rounded using a pelletizer with a rolling cutter to make spheres having a macroscopic large pore running through the two ends of the carrier. The hollow spheres were dried at 120 C. overnight, and calcined at 1250 C. for 8 hours to obtain the catalyst carrier of the present invention, namely a hollow spherical -alumina carrier having microscopic fine pores and one macroscopic large pore which runs through the two ends of the carrier in the form of a straight line with a diameter of the sphere as the central axis, wherein the average diameter of the carrier is 5 mm, the average pore diameter of the macroscopic large pore is 3.5 mm, the average pore diameter/average diameter ratio is 0.7, the specific surface area of the carrier is 5.3 m.sup.2/g, the water absorption rate is 30.1 wt %, and the packing density is 0.51 kg/L.

Preparation of Catalyst

[0056] 50 g of the inventive catalyst carrier of Example 1 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.21 g of palladium chloride and 0.31 g of ferric chloride hexahydrate in 14.5 g of water and 0.12 g of 61% hydrochloric acid with heating, subsequently impregnated in 50 g of an aqueous solution of 1N sodium hydroxide with stirring for 4 hours at 60 C. for alkali treatment, washed with deionized water until the washing liquor was free of chloride ions by silver nitrate detection, completely dried in a drying oven at 120 C., transferred to a quartz glass tube having an inner diameter of 20 mm, and subjected to a reduction treatment with a stream of hydrogen gas at 500 C. for 3 hours to obtain the catalyst of the present invention, namely a hollow spherical -alumina catalyst, wherein the amounts of palladium and iron loaded are 0.25 wt % and 0.13 wt %, respectively, and the loading densities are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0057] 30 ml of the catalyst of the present invention prepared as described above was charged into a glass reaction tube having an inner diameter of 20 mm and a length of 55 cm, and glass balls were filled in the upper and lower portions thereof. The temperature inside the catalyst layer was controlled at 120 C. A mixed gas consisting of 20 vol % of carbon monoxide, 15 vol % of methyl nitrite, 15 vol % of methanol, 3 vol % of nitric monoxide and 47 vol % of nitrogen was introduced from the upper portion of the reaction tube at a space velocity of 5000/h. The reaction product was brought into contact with methanol to absorb dimethyl oxalates in methanol, and the unabsorbed low boilers were captured by dry ice-methanol condensation. Gas chromatography was used to analyze the mixture of the methanol absorption liquid and the capture liquid obtained after the reaction became stable, and the time-space yield and selectivity of dimethyl oxalate were determined. The results are shown in Table 1.

Example 2

Preparation of Catalyst Carrier

[0058] Example 1 was repeated except for extruding into hollow cylinders having an inner diameter of 3.3 mm and an outer diameter of 6.5 mm, obtaining a hollow spherical -alumina carrier having an average pore diameter/average diameter ratio of 0.5, wherein the average diameter is 5 mm, the average pore diameter is 2.5 mm, the specific surface area is 5.3 m.sup.2/g, the water absorption rate is 30.1 wt %, and the packing density is 0.75 kg/L.

Preparation of Catalyst

[0059] 50 g of the inventive catalyst carrier of Example 2 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.14 g of palladium chloride and 0.21 g of ferric chloride hexahydrate in 14.6 g of water and 0.08 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.17 wt % and 0.09 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0060] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Example 3

Preparation of Catalyst Carrier

[0061] Example 1 was repeated except for extruding into hollow cylinders having an inner diameter of 2.0 mm and an outer diameter of 6.5 mm, obtaining a hollow spherical -alumina carrier having an average pore diameter/average diameter ratio of 0.3, wherein the average diameter is 5 mm, the average pore diameter is 1.5 mm, the specific surface area is 5.3 m.sup.2/g, the water absorption rate is 30.1 wt %, and the packing density is 0.91 kg/L.

Preparation of Catalyst

[0062] 50 g of the inventive catalyst carrier of Example 3 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.12 g of palladium chloride and 0.17 g of ferric chloride hexahydrate in 14.7 g of water and 0.07 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.14 wt % and 0.07 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

[0063] Evaluation of Catalyst Performance

[0064] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Example 4

Preparation of Catalyst Carrier

[0065] Example 1 was repeated except for extruding into hollow cylinders having an inner diameter of 2.7 mm and an outer diameter of 3.9 mm, obtaining a hollow spherical -alumina carrier having an average pore diameter/average diameter ratio of 0.7, wherein the average diameter is 3 mm, the average pore size is 2.1 mm, the specific surface area is 5.3 m.sup.2/g, the water absorption rate is 30.1 wt %, and the packing density is 0.51 kg/L.

Preparation of Catalyst

[0066] 50 g of the inventive catalyst carrier of Example 4 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.21 g of palladium chloride and 0.31 g of ferric chloride hexahydrate in 14.5 g of water and 0.12 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.25 wt % and 0.13 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0067] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Example 5

Preparation of Catalyst Carrier

[0068] Example 1 was repeated except for replacing the nitric acid used in the kneading with acetic acid, and extruding into hollow cylinders having an inner diameter of 5.1 mm and an outer diameter of 7.3 mm, obtaining a hollow spherical -alumina carrier having an average pore diameter/average diameter ratio of 0.7, wherein the average diameter is 5.6 mm, the average pore diameter is 3.9 mm, the specific surface area is 10.1 m.sup.2/g, the water absorption rate is 40.2 wt %, and the packing density is 0.42 kg/L.

Preparation of Catalyst

[0069] 50 g of the inventive catalyst carrier of Example 5 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.26 g of palladium chloride and 0.39 g of ferric chloride hexahydrate in 19.5 g of water and 0.15 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.31 wt % and 0.16 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0070] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Example 6

Preparation of Catalyst Carrier

[0071] Example 1 was repeated except for increasing the calcination temperature to 1300 C., obtaining a hollow spherical -alumina carrier having an average pore diameter/average diameter ratio of 0.7, wherein the average diameter is 4.9 mm, the average pore diameter is 3.4 mm, the specific surface area is 2.8 m.sup.2/g, the water absorption rate is 19.7 wt %, and the packing density is 0.58 kg/L.

Preparation of Catalyst

[0072] 50 g of the inventive catalyst carrier of Example 6 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.18 g of palladium chloride and 0.27 g of ferric chloride hexahydrate in 9.4 g of water and 0.11 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.22 wt % and 0.11 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0073] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Example 7

Preparation of Catalyst

[0074] 50 g of the inventive catalyst carrier of Example 1 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.42 g of palladium chloride and 0.62 g of ferric chloride hexahydrate in 14.0 g of water and 0.24 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.50 wt % and 0.26 wt %, respectively, and the loading densities of palladium and iron are 2.6 g/L and 1.3 g/L, respectively.

Evaluation of Catalyst Performance

[0075] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Comparative Example 1

Preparation of Catalyst Carrier

[0076] Example 1 was repeated except that no hollow mold was used for extrusion. In this way, a comparative catalyst carrier, i.e., a spherical -alumina carrier having only microscopic fine pores, was obtained, wherein the average diameter is 5 mm, the specific surface area was 5.3 m.sup.2/g, the water absorption is 30.1 wt % and the packing density is 1.0 kg/L.

Preparation of Catalyst

[0077] 50 g of the catalyst carrier of Comparative Example 1 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.11 g of palladium chloride and 0.16 g of ferric chloride hexahydrate in 14.7 g of water and 0.06 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.13 wt % and 0.07 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0078] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Comparative Example 2

Preparation of Catalyst Carrier

[0079] Example 1 was repeated except for extruding into hollow cylinders having an inner diameter of 0.7 mm and an outer diameter of 6.5 mm, obtaining a hollow spherical -alumina carrier having an average pore diameter/average diameter ratio of 0.1, wherein the average diameter is 5 mm, the average pore diameter is 0.5 mm, the specific surface area was 5.3 m.sup.2/g, the water absorption rate is 30.1 wt %, and the packing density is 0.99 kg/L.

Preparation of Catalyst

[0080] 50 g of the catalyst carrier of Comparative Example 2 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.11 g of palladium chloride and 0.16 g of ferric chloride hexahydrate in 14.7 g of water and 0.06 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.13 wt % and 0.07 wt %, respectively, and the loading densities of palladium and iron are 1.3 g/L and 0.7 g/L, respectively.

Evaluation of Catalyst Performance

[0081] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

Comparative Example 3

Preparation of Catalyst

[0082] 50 g of the catalyst carrier of Comparative Example 1 was impregnated in an equal volume for 2 hours with a mixed impregnating solution prepared by dissolving 0.22 g of palladium chloride and 0.32 g of ferric chloride hexahydrate in 14.5 g of water and 0.13 g of 61% hydrochloric acid with heating, and the other steps were the same as those in Example 1. In this way, a hollow spherical -alumina catalyst was obtained, wherein the amounts of palladium and iron loaded are 0.26 wt % and 0.13 wt %, respectively, and the loading densities of palladium and iron are 2.6 g/L and 1.3 g/L, respectively.

Evaluation of Catalyst Performance

[0083] The evaluation method is the same as that in Example 1, and the results are shown in Table 1.

TABLE-US-00001 Catalyst carrier Catalyst Catalyst performance Average Average Palla- Time-space diameter of pore Specific Water Palla- dium Iron yield of Selectivity Average macroscopic diameter/ surface absorption Packing dium Iron loading loading dimethyl of dimethyl diameter large pore average area rate density loading loading density density oxalate oxalate mm mm diameter m.sup.2/g % kg/L wt % wt % g/L g/L g/L .Math. h % Ex. 1 5 3.5 0.7 5.3 30.1 0.51 0.25 0.13 1.3 0.7 942 97.7 Ex. 2 5 2.5 0.5 5.3 30.1 0.75 0.17 0.09 1.3 0.7 850 97.5 Ex. 3 5 1.5 0.3 5.3 30.1 0.91 0.14 0.07 1.3 0.7 723 97.6 Ex. 4 3 2.1 0.7 5.3 30.1 0.51 0.25 0.13 1.3 0.7 991 97.8 Ex. 5 5.6 3.9 0.7 10.1 40.2 0.42 0.31 0.16 1.3 0.7 928 97.9 Ex. 6 4.9 3.4 0.7 2.8 19.7 0.58 0.22 0.11 1.3 0.7 931 97.6 Ex. 7 5 3.5 0.7 5.3 30.1 0.51 0.50 0.26 2.6 1.3 1189 97.4 Com. Ex. 1 5 0.0 0 5.3 30.1 1 0.13 0.07 1.3 0.7 576 97.4 Com. Ex. 2 5 0.5 0.1 5.3 30.1 0.99 0.13 0.07 1.3 0.7 588 97.5 Com. Ex. 3 5 0.0 0 5.3 30.1 1 0.26 0.13 2.6 1.3 810 97.3