A CATALYST AND A PROCESS FOR THE PRODUCTION OF ETHYLENICALLY UNSATURATED CARBOXYLIC ACIDS OR ESTERS

Abstract

The invention discloses a catalyst comprising a silica support, a modifier metal and a catalytic alkali metal. The silica support has a multimodal pore size distribution comprising a mesoporous pore size distribution having an average pore size in the range 2 to 50 nm and a pore volume of said mesopores of at least 0.1 cm.sup.3/g, and a macroporous pore size distribution having an average pore size of more than 50 nm and a pore volume of said macropores of at least 0.1 cm.sup.3/g. The level of catalytic alkali metal on the silica support is at least 2 mol %. The modifier metal is selected from Mg, B, Al, Ti, Zr and Hf. The invention also discloses a method of producing the catalyst, a method of producing an ethylenically unsaturated carboxylic acid or ester in the presence of the catalyst, and a process for preparing an ethylenically unsaturated acid or ester in the presence of the catalyst.

Claims

1. A catalyst comprising a silica support, a modifier metal and a catalytic alkali metal, wherein the silica support has a multimodal pore size distribution comprising: a) a mesoporous pore size distribution having an average pore size in the range 2 to 50 nm and a pore volume of said mesopores of at least 0.1 cm.sup.3/g; and b) a macroporous pore size distribution having an average pore size of more than 50 nm and a pore volume of said macropores of at least 0.1 cm.sup.3/g, wherein the level of catalytic alkali metal on the silica support is at least 2 mol %, and wherein the modifier metal is selected from Mg, B, Al, Ti, Zr and Hf.

2. A catalyst according to claim 1, wherein the level of catalytic alkali metal on the silica support is at least 3 mol % and up to 10 mol %.

3. A catalyst according to claim 1, wherein the amount of silica in the support is at least 50 wt %.

4. A catalyst according to claim 1, wherein the average mesopore volume of the catalyst particles is in the range of 0.2-3 cm.sup.3/g as measured by uptake of nitrogen.

5. A catalyst according to claim 1, wherein the average macropore volume of the catalyst particles is in the range of 0.1-3 cm.sup.3/g as measured by uptake of mercury.

6. A catalyst according to claim 1, wherein the macropore:mesopore volume ratio of the catalyst particles are in the range of 0.03-15.

7. A catalyst according to claim 1, wherein the catalyst is substantially free of a compound selected from the group consisting of tungsten, antimony, vanadium, bismuth, a metal of Group 3, a metal of Group 10, a metal of Group 13, a metal of Group 14, and a combination thereof.

8. (canceled)

9. A catalyst according to claim 1, wherein the modifier metal is an adsorbate adsorbed on the silica support surface.

10. A catalyst according to claim 1, wherein the modifier metal is present as modifier metal oxide moieties.

11. A catalyst according to claim 1, wherein the silica support is in the form of a silica gel.

12. A catalyst according to claim 11, wherein the modifier metal is present in the silica support in the form of a co-gel.

13. A catalyst according to claim 1, wherein the level of modifier metal present is up to 7.6×10.sup.−2 mol/mol of silica.

14. A catalyst according to claim 1, wherein the level of modifier metal is between 0.067×10.sup.−2 and 7.3×10.sup.−2 mol/mol of silica.

15. A catalyst according to claim 1, wherein the level of modifier metal present is at least 0.1×10.sup.−2 mol/mol of silica.

16. A catalyst according to claim 1, wherein the silica support is a calcined silica support.

17. A catalyst according to claim 1, wherein the catalytic alkali metal is one or more alkali metals selected from the group consisting of potassium, rubidium and caesium.

18. A catalyst according to claim 1, wherein catalytic alkali metal is present in the range 0.5-7.0 mol/mol modifier metal.

19. A catalyst according to claim 1, wherein the catalytic alkali metal:modifier metal mole ratio is in the range 1.4 to 5:1.

20. A catalyst according to claim 1, wherein the average surface area is in the range 20-1000 m.sup.2/g.

21. A catalyst according to claim 1, wherein the total metal content of the catalyst is at least 80 wt % of the catalytic alkali metal and the modifier metal.

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

Description

[0219] Embodiments of the invention will now be defined by reference to the accompanying examples and figures in which:

[0220] FIG. 1 shows the results of Mercury porosimetry for selected examples:

[0221] FIG. 2 shows the results of N.sub.2 adsorption for selected examples;

[0222] FIG. 3 shows the results of Mercury porosimetry for selected examples; and

[0223] FIG. 4 shows the results of N.sub.2 adsorption for selected examples.

EXPERIMENTAL

[0224] N.sub.2 adsorption

[0225] Catalysts from Example 1 to Example 4 were measured for their mesopore size distribution in mesopore range, 5 to 50 nm, by N.sub.2 adsorption, MICROMERITICS INSTRUMENT CORPORATION TrStar 113020. 0.1-0.2 g of sample was loaded into a dedicated sample cell. The cell was heated to 380° C. under air flow and this preconditioning was carried out for two hours at least. After preconditioning, the sample was weighed and the equipment set up to carry out the surface area determination. N.sub.2 adsorption of the sample was carried out at −196° C. to obtain adsorption-desorption isotherms. The BET surface area and the BJH mesopore size distribution were calculated from their isotherms.

[0226] Mercury Porosimetry

[0227] Catalysts from Example 1 to Example 4 were measured for their macropore size distribution in the macropore range, over 50 nm, by Mercury porosimetry, using a MICROMERITICS INSTRUMENT CORPORATION Autopore IV 9500 instrument. 0.3-1 g of dried sample was loaded into a dedicated sample cell. The cell was loaded into the equipment. Mercury (Hg) was inserted into the catalyst pores in the sample by varying the pressure to obtain the macropore size distribution.

[0228] Silica Support Description

Example 1 (Preparative) (Silica without Macropore)

[0229] Silica gel samples were prepared using a commercially available water glass, Sodium silicate solution EMD Millipore Corporation, containing 25.5 to 28.5 wt % SiO.sub.2 and 7.5 to 8.5 wt % Na.sub.2O, as a silica source.

[0230] 69 g of distilled water and 53 g of Nitric acid (65% HNO.sub.3, Sigma Aldrich), were placed into a plastic flask, to form Solution 1. 80 g of water glass and 73 g of distilled water were placed in a separate flask, to form Solution 2. These two solutions were then mixed, with stirring. This mixed solution was kept at room temperature for 10 to 60 minutes. The solution underwent gelation and was changed to a silica hydrogel. The silica hydrogel was washed by distilled water several times. The silica hydrogel was then aged by contact with a basic solution (0.1M NH.sub.3 solution), in a temperature controlled oil bath at 50° C. for 24 hours. After the ageing process, the silica hydrogel was dried at 50° C., and then calcined at 600° C. in a tubular furnace under a flow of air (1 l/min) for 3 hours. After the calcination process, silica support was sieved to the 1 to 4 mm fraction. After sieving, a silica support without macropores was obtained.

Example 2 (Preparative) (Silica with 0.13 μm Macropore Diameter)

[0231] Silica was prepared as described in Example 1 except that 10 g of polyacrylic acid (Polyacrylic Acid Mw=25000 from Wako Pure Chemicals Corporation), was added to Solution 1, and 66 g of 65% nitric acid was used. The macropore diameter in the resulting processed silica was obtained by Hg porosimetry.

Example 3 (Preparative) (Silica with 0.20 μm Macropore Diameter)

[0232] Silica was prepared as described in Example 1 except that 10 g of polyacrylic acid was added to Solution 1, and 65 g of 65% nitric acid was used. The macropore diameter in the resulting processed silica was obtained by Hg porosimetry.

Example 4 (Preparative) (Silica with 0.88 μm Macropore Diameter)

[0233] Silica was prepared as described in Example 1 except that 9.5 g of polyacrylic acid was added to Solution 1 and 59 g of 65% nitric acid was used. The macropore diameter in the resulting processed silica was obtained by Hg porosimetry.

[0234] Zr Modification of Silica Supports

Example 5 (Preparative) (2.2 wt % Zr, without Macropore)

[0235] 1.57 g of Zr(acac).sub.4 (97% Zirconium acetylacetonate, Sigma Aldrich) was dissolved in 25 ml of Methanol (99.9% anhydrous, Sigma Aldrich). In a separate flask, 11.3 g of the silica from Example 1 was weighed. The weighed silica was then added to the Zr-complex solution. The Zr-modified silica was left for 24 hours in a sealed flask. This was followed by a drying step at room temperature. Once all of the solvent had been removed the Zr-modified silica support was calcined in a tubular furnace at 500° C. under a flow of air (1 l/min) with a heating ramp rate of 5° C./min and a final hold of 5 hours. The Zr load (wt %) on the Zr-modified support was determined by either ion coupled plasma mass spectrometry (ICPMS) or ion coupled plasma atomic emission spectroscopy (ICPAES) analysis.

Example 6 (Preparative) (2.2 wt % Zr, with 0.13 μm Macropore Diameter)

[0236] A support modification as described in Example 5 was performed except that the silica from Example 2 was used. Additionally, 50 ml of methanol was used instead of 25 ml.

Example 7 (Preparative) (2.2 wt % Zr, with 0.20 μm Macropore Diameter)

[0237] A support modification as described in Example 5 was performed except that the silica from Example 3 was used. Additionally, 50 ml of methanol was used instead of 25 ml.

Example 8 (Preparative) (2.2 wt % Zr, with 0.88 μm Macropore Diameter)

[0238] A support modification as described in Example 5 was performed except that the silica from Example 4 was used. Additionally, 50 ml of methanol was used instead of 25 ml.

[0239] Cs Modification of Modified Supports

Example 9 (Comparative) (7.7 wt % Cs, 2.2 wt % Zr, without Macropore)

[0240] 0.329 g of CsOH.H.sub.2O (99.5% Sigma Aldrich) was weighed out in a glovebox and dissolved in 20 ml MeOH (99.9% anhydrous MeOH from Sigma Aldrich) solvent. 3.1 g of the modified silica from Example 5 was added to the CsOH solution. The sample was left for 24 hours in a sealed flask. This was followed by a drying step at room temperature. Following this step, the catalyst granules were placed into a drying oven at 110-120° C. and left to dry for 16 hours.

Example 10 (Comparative) (9.6 wt % Cs, 2.2 wt % Zr, without Macropore)

[0241] A catalyst was prepared as described in Example 9 except that 0.419 g of CsOH.H.sub.2O was used.

Example 11 (Comparative) (11.4 wt % Cs, 2.2 wt % Zr, without Macropore)

[0242] A catalyst was prepared as described in Example 9 except that 0.509 g of CsOH.H.sub.2O was used.

Example 12 (7.7 wt % Cs, 2.2 wt % Zr, with 0.13 μm Macropore Diameter)

[0243] A catalyst was prepared as described in Example 9 except that modified silica from Example 6 was used.

Example 13 (9.6 wt % Cs, 2.2 wt % Zr, with 0.13 μm Macropore Diameter)

[0244] A catalyst was prepared as described in Example 9 except that 0.419 g of CsOH.H.sub.2O was used and modified silica from Example 6 was used.

Example 14 (11.4 wt % Cs, 2.2 wt % Zr, with 0.13 μm Macropore Diameter)

[0245] A catalyst was prepared as described in Example 9 except that 0.509 g of CsOH.H.sub.2O was used and modified silica from Example 6 was used.

Example 15 (7.7 wt % Cs, 2.2 wt % Zr, with 0.20 μm Macropore Diameter)

[0246] A catalyst was prepared as described in Example 9 except that modified silica from Example 7 was used.

Example 16 (9.6 wt % Cs, 2.2 wt % Zr, with 0.20 μm Macropore Diameter)

[0247] A catalyst was prepared as described in Example 9 except that 0.419 g of CsOH.H.sub.2O was used and modified silica from Example 7 was used.

Example 17 (11.4 wt % Cs, 2.2 wt % Zr, with 0.20 μm Macropore Diameter)

[0248] A catalyst was prepared as described in Example 9 except that 0.509 g of CsOH.H.sub.2O was used and modified silica from Example 7 was used.

Example 18 (7.7 wt % Cs, 2.2 wt % Zr, with 0.88 μm Macropore Diameter)

[0249] A catalyst was prepared as described in Example 9 except that modified silica from Example 8 was used.

Example 19 (9.6 wt % Cs, 2.2 wt % Zr, with 0.88 μm Macropore Diameter)

[0250] A catalyst was prepared as described in Example 9 except that 0.419 g of CsOH.H.sub.2O was used and modified silica from Example 8 was used.

Example 20 (11.4 wt % Cs, 2.2 wt % Zr, with 0.88 μm Macropore Diameter)

[0251] A catalyst was prepared as described in Example 9 except that 0.509 g of CsOH.H.sub.2O was used and modified silica from Example 8 was used.

[0252] Silica-Zirconia Support Description (Co-Gel)

Example 21 (Preparative) (Silica-Zirconia without Macropore)

[0253] 2.16 g of Zirconium oxynitrate hydrate (Sigma Aldrich) was dissolved in 69 g of distilled water and 59 g of Nitric acid (65% HNO.sub.3 Sigma Aldrich) in a plastic flask, to form Solution 1. 80 g of water glass and 73 g of distilled water were mixed in a separate flask, to form Solution 2. These two solutions were then mixed with stirring. This mixed solution was kept at room temperature for 10 to 60 minutes. The solution underwent gelation and changed to a silica-zirconia hydrogel (co-gel). The silica hydrogel was washed by distilled water several times. The silica-zirconia hydrogel was then aged by contact with a basic solution (1M NH.sub.3 solution), in a temperature controlled oil bath at 70° C. After the ageing process, the silica-zirconia hydrogel was dried at 50° C. and calcined at 600° C. in a tubular furnace under a flow of air (1 I/min) for 3 hours. After the calcination process, the silica-zirconia support was sieved 1 to 4 mm. After sieving, a silica-zirconia support without macropores was obtained.

Example 22 (Preparative) (Silica-Zirconia with 0.42 μm Macropore Diameter)

[0254] Silica-Zirconia was prepared as described in Example 21 except that 10 g of polyacrylic acid (Polyacrylic Acid Mw=25000 Wako Pure Chemicals Corporation), was added to Solution 1, and 64 g of 65% nitric acid was used. The macropore diameter was obtained by Hg porosimetry.

Example 23 (Preparative) (Silica-Zirconia with 0.61 μm Macropore Diameter)

[0255] Silica-Zirconia was prepared as described in Example 21 except that 9.5 g of polyacrylic acid (Polyacrylic Acid Mw=25000 Wako Pure Chemicals Corporation), was added to Solution 1 and 53 g of 65% nitric acid was used. The macropore diameter was obtained by Hg porosimetry.

[0256] Cs Modification of Silica-Zirconia Supports

Example 24 (Comparative) (8.0 wt % Cs, 2.4 wt % Zr, without Macropore)

[0257] 0.341 g of CsOH.H.sub.2O (99.5% Sigma Aldrich) was weighed out in a glovebox and dissolved in 20 ml MeOH (99.9% anhydrous MeOH from Sigma Aldrich) solvent. 3.1 g of the Silica-Zirconia support from Example 21 was added to the CsOH solution. The sample was left for 24 hours in a sealed flask. This was followed by a drying step at room temperature. Following this step, the catalyst granules were placed into a drying oven at 110-120° C. and left to dry for 16 hours.

Example 25 (Comparative) (9.5 wt % Cs, 2.4 wt % Zr, without Macropore)

[0258] A catalyst was prepared as described in Example 24 except that 0.411 g of CsOH.H.sub.2O was used.

Example 26 (Comparative) (11 wt % Cs, 2.4 wt % Zr, without Macropore)

[0259] A catalyst was prepared as described in Example 24 except that 0.484 g of CsOH.H.sub.2O was used.

Example 27 (8.0 wt % Cs, 2.4 wt % Zr, with 0.42 μm Macropore Diameter)

[0260] A catalyst was prepared as described in Example 24 except that Silica-Zirconia from Example 22 was used.

Example 28 (9.5 wt % Cs, 2.4 wt % Zr, with 0.42 μm Macropore Diameter)

[0261] A catalyst was prepared as described in Example 24 except that 0.411 g of CsOH.H.sub.2O was used and Silica-Zirconia from Example 22 was used.

Example 29 (11 wt % Cs, 2.4 wt % Zr, with 0.42 μm Macropore Diameter)

[0262] A catalyst was prepared as described in Example 24 except that 0.484 g of CsOH.H.sub.2O was used and Silica-Zirconia from Example 22 was used.

Example 30 (8.0 wt % Cs, 2.4 wt % Zr, with 0.61 μm Macropore Diameter)

[0263] A catalyst was prepared as described in Example 24 except that Silica-Zirconia from Example 23 was used.

Example 31 (9.5 wt % Cs, 2.4 wt % Zr, with 0.61 μm Macropore Diameter)

[0264] A catalyst was prepared as described in Example 24 except that 0.411 g of CsOH.H.sub.2O was used and Silica-Zirconia from Example 23 was used.

Example 32 (11 wt % Cs, 2.4 wt % Zr, with 0.61 μm Macropore Diameter)

[0265] A catalyst was prepared as described in Example 24 except that 0.484 g of CsOH.H.sub.2O was used and Silica-Zirconia from Example 23 was used.

Example 33 (Catalytic Performance Testing)

[0266] Catalysts from Examples 9 to 20 and Examples 24 to 32 were tested for the reaction of methyl propionate and formaldehyde in a labscale microreactor. For this, 3 g of catalyst was loaded into a fixed bed reactor with an internal tube diameter of 18 mm. The reactor was heated to 350° C. and preconditioning was performed by feeding a vaporised stream comprising of 70 wt % methyl propionate, 20 wt % methanol, 6 wt % water and 4 wt % formaldehyde from a vaporiserfed by a Gilson pump at 0.032 ml/min. This preconditioning was continued overnight. After preconditioning, a feed stream comprising of 75.6 wt % methyl propionate, 18.1 wt % methanol, 5.7 wt % formaldehyde and 0.6 wt % water, was pumped by a Gilson pump to a vaporiser set at 350° C. before being fed to the heated reactor set at 350° C. containing the catalyst. The reactor exit vapour was cooled and condensed with samples being collected at five different liquid feed rates (between 0.64-0.032 m/min) so as to obtain conversions at varying vapour/catalyst contact times. The liquid feed and condensed ex-reactor liquid products were analysed by a Shimadzu 2010 Gas Chromatograph with a DB1701 column. The compositions of the samples were determined from the respective chromatograms and yields and selectivities at varying contact times determined. Activity was defined as the inverse of the contact time, in seconds, required to obtain 10% MMA+MAA yield on methyl propionate fed and was determined via an interpolation on a contact time vs. MMA+MAA yield graph.

[0267] This interpolated contact time was then used to obtain the MMA+MAA selectivity at 10% MMA+MAA yield.

[0268] Catalytic performance data for the aforementioned examples, along with composition and porosity data, is summarised below in Tables 1 and 2.

[0269] Pore size distribution data for the macroporous silica (Examples 1 to 4) and macroporous silica-zirconia supports (Examples 21 to 23) are shown in FIGS. 1 to 4. FIGS. 1 and 3 are macropore size distributions obtained by mercury porosimetry, and FIGS. 2 and 4 are mesopore size distributions obtained by N.sub.2 adsorption BJH analysis.

TABLE-US-00001 TABLE 1 Composition, Porosity, MMA + MAA and Heavies Selectivity Data for Catalysts Derived from Mesoporous and Mesoporous-Macroporous Silica Supports. Zr Cs Mesopore Macropore Macropore MMA + MAA Heavies load load volume volume diameter selectivity selectivity Example (wt %) (wt %) (cm.sup.3/g) (cm.sup.3/g) (μm) (%) (%) Example 9 2.2 7.7 0.82 — — 97.0 1.67 Example 10 2.2 9.6 0.82 — — 95.8 3.17 Example 11 2.2 11.4 0.82 — — 95.0 3.84 Example 12 2.2 7.7 1.30 0.97 0.13 97.3 1.03 Example 13 2.2 9.6 1.30 0.97 0.13 97.1 1.63 Example 14 2.2 11.4 1.30 0.97 0.13 96.5 2.09 Example 15 2.2 7.7 1.26 1.31 0.20 97.3 1.09 Example 16 2.2 9.6 1.26 1.31 0.20 97.4 1.44 Example 17 2.2 11.4 1.26 1.31 0.20 97.1 1.89 Example 18 2.2 7.7 1.24 1.98 0.88 96.7 1.28 Example 19 2.2 9.6 1.24 1.98 0.88 97.4 1.45 Example 20 2.2 11.4 1.24 1.98 0.88 97.1 1.89

TABLE-US-00002 TABLE 2 Composition, Porosity, MMA + MAA and Heavies Selectivity Data for Catalysts Derived from Mesoporous and Mesoporous-Macroporous Silica-Zirconia Supports (Co-gel). Zr Cs Mesopore Macropore Macropore MMA + MAA Heavies load load volume volume diameter selectivity selectivity Example (wt %) (wt %) (cm.sup.3/g) (cm.sup.3/g) (μm) (%) (%) Example 24 2.4 8.0 0.76 — — 95.5 2.94 Example 25 2.4 9.5 0.76 — — 95.9 2.97 Example 26 2.4 11.0 0.76 — — 94.9 3.86 Example 27 2.4 8.0 0.79 1.20 0.42 96.2 1.27 Example 28 2.4 9.5 0.79 1.20 0.42 96.9 1.69 Example 29 2.4 11.0 0.79 1.20 0.42 96.8 2.02 Example 30 2.4 8.0 0.78 1.26 0.61 95.6 1.36 Example 31 2.4 9.5 0.78 1.26 0.61 96.5 1.73 Example 32 2.4 11.0 0.78 1.26 0.61 96.7 1.82

[0270] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0271] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0272] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0273] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the preferred, typical or optional invention features disclosed in this specification (including any accompanying claims, abstract or drawings), or to any novel one, or any novel combination, of the preferred, typical or optional invention steps of any method or process so disclosed