Nitrided mixed oxide catalyst system and a process for the production of ethylenically unsaturated carboxylic acids or esters

Abstract

A method of producing an ethylenically unsaturated carboxylic acid or ester, preferably an , ethylenically unsaturated carboxylic acid or ester. The method includes contacting formaldehyde or a suitable source thereof with a carboxylic acid or ester in the presence of a catalyst and optionally in the presence of an alcohol. The catalyst includes a nitrided metal oxide having at least two types of metal cations, M.sup.1 and M.sup.2, wherein M.sup.1 is selected from the metals of group 2, 3, 4, 13 (called also IIIA) or 14 (called also IVA) of the periodic table and M2 is selected from the metals of groups 5 or 15 (called also VA) of the periodic table.

Claims

1. A method of producing an ethylenically unsaturated carboxylic acid or ester comprising the steps of contacting formaldehyde or a source thereof with a carboxylic acid or ester of formula R.sup.3CH.sub.2COOR.sup.4 wherein R.sup.4 is either hydrogen or an alkyl group and R.sup.3 is either hydrogen, an alkyl or an aryl group, in the presence of a catalyst and optionally in the presence of an alcohol, wherein the catalyst comprises a nitrided metal oxide having at least two metal cations, M.sup.1 and M.sup.2, wherein: the M.sup.1 type of metal is selected from one or more metals in the list consisting of:B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Ti, Zr, Hf and Rf, and the M.sup.2 type of metal is selected from one or more metals in the list consisting of:P(5+), Nb(5+), As(5+), Sb(5+) and Ta(5+).

2. A method according to claim 1, wherein the nitrided metal oxide consists of two to four metal cations, and oxygen and nitrogen anions.

3. A method according to claim 1, wherein the nitrided metal oxide is selected from the list consisting of:AlPON; ZrPON; SnPON; ZrNbON; GaSbON; and GaAlPON, either unsupported or supported on a support, the support comprising alumina, silica, silicon nitride, colloidal silica, titania or aluminium phosphate.

4. The method of claim 1, wherein the nitrided metal oxide is supported on a support selected from the group consisting of: alumina, silica, silicon nitride, colloidal silica, titania or aluminium phosphate.

5. A method according to claim 1, wherein the ethylenically unsaturated acid or ester produced by the process of the invention is selected from methacrylic acid, acrylic acid, methyl methacrylate, ethyl acrylate or butyl acrylate.

6. The method of claim 1, wherein the step of contacting formaldehyde with a carboxylic acid or ester in the presence of a catalyst is also carried out in the presence of alcohol.

7. The method of claim 1, wherein the ethylenically unsaturated carboxylic acid or ester is produced with a catalyst system by contacting formaldehyde or a source thereof with a carboxylic acid or ester of formula R.sup.3CH.sub.2COOR.sup.4 wherein R.sup.4 is either hydrogen or an alkyl group and R.sup.3 is either hydrogen, an alkyl or an aryl group, in the presence of a catalyst of the catalyst system, wherein the catalyst comprises a nitrided metal oxide having at least two metal cations, M.sup.1 and M.sup.2, wherein: the M.sup.1 type of metal is selected from one or more metals in the list consisting of:B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Ti, Zr, Hf and Rf, and the M.sup.2 type of metal is selected from one or more metals in the list consisting of:P(5+), Nb(5+), As (5+) Sb(5+) and Ta(5+) to produce the ethylenically unsaturated carboxylic acid or ester.

8. The method of claim 1, wherein the ethylenically unsaturated carboxylic acid or ester is an , ethylenically unsaturated acid.

Description

DETAILED DESCRIPTION

(1) It is to be understood by a person having ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention. The following example is provided to further illustrate the invention and is not to be construed to unduly limit the scope of the invention. Embodiments of the invention will now be described with reference to the following non-limiting examples and by way of illustration only.

EXPERIMENTAL

(2) TABLE-US-00001 TABLE 1 MMA + MMA + MAA MAA MAA + Contact MAA selectivity selectivity MAA Catalyst time [s] yield [%] [%] [%] yield/s Comp AlPO 5.20 4.9 10.4 59.3 0.9 Ex. 1 Comp AlPO 1.47 4.8 12.9 78.0 3.3 Ex. 1 Ex. 1 AlPON 1.47 3.1 13.4 95.2 2.1 03750 Ex. 1 AlPON 5.20 03750 Ex. 2 AlPON 5.20 7.6 16.5 92.4 1.5 06750 Ex. 3 AlPON 5.20 8.1 17.3 93.5 1.6 15750

Comparative Example 1 AlPO

(3) The acid catalyst that provided the base substrate for modification was an amorphous aluminium phosphate (AlPO) prepared by a sol-gel method involving co-gelation from a solution containing the component salts.

(4) Co-Gelation Method

(5) A high surface-area amorphous aluminium phosphate was prepared by co-gelation of a solution of salts containing the elements aluminium and phosphorus.

(6) 37.5 g of aluminium nitrate nonahydrate Al(NO.sub.3).sub.3.9H.sub.2O and 13.2 g of diammonium hydrogen phosphate (NH.sub.4).sub.2HPO.sub.4 were dissolved together in 160 ml of demineralised water acidified with nitric acid HNO.sub.3. Solution of ammonium hydroxide was added until pH 7 was reached. Formed hydrogel was mixed for further 1 hr, after that it was filtered and washed with water. It was dried at 80 C. overnight and then calcined in air at 600 C. for 1 hr. The calcined product was sieved to retain granules (0.5-1.4 mm in diameter) for a catalyst testing.

(7) Catalyst testing: 3 g of a catalyst was placed in a stainless steel tubular reactor connected to a vaporiser. The reactor was heated to 350 C. and vaporiser to 300 C. The mixture of 56.2 mole % of methyl propionate, 33.7 mole % of methanol, 9.6 mole % of formaldehyde and 0.5 mole % of water was passed through. The condensed reaction mixture was analysed by gas chromatography equipped with CP-Sil 1701 column.

Example 1 AlPON 03750

(8) Approximately 7 g of granule product from comparative example 1 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 600 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 750 C. and maintained at this temperature for 3 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(9) Catalyst was tested as described in comparative example 1.

Example 2 AlPON 06750

(10) Catalyst was prepared as in example 1, except that instead of 3 hrs of ammonia treatment 6 hrs were applied.

(11) Catalyst was tested as described in comparative example 1.

Example 3 ALPON15750

(12) Catalyst was prepared as in example 1, except that instead of 3 hrs of ammonia treatment 15 hrs was applied.

(13) Catalyst was tested as described in comparative example 1.

(14) TABLE-US-00002 TABLE 2 MMA + MMA + MAA MAA MMA + Contact MAA selectivity selectivity MAA Catalyst time [s] yield [%] [%] [%] yield/s Comp ZrPO 0.41 4.04 7.5 64.6 9.8 Ex. 2 Ex. 4 ZrPON 0.41 4.55 7.4 71.6 11.1 03750 Comp SnPO 2.00 2.1 11.0 64.3 1.0 Ex. 3 Ex. 5 SnPON 3.05 2.1 0.3 86.4 0.7 06400

Comparative Example 2 ZrPO

(15) 7.9 g of diammonium hydrogen phosphate (NH.sub.4).sub.2HPO.sub.4 dissolved in 50 ml of demineralised water were added dropwise to 19.3 g of zirconium oxychloride ZrOCl.sub.2.8H.sub.2O dissolved in 200 ml of demineralised water acidified with nitric acid HNO.sub.3 and stirred for 2 hrs. It was filtered and washed with water, then dried at 110 C. overnight and calcined in air at 550 C. for 1 hr. Catalyst was tested as described in comparative example 1.

Example 4 ZrPON 03750

(16) Approximately 7 g of granule product from comparative example 2 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 600 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 750 C. and maintained at this temperature for 3 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(17) Catalyst was tested as described in comparative example 1.

Comparative Example 3 SnPO

(18) 13.0 g of tin chloride SnCl.sub.4 in 200 ml of demineralised water was heated to 50 C. and stirred with a magnetic bar while adding dropwise 7.1 g of diammonium hydrogen phosphate (NH.sub.4).sub.2HPO.sub.4 dissolved in 300 ml of demineralised water. The mixing was continued for 2 hrs. After that the product was filtered and washed with water. It was dried at 110 C. overnight and then calcined in air at 400 C. for 1 hr.

(19) Catalyst was tested as described in comparative example 1.

Example 5 SnPON 06400

(20) Approximately 7 g of granule product from comparative example 3 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 250 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 400 C. and maintained at this temperature for 6 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(21) Catalyst was tested as described in comparative example 1.

(22) TABLE-US-00003 TABLE 3 MMA + MMA + MAA MAA MMA + Contact MAA selectivity selectivity MAA Catalyst time [s] yield [%] [%] [%] yield/s Comp ZrNbO 0.6 5.5 3.8 80.6 9.2 Ex. 4 Comp GaSbO 1.12 6.5 1.9 77.8 5.8 Ex. 5

Comparative Example 4 ZrNbO

(23) 10.1 g of niobium chloride NbCl.sub.5 in 25 ml of demineralised water acidified with nitric acid HNO.sub.3 were added to 12.1 g of zirconium oxychloride ZrOCl.sub.2.8H.sub.2O in 25 ml of demineralised water acidified with nitric acid HNO.sub.3 while stirring. After that a solution of ammonium hydroxide was added until pH 7 was reached. This was aged for 1 hr, and then it was filtered and washed with copious amount of water. It was dried at 80 C. overnight and then calcined in air at 600 C. for 1 hr.

(24) Catalyst was tested as described in comparative example 1.

Example 6 ZrNbON 06400

(25) Approximately 7 g of granule product from comparative example 4 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 250 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 400 C. and maintained at this temperature for 6 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(26) Catalyst was tested as described in comparative example 1 and found to have improved selectivity.

Comparative Example 5 GaSbO

(27) 5 g of gallium chloride GaCl.sub.3 in 25 ml of demineralised water acidified with nitric acid HNO.sub.3 were added dropwise to 8.6 g of antimony chloride SbCl.sub.5 in 5 ml of demineralised water while stirring. Subsequently a solution of ammonium hydroxide was added until pH 7 was reached. The reaction mixture was aged for 1 hr, after that it was filtered and washed with copious amount of water. It was dried at 80 C. overnight and then calcined in air at 600 C. for 1 hr. Catalyst was tested as described in comparative example 1.

Example 7 GaSbON 06400

(28) Approximately 7 g of granule product from comparative example 5 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 250 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 400 C. and maintained at this temperature for 6 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(29) Catalyst was tested as described in comparative example 1 and found to have improved selectivity.

(30) TABLE-US-00004 TABLE 4 MMA + MAA MAA MAA + Contact MMA + MAA selectivity selectivity MAA Catalyst time [s] yield [%] [%] [%] yield/s Comp. Ex. 6 Ga.sub.0.1Al.sub.0.9PO 2.40 4.3 10.4 64.1 1.8 Ex. 8 Ga.sub.0.1Al.sub.0.9PON 2.36 6.4 11.7 75.2 2.7 03750 Ex. 9 Ga.sub.0.1Al.sub.0.9PON 2.32 5.5 4.9 80.9 2.4 15750

Comparative Example 6 Ga0.1Al0.9PO

(31) 5 g of gallium chloride, 34 g of aluminium chloride AlCl.sub.3 were mixed with 19.4 g of phosphoric acid H.sub.3PO.sub.4 in 122 ml of demineralised water. This was cooled to 0 C. in a dry ice alcohol bath. Subsequently a large excess of propylene oxide was slowly added under vigorous stirring. The solution turned into a translucent gel after a few hours. The product was washed with isopropanol. It was dried at 110 C. overnight and then calcined in air at 650 C. for 1 hr. Catalyst was tested as described in comparative example 1.

Example 8 Ga0.1Al0.9PON 03750

(32) Approximately 7 g of granule product from comparative example 6 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 600 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 750 C. and maintained at this temperature for 3 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(33) Catalyst was tested as described in comparative example 1.

Example 9 Ga0.1Al0.9PON 15750

(34) Catalyst was prepared as in example 8, except that instead of 3 hrs of ammonia treatment 15 hrs was applied.

(35) Catalyst was tested as described in comparative example 1.

(36) TABLE-US-00005 TABLE 5 MMA + MMA + MAA MAA MMA + Contact MAA selectivity selectivity MAA Catalyst time [s] yield [%] [%] [%] yield/s Comp. ZrO.sub.2 0.89 5.8 1.5 50.9 6.5 Ex. 7 Comp. ZrON 4.58 5.7 0.5 50.0 1.2 Ex. 8 15500 Comp. SiO.sub.2 10.03 0.15 0.015 Ex. 9 Comp. SiON 14.57 0.6 0.04 Ex. 10 (Grace) 15400 Comp. SiON 8.53 0.6 0.07 Ex. 11 (Grace) 15750 Comp. Al.sub.2O.sub.3 4.0 5.6 6.3 64.0 10.2 Ex. 12 Comp. AlON 5.6 5.6 7.6 60.0 10.4 Ex. 13 03750

Comparative Example 7 ZrO2

(37) 14.5 g of zirconium oxychloride octahydrate ZrOCl.sub.2.8H.sub.2O were dissolved in 300 ml of demineralised water and stirred continuously while adding 10 ml of 30% ammonia in 110 ml of water. The suspension was agitated at room temperature for 3 hrs, then filtered and washed with water to remove any residues of chloride. The product was dried at 80 C. overnight and calcined at 500 C. for 1 hr.

(38) Catalyst was tested as described in comparative example 1.

Comparative Example 8 ZrON 15500

(39) Approximately 7 g of granule product from comparative example 7 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 350 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 500 C. and maintained at this temperature for 15 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(40) Catalyst was tested as described in comparative example 1.

Comparative Example 9 SiO2

(41) Pure SiO.sub.2 beads were purchased from Grace.

(42) Catalyst was tested as described in comparative example 1.

Comparative Example 10 SiON (Grace) 15400

(43) Approximately 7 g of granule product from comparative example 9 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 250 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 400 C. and maintained at this temperature for 15 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(44) Catalyst was tested as described in comparative example 1.

Comparative Example 11 SiON (Grace) 15750

(45) Approximately 7 g of granule product from comparative example 9 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 600 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 750 C. and maintained at this temperature for 15 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(46) Catalyst was tested as described in comparative example 1.

Comparative Example 12 Al2O3

(47) 75.0 g of aluminium nitrate were dissolved in demineralised water, which was acidified with drops of nitric acid to aid dissolution. The gel was precipitated by addition of aqueous ammonia. The gel was filtered and washed with water. After drying overnight at 110 C., it was calcined at 500 C. in air flow for 1 hr.

(48) Catalyst was tested as described in comparative example 1.

Comparative Example 13 AlON 03750

(49) Approximately 7 g of granule product from comparative example 12 were placed in an alumina boat in the centre of a tube furnace and heated at 5 C./min ramp in a flow of dry nitrogen at the rate of 150 ml/min. At 600 C. the gas feed was switched to dry ammonia at a rate of 150 ml/min while continuing to heat to 750 C. and maintained at this temperature for 3 hrs before the feed gas was switched back to dry nitrogen (150 ml/min). The furnace was allowed to cool to below 100 C. before sample recovery from the dry atmosphere.

(50) Catalyst was tested as described in comparative example 1.

(51) Several examples were tested for the generation of side products in the condensed reaction mixture. Three side products that may prove problematic during separation in an industrial process due to their being close in boiling point to one of the desired end products, methyl methacrylate, were tested. These are toluene, diethyl ketone and methyl isobutyrate. The results are shown in table 6 and show a marked reduction in such impurities for the nitrided mixed oxides compared with both non-nitrided mixed oxides and nitrided single metal oxides.

(52) TABLE-US-00006 TABLE 6 Contact MIB DEK toluene Catalyst time [s] [mole %] [mole %] [mole %] Comp. Ex. 1 AlPO 1.83 0.0240 0.0547 0.0054 Ex. 1 AlPON 1.47 0.0013 0.0031 0.0003 03750 Ex. 2 AlPON 5.20 0.0126 0.0038 0.0008 06750 Comp. Ex. 2 ZrPO 0.42 0.0228 0.0569 0.0042 Ex. 4 ZrPON 0.41 0.0150 0.0370 0.0028 03750 Comp. Ex. 7 ZrO2 1.01 0.1819 0.7004 0.0001 Comp. Ex. 8 ZrON 4.70 0.2591 0.8241 0.0001 15500

(53) 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.

(54) 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.

(55) 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.

(56) 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 features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.