Catalyst and a process for the production of ethylenically unsaturated carboxylic acids or esters
11602733 · 2023-03-14
Assignee
Inventors
Cpc classification
B01J37/086
PERFORMING OPERATIONS; TRANSPORTING
B01J37/0203
PERFORMING OPERATIONS; TRANSPORTING
C07C51/353
CHEMISTRY; METALLURGY
B01J21/066
PERFORMING OPERATIONS; TRANSPORTING
C07C69/54
CHEMISTRY; METALLURGY
C07C69/54
CHEMISTRY; METALLURGY
C07C67/313
CHEMISTRY; METALLURGY
International classification
Abstract
A catalyst has a modified silica support and comprises a modifier metal, zirconium and/or hafnium, and a catalytic metal on the modified support. The catalyst has at least a proportion, typically, at least 25%, of modifier metal present in moieties having a total of up to 2 modifier metal atoms. The moieties may be derived from a monomeric and/or dimeric cation source. A method of production:— provides a silica support with isolated silanol groups with optional treatment to provide isolated silanol groups (—SiOH) at a level of <2.5 groups per nm.sup.2; contacting the optionally treated silica support with a monomeric zirconium or hafnium modifier metal compound to effect adsorption onto the support; optionally calcining the modified support for a time and temperature sufficient to convert the monomeric zirconium or hafnium compound adsorbed on the surface to an oxide or hydroxide of zirconium or hafnium in preparation for catalyst impregnation.
Claims
1. A catalyst comprising a) a silica support modified with a modifier metal present on a surface thereof, and b) a catalytic metal on the silica support, wherein the modifier metal is selected from the group consisting of zirconium and hafnium with at least a proportion of the modifier metal present as a monomeric and/or dimeric metal moiety, wherein the catalytic metal is at least one alkali metal.
2. A catalyst according to claim 1, wherein the modifier metal is present in the silica support in an effective amount to reduce sintering and improve selectivity of the catalyst.
3. A catalyst according to claim 1, wherein the catalytic metal is caesium.
4. A catalyst according to claim 1, wherein catalytic metal is present in the range 0.5-7.0 mol/mol modifier metal.
5. A modified silica support for a catalyst having at least one alkali metal comprising a silica support modified with a modifier metal present on a surface thereof, wherein the modifier metal is selected from the group consisting of zirconium and/or hafnium with at least a proportion of the modifier metal present as a monomeric and/or dimeric metal oxide moiety.
6. A modified silica support according to claim 5, wherein the modifier metal is an adsorbate adsorbed on the silica support surface.
7. A modified silica support according to claim 5, wherein the silica support is in the form of a silica gel.
8. A modified silica support according to claim 5, wherein the modifier metal is present in the support in the form of a co-gel.
9. A modified silica support according to claim 5, wherein at least 25% of the modifier metal in the modified silica support is present as the monomeric and/or dimeric metal oxide moiety.
10. A modified silica support according to claim 5, wherein the level of modifier metal present is up to 7.6×10−2 mol/mol of silica.
11. A modified silica support according to claim 5, wherein the level of modifier metal is between 0.067×10−2 and 7.3×10−2 mol/mol of silica.
12. A modified silica support according to claim 5, wherein the level of modifier metal present is at least 0.1×10−2 mol/mol of silica.
13. A modified silica support according to claim 5, wherein the modified silica support is a calcined modified silica support.
Description
(1) Embodiments of the invention will now be defined by reference to the accompanying examples and figures in which:
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EXPERIMENTAL
Silica Support Description
Example 1
(11) Fuji Silysia CARiACT Q10 silica (Q10) 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 (Micromeretics Tristar II). A silanol number of 0.8 OH/nm.sup.2 was found through TGA analysis. This silica is primarily composed of spherical silica beads in the diameter range of 2-4 mm.
Example 2
(12) Fuji Silysia CARiACT Q30 silica (Q30) was calcined in a tubular furnace at 900° C. for 5 hours with a heating ramp rate of 5° C./min under a flow of nitrogen gas. It was then cooled down to room temperature and stored in a sealed flask in a desiccator. This silica had a surface area of 112 m.sup.2/g, a pore volume of 1.0 ml/g, an average pore diameter of 30 nm and is primarily composed of spherical silica beads in the diameter range of 2-4 mm.
Zr Modification of Silica Supports
Example 3 (0.92 wt % Zr, Monomeric Zr on Q10)
(13) 0.542 g of, Zr(acac).sub.4 (97%, Sigma Aldrich) was dissolved in 11 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 all of the Zr(acac).sub.4 solution had been taken up into the pore volume of the silica. 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 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 I/min) 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 a 100% 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 4 (1.5 wt % Zr, Monomeric Zr on Q10)
(14) A support modification as described in Example 3 was performed except that 0.874 g of Zr(acac).sub.4 was used.
Example 5 (2.3 wt % Zr, Monomeric Zr on Q10)
(15) A support modification as described in Example 3 was performed except that 1.38 g of Zr(acac).sub.4 was used and 20 ml of 1-PrOH (99% Sigma Aldrich) was used instead of MeOH. Additionally, agitation was continued throughout the 16 h ageing step prior to solvent removal. This resulted in a 90% Zr usage efficiency.
Example 6 (2.7 wt % Zr, Monomeric Zr on Q10)
(16) A support modification as described in Example 5 was performed except that 1.67 g of Zr(acac).sub.4 was used and 20 ml of MeOH (99% Sigma Aldrich) was used instead of 1-PrOH. This resulted in an 89% Zr usage efficiency.
Example 7 (4.2 wt % Zr, Monomeric Zr on Q10)
(17) A support modification as described in Example 5 was performed except that 2.56 g of Zr(acac).sub.4 was used and 20 ml of toluene (99% Sigma Aldrich) was used instead of 1-PrOH. This resulted in a 93% Zr usage efficiency.
Example 8 (0.7 wt % Zr, Monomeric Zr on Q30)
(18) A support modification as described in Example 6 was performed except that 0.43 g of Zr(acac).sub.4 was used and silica from Example 2 was used. This resulted in a 93% Zr usage efficiency.
Example 9 (1.1 wt % Zr, Monomeric Zr on Q10)
(19) A support modification as described in Example 5 was performed except that 2.15 g of Zr(thd).sub.4 was used and 20 ml of MeOH was used instead of 1-PrOH. This resulted in a 47% Zr usage efficiency.
Example 10 (2.2 wt % Zr, Monomeric Zr on Q10)
(20) A support modification as described in Example 9 was performed except 20 ml of toluene was used instead of MeOH. This resulted in a 93% Zr usage efficiency.
Example 11 (3.9 wt % Zr, Monomeric Zr on Q10)
(21) A support modification as described in Example 5 was performed except that 3.19 g of Zr(EtOAc).sub.4 was used and 20 ml of heptane (99% Sigma Aldrich) was used instead of 1-PrOH. This resulted in an 86% Zr usage efficiency.
Example 12 (6.7 wt % Zr, Dimeric Zr on Q10)
(22) A support modification as described in Example 5 was performed except that 3.12 g of [Zr(OPr).sub.3(acac)]2 was used and 20 ml of heptane was used instead of 1-PrOH. This resulted in a 95% Zr usage efficiency.
Example 13 (2.2 wt % Zr, Trimeric Zr on Q30) (Comparative)
(23) A support modification as described in Example 5 was performed except that 1.16 g of Zr(nOPr).sub.4 (70 wt % in 1-propanol, Sigma Aldrich). Additionally 10 g of silica from Example 2 was used instead of the silica from Example 1. This resulted in a 100% Zr usage efficiency.
Example 14 (6.0 wt % Zr, Trimeric Zr on Q10) (Comparative)
(24) A support modification as described in Example 5 was performed except that 3.35 g of Zr(nOPr).sub.4 (70 wt % in 1-propanol, Sigma Aldrich). This resulted in a 100% Zr usage efficiency.
Example 15 (8.0 wt % Zr, Pentameric Zr on Q10) (Comparative)
(25) A support modification as described in Example 5 was performed except that 2.67 g of zirconium(IV) ethoxide (97% Sigma Aldrich) was dissolved 20 ml of ethanol (anhydrous, Sigma Aldrich) with 1.77 g of acetic acid (glacial, Sigma Aldrich) instead of 1-PrOH. This resulted in a 100% Zr usage efficiency.
Hf Modification of Silica Supports
Example 16 (5.4 wt % Hf, Monomeric Hf on Q10)
(26) A support modification as described in Example 5 was performed except that 1.37 g of Hf(iOPr).sub.4 (99% Sigma Aldrich) was dissolved in 20 ml of 1-PrOH along with 1.32 g of acetyl acetone (99% Sigma Aldrich) and allowed to mix for 30 min prior to the introduction of 10 g of silica from Example 1. This resulted in a 98% Hf usage efficiency.
Example 17 (7.8 wt % Hf, Monomeric Hf on Q10)
(27) A support modification as described in Example 5 was performed except that 2.00 g of Hf(iOPr).sub.4 was dissolved in 20 ml of toluene along with 1.93 g of acetyl acetone and allowed to mix for 30 min prior to the introduction of 10 g of silica from Example 1. This resulted in a 100% Hf usage efficiency.
Example 18 (11.8 wt % Hf, Trimeric Hf on Q10) (Comparative)
(28) A support modification as described in Example 5 was performed except that 3.19 g of Hf(iOPr).sub.4 was dissolved in 20 ml of toluene instead of 1-PrOH. This resulted in a 100% Hf usage efficiency.
HRTEM Analysis of Modified Supports
Example 19 (HRTEM Analysis of Monomeric Zr)
(29) High-Resolution Transmission Electron Microscopy (HRTEM) analysis was performed on selected modified silica examples. For this, the modified silica was flaked into particles of 100-200 nm thickness using a microtome. These flaked particles where then mounted onto a copper mesh and an antistatic osmium vapour coating was applied. The mounted sample was then analysed using a Tecnai G2 F20 (manufactured by FEI) in transmission mode. The electron beam was set at an acceleration voltage between 100 and 300 kV with a spacing resolution of 1 nm. The electron beam was focussed by a 30 μm diaphragm. HRTEM images were recorded so as to include 50-200 metal nanoparticles in an image at a magnification of 25 million times. This analysis was performed on modified silica Example 5, Example 7, Example 14, Example 15, Example 17 and Example 18. The HRTEM images are shown in
Cs Modification of Modified Supports
Example 20 (3.2 wt % Cs, 0.9 wt % Zr, Monomeric Zr)
(30) 0.458 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 3 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 step, 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 21 (3.7 wt % Cs, 0.9 wt % Zr, Monomeric Zr)
(31) A catalyst was prepared as described in Example 20 except that 0.534 g of CsOH.H.sub.2O was used.
Example 22 (4.0 wt % Cs, 0.9 wt % Zr, Monomeric Zr)
(32) A catalyst was prepared as described in Example 20 except that 0.588 g of CsOH.H.sub.2O was used.
Example 23 (4.8 wt % Cs, 0.9 wt % Zr, Monomeric Zr)
(33) A catalyst was prepared as described in Example 20 except that 0.716 g of CsOH.H.sub.2O was used.
Example 24 (5.1 wt % Cs, 1.5 wt % Zr, Monomeric Zr)
(34) A catalyst was prepared as described in Example 20 except that 0.754 g of CsOH.H.sub.2O was used and modified silica from Example 4 was used.
Example 25 (5.7 wt % Cs, 1.5 wt % Zr, Monomeric Zr)
(35) A catalyst was prepared as described in Example 24 except that 0.852 g of CsOH.H.sub.2O was used.
Example 26 (6.7 wt % Cs, 1.4 wt % Zr, Monomeric Zr)
(36) A catalyst was prepared as described in Example 24 except that 1.00 g of CsOH.H.sub.2O was used.
Example 27 (7.7 wt % Cs, 1.4 wt % Zr, Monomeric Zr)
(37) A catalyst was prepared as described in Example 24 except that 1.17 g of CsOH.H.sub.2O was used.
Example 28 (9.7 wt % Cs, 2.0 wt % Zr, Monomeric Zr)
(38) A catalyst was prepared as described in Example 20 except that 1.37 g of CsOH.H.sub.2O was used and modified silica from Example 5 was used. Additionally, the Cs adsorption time was shortened from 16 hours to 2 hours with the filtration step being excluded. The excess organic solvent was dried into the pore volume of the modified silica support and resulted in a Cs usage efficiency of 100%.
Example 29 (10.2 wt % Cs, 2.0 wt % Zr, Monomeric Zr)
(39) A catalyst was prepared as described in Example 28 except that 1.45 g of CsOH.H.sub.2O was used.
Example 30 (10.8 wt % Cs, 2.0 wt % Zr, Monomeric Zr)
(40) A catalyst was prepared as described in Example 28 except that 1.54 g of CsOH.H.sub.2O was used.
Example 31 (11.3 wt % Cs, 2.0 wt % Zr, Monomeric Zr)
(41) A catalyst was prepared as described in Example 28 except that 1.62 g of CsOH.H.sub.2O was used.
Example 32 (9.2 wt % Cs, 2.4 wt % Zr, Monomeric Zr)
(42) A catalyst was prepared as described in Example 20 except that 1.44 g of CsOH.H.sub.2O was used and modified silica from Example 6 was used.
Example 33 (10.9 wt % Cs, 2.4 wt % Zr, Monomeric Zr)
(43) A catalyst was prepared as described in Example 32 except that 1.74 g of CsOH.H.sub.2O was used.
Example 34 (13.0 wt % Cs, 2.3 wt % Zr, Monomeric Zr)
(44) A catalyst was prepared as described in Example 32 except that 2.12 g of CsOH.H.sub.2O was used.
Example 35 (14.0 wt % Cs, 2.3 wt % Zr, Monomeric Zr)
(45) A catalyst was prepared as described in Example 32 except that 2.30 g of CsOH.H.sub.2O was used.
Example 36 (12.3 wt % Cs, 3.7 wt % Zr, Monomeric Zr)
(46) A catalyst was prepared as described in Example 20 except that 2.00 g of CsOH.H.sub.2O was used and modified silica from Example 7 was used.
Example 37 (12.6 wt % Cs, 3.7 wt % Zr, Monomeric Zr)
(47) A catalyst was prepared as described in Example 36 except that 2.05 g of CsOH.H.sub.2O was used.
Example 38 (13.9 wt % Cs, 3.6 wt % Zr, Monomeric Zr)
(48) A catalyst was prepared as described in Example 36 except that 2.30 g of CsOH.H.sub.2O was used.
Example 39 (15.4 wt % Cs, 3.6 wt % Zr, Monomeric Zr)
(49) A catalyst was prepared as described in Example 36 except that 2.60 g of CsOH.H.sub.2O was used.
Example 40 (2.8 wt % Cs, 0.7 wt % Zr, Monomeric Zr)
(50) A catalyst was prepared as described in Example 28 except that 0.37 g of CsOH.H.sub.2O was used and modified silica from Example 8 was used.
Example 41 (3.4 wt % Cs, 0.7 wt % Zr, Monomeric Zr)
(51) A catalyst was prepared as described in Example 40 except that 0.45 g of CsOH.H.sub.2O was used.
Example 42 (3.9 wt % Cs, 0.7 wt % Zr, Monomeric Zr)
(52) A catalyst was prepared as described in Example 40 except that 0.51 g of CsOH.H.sub.2O was used.
Example 43 (4.1 wt % Cs, 1.0 wt % Zr, Monomeric Zr)
(53) A catalyst was prepared as described in Example 20 except that 0.60 g of CsOH.H.sub.2O was used and modified silica from Example 9 was used.
Example 44 (4.6 wt % Cs, 1.0 wt % Zr, Monomeric Zr)
(54) A catalyst was prepared as described in Example 43 except that 0.68 g of CsOH.H.sub.2O was used.
Example 45 (5.5 wt % Cs, 1.0 wt % Zr, Monomeric Zr)
(55) A catalyst was prepared as described in Example 43 except that 0.82 g of CsOH.H.sub.2O was used.
Example 46 (9.1 wt % Cs, 2.0 wt % Zr, Monomeric Zr)
(56) A catalyst was prepared as described in Example 20 except that 1.42 g of CsOH.H.sub.2O was used and modified silica from Example 10 was used.
Example 47 (9.9 wt % Cs, 1.9 wt % Zr, Monomeric Zr)
(57) A catalyst was prepared as described in Example 46 except that 1.55 g of CsOH.H.sub.2O was used.
Example 48 (13.8 wt % Cs, 3.3 wt % Zr, Monomeric Zr)
(58) A catalyst was prepared as described in Example 20 except that 2.28 g of CsOH.H.sub.2O was used and modified silica from Example 11 was used.
Example 49 (15.0 wt % Cs, 3.3 wt % Zr, Monomeric Zr)
(59) A catalyst was prepared as described in Example 48 except that 2.51 g of CsOH.H.sub.2O was used.
Example 50 (14.0 wt % Cs, 5.7 wt % Zr, Dimeric Zr) (Comparative)
(60) A catalyst was prepared as described in Example 20 except that 2.34 g of CsOH.H.sub.2O was used and modified silica from Example 12 was used.
Example 51 (15.0 wt % Cs, 5.7 wt % Zr, Dimeric Zr) (Comparative)
(61) A catalyst was prepared as described in Example 50 except that 2.54 g of CsOH.H.sub.2O was used.
Example 52 (16.1 wt % Cs, 5.6 wt % Zr, Dimeric Zr) (Comparative)
(62) A catalyst was prepared as described in Example 50 except that 2.76 g of CsOH.H.sub.2O was used.
Example 53 (17.3 wt % Cs, 5.5 wt % Zr, Dimeric Zr) (Comparative)
(63) A catalyst was prepared as described in Example 50 except that 3.01 g of CsOH.H.sub.2O was used.
Example 54 (6.0 wt % Cs, 2.1 wt % Zr, Trimeric Zr) (Comparative)
(64) A catalyst was prepared as described in Example 28 except that 0.81 g of CsOH.H.sub.2O was used and modified silica from Example 13 was used.
Example 55 (7.7 wt % Cs, 2.0 wt % Zr, Trimeric Zr) (Comparative)
(65) A catalyst was prepared as described in Example 54 except that 1.06 g of CsOH.H.sub.2O was used.
Example 56 (13.6 wt % Cs, 5.2 wt % Zr, Trimeric Zr) (Comparative)
(66) A catalyst was prepared as described in Example 28 except that 2.03 g of CsOH.H.sub.2O was used and modified silica from Example 14 was used.
Example 57 (14.9 wt % Cs, 5.1 wt % Zr, Trimeric Zr) (Comparative)
(67) A catalyst was prepared as described in Example 56 except that 2.26 g of CsOH.H.sub.2O was used.
Example 58 (16.1 wt % Cs, 5.0 wt % Zr, Trimeric Zr) (Comparative)
(68) A catalyst was prepared as described in Example 56 except that 2.48 g of CsOH.H.sub.2O was used.
Example 59 (17.3 wt % Cs, 5.0 wt % Zr, Trimeric Zr) (Comparative)
(69) A catalyst was prepared as described in Example 56 except that 2.70 g of CsOH.H.sub.2O was used.
Example 60 (12.3 wt % Cs, 7.0 wt % Zr, Pentameric Zr) (Comparative)
(70) A catalyst was prepared as described in Example 28 except that 1.82 g of CsOH.H.sub.2O was used and modified silica from Example 15 was used.
Example 61 (14.0 wt % Cs, 6.9 wt % Zr, Pentameric Zr) (Comparative)
(71) A catalyst was prepared as described in Example 60 except that 2.12 g of CsOH.H.sub.2O was used.
Example 62 (15.7 wt % Cs, 6.7 wt % Zr, Pentameric Zr) (Comparative)
(72) A catalyst was prepared as described in Example 60 except that 2.42 g of CsOH.H.sub.2O was used.
Example 63 (18.9 wt % Cs, 6.5 wt % Zr, Pentameric Zr) (Comparative)
(73) A catalyst was prepared as described in Example 60 except that 2.99 g of CsOH.H.sub.2O was used.
Example 64 (8.8 wt % Cs, 4.9 wt % Hf, Monomeric Hf)
(74) A catalyst was prepared as described in Example 28 except that 1.23 g of CsOH.H.sub.2O was used and modified silica from Example 16 was used.
Example 65 (10.1 wt % Cs, 4.9 wt % Hf, Monomeric Hf)
(75) A catalyst was prepared as described in Example 64 except that 1.43 g of CsOH.H.sub.2O was used.
Example 66 (11.4 wt % Cs, 4.8 wt % Hf, Monomeric Hf)
(76) A catalyst was prepared as described in Example 64 except that 1.64 g of CsOH.H.sub.2O was used.
Example 67 (12.6 wt % Cs, 4.7 wt % Hf, Monomeric Hf)
(77) A catalyst was prepared as described in Example 64 except that 1.84 g of CsOH.H.sub.2O was used.
Example 68 (11.1 wt % Cs, 6.9 wt % Hf, Monomeric Hf)
(78) A catalyst was prepared as described in Example 28 except that 1.60 g of CsOH.H.sub.2O was used and modified silica from Example 17 was used.
Example 69 (12.7 wt % Cs, 6.8 wt % Hf, Monomeric Hf)
(79) A catalyst was prepared as described in Example 68 except that 1.86 g of CsOH.H.sub.2O was used.
Example 70 (14.3 wt % Cs, 6.7 wt 5 Hf, Monomeric Hf)
(80) A catalyst was prepared as described in Example 68 except that 2.14 g of CsOH.H.sub.2O was used.
Example 71 (15.8 wt % Cs, 6.6 wt % Hf, Monomeric Hf)
(81) A catalyst was prepared as described in Example 68 except that 2.41 g of CsOH.H.sub.2O was used.
Example 72 (13.7 wt % Cs, 10.2 wt % Hf, Trimeric Hf) (Comparative)
(82) A catalyst was prepared as described in Example 20 except that 2.28 g of CsOH.H.sub.2O was used and modified silica from Example 18 was used.
Example 73 (14.9 wt % Cs, 10.0 wt % Hf, Trimeric Hf) (Comparative)
(83) A catalyst was prepared as described in Example 72 except that 2.51 g of CsOH.H.sub.2O was used.
Example 74 (16.2 wt % Cs, 9.9 wt % Hf, Trimeric Hf) (Comparative)
(84) A catalyst was prepared as described in Example 72 except that 2.77 g of CsOH.H.sub.2O was used.
Example 75 (16.0 wt % Cs, 3.4 wt % Zr, 100% Monomeric Zr)
(85) A catalyst was prepared as described in Example 20 except that 2.71 g of CsOH.H.sub.2O was used and 10 g of modified silica from Example 7 was used. Additionally, after the catalyst had been dried it was crushed using a mortar and pestle and sieved into a 0.1-1.0 mm size fraction. This resulted in a catalyst with a 100% monomeric content based on wt % Zr basis.
Example 76 (15.8 Wt % Cs, 3.6 wt % Zr, 79% Monomeric Zr) (Comparative)
(86) A catalyst was prepared as described in Example 75 except that 2.67 g of CsOH.H.sub.2O was used. Additionally 8.5 g of modified silica from Example 7 and 1.5 g of modified silica from Example 14 were used as catalyst support. This resulted in a catalyst with a 79% monomeric content based on wt % Zr basis.
Example 77 (15.4 wt % Cs, 3.9 wt % Zr, 61% Monomeric Zr) (Comparative)
(87) A catalyst was prepared as described in Example 75 except that 2.60 g of CsOH.H.sub.2O was used. Additionally 7 g of modified silica from Example 7 and 3 g of modified silica from Example 14 were used as catalyst support. This resulted in a catalyst with a 61% monomeric content based on wt % Zr basis.
Example 78 (15.7 wt % Cs, 4.4 wt % Zr, 31% Monomeric Zr) (Comparative)
(88) A catalyst was prepared as described in Example 75 except that 2.66 g of CsOH.H.sub.2O was used. Additionally, 4 g of modified silica from Example 7 and 6 g of modified silica from Example 14 were used as catalyst support. This resulted in a catalyst with a 31% monomeric content based on wt % Zr basis.
Example 79 (16.9 wt % Cs, 5.0 wt % Zr, 0% Monomeric Zr) (Comparative)
(89) A catalyst was prepared as described in Example 75 except that 2.92 g of CsOH.H.sub.2O was used. Additionally, 10 g of modified silica from Example 14 were used as catalyst support. This resulted in a catalyst with a 0% monomeric content based on wt % Zr basis.
Example 80 (Catalytic Performance Testing)
(90) Catalysts from Example 20 to Example 79 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 10% 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 10% MMA+MAA yield.
(91) TABLE-US-00001 TABLE 1 Activity and MMA + MAA selectivity results for catalyst prepared on the Zr modified support examples with varying Zr nuclearity. Cs:Zr Activity at 10% MMA + MAA Zirconium Zr load Cs load (molar MMA + MAA selectivity Example nuclearity (wt %) (wt %) ratio) yield (1/s) (%) Example 20 1 0.9 3.2 2.4 0.12 95.8 Example 21 1 0.9 3.7 2.8 0.15 97.3 Example 22 1 0.9 4.0 3.1 0.18 97.6 Example 23 1 0.9 4.8 3.8 0.24 98.0 Example 24 1 1.5 5.1 2.4 0.32 97.4 Example 25 1 1.5 5.7 2.7 0.39 97.1 Example 26 1 1.4 6.7 3.2 0.41 97.0 Example 27 1 1.4 7.7 3.7 0.47 97.3 Example 28 1 2.0 9.7 3.3 0.45 96.1 Example 29 1 2.0 10.2 3.5 0.39 95.8 Example 30 1 2.0 10.8 3.7 0.49 95.8 Example 31 1 2.0 11.3 3.9 0.46 95.5 Example 32 1 2.4 9.2 2.6 0.48 96.8 Example 33 1 2.4 10.9 3.2 0.64 96.2 Example 34 1 2.3 13.0 3.9 0.67 95.5 Example 35 1 2.3 14.0 4.2 0.75 95.5 Example 36 1 3.7 12.3 2.3 0.76 95.3 Example 37 1 3.7 12.6 2.4 0.80 95.0 Example 38 1 3.6 13.9 2.7 0.86 94.1 Example 39 1 3.6 15.4 3.0 0.93 94.5 Example 40 1 0.7 2.8 2.7 0.13 97.5 Example 41 1 0.7 3.4 3.3 0.17 97.9 Example 42 1 0.7 3.9 3.8 0.25 97.8 Example 43 1 1.0 4.1 2.7 0.25 96.3 Example 44 1 1.0 4.6 3.1 0.28 97.8 Example 45 1 1.0 5.5 3.7 0.35 96.7 Example 46 1 2.0 9.1 3.2 0.47 96.5 Example 47 1 1.9 9.9 3.5 0.71 96.5 Example 48 1 3.3 13.8 2.9 0.75 94.5 Example 49 1 3.3 15.0 3.2 0.76 94.8 Example 50 2 5.7 14.0 1.7 0.69 93.0 Example 51 2 5.7 15.0 1.8 0.82 93.0 Example 52 2 5.6 16.1 2.0 0.85 93.2 Example 53 2 5.5 17.3 2.2 0.68 92.0 Example 54 3 2.1 6.0 2.0 0.26 89.2 Example 55 3 2.0 7.7 2.5 0.34 88.8 Example 56 3 5.2 13.6 1.8 0.38 85.7 Example 57 3 5.1 14.9 2.0 0.47 88.7 Example 58 3 5.0 16.1 2.2 0.51 90.7 Example 59 3 5.0 17.3 2.4 0.41 90.2 Example 60 5 7.0 12.3 1.2 0.24 76.0 Example 61 5 6.9 14.0 1.4 0.45 85.0 Example 62 5 6.7 15.7 1.6 0.56 87.0 Example 63 5 6.5 18.9 2.0 0.85 87.6
(92) TABLE-US-00002 TABLE 2 Activity and MMA + MAA selectivity results for catalyst prepared on the Hf modified support examples with varying Hf nuclearity. Cs:Hf Activity at 10% MMA + MAA Hafnium Hf load Cs load (molar MMA + MAA selectivity Example nuclearity (wt %) (wt %) ratio) yield (1/s) (%) Example 64 1 4.9 8.8 2.4 0.51 97.2 Example 65 1 4.9 10.1 2.8 0.58 97.1 Example 66 1 4.8 11.4 3.2 0.64 96.5 Example 67 1 4.7 12.6 3.6 0.73 96.5 Example 68 1 6.9 11.1 2.2 0.68 96.4 Example 69 1 6.8 12.7 2.5 0.82 96.5 Example 70 1 6.7 14.3 2.9 0.88 96.0 Example 71 1 6.6 15.8 3.2 0.88 95.1 Example 72 3 10.2 13.7 1.8 0.58 89.8 Example 73 3 10.0 14.9 2.0 0.71 91.6 Example 74 3 9.9 16.2 2.2 0.69 91.2
(93) TABLE-US-00003 TABLE 3 Activity and MMA + MAA selectivity results for catalyst prepared with varying amounts of Zr monomer and trimer. Monomeric Zr Cs:Zr Activity at 10% MMA + MAA content (% of Zr load Cs load (molar MMA + MAA selectivity Example Zr content) (wt %) (wt %) ratio) yield (1/s) (%) Example 75 100 3.4 16.0 3.3 1.43 95.8 Example 76 79 3.6 15.8 3.0 1.44 94.9 Example 77 61 3.9 15.4 2.7 1.40 93.7 Example 78 31 4.4 15.7 2.5 1.31 92.0 Example 79 0 5.0 16.9 2.4 1.29 88.6
Example 81 (Accelerated Ageing Tests)
(94) 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. 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 (Micromeretics Tristar II). The measured surface area values were used to determine sintering rates constants for each catalyst and is described as g.sup.3.Math.m.sup.−6.Math.d.sup.−1. The higher the sintering constant, the lower the sintering resistance of the catalyst. This test was performed on Example 32, Example 38, Example 57 and Example 63.
(95) TABLE-US-00004 TABLE 4 Accelerating ageing data for the catalysts of varying Zr nuclearity with comparable activity. Sintering rate Catalyst constant Surface area at time (days) activity (g.sup.3 .Math. m.sup.−6 .Math. Example 1 7 14 21 28 (1/s) d.sup.−1) Example 32 189 187 177 176 178 0.48 1.28E−09 (inventive) Example 38 163 147 144 135 135 0.86 6.35E−09 (inventive) Example 57 218 209 192 192 185 0.47 2.26E−09 (comparative) Example 63 148 132 124 127 119 0.85 8.94E−09 (comparative)
Comparative Examples 82 and 83
(96) Examples were prepared according to experimental examples disclosed in EP 1233330. In these examples the silica employed was a gel silica in the form of spheres of diameter in the range 2-4 mm having a purity of over 99%, a total surface area of about 300-350 m.sup.2/g, and a pore volume of 1.04 cm.sup.3/g with 76% of the pore volume provided by pores having a diameter in the range 7-23 nm.
(97) Two catalysts were prepared by impregnating the silica with an aqueous solution of zirconium nitrate, sufficient to fill the pores of the support, and drying in a rotary evaporator and then in an air oven at 120° C. for 2 hours. In one case (example 82), the impregnation of the zirconium solution was assisted by evacuation of the pores of the support prior to addition of the solution. In the other case (example 83), impregnation of the zirconium solution was carried out in an atmospheric pressure of air. Caesium was then incorporated by a similar procedure using an aqueous solution of caesium carbonate, to give a caesium content of 4% by weight (expressed as metal). The catalysts were then calcined in air at 450° C. for 3 hours.
(98) Catalysts were tested under the same conditions as described in example 80. One catalyst (example 82) failed to achieve 10% yield and selectivities are shown for the highest obtained yield (9.6%).
(99) TABLE-US-00005 TABLE 5 Activity and MMA + MAA selectivity results for comparative examples 82 and 83. Activity at MMA + Zr Cs Cs:Zr 10% MMA + MAA selec- load load (molar MAA yield tivity Example (wt %) (wt %) ratio) (1/s) (%) Example 82 1.7 4.0 1.6 0.05 65.2 Example 83 1.7 4.0 1.6 0.12 73.2
(100) HRTEM Results for Zr and Hf Modified Silica Supports
(101) The HRTEM images (Example 19) for the Zr and Hf modified silica examples (Example 5, Example 7, Example 14, Example 15, Example 17 and Example 18) are shown in
(102) Graphed Data
(103) Activity and Selectivity Data Constructed from Table 1 and Table 2
(104) The MMA+MAA selectivity (%) vs. catalyst activity for the catalysts prepared in Example 20 to Example 74 is shown in
(105) Activity and Selectivity Data Constructed from Table 3
(106) The catalyst selectivity for mixed monomer/trimer catalysts prepared in Example 75 to Example 79 is shown in
(107) Sintering Resistance Data Constructed from Table 4
(108) The catalyst sintering constants as determined by the advanced ageing test described in Example 81 is shown in
(109) 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.
(110) 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.
(111) 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.
(112) 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.