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

Abstract

A process for producing a catalyst including a) providing an uncalcined metal modified porous silica support wherein the modifier metal is selected from one or more of boron, magnesium, aluminium, zirconium, hafnium and titanium, wherein the modifier metal is present in mono- or dinuclear modifier metal moieties; b) optionally removing any solvent or liquid carrier from the modified silica support; c) optionally drying the modified silica support; d) treating the uncalcined metal modified silica support with a catalytic metal to effect adsorption of the catalytic metal onto the metal modified silica support; and e) calcining the impregnated silica support of step d). The invention extends to an uncalcined catalyst intermediate and a method of producing a catalyst by providing a porous silica support having isolated silanol groups.

Claims

1. A process for producing a catalyst comprising the steps of: a) providing an uncalcined metal modified porous silica support wherein the modifier metal is selected from one or more of boron, magnesium, aluminium, zirconium, hafnium and titanium, and wherein the modifier metal is present in mono- or dinuclear modifier metal moieties b) optionally removing any solvent or liquid carrier from the modified silica support; c) optionally drying the modified silica support; d) treating the uncalcined metal modified silica support with a catalytic metal to effect adsorption of the catalytic metal onto the metal modified silica support; and e) calcining the impregnated silica support of step d).

2. (canceled)

3. A method of producing a catalyst comprising the steps of: a) providing a porous silica support having isolated silanol groups; b) treating the said porous silica support with mono- or dinuclear modifier metal compound so that modifier metal is adsorbed onto the surface of the silica support through reaction with said isolated silanol groups, wherein the adsorbed modifier metal atoms are sufficiently spaced apart from each other to substantially prevent oligomerisation thereof with neighbouring modifier metal atoms prior to and preferably after calcination, more preferably, sufficiently spaced apart from each other to substantially prevent dimerisation or trimerisation thereof with neighbouring modifier metal atoms thereof wherein the modifier metal is selected from boron, magnesium, aluminium, zirconium, hafnium and titanium; c) optionally removing any solvent or liquid carrier from the modified silica support; d) optionally drying the modified silica support; e) treating the uncalcined modified silica support with a catalytic metal to effect adsorption of the catalytic metal onto the modified silica support; and f) calcining the impregnated silica support of step e).

4. The process according to claim 1: wherein the porous silica support modified with a modifier metal is a modifier metal oxide-silica co-gel support.

5. (canceled)

6. (canceled)

7. The process according to claim 1, wherein the calcination step is carried out at a temperature of at

8. (canceled)

9. (canceled)

10. The process according to claim 1, wherein the silica support is a hydrogel or xerogel.

11. (canceled)

12. (canceled)

13. (canceled)

14. (canceled)

15. The process according to claim 1, wherein the modifier metal is an adsorbate adsorbed on the silica support surface.

16. (canceled)

17. The process according to claim 1, wherein the modifier metal is selected from zirconium, hafnium or titanium.

18. The process according to claim 1, wherein the catalytic metal is an alkali metal.

19. The process according to claim 1, wherein the silica support comprises the said modifier metal at a level of <5 metal atoms per nm.sup.2.

20. The process according to claim1 , wherein at least 25%, of the said modifier metal on the support either before or after catalytic metal calcination is present in the form of mono- or dinuclear modifier metal moieties.

21. The process according to claim 1, wherein the adsorbed or co-gelated modifier metal cations are sufficiently spaced apart from each other to substantially prevent oligomerisation thereof during subsequent treatment steps such as the impregnation of catalytic metal and/or, calcination.

22. The process according to claim 1, wherein the silica support comprises isolated silanol groups (—SiOH) at a level of <2.5 groups per nm.sup.2.

23. (canceled)

24. (canceled)

25. The process according to claim 1, wherein the support comprises the said modifier metal moieties at a level of >0.025 and <2.5 groups per nm.sup.2.

26. (canceled)

27. The process according to claim 1, wherein the silica component of the modified silica support may typically form 80-99.9 wt % of the modified support.

28. The process according to claim1 , wherein the silica support has an average pore size of between 2 and 1000 nm.

29. The process according to claim 1, wherein the catalytic metal is an adsorbate adsorbed on the modified silica support surface of the catalyst.

30. The process according to claim1, wherein the catalytic metals such as caesium may be present in the catalyst at a level of at least 1 mol/100 (silicon+modifier metal) mol.

31. The process according to claim 1, the catalytic metal:modifier metal mole ratio in the catalyst is in the range 1.4 to 5:1.

32. The process according to claim 1, wherein, the catalytic metal is present in the range 0.5-7.0 mol.

33. The process according to claim 1, wherein the level of catalytic metal in the catalyst is in the range from 1-10 mol/100 (silicon+modifier metal) mol.

34. The process according to claim 1, wherein, the level of modifier metal present in the modified silica or catalyst may be up to 7.6×10.sup.−2 mol/mol of silica.

35. The process 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.

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

37. The process according to claim 1, wherein the average pore volume of the catalyst particles may be less than 0.1 cm.sup.3/g but is generally in the range 0.1-5 cm.sup.3/g as measured by uptake of a fluid such as water.

38. The process according to claim 1, wherein average pore volume of the catalyst is between 0.2-2.0 cm.sup.3/g.

39. (canceled)

40. (canceled)

41. (canceled)

42. (canceled)

43. (canceled)

44. The process according to claim1 , wherein the moieties or compounds are mononuclear.

45. The process according to claim 1, wherein the moieties are uniformly distributed throughout the surface of the silica support.

46. The process according to claim1, wherein the modifier metal compounds are uniformly distributed throughout the surface of the silica support.

Description

EXPERIMENTAL

Silica Support Description

Example 1 (Preparative)

[0152] Fuji Silysia CARiACT Q10 silica was dried in a laboratory oven at 160° C. for 16 hours, after which it was removed from the oven and cooled to room temperature in a sealed flask stored in a desiccator. This silica had a surface area of 333 m.sup.2/g, a pore volume of 1.0 ml/g, and an average pore diameter of 10 nm as determined by nitrogen adsorption/desorption isotherm analysis (Micromeritics Tristar II). This silica is primarily composed of spherical silica beads in the diameter range of 2.0-4.0 mm.

Zr Modification of Silica Supports

Example 2 (2.7 wt % Zr, Comparative)

[0153] 1.671 g of, Zr(acac)4 (97%, Sigma Aldrich) was dissolved in 20 ml of MeOH (99% Sigma Aldrich). In a separate flask 10 g of the silica from Example 1 was weighed off. The weighed off silica was then added to the Zr(acac).sub.4 solution with agitation. Agitation was continued until the pore volume of the silica was completely occupied by solvent effectively forming a slurry. Once pore filling had been completed the Zr-modified silica was left for 16 hours in a sealed flask with periodic agitation. After this time the extra-porous solution was removed by filtration. This was followed by a drying step where the intra-porous organic solvent was removed by passing a flow of nitrogen gas over the wet Zr-modified silica at room temperature. Alternatively, the intra-porous solvent was removed on a rotary evaporator at reduced pressure. Once all the solvent had been removed the Zr-modified silica support was calcined in a furnace at 500 ° C. under a flow of air with a heating ramp rate of 5 ° C./min and a final hold of 5 hours. Upon cooling this yielded the Zr grafted silica support with an 89% Zr usage efficiency. The Zr load (wt %) on the Zr-modified support was determined via powder Energy Dispersive X-Ray Fluorescence analysis (Oxford Instruments X-Supreme8000).

Example 3 (2.7 wt % Zr)

[0154] A support modification as described in Example 2 was performed except that after the drying step had been completed an additional 16 h drying step in a laboratory oven set at 110-120° C. was performed. Additionally, the high temperature calcination step at 500° C. was not performed. This yielded a Zr grafted silica support with an 89% Zr usage efficiency. (Note: the Zr loading was determined after an oxidative calcination at 500° C. of a sample of the Zr grafted material).

Cs Modification of Modified Supports

Example 4 (11.3 wt % Cs, 2.4 wt % Zr, Comparative)

[0155] 1.80 g of CsOH.H.sub.2O (99.5% Sigma Aldrich) was weighed out in a glovebox and dissolved in 20 ml of a 9:1 v/v MeOH:H.sub.2O solvent mixture. 10 g of the modified silica from Example 2 was added to the CsOH solution with agitation. Agitation was continued for an additional 15 min after which the sample was left for 16 hours in a sealed flask with periodic agitation. After this time the extra-porous solution was removed by filtration. This was followed by a drying step where the intra-porous solvent was removed by passing a flow of nitrogen gas over the wet Cs/Zr-modified silica at room temperature. Alternatively, the intra-porous solvent was removed on a rotary evaporator at reduced pressure. Following this the catalyst beads were placed into a drying oven at 110-120° C. and left to dry for 16 hours. Upon cooling this yielded the Cs/Zr/SiO.sub.2 catalyst with a 90% Cs usage efficiency. The Cs load (wt %) on the catalyst was determined via powder Energy Dispersive X-Ray Fluorescence analysis (Oxford Instruments X-Supreme8000).

Example 5 (11.0 wt % Cs, 2.4 wt % Zr, Comparative)

[0156] A catalyst was prepared as described in Example 4 except that 1.75 g of CsOH.H.sub.2O was used. Additionally, after the drying step at 120° C. the catalyst was calcined in a furnace at 700° C. under a flow of air with a heating ramp rate of 5° C./min and a final hold of 5 hours. Upon cooling this yielded the Cs/Zr/SiO.sub.2 catalyst.

Example 6 (11.3 wt % Cs, 2.4 wt % Zr)

[0157] A catalyst was prepared as described in Example 4 except that 10.5 g of silica from Example 3 was used. Additionally, after the drying step at 120° C. the catalyst was calcined in a furnace at 700° C. under a flow of air with a heating ramp rate of 5° C./min and a final hold of 5 hours. Upon cooling this yielded the Cs/Zr/SiO.sub.2 catalyst.

Example 7 (10.6 wt % Cs, 2.4 wt % Zr)

[0158] A catalyst was prepared as described in Example 4 except that 10.5 g of silica from Example 3 was used and water was used as a solvent instead of 9:1 v/v MeOH:H.sub.2O. Additionally, after the drying step at 120° C. the catalyst was calcined in a furnace at 400° C. under a flow of air with a heating ramp rate of 5° C./min and a final hold of 5 hours. Upon cooling this yielded the Cs/Zr/SiO.sub.2 catalyst.

Example 8 (10.6 wt % Cs, 2.4 wt % Zr)

[0159] A catalyst was prepared as described in Example 7 except that final calcination was performed at 600° C.

Example 9 (10.6 wt % Cs, 2.4 wt % Zr)

[0160] A catalyst was prepared as described in Example 7 except that final calcination was performed at 700° C.

Example 10 (Catalytic Performance Testing)

[0161] Catalysts from Example 4 to Example 9 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 10 mm. The reactor was heated to 330° 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 vaporiser fed 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 330° C. before being fed to the heated reactor set at 330° 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 ml/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 12% MMA+MAA yield on methyl propionate fed and was determined via an interpolation on a contact time vs. MMA+MAA yield graph. This interpolated contact time was then used to obtain the MMA+MAA selectivity at 12% MMA+MAA yield.

TABLE-US-00001 TABLE 1 Activity and MMA + MAA selectivity results for catalysts prepared according to Example 4 to Example 9 and tested according to Example 10. Cs:Zr Activity at 12% Zr load Cs load (molar Catalyst calcination MMA + MAA yield MMA + MAA Example (wt %) (wt %) ratio) temperature (° C.) (1/s) selectivity (%) Example 4 (comp) 2.4 11.3 3.2 None 0.51 96.1 Example 5 (comp) 2.4 11.0 3.1 700 0.61 96.1 Example 6 2.4 11.3 3.2 700 0.49 97.5 Example 7 2.4 10.6 3.0 400 0.44 94.5 Example 8 2.4 10.6 3.0 600 0.49 96.4 Example 9 2.4 10.6 3.0 700 0.52 97.5

Example 11 (Catalyst Stability Determination)

[0162] Initial catalyst stability was assessed by measurement of the surface area (nitrogen adsorption/desorption isotherm analysis, Micromeritics Tristar II) after a calcination treatment at 700° C. according to Example 5. This provided a means to assess the surface stabilisation imparted to the catalyst.

TABLE-US-00002 TABLE 2 Surface area of catalysts subjected to a 700° C. calcination treatment as a measure of initial stabilisation. Surface area after 700° C. Example calcination (m.sup.2/g) Example 4 (comp) 118 Example 5 (comp) 156 Example 6 210

Example 12 (Accelerated Ageing Test)

[0163] Catalyst sintering resistance was assessed in an accelerated ageing test. For this, 1 g of catalyst was loaded into a U-tube stainless steel reactor and loaded into an oven.

[0164] The oven was heated to 385° C. and a stream of nitrogen (10 ml/min) was passed through a saturating vaporiser containing water that was heated to 92° C. This ensured that a feed stream with a water partial pressure of 0.75 bara was passed over the catalyst heated to 385° C. Periodically the surface area of the catalyst samples was determined ex-situ using nitrogen adsorption/desorption isotherm analysis (Micromeritics Tristar II).

TABLE-US-00003 TABLE 3 Accelerated ageing data for catalysts prepared according to Example 4 to Example 8 and tested according to Example 12. Surface area (m.sup.2/g) at time (days) Example 0 1 7 14 21 28 Example 4 229 179 162 149 151 154 (comp) Example 5 156 140 136 132 134 129 (comp) Example 6 210 200 203 203 194 187 Example 7 258 258 192 202 199 199 Example 8 242 224 208 197 200 200

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.