Patent Application
20080033213
150 g of aluminium oxide I were impregnated with 21.0% by weight of caesium tungstate (Cs2.0WO4) with the aid of vacuum impregnation. To this end, the specific procedure was as follows:
To prepare the impregnation solution, 55.7 g of tungstic acid were suspended in 44.5 g of water and dissolved by adding 111.4 g of 25% ammonia solution and heating to 50° C. 74.6 g of Cs(OH).H2O were dissolved in 37.3 g of water and mixed with the first solution. The solution was subsequently stirred in a covered beaker for 48 hours. Thereafter, the solution was made up to a volume of 234 ml with 25 g of water.
The aluminium oxide was initially charged in a glass vessel which was evacuated to 150 mbar. By virtue of the opening of a tap, the impregnation solution was sucked into the evacuated glass vessel until the entire bed of shaped bodies was covered with the solution. After a wait time of 15 minutes and aeration of the glass vessel, the solution which had not been absorbed by the aluminium oxide ran back into the beaker. 79 ml of impregnation solution were absorbed by the aluminium oxide.
The granules were dried to remove the residual moisture at room temperature in an air current for the period of 1 hour and subsequently at 120° C. for 3 hours. Afterward, the granules were calcined at 455° C. for 3 hours.
Comparative Example 1 was repeated with 26.3% loading of the aluminium oxide with caesium tungstate (Cs2.0WO4).
Comparative Example 1 was repeated with 19.6% loading of the aluminium oxide with potassium tungstate (K2.0WO4) with use of KOH instead of Cs(OH).H2O.
150 g of aluminium oxide (Spheralite 501A) was impregnated in a two-stage impregnation with a total of 26.7% by weight of promoter (K1.6WOy) with the aid of vacuum impregnation. The specific procedure was as follows:
64.5 g of tungstic acid were suspended in 50.7 g of water and dissolved by adding 126.9 g of 25% ammonia solution and heating to 50° C. 22.8 g of KOH were dissolved in 11.5 g of water and mixed with the first solution. The solution was subsequently stirred in a covered beaker for 48 hours. Thereafter, the solution was made up to a volume of 234 ml with 39 g of water. The aluminium oxide was initially charged in a glass vessel which was evacuated to 150 mbar. By virtue of the opening of a tap, the impregnation was sucked in until the entire bed of mouldings was covered with the solution. After a wait time of 15 minutes and aeration of the glass vessel, the solution which had not been absorbed by the aluminium oxide flowed back into the beaker. 76 ml of impregnation solution were absorbed by the aluminium oxide. Subsequently, the granules were dried at room temperature for 1 hour and at 120° C. for 3 hours, and calcined at 455° C. for 3 hours.
To carry out the second impregnation, an identical impregnation solution to that in the first step was prepared and applied in the same way by vacuum impregnation to the already laden catalyst from the first step. This was then followed again by drying at room temperature for 1 hour, followed by drying at 120° C. for 3 hours. Finally, the catalyst particles were calcined under air at 455° C. for 4 hours.
150 g of aluminium oxide (Spheralite 501A) was impregnated in a two-stage impregnation with a total of 30.1% by weight of promoter (Rb0.9WOy) with the aid of vacuum impregnation. The specific procedure was as follows:
59.0 g of tungstic acid were suspended in 48.3 g of water and dissolved by adding 110.7 g of 25% ammonia solution and heating to 50° C. 41.5 g of RbOH were dissolved in 17.5 g of water and mixed with the first solution. The solution was subsequently stirred in a covered beaker for 48 hours. Thereafter, the solution was made up to a volume of 234 ml with 25 g of water. The aluminium oxide was initially charged in a glass vessel which was evacuated to 150 mbar. By virtue of the opening of a tap, the impregnation was sucked in until the entire bed of mouldings was covered with the solution. After a wait time of 15 minutes and aeration of the glass vessel, the solution which had not been absorbed by the aluminium oxide flowed back into the beaker. 75 ml of impregnation solution were absorbed by the aluminium oxide. Subsequently, the granules were dried at room temperature for 1 hour and at 120° C. for 3 hours, and calcined at 455° C. for 3 hours.
To carry out the second impregnation, an identical impregnation solution to that in the first step was prepared and applied in the same way by vacuum impregnation to the already laden catalyst from the first step. This was then followed again by drying at room temperature for 1 hour, followed by drying at 120° C. for 3 hours. Finally, the catalyst particles were calcined under air at 455° C. for 4 hours.
150 g of aluminium oxide (Spheralite 501A) was impregnated in a two-stage impregnation with a total of 29.4% by weight of promoter (K0.7CS0.7WOy) with the aid of vacuum impregnation. The specific procedure was as follows:
61.3 g of tungstic acid were suspended in 49.1 g of water and dissolved by adding 122.7 g of 25% ammonia solution and heating to 50° C. 9.8 g of KOH and 29.0 g of Cs(OH).H2O were dissolved in 14.5 g of water and mixed with the first solution. The solution was subsequently stirred in a covered beaker for 48 hours. Thereafter, the solution was made up to a volume of 234 ml with 47 g of water. The aluminium oxide was initially charged in a glass vessel which was evacuated to 150 mbar. By virtue of the opening of a tap, the impregnation was sucked in until the entire bed of mouldings was covered with the solution. After a wait time of 15 minutes and aeration of the glass vessel, the solution which had not been absorbed by the aluminium oxide flowed back into the beaker. 75 ml of impregnation solution were absorbed by the aluminium oxide. Subsequently, the granules were dried at room temperature for 1 hour and at 120° C. for 3 hours, and calcined at 455° C. for 3 hours.
To carry out the second impregnation, an identical impregnation solution to that in the first step was prepared and applied in the same way by vacuum impregnation to the already laden catalyst from the first step. This was then followed again by drying at room temperature for 1 hour, followed by drying at 120° C. for 3 hours. Finally, the catalyst particles were calcined under air at 455° C. for 4 hours.
150 g of aluminium oxide (Spheralite 501A) was impregnated in a two-stage impregnation with a total of 31.0% by weight of promoter (Na0.3Cs1.1WOy) with the aid of vacuum impregnation. The specific procedure was as follows:
61.1 g of tungstic acid were suspended in 48.9 g of water and dissolved by adding 122.1 g of 25% ammonia solution and heating to 50° C. 3.2 g of NaOH and 44.6 g of Cs(OH).H2O were dissolved in 22.3 g of water and mixed with the first solution. The solution was subsequently stirred in a covered beaker for 48 hours. Thereafter, the solution was made up to a volume of 234 ml with 40 g of water. The aluminium oxide was initially charged in a glass vessel which was evacuated to 150 mbar. By virtue of the opening of a tap, the impregnation was sucked in until the entire bed of mouldings was covered with the solution. After a wait time of 15 minutes and aeration of the glass vessel, the solution which had not been absorbed by the aluminium oxide flowed back into the beaker. 74 ml of impregnation solution were absorbed by the aluminium oxide. Subsequently, the granules were dried at room temperature for 1 hour and at 120° C. for 3 hours, and calcined at 455° C. for 3 hours.
To carry out the second impregnation, an identical impregnation solution to that in the first step was prepared and applied in the same way by vacuum impregnation to the already laden catalyst from the first step. This was then followed again by drying at room temperature for 1 hour, followed by drying at 120° C. for 3 hours. Finally, the catalyst particles were calcined under air at 455° C. for 4 hours.
The catalysts were tested with regard to their performance data in the synthesis of methyl mercaptan from hydrogen sulphide and methanol.
The synthesis was carried out in a stainless steel tube of internal diameter 18 mm and a length of 500 mm. The catalyst bed of in each case 76 ml was secured in the reaction tube on both sides by inert beds of glass spheres. The reaction tube was heated to the reaction temperature of about 320° C. using a jacket comprising a thermal oil.
The experimental conditions can be taken from the following list:
The reaction mixture comprising the products methyl mercaptan, dimethyl sulphide and dimethyl ether, and comprising the unconverted starting materials methanol and hydrogen sulphide is analyzed by online gas chromatography.
When the tungsten fraction in relation to the alkali metal fraction in the catalyst is increased, a distinct increase in activity can be seen with simultaneously improved selectivity. In comparison to the prior art, this leads to a yield increase of up to 10%. The selectivity can be increased to up to ˜96.5% by adjusting the alkali metal-tungstate ratio, and the methanol conversion rises. In the industrial scale synthesis of methyl mercaptan, this also leads to considerable cost savings in the removal of the reaction products from unconverted methanol and by-products.
In addition, the results of Examples 4 to 7 show that at least a portion of the alkali metals can be exchange for one another in order to selectively adjust the activity and selectivity of the catalyst or in order to save raw material costs in the catalyst synthesis.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 037 739.1 | Aug 2004 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP05/07211 | 7/5/2005 | WO | 00 | 12/6/2006 |
