Tin-containing zeolitic material having a BEA framework structure

Abstract

A process for preparing a tin-containing zeolitic material having a BEA framework structure comprising providing a zeolitic material having a BEA framework structure having vacant tetrahedral framework sites, providing a tin-ion source in solid form, incorporating tin into the zeolitic material via solid-state ion exchange, calcining the zeolitic material, and treating the calcined zeolitic material with an aqueous solution having a pH of at most 5.

Claims

1. A process for preparing a tin-containing zeolitic material having a BEA framework structure comprising (i) providing a zeolitic material having a BEA framework structure comprising X.sub.2O.sub.3 and YO.sub.2, wherein Y is a tetravalent element selected from the group consisting of Si, Ti, Zr, Ge, and combinations of two or more thereof, and X is a trivalent element selected from the group consisting of Al, B, In, Ga, Fe, and combinations of two or more thereof, said BEA framework structure having vacant tetrahedral framework sites; (ii) providing a tin-ion source in solid form; (iii) incorporating tin into the zeolitic material provided in (i) by contacting the zeolitic material with the tin-ion source under solid-state ion exchange conditions; (iv) subjecting the zeolitic material obtained from (iii) to a heat treatment; (v) treating the heat-treated zeolitic material with an aqueous solution having a pH of at most 5.

2. The process of claim 1, wherein Y is Si and X is B.

3. The process of claim 1, wherein the zeolitic material having a BEA framework structure with vacant tetrahedral framework sites according to (i) is produced by a process comprising: (i.1) providing a zeolitic starting material having a BEA framework structure, wherein the framework structure of the zeolitic starting material comprises X.sub.2O.sub.3 and YO.sub.2 and the molar ratio X.sub.2O.sub.3:YO.sub.2 is in a range of from 0.03:1 to 0.07:1; (i.2) creating vacant tetrahedral framework sites by treating the zeolitic starting material provided in (i.1) with a liquid solvent system, 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, and the treating is carried out at a temperature in a range of from 50 to 125 C.; (i.3) at least partially separating the zeolitic material obtained from (i.2) from the liquid solvent system, and optionally drying the separated zeolitic material; (i.4) optionally calcining the separated zeolitic material at a temperature in a range of from 400 to 700 C.

4. The tin-containing zeolitic material obtainable or obtained by a process according to claim 3.

5. The process of claim 1, wherein in the framework structure of the zeolitic material a molar ratio X.sub.2O.sub.3:YO.sub.2 is in a range of from 0.01:1.

6. The process of claim 1, wherein the framework structure of the zeolitic material consists of at least 98 weight-% of X.sub.2O.sub.3 and YO.sub.2.

7. The process of claim 1, wherein the tin-ion source is selected from the group consisting of tin(II) alkoxides, tin(IV) alkoxides, tin(II) salts of organic acids, tin(IV) salts of organic acids, and a mixture a two or more thereof.

8. The process of claim 7, wherein the tin(II) alkoxides have from 1 to 4 carbon atoms, the tin(IV) alkoxides have from 1 to 4 carbon atoms, the tin(II) salts of organic acids have from 1 to 6 carbon atoms, the tin(IV) salts of organic acids have from 1 to 6 carbon atoms.

9. The process of claim 1, wherein the molar ratio of tin to the vacant tetrahedral framework sites of the zeolitic material is at most 1:1.

10. The process of claim 1, wherein the contacting of the zeolitic material includes mixing of the zeolitic material with the tin-ion source.

11. The process of claim 10, wherein the mixing is carried out under stirring at a stirring energy input min the range of from 100 to 1000 W.

12. The process of claim 10, further comprising grinding and/or milling the zeolitic material prior to mixing the zeolitic material together with the tin-ion source, or grinding and/or milling the tin-ion source prior to mixing the zeolitic material together with the tin-ion source, or grinding and/or milling the zeolitic material prior to mixing the zeolitic material together with the tin-ion source and grinding and/or milling the tin-ion source prior to mixing the zeolitic material together with the tin-ion source.

13. The process of claim 1, wherein the heat-treating includes calcining, wherein the calcining is carried out at a temperature in a range of from 400 to 700 C., at least partially in an atmosphere comprising oxygen.

14. The process of claim 1, wherein in (v), the aqueous solution comprises an organic acid selected from the group consisting of oxalic acid, acetic acid, citric acid, methane sulfonic acid, and a mixture of two or more thereof, or the aqueous solution comprises an inorganic acid selected from the group consisting of phosphoric acid, sulphuric acid, hydrochloric acid, nitric acid, and a mixture of two or more thereof, or a mixture of the organic acid and the inorganic acid.

15. The process of claim 14, wherein the aqueous solution has a pH in the range of from 0 to 2.

16. The process of claim 1, wherein in (v), the heat-treated zeolitic material is treated with the aqueous solution at a weight ratio of the aqueous solution relative to the heat-treated zeolitic material in a range of from 2:1 to 50:1.

17. The process of claim 1, further comprising (vi) drying and/or calcining the zeolitic material obtained from (v), optionally after washing, wherein the drying is carried out at a temperature in the range of from 100 to 180 C., and calcination is carried out at a temperature in the range of from 550 to 700 C.

18. The process of claim 17, further comprising (vii) shaping the tin-containing zeolitic material having a BEA framework structure obtained from (v) or (vi), to provide a molding; (viii) drying and/or calcining the molding obtained from (vii); (ix) optionally subjecting the molding obtained from (vii) or (viii), to a water-treatment, wherein the water-treatment comprises treating the molding with liquid water in an autoclave under autogenous pressure at a temperature in a range of from 100 to 200 C.; (x) optionally drying and/or calcining the water-treated molding obtained from (ix).

19. The process of claim 18, wherein (vii) comprises (vii.1) preparing a mixture comprising the tin-containing zeolitic material having a BEA framework structure and an aqueous solution having a pH of at most 5; (vii.2) adding a binder or a precursor thereof, and optionally a pore-forming agent, and optionally a plasticizing agent to the mixture obtained from (vii.1); (vii.3) subjecting the mixture obtained from (vii.2) to shaping.

20. The process of claim 19, wherein (viii) comprises (viii.1) drying the molding obtained from (vii) at a temperature in the range of from 75 to 200 C.; and (viii.2) calcining the dried molding obtained from (viii.1) at a temperature in the range of from 400 to 650 C.

21. A tin-containing zeolitic material having a BEA framework structure comprising X.sub.2O.sub.3 and YO.sub.2, wherein Y is a tetravalent element selected from the group consisting of Si, Ti, Zr, Ge, and combinations of two or more thereof X is a trivalent element selected from the group consisting of Al, B, In, Ga, Fe, and combinations of two or more thereof, wherein the framework structure additionally comprises tin, wherein in the framework structure of the zeolitic material, the molar ratio X.sub.2O.sub.3:YO.sub.2, is at most 0.02:1, wherein at least 95 weight-% of the framework structure of the zeolitic material consist of X, Y, O, H, and tin, and wherein the tin-containing zeolitic material has a water uptake of at most 12 weight-%.

22. The tin-containing zeolitic material of claim 21, having a tin content in a range of from 5 to 18 weight-%, based on the total weight of the tin-containing zeolitic material.

23. The tin-containing zeolitic material of claim 21, having a UV/Vis spectrum exhibiting a maximum in the range of from 200 to 220 nm.

24. The tin-containing zeolitic material of claim 23, having an XRD spectrum exhibiting peaks at 2theta values at (21.50.2), (22.60.2), (25.50.2), (26.60.2), (28.80.2), (29.70.2), (32.20.2), (34.00.2), and (37.90.2).

25. A process for the oxidation of cyclic ketones, the process comprising contacting the cyclic ketones with the tin-containing zeolitic material having a BEA framework structure according to claim 21 to provide a Baeyer Villiger oxidation of the cyclic ketones.

26. A molding comprising the tin-containing zeolitic material having a BEA framework structure according to claim 21, and a binder, the molding present as a catalyst for the BaeyerVilliger oxidation of cyclic ketones.

Description

EXAMPLES

Reference Example 1

Determination of the Water Uptake

(1) 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 2

Determination of the Crystallinity

(2) The crystallinity of the zeolitic materials according to the present invention was determined by XRD analysis using the EVA method as described in the User Manual DIF-FRAC.EVA Version 3, page 105, from Bruker AXS GmbH, Karlsruhe. The respective data were collected on a standard Bruker D8 Advance Diffractometer Series II using a Sol-X detector, from 2 to 50 2theta, using variable slits (V20), a step size of 0.02 2theta and a scan speed of 2.4 s/step. Default parameters were used for estimating the background/amorphous content (Curvature=1, Threshold=1).

Reference Example 3

FT-IR Measurements

(3) 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 Crush Strength of the Moldings of the Present Invention

(4) The crush strength as referred to in the context of the present invention is to be understood as determined via a crush strength test machine Z2.5/TS1S, supplier Zwick GmbH & Co., D-89079 Ulm, Germany. As to fundamentals of this machine and its operation, reference is made to the respective instructions handbook Register 1: Betriebsanleitung/Sicherheitshandbuch fr die Material-Prfmaschine Z2.5/TS1S, version 1.5, December 2001 by Zwick GmbH & Co. Technische Dokumentation, August-Nagel-Strasse 11, D-89079 Ulm, Germany. With said machine, a given strand as described in Example 5, having a diameter of 1.5 mm, is subjected to an increasing force via a plunger having a diameter of 3 mm until the strand is crushed. The force at which the strand crushes is referred to as the crushing strength of the strand. The machine is equipped with a fixed horizontal table on which the strand is positioned. A plunger which is freely movable in vertical direction actuates the strand against the fixed table. The apparatus was operated with a preliminary force of 0.5 N, a shear rate under preliminary force of 10 mm/min and a subsequent testing rate of 1.6 mm/min. The vertically movable plunger was connected to a load cell for force pick-up and, during the measurement, moved toward the fixed turntable on which the molding (strand) to be investigated is positioned, thus actuating the strand against the table. The plunger was applied to the stands perpendicularly to their longitudinal axis. Controlling the experiment was carried out by means of a computer which registered and evaluated the results of the measurements. The values obtained are the mean value of the measurements for 10 strands in each case.

Reference Example 5

Preparation of a Deboronated Zeolitic Material Having a BEA Framework Structure

(5) 5.1 Preparing a Boron-Containing Zeolitic Material Having a BEA Framework Structure

(6) 209 kg de-ionized water were provided in a vessel. Under stirring at 120 rpm (rounds 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.

(7) 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: drying gas, nozzle gas: technical nitrogen temperature drying gas: temperature spray tower (in): 235 C. temperature spray tower (out): 140 C. nozzle: top-component nozzle supplier Gerig; size 0 nozzle gas temperature: room temperature nozzle gas pressure: 1 bar operation mode: nitrogen straight apparatus used: spray tower with one nozzle configuration: spray tower-filter-scrubber gas flow: 1,500 kg/h filter material: Nomex needle-felt 20 m.sup.2 dosage via flexible tube pump: SP VF 15 (supplier: Verder)

(8) 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.

(9) 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 by DIN 66131 of 498 m.sup.2/g.

(10) 5.2 DeboronationForming Vacant Tetrahedral Sites

(11) 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 5.1 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.

(12) 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.

Comparative Example 1

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure without Acid Treatment

(13) 25 g of the deboronated zeolitic material having a BEA framework structure described in Reference Example 5, section 5.2, were added to a mixer (mill type Microton MB550) together with 5.5 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 550 C. for 5 h, with a heating ramp of 2 K/min.

(14) The obtained powder material had a Sn content of 9.6 weight-%, a silicon (Si) content of 38 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 423 m.sup.2/g, the crystallinity was 51% determined by XRD, and the water uptake was 18 weight-%. The UV/Vis spectrum showed two maxima, one at a wavelength of 200 nm and a second around 250 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 1.49.

Comparative Example 2

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure without Acid Treatment

(15) 50 g of the deboronated zeolitic material having a BEA framework structure described in Reference Example 5, section 5.2, were added to a mixer (mill type Microton MB550) together with 14.2 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, with a heating ramp of 2 K/min.

(16) The obtained powder material had a Sn content of 12.0 weight-%, a silicon (Si) content of 35 wt. % and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 391 m.sup.2/g, the crystallinity determined by XRD 44%, and the water uptake 15 weight-%. The UV/Vis spectrum showed two maxima, one at wavelength of 200 nm with a shoulder around 250 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 1.32.

Comparative Example 3

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure without Acid Treatment

(17) 50 g of the deboronated zeolitic material having a BEA framework structure described in Reference Example 5, section 5.2, were added to a mixer (mill type Microton MB550) together with 14.2 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.

(18) The obtained powder material had a Sn content of 13.1 weight-%, a silicon (Si) content of 38 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 442 m.sup.2/g, the crystallinity determined by XRD 44%, and the water uptake 11.5 weight-%. The UV/Vis spectrum showed two maxima, one at wavelength of 200 nm with a shoulder around 250 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 1.62.

Comparative Example 4

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure without Acid Treatment

(19) 50 g of the deboronated zeolitic material having a BEA framework structure described in Reference Example 5, section 5.2, were added to a ball mill (17 balls, total weight of the balls 904 g), together with 14.2 g of tin(II) acetate (Sn(OAc).sub.2 [CAS-Nr:638-39-1]), and the mixture was milled for 15 minutes with 80 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, with a heating ramp of 2 K min.

(20) The obtained powder material had a Sn content of 12.4 weight-%, a silicon (Si) content of 36 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 426 m.sup.2/g, the crystallinity determined by XRD 42%, and the water uptake 12 weight-%.

Example 1

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure with Acid Treatment

(21) 10 g zeolitic material obtained according to comparative example 1 were provided in a round bottom flask and 300 g of a 30 weight-% HNO.sub.3 aqueous solution, having a pH in the range of from 0 to 1, were added. The mixture was stirred at a temperature of 100 C. for a period of 20 h (200 r.p.m.). The suspension was filtered and the filter cake was then washed with de-ionized water at room temperature until the washing water had a pH of approximately 7.

(22) The obtained zeolitic material was dried at 120 C. for 10 h and calcined by heating to 550 C. (2 K/min) and subsequent heating at 550 C. for 10 h. The dried and calcined zeolitic material had a Si content of 36 weight-%, a Sn content of 9.3 weight-% and a crystallinity determined via XRD of 53%. Further, the zeolitic material had a BET specific surface area, determined according to DIN 66131, of 380 m.sup.2/g and a water uptake of 6 weight-%. The UV/Vis spectrum showed two maxima at 208 and 250 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 0.93.

Example 2

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure with Acid Treatment

(23) 12 g zeolitic material obtained according to comparative example 2 were provided in a round bottom flask and 360 g of a 30 weight-% HNO.sub.3 aqueous solution, having a pH in the range from 0 to 1, were added. The mixture was stirred at a temperature of 100 C. for a period of 20 h (200 r.p.m.). The suspension was filtered and the filter cake was then washed with de-ionized water at room temperature until the washing water had a pH of approximately 7.

(24) The obtained zeolitic material was dried at 120 C. for 10 h and calcined by heating to 550 C. (2 K/min) and subsequent heating at 550 C. for 5 h. The dried and calcined zeolitic material hat a Si content of 37 weight-%, a Sn content of 12.7 weight-%, a TOC of less than 0.1 weight-% and a crystallinity determined via XRD of 48%. Further, the zeolitic material had a BET specific surface area, determined according to DIN 66131, of 395 m.sup.2/g and a water uptake of 9 weight-%. The UV/Vis spectrum had a maximum at 208 nm and a shoulder around 257 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 1.33,

(25) The XRD spectrum of the obtained calcined zeolitic material exhibited the following characteristics:

(26) TABLE-US-00001 2theta angle/ d value/Angstrom Intensity/% 11.68 7.57 13.2 13.50 6.56 17.0 14.77 5.99 18.3 21.51 4.13 38.1 22.59 3.93 84.0 25.52 3.49 47.5 26.57 3.35 87.2 28.84 3.09 36.9 29.69 3.01 35.7 32.16 2.78 33.5 33.97 2.64 100 36.09 2.49 28.2 37.90 2.37 42.6 38.94 2.31 28.0 43.72 2.07 28.2

Example 3

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure with Acid Treatment

(27) 12 g zeolitic material obtained according to comparative example 3 were provided in a round bottom flask and 360 g of a 30 weight-% HNO.sub.3 aqueous solution, having a pH in the range from 0 to 1, were added. The mixture was stirred at a temperature of 100 C. for a period of 20 h (200 r.p.m.). The suspension was filtered and the filter cake was then washed with de-ionized water at room temperature until the washing water had a pH of approximately 7.

(28) The obtained zeolitic material was dried at 120 C. for 10 h and calcined by heating to 550 C. (2 K/min) and subsequent heating at 550 C. for 5 h. The dried and calcined zeolitic material hat a Si content of 37 weight-%, a Sn content of 12.6 weight-%, a TOC of less than 0.1 weight-% and a crystallinity determined via XRD of 49%. Further, the zeolitic material had a BET specific surface area, determined according to DIN 66131 of 405 m.sup.2/g, and a water uptake of 8.7 weight-%. The UV/Vis spectrum had a maximum at 210 nm and a shoulder around 257 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 1.5.

Example 4

Preparation of a Tin-Containing Zeolitic Material Having a BEA Framework Structure with Acid Treatment

(29) 900 g of a 30 weight-% HNO.sub.3 aqueous solution, having a pH in the range from 0 to 1, were provided in a 2 L stirring apparatus, and 30 g zeolitic material obtained according to comparative example 4 were added. The mixture was stirred at a temperature of 100 C. for a period of 20 h (200 r.p.m.). The suspension was filtered and the filter cake was then washed with de-ionized water at room temperature until the washing water had a pH of approximately 7.

(30) The obtained zeolitic material was dried at 120 C. for 10 h (3 K/min) and calcined in air by heating to 550 C. (2 K/min) and subsequent heating at 550 C. for 10 h. The dried and calcined zeolitic material hat a Si content of 36 weight-%, a Sn content of 12.8 weight-%, a TOC of less than 0.1 weight-% and a crystallinity determined via XRD of 46%. Further, the zeolitic material had a BET specific surface area, determined according to DIN 66131 of 374 m.sup.2/g, and a water uptake of 8 weight-%.

Comparative Example 5

Use of the Tin-Containing Zeolitic Material According to Comparative Examples 1 to 4

(31) Baeyer-Villiger Oxidation of Cyclohexanone to Epsilon-Caprolactone in 1,4-Dioxane with an Aqueous Solution of Hydrogen Peroxide

Comparative Example 5.1

Use of the Tin-Containing Zeolitic Material According to Comparative Example 1

(32) A 100 mL glass flask was charged with cyclohexanone (1.5 g), the zeolitic material prepared according to comparative example 1 as catalyst (0.1 g, Sn loading=9.6 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 herein below.

Comparative Example 5.2

Use of the Tin-Containing Zeolitic Material According to Comparative Example 2

(33) A 100 mL glass flask was charged with cyclohexanone (1.5 g), the zeolitic material prepared according to comparative example 2 as catalyst (0.1 g, Sn loading=12.0 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

Comparative Example 5.3

Use of the Tin-Containing Zeolitic Material According to Comparative Example 3

(34) A 100 mL glass flask was charged with cyclohexanone (i.5 g), the zeolitic material prepared according to comparative example 3 as catalyst (0.1 g, Sn loading=13.1 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

Comparative Example 5.4

Use of the Tin-Containing Zeolitic Material According to Comparative Example 4

(35) A 100 mL glass flask was charged with cyclohexanone (i.5 g), the zeolitic material prepared according to comparative example 4 as catalyst (0.1 g, Sn loading=12.4 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

Example 5

Use of the Tin-Containing Zeolitic Material According to Examples 1 to 4

Baeyer-Villiger Oxidation of Cyclohexanone to Epsilon-Caprolactone in 1,4-Dioxane with an Aqueous Solution of Hydrogen Peroxide

Example 5.1

Use of the Tin-Containing Zeolitic Material According to Example 1

(36) A 100 mL glass flask was charged with cyclohexanone (i.5 g), the zeolitic material prepared according to example 1 as catalyst (0.1 g, Sn loading=9.3 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

Example 5.2

Use of the Tin-Containing Zeolitic Material According to Example 2

(37) A 100 mL glass flask was charged with cyclohexanone (1.5 g), the zeolitic material prepared according to example 2 as catalyst (0.1 g, Sn loading=12.7 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

Example 5.3

Use of the Tin-Containing Zeolitic Material According to Example 3

(38) A 100 mL glass flask was charged with cyclohexanone (i.5 g), the zeolitic material prepared according to example 3 as catalyst (0.1 g, Sn loading=12.6 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

Example 5.4

Use of the Tin-Containing Zeolitic Material According to Example 4

(39) A 100 mL glass flask was charged with cyclohexanone (i.5 g), the zeolitic material prepared according to example 4 as catalyst (0.1 g, Sn loading=12.8 weight-%) and 1,4-dioxane (45 g). The mixture was heated to 95 C. An aqueous solution of hydrogen peroxide (70 weight-%, 0.5 g) was then added, and the reaction mixture was stirred for 4 hours. After cooling down to room temperature, the solution was filtered and the filtrate was analyzed by GC using di-n-butylether as internal standard. The concentrations of epsilon-caprolactone and cyclohexanone in the product mixture were determined by using quantitative GC analysis using di-n-butylether as internal standard. With these data the selectivities to epsilon-caprolactone based on cyclohexanone and hydrogen peroxide and the cyclohexanone conversion were calculated. The results are shown in Table 1 hereinbelow.

(40) TABLE-US-00002 TABLE 1 Results of Example 5 and Comparative Example 5 Selectivity to epsilon- Selectivity to epsilon- (Comparative) caprolactone based on caprolactone based on Example cyclohexanone/% H.sub.2O.sub.2/% Comparative 82 99 Example 5.1 Example 5.1 99 99 Comparative 83 99 Example 5.2 Example 5.2 98 99 Comparative 82 99 Example 5.3 Example 5.3 91 99 Comparative 90 99 Example 5.4 Example 5.4 99 99

(41) These examples and comparative examples clearly show that by subjecting a tin-containing zeolitic material of BEA framework structure which is prepared by solid-state ion exchange to step (v) according to the present invention. i.e. to a treatment with an acidic aqueous solution, the catalytic characteristics with regard to the most important parameter, the selectivity of the zeolitic material, is significantly improved. In particular, while the selectivity to epsilon-caprolactone based on hydrogen peroxide remained constant at the very high level of 99%, the selectivity to epsilon-caprolactone based on the starting material cyclohexanone was increased from 82 to 99% when treating the catalyst according to comparative example 1 according to step (v), from 83 to 98% when treating the catalyst according to comparative example 2 according to step (v), from 82 to 91% when treating the catalyst according to comparative example 3 according to step (v), and from 90 to 99% when treating the catalyst according to comparative example 4 according to step (v).

Example 6

Preparation of a Molding Based on a Tin-Containing Zeolitic Material Having a BEA Framework Structure with Acid Treatment

(42) 6.1 Preparing the Zeolitic Material

(43) 150 g of deboronated zeolitic material having a BEA framework structure described in Reference Example 5, section 5.2, were added to a mixer (mill type Microton MB550) together with 42.6 g of tin(II) acetate (Sn(OAc).sub.2[CAS-Nr:638-39-1]), and the mixture was milled for 15 min 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, with a heating ramp of 2 K/min. The obtained powder material had a Sn content of 12.0 weight-%, a Si content of 37.0 weight-%, and a TOC of less than 0.1 weight-%. The BET specific surface area measured by DIN 66131 was 464 m.sup.2/g, the crystallinity determined by XRD was 51%.

(44) 6.2 Acidic Treatment

(45) 165 g zeolitic material obtained according to 6.1 above were provided in a round bottom flask and 4,950 g of a 30 weight-% HNO.sub.3 aqueous solution, having a pH in the range from 0 to 1, were added. The mixture was stirred at a temperature of 100 C. for a period of 20 h (200 r.p.m.). The suspension was filtered and the filter cake was then washed with de-ionized water at room temperature until the washing water had a pH of approximately 7. The obtained zeolitic material was dried at 120 C. for 10 h and calcined by heating to 550 C. (2 K/min) and subsequent heating at 550 C. for 5 h. The dried and calcined zeolitic material hat a Si content of 37.0 weight-%, a Sn content of 12.4 weight-%, a TOC of less than 0.1 weight-%, and a crystallinity determined via XRD of 62%. Further, the zeolitic material had a BET specific surface area, determined according to DIN 66131 of 391 m.sup.2/g.

(46) 6.3 Shaping

(47) In a kneader, 34 g of the zeolitic material obtained according to 6.2 above were added and mixed with an acidic solution made from 3.9 g of HNO.sub.3 (65 weight-%) dissolved in 15 ml distilled water. The suspension was mixed (kneaded) for 10 min. To the resulting mixture 6.5 g Walocel and 108.3 g Ludox AS-40 were added and mixed for another 30 min. Finally, 45 ml distilled water were added to the mixture and mixed for another 20 min. The paste was then extruded in a Loomis extruder with a pressure (apparatus pressure) of from 100 to 110 bar and an extrudate mass pressure of from 32 to 49 bar. Extrudates of 1.5 mm were obtained and dried in a static oven at 120 C. for 5 h, followed by calcination at 500 C. for 5 h under air and a heating rate of 2 K/min. The calcined extrudates had a bulk density of 535 g/I with a mechanical strength of 11.2 N. The elemental composition was Sn 9.2 weight-%, Si 41 weight-% and a TOC of 0.12 weight-%. Further, the shaped material had a BET specific surface area, determined according to DIN 66131 of 55 m.sup.2/g, a water uptake of 8 weight-% and a total pore volume determined by Hg porosimetry according to DIN 66133 of 0.5 ml/g. The UV/Vis spectrum had a maximum at 208 nm and a shoulder around 259 nm. In the FT-IR spectrum the intensity ratio between a first adsorption band with a maximum between 3701 to 3741 cm.sup.1 and a second adsorption with the maximum between 3600 to 3690 cm.sup.1 was 3.3.

CITED LITERATURE

(48) Hammond C., et al., Simple and Scalable Preparation of Highly Active Lewis Acidic Sn-beta; Angw. Chem. Int. Ed. 2012 (51), pp. 11736-11739