A TIN-CONTAINING ZEOLITIC MATERIAL HAVING A BEA FRAMEWORK STRUCTURE

Abstract

An incipient wetness impregnation method for preparing a tin-containing zeolitic material having framework type BEA, a novel tin-containing zeolitic material having framework type BEA and its use.

Claims

1.-15. (canceled)

16. A process for preparing a tin-containing zeolitic material having framework type BEA, comprising (i) providing a zeolitic material having framework type BEA wherein the framework comprises B.sub.2O.sub.3 and SiO.sub.2, wherein said framework has vacant tetrahedral framework sites; (ii) providing a liquid aqueous mixture comprising a tin-ion source and an acid; (iii) preparing a mixture of the zeolitic material provided in (i) and the aqueous mixture provided in (ii) obtaining a tin-containing zeolitic material having framework type BEA, wherein the ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV is in the range of from 0.1:1 to 1.7:1, wherein the TPV is the total pore volume of the zeolitic material in cm.sup.3/g as determined by nitrogen absorption according to DIN 66134; (iv) drying the zeolitic material obtained from (iii).

17. The process of claim 16, wherein the ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV is in the range of from 0.2:1 to 1.6:1.

18. The process of claim 16, wherein according to (i), the zeolitic material having framework type BEA having vacant tetrahedral framework sites is provided by a method comprising (i.1) providing a zeolitic material having framework type BEA, wherein the framework of the zeolitic starting material comprises B.sub.2O.sub.3 and SiO.sub.2 and the molar ratio B.sub.2O.sub.3:SiO.sub.2 is greater than 0.02:1; (i.2) creating vacant tetrahedral framework sites by treating the zeolitic material provided in (i.1) with a liquid solvent system, obtaining a zeolitic material having a molar ratio B.sub.2O.sub.3:SiO.sub.2 of at most 0.02:1, wherein the liquid solvent system is selected from the group consisting of water, methanol, ethanol, propanol, ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, propane-1,2,3-triol, and mixtures of two or more thereof; (i.3) at least partially separating the zeolitic material obtained from (i.2) from the liquid solvent system, optionally including drying; (i.4) optionally calcining the separated zeolitic material obtained from (i.3), wherein providing a zeolitic material having framework type BEA according to (i.1) optionally comprises: (i.1.1) preparing a mixture comprising at least one BEA template compound, at least one source for SiO.sub.2 and at least one source for B.sub.2O.sub.3; (i.1.2) crystallizing the zeolitic material from the mixture prepared in (i.1.1); (i.1.3) isolating and/or washing the crystallized material obtained from (i.1.2); (i.1.4) subjecting the zeolitic material obtained from (i.1.3) to a heat-treatment stage, wherein creating vacant tetrahedral framework sites according to (i.2) optionally comprises treating the zeolitic material provided in (i.1) with a liquid solvent system, thereby obtaining a zeolitic material having a molar ratio B.sub.2O.sub.3:SiO.sub.2, of at most 0.02:1 in an open system at a temperature in the range of from 95 to 105 C., and wherein at least partially separating the zeolitic material according to (i.3) comprises at least partially separating the zeolitic material obtained from (i.2) from the liquid solvent system including drying.

19. The process of claim 16, wherein in the framework of the zeolitic material provided in (i), the molar ratio B.sub.2O.sub.3:SiO.sub.2 is at most 0.02:1 and wherein at least 95 weight-%, of the framework of the zeolitic material provided in (i) consist of B, Si, O, and H.

20. The process of claim 16, wherein the tin-ion source according to (ii) is one or more of tin(II) alkoxides, tin(IV) alkoxides, tin(II) salts of organic acids, tin(IV) salts of organic acids.

21. The process of claim 16, wherein the acid comprised in the liquid aqueous mixture provided in (ii) is one or more organic acids, or one or more inorganic acids, or one or more organic acids and one or more inorganic acids.

22. The process of claim 21, wherein the liquid aqueous mixture comprises acetic acid in an amount in the range of from 2 to 43 weight-%, based on the amount of the liquid aqueous mixture, wherein the liquid aqueous mixture provided in (ii) has a pH in the range of from 1 to 5, as determined via a pH sensitive glass electrode, and wherein the liquid aqueous mixture provided in (ii) comprises the tin-ion source, calculated as elemental Sn, in an amount in the range of from 1 to 25 weight-%, based on the amount of water comprised in the acidic liquid aqueous mixture.

23. The process of claim 16, wherein at least 95 weight-%, of the acidic liquid aqueous mixture provided in (ii) consist of the tin-ion source, the acid, and water.

24. The process of claim 16, wherein preparing the mixture according to (iii) comprises agitating the mixture, and wherein the mixture is prepared at a temperature of the mixture in the range of from 10 to 40 C.

25. The process of claim 16, wherein according to (iv), the zeolitic material is dried in one or more of nitrogen and an atmosphere comprising oxygen.

26. The process of claim 16, further comprising (v) calcining the dried zeolitic material obtained from (iv), in an atmosphere comprising nitrogen.

27. A tin-containing zeolitic material having framework type BEA comprising B.sub.2O.sub.3 and SiO.sub.2, wherein the framework additionally comprises tin, wherein in the framework structure of the zeolitic material, the molar ratio B.sub.2O.sub.3:SiO.sub.2 is at most 0.02:1, wherein at least 95 weight-%, of the framework of the zeolitic material consist of Si, B, O, H, and tin, obtained by the process according to claim 16.

28. A tin-containing zeolitic material having framework type BEA comprising B.sub.2O.sub.3 and SiO.sub.2, wherein the framework additionally comprises tin, wherein in the framework structure of the zeolitic material, the molar ratio B.sub.2O.sub.3:SiO.sub.2 is at most 0.02:1, wherein at least 95 weight-%, of the framework of the zeolitic material consist of Si, B, O, H, and tin, said tin-containing zeolitic material having framework type BEA having a crystallinity, as determined via XRD, in the range of from 55 to 80%, and having BET specific surface area determined according to DIN 66131 of at least 400 m.sup.2/g.

29. The tin-containing zeolitic material of claim 28, wherein in the UV-VIS spectrum of the tin-containing zeolitic material, the ratio of the intensity of the maximum absorption peak which is in the range of from 200 to 220 relative to the intensity of the shoulder which is in the range of from 245 to 260 nm to is in the range of from 2.1 to 8.0, the tin-containing zeolitic material having a tin content in the range of from 0.5 to 20 weight-%, based on the total weight of the tin-containing zeolitic material.

30. A catalytically active material comprising the tin-containing zeolitic material having framework type BEA according to claim 27.

31. The process of claim 16, wherein the ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV is in the range of from 0.4:1 to 1.5:1.

32. The process of claim 16, wherein the ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV is in the range of from 0.6:1 to 1.4:1.

33. The process of claim 16, wherein in the framework of the zeolitic material provided in (i), the molar ratio B.sub.2O.sub.3:SiO.sub.2 is at most 0.01:1 and wherein at least 98 weight-%, of the framework of the zeolitic material provided in (i) consist of B, Si, O, and H.

34. The process of claim 16, wherein in the framework of the zeolitic material provided in (i), the molar ratio B.sub.2O.sub.3:SiO.sub.2 is at most in the range of from 0.0005:1 to 0.01:1, and wherein at least 99 weight-% of the framework of the zeolitic material provided in (i) consist of B, Si, O, and H.

35. The process of claim 16, wherein the tin-ion source according to (ii) is tin(II) acetate.

Description

EXAMPLES

Reference Example 1: Preparation of a Deboronated Zeolitic Material Having a BEA Framework Structure

1.1 Preparing a Boron-Containing Zeolitic Material Having a BEA Framework Structure

[0329] 209 kg de-ionized water were provided in a vessel. Under stirring at 120 rpm (revolutions per minute), 355 kg tetraethylammonium hydroxide were added and the suspension was stirred for 10 minutes at room temperature. Thereafter, 61 kg boric acid were suspended in the water and the suspension was stirred for another 30 minutes at room temperature. Subsequently, 555 kg Ludox AS-40 were added, and the resulting mixture was stirred at 70 rpm for another hour at room temperature. The liquid gel had a pH of 11.8 as determined via measurement with a pH electrode. The finally obtained mixture was transferred to a crystallization vessel and heated to 160 C. within 6 h under a pressure of 7.2 bar and under stirring (140 rpm). Subsequently, the mixture was cooled to room temperature. The mixture was again heated to 160 C. within 6 h and stirred at 140 rpm for additional 55 h. The mixture was cooled to room temperature and subsequently, the mixture was heated for additional 45 h at a temperature of 160 C. under stirring at 140 rpm. 7800 kg de ionized water were added to 380 kg of this suspension. The suspension was stirred at 70 rpm and 100 kg of a 10 weight-% HNO.sub.3 aqueous solution was added. From this suspension the boron containing zeolitic material having a BEA framework structure was separated by filtration. The filter cake was then washed with de-ionized water at room temperature until the washing water had a conductivity of less than 150 microSiemens/cm. The thus obtained filter cake was subjected to pre-drying in a nitrogen stream. The thus obtained zeolitic material was subjected, after having prepared an aqueous suspension having a solids content of 15 weight-%, based on the total weight of the suspension, using de-ionized water, to spray-drying in a spray-tower with the following spray-drying conditions: [0330] drying gas, nozzle gas: technical nitrogen [0331] temperature drying gas: [0332] temperature spray tower (in): 235 C. [0333] temperature spray tower (out): 140 C. [0334] nozzle: [0335] top-component nozzle supplier Gerig; size 0 [0336] nozzle gas temperature: room temperature [0337] nozzle gas pressure: 1 bar [0338] operation mode: nitrogen straight [0339] apparatus used: spray tower with one nozzle [0340] configuration: spray tower-filter-scrubber [0341] gas flow: 1,500 kg/h [0342] filter material: Nomex needle-felt 20 m.sup.2 [0343] dosage via flexible tube pump: SP VF 15 (supplier: Verder)

[0344] The spray tower was comprised of a vertically arranged cylinder having a length of 2,650 mm, a diameter of 1,200 mm, which cylinder was conically narrowed at the bottom. The length of the conus was 600 mm. At the head of the cylinder, the atomizing means (a two-component nozzle) were arranged. The spray-dried material was separated from the drying gas in a filter downstream of the spray tower, and the drying gas was then passed through a scrubber. The suspension was passed through the inner opening of the nozzle, and the nozzle gas was passed through the ring-shaped slit encircling the opening. The spray-dried material was then subjected to calcination at 500 C. for 5 h. The calcined material had a B.sub.2O.sub.3:SiO.sub.2 molar ratio of 0.045, a total carbon content of (TOC) 0.08 weight-%, a crystallinity determined by XRD of 56%, and a BET specific surface area determined according to DIN 66131 of 498 m.sup.2/g. The total pore volume (TPV) determined according to DIN 66134 was 0.4 cm.sup.3/g.

1.2 DeboronationForming Vacant Tetrahedral Sites

[0345] 840 kg de-ionized water were provided in a vessel equipped with a reflux condenser. Under stirring at 40 rpm, 28 kg of the spray-dried and calcined zeolitic material described above in 1.1 were employed. Subsequently, the vessel was closed and the reflux condenser put into operation. The stirring rate was increased to 70 rpm. Under stirring at 70 rpm, the content of the vessel was heated to 100 C. within 1 h and kept at this temperature for 20 h. Then, the content of the vessel was cooled to a temperature of less than 50 C. The resulting deboronated zeolitic material having a BEA framework structure was separated from the suspension by filtration under a nitrogen pressure of 2.5 bar and washed four times with deionized water at room temperature. After the filtration, the filter cake was dried in a nitrogen stream for 6 h. The obtained deboronated zeolitic material was subjected, after having re-suspended the zeolitic material in de-ionized water, to spray-drying under the conditions as described in 5.1. The solid content of the aqueous suspension was 15 weight-%, based on the total weight of the suspension. The obtained zeolitic material had a B.sub.2O.sub.3:SiO.sub.2 molar ratio of less than 0.002, a water uptake of 15 weight-%, a crystallinity determined by XRD of 48% and a BET specific surface area determined by DIN 66131 of 489 m.sup.2/g.

Reference Example 2: UV-VIS Measurements

[0346] The UV-VIS measurements were performed using a PerkinElmer Lambda 950 equipped with a Labsphere 150 mm integrating sphere for the measurement of diffuse reflection (gloss trap closed). The powder cuvette used for the solid samples was filled with the solid samples so that the area measured was completely covered by the sample. As reference, Spectralon standard was used, integration time 0.2 s, scan speed 267 nm/min, spectral range 200-800 nm, measurement at room temperature. The spectra obtained were transformed to Kubelka-Munk spectra.

Reference Example 3: FT-IR Measurements

[0347] The FT-IR (Fourier-Transformed-Infrared) measurements were performed on a Nicolet 6700 spectrometer. The powdered material was pressed into a self-supporting pellet without the use of any additives. The pellet was introduced into a high vacuum (HV) cell placed into the FT-IR instrument. Prior to the measurement the sample was pretreated in high vacuum (10.sup.5 mbar) for 3 h at 300 C. The spectra were collected after cooling the cell to 50 C. The spectra were recorded in the range of 4000 to 800 cm.sup.1 at a resolution of 2 cm.sup.1. The obtained spectra are represented in a plot having on the x axis the wavenumber (cm.sup.1) and on the y axis the absorbance (arbitrary units, a.u.). For the quantitative determination of the peak heights and the ratio between these peaks a baseline correction was carried out. Changes in the 3000-3900 cm.sup.1 region were analyzed and for comparing multiple samples, as reference the band at 18805 cm-.sup.1 was taken.

Reference Example 4: Determination of the Water Uptake

[0348] Water adsorption/desorption isotherms were performed on a VTI SA instrument from TA Instruments following a step-isotherm program. The experiment consisted of a run or a series of runs performed on a sample material that has been placed on the microbalance pan inside of the instrument. Before the measurement was started, the residual moisture of the sample was removed by heating the sample to 100 C. (heating ramp of 5 C./min) and holding it for 6 h under a nitrogen flow. After the drying program, the temperature in the cell was decreased to 25 C. and kept isothermal during the measurement. The microbalance was calibrated, and the weight of the dried sample was balanced (maximum mass deviation 0.01 weight-%). Water uptake by the sample was measured as the increase in weight over that of the dry sample. First, as adsorption curve was measured by increasing the relative humidity (RH) (expressed as weight-% water in the atmosphere inside of the cell) to which the sample was exposed and measuring the water uptake by the sample as equilibrium. The RH was increased with a step of 10 weight-% from 5% to 85% and at each step the system controlled the RH and monitored the sample weight until reaching the equilibrium conditions after the sample was exposed from 85 weight-% to 5 weight-% with a step of 10% and the change in the weight of the sample (water uptake) was monitored and recorded.

Reference Example 5: Determination of the Crystallinity

[0349] The crystallinity was determined according to the method as described in the User Manual DIFFRAC.EVA Version 3, page 105, from Bruker AXS GmbH, Karlsruhe (published February 2003). The respective data were collected on a standard Bruker D8 Advance Diffractometer Series II using a LYNXEYE detector, from 2 to 50 2theta, using fixed slits, a step size of 0.02 2theta and a scan speed of 2.4 s/step. The parameters used for estimating the background/amorphous content were Curvature=0 and Threshold=0.8.

Example 1: Preparation of a Tin-Containing Zeolitic Material Having a BEA Frame-Work Structure Via Impregnation in the Presence of an Acid

[0350] 3.55 g tin acetate Sn(OAc).sub.2 (from Aldrich) were admixed with 6.25 g acetic acid. 24.75 g de-ionized water were added, resulting in a grey suspension. 25 g of the zeolitic material obtained according to Reference Example 1 were filled in a bowl and admixed with the suspension and thoroughly mixed. The ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV was 1.28:1. The suspension was dried overnight under air at 60 C. in an oven. In a rotary kiln, the dried suspension was heated with a temperature ramp of 2 K/min to a temperature of 500 C. under nitrogen with a flow rate of 80 Nl/h. Then, the temperature of 500 C. was maintained for 3 h. Subsequently, the nitrogen flow was stopped and replaced by air with a flow rate of 80 Nl/h (Nl/h is defined as flow rate of a gas measured at 101.325 kPa and 0 C. according to DIN 1343). The air flow at 500 C. was maintained for 3 h. Then, the dried and calcined material was cooled to room temperature. 25.1 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 6.4 weight-% Sn, 40 weight-% Si, <0.1 weight-% C (TOC). The BET surface as determined according to DIN 66133 was 519 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 68%. The water adsorption, as determined according to Reference Example 4, was 20.4 weight-%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 1. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 2.6. The FT-IR spectrum, as determined according to Reference Example 3, is shown in FIG. 2.

Example 2: Preparation of a Tin-Containing Zeolitic Material Having a BEA Frame-Work Structure Via Impregnation in the Presence of an Acid

[0351] 14.2 g tin acetate Sn(OAc).sub.2 (from Aldrich) were admixed with 25 g acetic acid. 37.5 g de-ionized water were added, resulting in a grey suspension. 50 g of the zeolitic material obtained according to Reference Example 1 were filled in a bowl and admixed with the suspension and thoroughly mixed. The ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV was 1.3:1. The suspension was dried overnight under air at 60 C. in an oven. In a rotary kiln, the dried suspension was heated with a temperature ramp of 2 K/min to a temperature of 500 C. under nitrogen with a flow rate of 80 Nl/h. Then, the temperature of 500 C. was maintained for 3 h. Subsequently, the nitrogen flow was stopped and replaced by air with a flow rate of 80 Nl/h. The air flow at 500 C. was maintained for 3 h. Then, the dried and calcined material was cooled to room temperature. 55.1 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 12.9 weight-% Sn, 38 weight-% Si, <0.1 weight-% C (TOC). The BET surface as determined according to DIN 66131 was 450 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 63%. The water adsorption, as determined according to Reference Example 4, was 16.9 weight-%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 3. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 5.9. The FT-IR spectrum, as determined according to Reference Example 3, is shown in FIG. 4.

Example 3: Preparation of a Tin-Containing Zeolitic Material Having a BEA Frame-Work Structure Via Impregnation in the Presence of an Acid

[0352] 7.1 g tin acetate Sn(OAc).sub.2 (from Aldrich) were admixed with 12.5 g acetic acid. 18.75 g de-ionized water were added, resulting in a grey suspension. 25 g of the zeolitic material obtained according to Reference Example 1 were filled in a bowl and admixed with the suspension and thoroughly mixed. The ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV was 1.36:1. The suspension was dried overnight under air at 60 C. in an oven. In a rotary kiln, the dried suspension was heated with a temperature ramp of 2 K/min to a temperature of 300 C. Then, the temperature of 300 C. was maintained for 3 h under said nitrogen flow. Then, the temperature was raised with a temperature ramp of 2 K/min to a temperature of 500 C. Then, the temperature of 500 C. was maintained for 3 h under said nitrogen flow. Subsequently, the nitrogen flow was stopped and replaced by air with a flow rate of 80 Nl/h. The air flow at 500 C. was maintained for 3 h. Then, the dried and calcined material was cooled to room temperature. 27.4 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 12.9 weight-% Sn, 38 weight-% Si, <0.1 weight-% C (TOC). The BET surface as determined according to DIN 66131 was 432 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 63%. The water adsorption, as determined according to Reference Example 4, was 16 weight-%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 9. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 4.6.

Example 4: Preparation of a Tin-Containing Zeolitic Material Having a BEA Frame-Work Structure Via Impregnation in the Presence of an Acid

[0353] 7.1 g tin acetate Sn(OAc).sub.2 (from Aldrich) were admixed with 12.5 g acetic acid. 18.75 g de-ionized water were added, resulting in a grey suspension. 25 g of the zeolitic material obtained according to Reference Example 1 were filled in a bowl and admixed with the suspension and thoroughly mixed. The ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV was 1.36:1. The suspension was dried overnight under air at 60 C. in an oven. In a rotary kiln, the dried suspension was heated with a temperature ramp of 2 K/min to a temperature of 500 C. under N2 80 nL/h. Then, the temperature of 500 C. was maintained for 3 h under said nitrogen flow. Subsequently, the nitrogen flow was stopped and replaced by air with a flow rate of 80 Nl/h. The air flow at 500 C. was maintained for 3 h. Then, the dried and calcined material was cooled to room temperature. 27.2 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 14.0 weight-% Sn, 37 weight-% Si, <0.1 weight-% C (TOC). The BET surface as determined according to DIN 66131 was 460 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 68%. The water adsorption, as determined according to Reference Example 4, was 17 weight-%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 10. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 2.86. The FT-IR spectrum, as determined according to Reference Example 3, is shown in FIG. 11.

Example 5: Preparation of a Tin-Containing Zeolitic Material Having a BEA Frame-Work Structure Via Impregnation in the Presence of an Acid

1.1 Preparing a Boron-Containing Zeolitic Material Having a BEA Framework Structure

[0354] 259 g de-ionized water were filled in a beaker. Under stirring at 200 r.p.m. (revolutions per minute), 440 g tetraethylammonium hydroxide were added. The stirring was continued for 10 min. Then, 75.6 g boric acid were added and the stirring was continued until a clear solution was obtained (about 30 min). Then, 687.9 g stabilized colloidal silica (Ludox AS-40) were added and the stirring was continued overnight. The pH of the mixture was 10.8. Then, the mixture was transferred to an autoclave and subjected to hydrothermal crystallization at 160 C. for 48 h under stirring at 140 r.p.m. The, the mixture was cooled within 5 h to 28 C. After a total of 7 h, it was heated again to 160 C. under stirring at 140 r.p.m. and then stirred at this rate for 96 h at 160 C. After cooling, the mixture was admixed with the double amount of de-ionized water to achieve a pH of the mixture of 8.9. Then, the pH of the mixture was adjusted to a value in the range of from 7-8 with nitric acid (10% in water). Then, the liquid portion of the mixture was removed, and the mixture was washed with de-ionized water until the washing water had a conductivity of less than 150 microSiemens. The resulting boron-containing zeolitic material having a BEA framework structure was dried for 12 h at 120 C. under air and calcined (heating ramp: 2 K/min) for 5 h at 490 C. under air. 285 g boron-containing zeolitic material having a BEA framework structure were obtained, having a B content of 1.5 weight-% and a Si content of 43 weight-%.

1.2 Deboronation and Forming Vacant Tetrahedral Sites

[0355] In a stirred vessel, 2,100 g de-ionized water were admixed with 200 g of the boron-containing zeolitic material having a BEA framework structure obtained according to 1.1. The mixture was heated to 100 C. and kept at 100 C. under reflux for 10 h. After cooling and removal of the liquid portion of the mixture (filtration), the solid was washed with de-ionized water. The resulting deboronated zeolitic material having a BEA framework structure was dried (heating ramp: 3 K/min) for 12 h at 120 C. under air and calcined (heating ramp: 2 K/min) for 5 h at 550 C. under nitrogen. 183 g deboronated zeolitic material having a BEA framework structure were obtained, having a B content of 0.1 weight-% and a Si content of 47 weight-%.

1.3 Incorporating Tin Via Incipient Wetness Impregnation

[0356] 7.1 g tin acetate Sn(OAc).sub.2 (from Aldrich) were admixed with 12.5 g acetic acid. 18.75 g de-ionized water were added, resulting in a grey suspension. 25 g of the zeolitic material obtained according to Reference Example 1 were filled in a bowl and admixed with the suspension and thoroughly mixed. The ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV was 1.36:1. The suspension was dried overnight under air at 60 C. in an oven. The suspension was dried overnight under air at 60 C. in an oven. In a rotary kiln, the dried suspension was heated with a temperature ramp of 2 K/min to a temperature of 500 C. under nitrogen with a flow rate of 80 Nl/h. Then, the temperature of 500 C. was maintained for 3 h. Subsequently, the nitrogen flow was stopped and replaced by air with a flow rate of 80 Nl/h. The air flow at 500 C. was maintained for 3 h. Then, the dried and calcined material was cooled to room temperature. 27.2 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 10.6 weight-% Sn, 37 weight-% Si, <0.1 weight-% C (TOC). The BET surface as determined according to DIN 66131 was 450 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 60%. The water adsorption, as determined according to Reference Example 4, was 18.9 weight-%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 5. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 2.2. The FT-IR spectrum, as determined according to Reference Example 3, is shown in FIG. 6.

Example 6: Preparation of a Tin-Containing Zeolitic Material Having a BEA Frame-Work Structure Via Impregnation in the Presence of an Acid

[0357] 1.02 g tin acetate Sn(OAc).sub.2 (from Aldrich) were admixed with 1.80 g acetic acid. 18.75 g de-ionized water were added, resulting in a grey suspension. 25 g of the zeolitic material obtained according to Reference Example 1 were filled in a bowl and admixed with the suspension and thoroughly mixed. The ratio of the volume of the aqueous mixture divided by the mass of the zeolitic material, in cm.sup.3/g, to the TPV was 0.88:1. The suspension was dried overnight under air at 60 C. in an oven. In a rotary kiln, the dried suspension was heated with a temperature ramp of 2 K/min to a temperature of 500 C. under nitrogen with a flow rate of 80 Nl/h. Then, the temperature of 500 C. was maintained for 3 h under said nitrogen flow. Subsequently, the nitrogen flow was stopped and replaced by air with a flow rate of 80 Nl/h. The air flow at 500 C. was maintained for 3 h. Then, the dried and calcined material was cooled to room temperature. 23.4 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 2 weight-% Sn, 42 weight-% Si, <0.1 weight-% C (TOC). The BET surface as determined according to DIN 66131 was 526 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 70%. The water adsorption, as determined according to Reference Example 4, was 21.9 weight-%. The FT-IR spectrum, as determined according to Reference Example 3, is shown in FIG. 7.

Example 6.1: Post-Treatment of a Tin-Containing Zeolitic Material Having a BEA Framework Structure Having been Prepared Via Impregnation in the Presence of an Acid

[0358] The tin-containing zeolitic material according to Example 6 having a BEA framework structure was subjected to a post-treatment as follows: 18.46 g de-ionized water were filled in a beaker. Under stirring at 200 r.p.m., 31.36 g tetraethylammonium hydroxide were admixed with the water, followed by stirring for 30 min at 200 r.p.m. Then, 20 g of the tin-containing zeolitic material having a BEA framework structure were admixed with the stirred mixture, and stirring was continued for 1 h. In an oven, the mixture was subjected to a temperature of 160 C. for 36 h. After cooling, the mixture was admixed with the double amount of de-ionized water to achieve a pH of the mixture of 10.9. Then, the pH of the mixture was adjusted to a value in the range of from 7-8 with nitric acid (10% in water). Then, the liquid portion of the mixture was removed, and the mixture was washed with de-ionized water until the washing water had a conductivity of less than 150 microSiemens. The resulting tin-containing zeolitic material having a BEA framework structure was dried for 12 h at 120 C. under air and calcined (heating ramp: 2 K/min) for 5 h at 490 C. under air. 20.2 g tin-containing zeolitic material having a BEA framework structure were obtained. The tin-containing zeolitic material having a BEA framework structure had the following composition: 2 weight-% Sn, 42 weight-% Si, 0.11 weight-% C (TOC). The BET surface as determined according to DIN 66131 was 601 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 75%. The water adsorption, as determined according to Reference Example 4, was 29.2 weight-%. The FT-IR spectrum, as determined according to Reference Example 3, is shown in FIG. 8.

Comparative Example 1: Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure Via Solid State Ion Exchange

1.1 Preparing a Boron-Containing Zeolitic Material Having a BEA Framework Structure

[0359] 259 g de-ionized water were provided in a vessel. Under stirring at 120 rpm (rounds per minute), 440 g tetraethylammonium hydroxide were added and the suspension was stirred for 10 minutes at room temperature. Thereafter, 75.6 g boric acid were suspended and the suspension was stirred for another 30 minutes at room temperature. Subsequently, 687.9 g Ludox AS-40 were added, and the resulting mixture was stirred for another hour at room temperature. The finally obtained mixture was transferred to a crystallization vessel and heated to 160 C. and stirred at 140 rpm for 120 h. The mixture was cooled to room temperature and subsequently. De-ionized water (twice the amount of the mixture), resulting in a mixture having a pH of 10.0. This mixture was adjusted to a pH of 7-8 by adding aqueous HNO.sub.3 (10 weight-% HNO.sub.3). The mixture was subjected to filtration and the filter cake was washed with de-ionized water until the washing water had a conductivity of less than 150 microSiemens. The thus obtained filter cake was subjected to drying at 120 C. for 2 h under air, followed by calcination at 490 C. for 5 h under air (heating ramp: 2 K/min). The calcined material had a B content of 0.89 weight-%, a Si content of 47 weight-%, a total carbon content of (TOC) of less than 0.1 weight-%, a crystallinity determined by XRD of 42%, and a BET specific surface area determined by DIN 66131 of 257 m.sup.2/g.

1.2 Deboronation and Forming Vacant Tetrahedral Sites

[0360] 2,100 g de-ionized water were passed in a 4 l stirred vessel. Under stirring, 140 g of the material obtained from 1.1 above were added, and the resulting mixture heated to 100 C. The mixture was kept at this temperature under reflux for 10 h. Then, the mixture was cooled to room temperature. The cooled mixture was subjected to filtration and the filter cake was washed with de-ionized water. The thus obtained filter cake was subjected to drying at 120 C. for 12 h under air (heating ramp: 3 K/min), followed by calcination at 550 C. for 5 h under air (heating ramp: 2 K/min). The calcined material had a B content of 0.15 weight-%, a Si content of 49 weight-%, a total carbon content of (TOC) of less than 0.1 weight-%.

1.3 Incorporating Tin Via Solid-State Ion-Exchange

[0361] 25 g of the deboronated zeolitic material having a BEA framework structure described in 1.2 above were added to a mixer (mill type Microton MB550) together with 1.02 g of tin(II) acetate (Sn(OAc).sub.2[CAS-Nr:638-39-1]), and the mixture was milled for 15 minutes with 14,000 r.p.m. (rounds per minute). After the milling, the mixture was transferred to a porcelain basket and calcined in air at 500 C. for 3 h under N.sub.2 followed by 3 h under air, with a heating ramp of 2 K/min. The obtained powder material had a Sn content of 1.1 weight-%, a silicon (Si) content of 47 weight-%, a B content of less than 0.1 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 170 m.sup.2/g. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 12. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 220 nm relative to the intensity of the shoulder at about 250 nm was 4.0.

Comparative Example 2: Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure Via Solid State Ion Exchange

[0362] 30 g of the zeolitic material obtained according to Reference Example 1 were thoroughly admixed for 5 min with 8.52 g tin acetatewhich had been milled in ball-milling apparatus for 15 min, heated in a rotary kiln to 500 C. (temperature ramp: 2 K/min) under nitrogen flow (80 Nl/h) and kept at this temperature under said nitrogen flow for 3 h. Then, the nitrogen flow was switched to air flow (80 Nl/h) and calcination was continued for another 3 h at 500 C. The obtained powder material had a Sn content of 11.8 weight-%, a silicon (Si) content of 37 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 386 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 65%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 13. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 3.2.

Comparative Example 3: Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure Via Spraying

[0363] 14.2 g tin acetate were dissolved in 400 ml de-ionized water. Under stirring, 50 g of the zeolitic material obtained according to Reference Example 1 were admixed, and stirring was continued for 3 h at room temperature. The resulting mixture was subjected to spraying using a spray-drying apparatus. The same apparatus and the same spray-drying conditions as described in Reference Example 1 (section 1.1) were used. 50% of the obtained spray-dried material were heated in a rotary kiln to 500 C. (temperature ramp: 2 K/min) under nitrogen flow (80 Nl/h) and kept at this temperature under said nitrogen flow for 3 h. Then, the nitrogen flow was switched to air flow (80 Nl/h) and calcination was continued for another 3 h at 500 C. 8.4 g g of tin-containing zeolitic material having a BEA framework structure were obtained. The obtained powder material had a Sn content of 13.4 weight-%, a silicon (Si) content of 38.5 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 389 m.sup.2/g. The crystallinity, as determined according to Reference Example 5, was 34%. The UV-VIS spectrum, as determined according to Reference Example 2, is shown in FIG. 14. In the UV-VIS spectrum, the ratio of the intensity of the peak of the maximum at about 210 nm relative to the intensity of the shoulder at about 250 nm was 2.5.

Example 7: Baeyer-Villiger Oxidation of Citral (Compound of Formula (I)) with Hydrogen Peroxide in MTBE as Solvent Using a Tin-Containing Zeolitic Material Having a BEA Framework Structure

[0364] A 1 L glass flask was charged with citral (122.5 g, 98% trans-citral, 2% cis-citral) as indicated in Table 1 below, the zeolitic material according to the Examples and the Comparative Examples above (8.8 g) and MTBE (methyl tert-butyl ether) as solvent (367.5 g) and heated to 50 C. An aqueous solution of hydrogen peroxide 70 w/w %, 29.75 g) was then added and the reaction mixture was stirred. After cooling to room temperature, the resulting solution was filtered and the filtrate was analyzed by GC using dioxane as internal standard. The results are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Results of Example 7 Example (E) and Sn content Comparative Reaction of zeolitic Citral Selectivity .sup.1) Example (CE)/ Time/ material/ Conversion/ based on # min weight-% % citral/% E1 150 6.4 35 75 E2 150 12.9 39 77 E2 .sup.2) 150 12.9 29 94 E3 150 12.9 36 61 E4 150 14.0 34 69 E5 150 10.6 31 79 CE1 150 1.1 11 63 CE2 150 11.8 23 66 CE3 150 13.4 11 38 .sup.1) molar amount of melonal (compound of formula III)) + molar amount of enol formate (compound of formula (II)) obtained from the reaction divided by the molar amount of citral (compound of formula (I)) converted in the reaction .sup.2) 24 g hydrogen peroxide (50 w/w %), 70 g citral (98% trans-citral, 2% cis-citral) in 359 g MTBE, and 5 g zeolitic material were used

Results of Example 7

[0365] As shown in Example 7, the zeolitic materials according to the invention, prepared by impregnation in the presence of an acid, are characterized by both a high conversion of citral (well above 30% for all Examples) and a high selectivity (above 60% for all Examples). The Sn content of the inventive materials did not play a decisive role, as exemplified, for example, by a comparison of Example 1 and Example 2 exhibiting very similar conversions and selectivities whereas the Sn content according to Example 2 was about twice the Sn content according to Example 1. Compared to the inventive zeolitic materials, other Sn containing materials, prepared, e.g. via solid state ion exchange (Comparative Examples 1 and 2) or spraying (Comparative Example 3), only the materials according to Comparative Examples 1 and 2 exhibited somewhat tolerable selectivity values whereas, for all comparative materials, only very low citral conversions were observed.

Example 8: Comparison of Tin-Containing Zeolitic Materials Having a BEA Framework Structure

[0366] In the following Table 2, the tin-containing zeolitic material having a BEA framework structure of the present invention, according to the comparative examples and of the prior art are compared with respect to their crystallinity, their BET specific surface area, and their UV-VIS characteristics:

TABLE-US-00002 TABLE 2 Comparison of tin-containing zeolitic materials BET specific Zeolitic material Sn content/ surface area/ Crystallinity/ UV-VIS according to weight-% m.sup.2/g % ratio .sup.1) E1 6.4 519 68 2.6 E2 12.9 450 63 4.6 E3 12.9 432 63 5.9 E4 14.0 460 68 2.9 E5 10.6 450 60 2.2 E6 2.0 526 70 n.d. .sup.8) CE1 1.1 170 n.d. .sup.8) 4.0 CE2 11.8 386 65 3.2 CE3 13.4 389 34 2.5 Prior art .sup.2) 9.3 380 53 n.d. .sup.8) Prior art .sup.3) 12.7 395 48 1.44 Prior art .sup.4) 12.6 405 49 1.32 Prior art .sup.5) 9.6 423 51 n.d. .sup.8) Prior art .sup.6) 12.0 391 44 2.0 Prior art .sup.7) 13.1 442 44 1.75 .sup.1) ratio of the intensity of the maximum peak at about 200-220 nm and the intensity of the shoulder at about 250 nm in the UV-VIS spectrum .sup.2) Example 1 of WO 2015/067654 A .sup.3) Example 2 of WO 2015/067654 A .sup.4) Example 3 of WO 2015/067654 A .sup.5) Comparative Example 1 of WO 2015/067654 A .sup.6) Comparative Example 2 of WO 2015/067654 A .sup.7) Comparative Example 3 of WO 2015/067654 A .sup.8) not determined

Results of Example 8

[0367] As shown in Example 8, the zeolitic materials according to the invention exhibit a higher crystallinity. Since, e.g., in catalytic reactions, it is the crystalline material which is active as catalyst, a higher crystallinity means that more active mass of catalytically active material is present. Further, with the regard to the UV-VIS ratio, it is observed that the zeolitic materials according to the invention exhibit higher values which are an indication that, compared to the other materials, a lower amount of extra-framework tin is comprised in the zeolitic materials according to the invention. This means that the zeolitic materials according to the invention have more active sites than the prior art materials. Yet further, it was observed that the zeolitic materials according to the invention exhibit higher BET specific surface areas than the other materials. This means that a larger surface area is available for catalytic reactions.

SHORT DESCRIPTION OF THE FIGURES

[0368] FIG. 1 shows the UV-VIS spectrum of the zeolitic material prepared according to Example 1, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 300; 400; 500; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0369] FIG. 2 shows the FT-IR spectrum of the zeolitic material prepared according to Example 1, determined as described in Reference Example 3. The x axis shows the wavenumbers in cm.sup.1, with tick marks, from left to right, at 4000; 3000; 2000. The y axis shows the extinction, with tick marks, from bottom to top, at 0,0; 0,2; 0,4; 0,6; 0,8.

[0370] FIG. 3 shows the UV-VIS spectrum of the zeolitic material prepared according to Example 2, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 300; 400; 500; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0371] FIG. 4 shows the FT-IR spectrum of the zeolitic material prepared according to Example 2, determined as described in Reference Example 3. The x axis shows the wavenumbers in cm.sup.1, with tick marks, from left to right, at 4000; 3000; 2000. The y axis shows the extinction, with tick marks, from bottom to top, at 0,0; 0,1; 0,2; 0,3; 0,4; 0,5.

[0372] FIG. 5 shows the UV-VIS spectrum of the zeolitic material prepared according to Example 5, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 300; 400; 500; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0373] FIG. 6 shows the FT-IR spectrum of the zeolitic material prepared according to Example 5, determined as described in Reference Example 3. The x axis shows the wavenumbers in cm.sup.1, with tick marks, from left to right, at 4000; 3000; 2000. The y axis shows the extinction, with tick marks, from bottom to top, at 0,00; 0,10; 0,20; 0,30; 0,40; 0,50, 0,60.

[0374] FIG. 7 shows the FT-IR spectrum of the zeolitic material prepared according to Example 6, determined as described in Reference Example 3. The x axis shows the wavenumbers in cm.sup.1, with tick marks, from left to right, at 4000; 3500; 3000; 2500; 2000; 1500. The y axis shows the extinction, with tick marks, from bottom to top, at 0,0; 0,1; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 0,8; 0,9; 1,0; 1.1; 1,2; 1,3; 1,4; 1,5; 1,6; 1,7.

[0375] FIG. 8 shows the FT-IR spectrum of the zeolitic material prepared according to Example 6.1, determined as described in Reference Example 3. The x axis shows the wavenumbers in cm.sup.1, with tick marks, from left to right, at 4000; 3500; 3000; 2500; 2000; 1500. The y axis shows the extinction, with tick marks, from bottom to top, at 0,00; 0,05; 0,10; 0,15; 0,20; 0,25; 0,30; 0,35; 0,40; 0,45; 0,50; 0,55; 0,60; 0,65; 0,70; 0,75; 0,80; 0,85.

[0376] FIG. 9 shows the UV-VIS spectrum of the zeolitic material prepared according to Example 3, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 300; 400; 500; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0377] FIG. 10 shows the UV-VIS spectrum of the zeolitic material prepared according to Example 4, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 250; 300; 350; 400; 450; 500; 550; 600. They axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0378] FIG. 11 shows the FT-IR spectrum of the zeolitic material prepared according to Example 4, determined as described in Reference Example 3. The x axis shows the wavenumbers in cm.sup.1, with tick marks, from left to right, at 4000; 3000; 2000. The y axis shows the extinction, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0379] FIG. 12 shows the UV-VIS spectrum of the zeolitic material prepared according to Comparative Example 1, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 300; 400; 500; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,1; 0,2; 0,3; 0,4; 0,5.

[0380] FIG. 13 shows the UV-VIS spectrum of the zeolitic material prepared according to Comparative Example 2, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 250; 300; 350; 400; 450; 500; 550; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0.

[0381] FIG. 14 shows the UV-VIS spectrum of the zeolitic material prepared according to Comparative Example 3, determined as described in Reference Example 2. The x axis shows the wavelength in nm, with tick marks, from left to right, at 200; 300; 400; 500; 600. The y axis shows the K-M value, with tick marks, from bottom to top, at 0,0; 0,5; 1,0; 1,5; 2,0; 2,5; 3,0.

CITED LITERATURE

[0382] Hammond C., et al., Simple and Scalable Preparation of Highly Active Lewis Acidic Sn-beta; Angw. Chem. Int. Ed. 2012 (51), pp. 11736-11739 [0383] WO 2015/067654 A