MOLDING COMPRISING A TYPE MFI ZEOLITIC TITANOSILICATE AND A SILICA BINDER, ITS PREPARATION PROCESS AND USE AS CATALYST

Abstract

A chemical molding comprising a zeolitic material which exhibits a type I nitrogen adsorption/desorption isotherm determined as described in Reference Example 1, and which has framework type MFI and a framework structure comprising Si, O, and Ti, the molding further comprising a binder for said zeolitic material, the binder comprising Si and O, wherein the molding exhibits a total pore volume of at least 0.4 mL/g and a crushing strength of at least 6 N.

Claims

1.-20. (canceled)

21. A chemical molding comprising a zeolitic material which exhibits a type I nitrogen adsorption/desorption isotherm and which has framework type MFI and a framework structure comprising Si, O, and Ti, the molding further comprising a binder for said zeolitic material, the binder comprising Si and O, wherein the molding exhibits a total pore volume of at least 0.4 mL/g and a crushing strength of at least 6 N.

22. The molding of claim 21, wherein from 95 to 100 weight-% of the zeolitic material comprised in the molding consist of Si, O, Ti and optionally H, and wherein the zeolitic material comprises Ti in an amount in the range of from 0.2 to 5 weight-%, calculated as elemental Ti and based on the total weight of the zeolitic material.

23. The molding of claim 21, wherein from 95 to 100 weight-% of the binder comprised in the molding consist of Si and O, and wherein the molding comprises the binder, calculated as SiO.sub.2, in an amount in the range of from 2 to 90 weight-% based on the total weight of the molding.

24. The molding of claim 21, wherein from 95 to 100 weight-% of the molding consist of the zeolitic material and the binder.

25. The molding of claim 21, exhibiting a total pore volume in the range of from 0.4 to 1.5 mL/g, and exhibiting a crushing strength in the range of from 6 to 25 N.

26. The molding of claim 21, exhibiting one or more of the following characteristics: a tortuosity parameter relative to water in the range of from 1.0 to 2.5, determined as described in Reference Example 11; a BET specific surface area in the range of from 300 to 450 m.sup.2/g, determined as described in Reference Example 6; a crystallinity in the range of from 50 to 100%, determined as described in Reference Example 7; a propylene oxide activity of at least 4.5 weight-%, determined as described in Reference Example 9; a pressure drop rate in the range of from 0.005 to 0.019 bar(abs)/min, determined as described in Reference Example 9; a hydrogen peroxide conversion in the range of from 90 to 95% when used as catalyst in a reaction for preparing propylene oxide from propene and hydrogen peroxide, determined in a continuous epoxidation reaction as described in Reference Example 10 at a temperature of the cooling medium in the range of from 55 to 56° C. at a time on stream in the range of from 200 to 600 hours, wherein the term “time on stream” refers to the duration of the continuous epoxidation reaction without regeneration of the catalyst.

27. A process for preparing a chemical molding comprising a zeolitic material which exhibits a type I nitrogen adsorption/desorption isotherm determined as described in Reference Example 1, and which has framework type MFI and a framework structure comprising Si, O, and Ti, the molding further comprising a binder for said zeolitic material, the binder comprising Si and O, for preparing a chemical molding according to claim 21, the process comprising (i) providing a zeolitic material exhibiting a type I nitrogen adsorption/desorption isotherm determined as described in Reference Example 1, having framework type MFI and a framework structure comprising Si, O, and Ti; (ii) providing a binder precursor comprising a colloidal dispersion of silica in water, said binder precursor exhibiting a volume-based particle size distribution characterized by a Dv10 value of at least 35 nanometer, a Dv50 value of at least 45 nanometer, and a Dv90 value of at least 65 nanometer, determined as described in Reference Example 5; (iii) preparing a mixture comprising the zeolitic material provided in (i) and the binder precursor provided in (ii); (iv) shaping the mixture obtained from (iii), obtaining a precursor of the molding; (v) preparing a mixture comprising the precursor of the molding obtained from (iv) and water, and subjecting the mixture to a water treatment under hydrothermal conditions, obtaining a water-treated precursor of the molding; (vi) calcining the water-treated precursor of the molding in a gas atmosphere, obtaining the molding.

28. The process of claim 27, wherein the volume-based particle size distribution of the colloidal dispersion of silica in water according to (ii) is characterized by a Dv10 value in the range of from 35 to 80 nanometer, a Dv50 value in the range of from 45 to 125 nanometer, and a Dv90 value in the range of from 65 to 200 nanometer, determined as described in Reference Example 5, wherein from 95 to 100 weight-% of the binder precursor according to (ii) consist of the colloidal dispersion of silica in water.

29. The process of claim 27, wherein in the mixture prepared according to (iii) and subjected to (iv), the weight ratio of the zeolitic material, relative to the sum of the zeolitic material and the binder calculated as SiO.sub.2, is in the range of from 2 to 90%, wherein the mixture prepared according to (iii) and subjected to (iv) further comprises one or more additives, one or more viscosity modifying agents, or one or more mesopore forming agents, or one or more viscosity modifying agents and one or more mesopore forming agents, wherein the one or more additives are selected from the group consisting of water, alcohols, organic polymers, and mixtures of two or more thereof, wherein the organic polymers are selected from the group consisting of celluloses, cellulose derivatives, starches, polyalkylene oxides, polystyrenes, polyacrylates, polymethacrylates, polyolefins, polyamides, polyesters, and mixtures of two or more thereof, wherein the organic polymers are more selected from the group consisting of cellulose ethers, polyalkylene oxides, polystyrenes, and mixtures of two or more thereof, wherein the organic polymers are more selected from the group consisting of a methyl celluloses, carboxymethyl celluloses, polyethylene oxides, polystyrenes, and mixtures of two or more thereof.

30. The process of claim 29, wherein in the mixture prepared according to (iii) and subjected to (iv) the weight ratio of the zeolitic material, relative to the one or more additives, is in the range of from 0.3:1 to 1:1; the weight ratio of the zeolitic material, relative to the cellulose derivative, is in the range of from 10:1 to 53:1; the weight ratio of the zeolitic material, relative to the polyethylene oxide, is in the range of from 70:1 to 110:1; the weight ratio of the zeolitic material, relative to the polystyrene, is in the range of from 2:1 to 8:1; the weight ratio of the zeolitic material, relative to the water, is in the range of from 0.7:1 to 0.85:1; wherein the mixture obtained from (iii) and subjected to (iv) has a plasticity in the range of from 500 to 3000 N, determined as described in Reference Example 12.

31. The process of claim 27, wherein shaping according to (iv) further comprises drying the precursor of the molding in a gas atmosphere, wherein said drying is carried out at a temperature of the gas atmosphere in the range of from 80 to 160° C., wherein the gas atmosphere comprises nitrogen, oxygen, or a mixture thereof, wherein the gas atmosphere is oxygen, air, or lean air, and wherein shaping according to (iv) further comprises calcining the dried precursor of the molding in a gas atmosphere, wherein calcining is carried out at a temperature of the gas atmosphere in the range of from 450 to 530° C., wherein the gas atmosphere comprises nitrogen, oxygen, or a mixture thereof, wherein the gas atmosphere is more oxygen, air, or lean air.

32. The process of claim 27, wherein in the mixture prepared in (v), the weight ratio of the precursor of the molding relative to the water is in the range of from 1:1 to 1:30, wherein from 95 to 100 weight-% of the mixture prepared according to (v) consist of the precursor of the molding and water.

33. The process of claim 27, wherein the water treatment according to (v) comprises a temperature of the mixture in the range of from 100 to 200° C., wherein the water treatment according to (v) is carried out under autogenous pressure.

34. The process of claim 27, wherein (v) further comprises separating the water-treated precursor of the molding from the mixture obtained from the water treatment, said separating comprising subjecting the mixture obtained from the water treatment to solid-liquid separation, washing the separated precursor, and drying the washed precursor, wherein said drying according to (v) comprises drying the precursor in a gas atmosphere, wherein drying is carried out at a temperature of the gas atmosphere in the range of from 80 to 160° C. wherein the gas atmosphere comprises nitrogen, oxygen, or a mixture thereof.

35. The process of claim 27, wherein calcining according to (vi) is carried out at a temperature of the gas atmosphere in the range of from 400 to 490° C., wherein the gas atmosphere comprises nitrogen, oxygen, or a mixture thereof.

36. A chemical molding comprising particles of a zeolitic material exhibiting a type I nitrogen adsorption/desorption isotherm determined as described in Reference Example 1, having framework type MFI and a framework structure comprising Si, O, and Ti, the molding further comprising a binder for said particles, the binder the chemical molding according to claim 21.

37. A method comprising utilizing the molding according to claim 21 as an adsorbent, an absorbent, a catalyst or a catalyst component.

38. A method comprising utilizing a colloidal dispersion of silica in water as a binder precursor for preparing a chemical molding comprising a zeolitic material which exhibits a type I nitrogen adsorption/desorption isotherm determined as described in Reference Example 1, and which has framework type MFI and a framework structure comprising Si, O, and Ti, the molding further comprising a binder resulting from said binder precursor, for preparing a molding according to claim 21, said silica exhibiting a volume-based particle size distribution characterized by a Dv10 value of at least 35 nanometer, a Dv50 value of at least 45 nanometer, and a Dv90 value of at least 65 nanometer, said molding exhibiting a total pore volume of at least 0.4 mL/g, and a crushing strength of at least 6 N

39. A mixture comprising a zeolitic material which exhibits a type I nitrogen adsorption/desorption isotherm determined as described in Reference Example 1, and which has framework type MFI and a framework structure comprising Si, O, and Ti, the mixture further comprising a colloidal dispersion of silica in water, said binder precursor exhibiting a volume-based particle size distribution characterized by a Dv10 value of at least 35 nanometer, a Dv50 value of at least 45 nanometer, and a Dv90 value of at least 65 nanometer, said mixture having a plasticity in the range of from 500 to 3000 N, wherein the colloidal dispersion of silica in water comprises the silica in an amount in the range of from 25 to 65 weight-%, based on the total weight of the silica and the water and wherein from 95 to 100 weight-% of the binder precursor consist of the colloidal dispersion of silica in water, wherein in said mixture, the weight ratio of the zeolitic material, relative to the sum of the zeolitic material and the binder calculated as SiO.sub.2, is in the range of from 2 to 90%, wherein said mixture further comprises one or more additives

40. A method comprising utilizing the mixture according to claim 39 for preparing a chemical molding.

Description

REFERENCE EXAMPLE 1: DETERMINATION OF N.SUB.2 .ADSORPTION/DESORPTION ISOTHERMS

[0249] The nitrogen adsorption/desorption isotherms were determined at 77 K according to the method disclosed in DIN 66131. The isotherms, at the temperature of liquid nitrogen, were measured using Micrometrics ASAP 2020M and Tristar system.

REFERENCE EXAMPLE 2: DETERMINATION OF THE TOTAL PORE VOLUME

[0250] The total pore volume was determined via intrusion mercury porosimetry according to DIN 66133.

REFERENCE EXAMPLE 3: DETERMINATION OF THE CRUSHING STRENGTH

[0251] The crush strength as referred to in the context of the present invention is to be understood as having been 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 für die Material-Prüfmaschine Z2.5/TS1S ”, version 1.5, December 2001 by Zwick GmbH & Co. Technische Dokumentation, August-Nagel-Strasse 11, D-89079 Ulm, Germany. The machine was equipped with a fixed horizontal table on which the strand was positioned. A plunger having a diameter of 3 mm which was freely movable in vertical direction actuated 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 strands perpendicularly to their longitudinal axis. With said machine, a given strand as described below was subjected to an increasing force via a plunger until the strand was crushed. The force at which the strand crushes is referred to as the crushing strength of the strand. 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: DETERMINATION OF Dv10, Dv50, AND Dv90 VALUES

[0252] The samples were analysed with Zetasizer Nano from Malvern Instruments GmbH, Herrenberg, Germany. First, the pH values of a given sample was determined in order to allow a dilution in the same pH range. The samples were diluted with Millipore water, pH=9.1, to a measurement concentration of 0.005% and then filtrated (5 micrometer). The measurement was carried out atg 25° C.

REFERENCE EXAMPLE 6: DETERMINATION OF THE BET SPECIFIC SURFACE AREA

[0253] The BET specific surface area was determined via nitrogen physisorption at 77 K according to the method disclosed in DIN 66131. The N.sub.2 sorption isotherms at the temperature of liquid nitrogen were measured using Micrometrics ASAP 2020M and Tristar system for determining the BET specific surface area.

REFERENCE EXAMPLE 7: X-RAY POWDER DIFFRACTION AND DETERMINATION OF THE CRYSTALLINITY

[0254] Powder X-ray diffraction (PXRD) data was collected using a diffractometer (D8 Advance Series II, Bruker AXS GmbH) equipped with a LYNXEYE detector operated with a Copper anode X-ray tube running at 40 kV and 40 mA. The geometry was Bragg-Brentano, and air scattering was reduced using an air scatter shield.

[0255] Computing crystallinity: The crystallinity of the samples was determined using the software DIFFRAC.EVA provided by Bruker AXS GmbH, Karlsruhe. The method is described on page 121 of the user manual. The default parameters for the calculation were used.

[0256] Computing phase composition: The phase composition was computed against the raw data using the modelling software DIFFRAC.TOPAS provided by Bruker AXS GmbH, Karlsruhe. The crystal structures of the identified phases, instrumental parameters as well the crystallite size of the individual phases were used to simulate the diffraction pattern. This was fit against the data in addition to a function modelling the background intensities.

[0257] Data collection: The samples were homogenized in a mortar and then pressed into a standard flat sample holder provided by Bruker AXS GmbH for Bragg-Brentano geometry data collection. The flat surface was achieved using a glass plate to compress and flatten the sample powder. The data was collected from the angular range 2 to 70° 2Theta with a step size of 0.02° 2Theta, while the variable divergence slit was set to an angle of 0.1°. The crystalline content describes the intensity of the crystalline signal to the total scattered intensity. (User Manual for DIFFRAC.EVA, Bruker AXS GmbH, Karlsruhe.)

REFERENCE EXAMPLE 8: DETERMINATION OF THE C VALUE (BET C CONSTANT)

[0258] The C value was determined by usual calculation ((slope/intercept)+1) based on the plot of the BET value 1/(V((p/p.sub.0)−1)) against p/p.sub.0, as known by the skilled person. p is the partial vapour pressure of adsorbate gas in equilibrium with the surface at 77.4 K (b.p. of liquid nitrogen), in Pa, p.sub.0 is the saturated pressure of adsorbate gas, in Pa, and V is the volume of gas adsorbed at standard temperature and pressure (STP) [273.15 K and atmospheric pressure (1.013×10.sup.5 Pa)], in mL.

REFERENCE EXAMPLE 9: DETERMINATION OF THE PROPYLENE OXIDE ACTIVITY AND THE PRESSURE DROP RATE (PO TEST)

[0259] In the PO test, a preliminary test procedure to assess the possible suitability of the moldings as catalyst for the epoxidation of propene, the moldings were tested in a glass autoclave by reaction of propene with an aqueous hydrogen peroxide solution (30 weight-%) to yield propylene oxide. In particular, 0.5 g of the molding were introduced together with 45 mL of methanol in a glass autoclave, which was cooled to −25° C. 20 mL of liquid propene were pressed into the glass autoclave and the glass autoclave was heated to 0° C. At this temperature, 18 g of an aqueous hydrogen peroxide solution (30 weight-% in water) were introduced into the glass autoclave. After a reaction time of 5 h at 0° C., the mixture was heated to room temperature and the liquid phase was analyzed by gas chromatography with respect to its propylene oxide content. The propylene oxide content of the liquid phase (in weight-%) is the result of the PO test, i.e. the propylene oxide activity of the molding. The pressure drop rate was determined following the pressure progression during the PO test described above. The pressure progression was recorded using a S-11 transmitter (from Wika Alexander Wiegand SE & Co. KG), which was positioned in the pressure line of the autoclave, and a graphic plotter Buddeberg 6100A. The respectively obtained data were read out and depicted in a pressure progression curve. The pressure drop rate (PDR) was determined according to the following equation:

PDR=[p(max)−p(min)]/delta t, with

PDR/(bar/min)=pressure drop rate

p(max)/bar=maximum pressure at the start of the reaction

p(min)/bar=minimum pressure observed during the reaction

delta t/min=time difference from the start of the reaction to the point in time where p(min) was observed

REFERENCE EXAMPLE 10: DETERMINATION OF THE PROPYLENE EPOXIDATION CATALYTIC PERFORMANCE

[0260] In a continuous epoxidation reaction setup, a vertically arranged tubular reactor (length: 1.4 m, outer diameter 10 mm, internal diameter: 7 mm) equipped with a jacket for thermostatization was charged with 15 g of the moldings in the form of strands as described in the respective examples below. The remaining reactor volume was filled with inert material (steatite spheres, 2 mm in diameter) to a height of about 5 cm at the lower end of the reactor and the remainder at the top end of the reactor. Through the reactor, the starting materials were passed with the following flow rates: methanol (49 g/h); hydrogen peroxide (9 g/h; employed as aqueous hydrogen peroxide solution with a hydrogen peroxide content of 40 weight-%); propylene (7 g/h; polymer grade). Via the cooling medium passed through the cooling jacket, the temperature of the reaction mixture was adjusted so that the hydrogen peroxide conversion, determined on the basis of the reaction mixture leaving the reactor, was essentially constant at 90%. The pressure within the reactor was held constant at 20 bar(abs), and the reaction mixture—apart from the fixed-bed catalyst—consisted of one single liquid phase. The reactor effluent stream downstream the pressure control valve was collected, weighed and analyzed. Organic components were analyzed in two separate gas-chromatographs. The hydrogen peroxide content was determined colorimetrically using the titanyl sulfate method. The selectivity for propylene oxide given was determined relative to propene and hydrogen peroxide), and was calculated as 100 times the ratio of moles of propylene oxide in the effluent stream divided by the moles of propene or hydrogen peroxide in the feed.

REFERENCE EXAMPLE 11: DETERMINATION OF THE TORTUOSITY PARAMETER RELATIVE TO WATER

[0261] The tortuosity parameter was determined as described in the experimental section of US 20070099299 A1. In particular, the NMR analyses to this effect were conducted at 25° C. and 1 bar at 125 MHz 1 H resonance frequency with the FEGRIS NT NMR spectrometer (cf. Stallmach et al. in Annual Reports on NMR Spectroscopy 2007, Vol. 61, pp. 51-131). The pulse program used for the PFG NMR self-diffusion analyses was the stimulated spin echo with pulsed field gradients according to FIG. 1b of US 20070099299 A1. For each sample, the spin echo attenuation curves were measured at different diffusion times (between 7 and 100 ms) by stepwise increase in the intensity of the field gradients (to a maximum gmax=10 T/m). From the spin echo attenuation curves, the time dependence of the self-diffusion coefficient of the pore water was determined by means of equations (5) and (6) of US 20070099299 A1. Calculation of the Tortuosity: Equation (7) of US 20070099299 A1 was used to calculate the time dependency of the mean quadratic shift z.sup.2(Δ)=⅓r.sup.2(Δ) from the self-diffusion coefficients D(Δ) thus determined. By way of example, in FIG. 2 of US 20070099299 A1, the data is plotted for exemplary catalyst supports of said document in double logarithmic form together with the corresponding results for free water. FIG. 2 of US 20070099299 A1 also shows in each case the best fit straight line from the linear fitting of r.sup.2(Δ) as a function of the diffusion time Δ. According to equation (7) of US 2007/0099299 A1, its slope corresponds precisely to the value 6D where D corresponds to the self-diffusion coefficient averaged over the diffusion time interval. According to equation (3) of US 20070099299 A1, the tortuosity is then obtained from the ratio of the mean self-diffusion coefficient of the free solvent (D0) thus determined to the corresponding value of the mean self-diffusion coefficient in the molding.

REFERENCE EXAMPLE 12: DETERMINATION OF THE PLASTICITY

[0262] The plasticity as referred to in the context of the present invention is to be understood as determined via a table-top testing machine Z010/TN2S, supplier Zwick, D-89079 Ulm, Germany. As to fundamentals of this machine and its operation, reference is made to the respective instructions handbook “Betriebsanleitung der Material-Prüfmaschine”, version 1.1, by Zwick Technische Dokumentation, August-Nagel-Strasse 11, D-89079 Ulm, Germany (1999). The Z010 testing machine was equipped with a fixed horizontal table on which a steel test vessel was positioned comprising a cylindrical compartment having an internal diameter of 26 mm and an internal height of 75 mm. This vessel was filled with the composition to be measured so that the mass filled in the vessel did not contain air inclusions. The filling level was 10 mm below the upper edge of the cylindrical compartment. Centered above the cylindrical compartment of the vessel containing the composition to be measured was a plunger having a spherical lower end, wherein the diameter of the sphere was 22.8 mm, and which was freely movable in vertical direction. Said plunger was mounted on the load cell of the testing machine having a maximum test load of 10 kN. During the measurement, the plunger was moved vertically downwards, thus plunging into the composition in the test vessel. Under testing conditions, the plunger was moved at a preliminary force (Vorkraft) of 1.0 N, a preliminary force rate (Vorkraftgeschwindigkeit) of 100 mm/min and a subsequent test rate (Prüfgeschwindigkeit) of 14 mm/min. A measurement was terminated when the measured force reached a value of less than 70% of the previously measured maximum force of this measurement. The experiment was controlled by means of a computer which registered and evaluated the results of the measurements. The maximum force (F_max in N) measured corresponds to the plasticity referred to in the context of the present invention.

EXAMPLE 1: PROVIDING PARTICLES OF A ZEOLITIC MATERIAL HAVING FRAMEWORK TYPE MFI

[0263] A titanium silicalite-1 (TS-1) powder was prepared according to the following recipe: TEOS (tetraethyl orthosilicate) (300 kg) were loaded into a stirred tank reactor at room temperature and stirring (100 r.p.m.) was started. In a second vessel, 60 kg TEOS and 13.5 kg TEOT (tetraethyl orthotitanate) were first mixed and then added to the TEOS in the first vessel. Subsequently, another 360 kg TEOS were added to the mixture in the first vessel. Then, the content of the first vessel was stirred for 10 min before 950 g TPAOH (tetrapropylammonium hydroxide) were added. Stirring was continued for 60 min. Ethanol released by hydrolysis was separated by distillation at a bottoms temperature of 95° C. 300 kg water were then added to the content of the first vessel, and water in an amount equivalent to the amount of distillate was further added. The obtained mixture was stirred for 1 h. Crystallization was performed at 175° C. within 12 h at autogenous pressure. The obtained titanium silicalite-1 crystals were separated, dried, and calcined at a temperature of 500° C. in air for 6 h. The obtained particles of the zeolitic material exhibited a Ti content of 1.9 weight-%, calculated as elemental Ti.

EXAMPLE 2: PREPARING a MOLDING USING A COLLOIDAL SILICA BINDER PRECURSOR WITH A PARTICLE SIZE DISTRIBUTION ACCORDING TO THE INVENTION

[0264] Shaping: The particles of the zeolitic material of Example 1 (105.3 g) and carboxymethyl cellulose (4.0 g; Walocel™, Mw=15,000 g) were mixed in a kneader for 5 min. Then, an aqueous polystyrene dispersion (100.7 g; 33.7 g polystyrene) was continuously added. After 10 min, polyethylene oxide (1.33 g) was added. After 10 min, an aqueous colloidal silica binder precursor (70 g; 50 weight-% SiO.sub.2; Dv10=51 nm; Dv50=72 nm; Dv90=111; from Nalco Chemical Co.) was added. After a further 10 min, 10 mL water were added, after further 5 min additional 10 mL water. The total kneading time was 40 min. The resulting formable mass obtained from kneading, having a plasticity of 1283 N, was extruded at a pressure of 130 bar through a matrix having circular holes with a diameter of 1.9 mm. The obtained strands were dried in air in an oven at a temperature of 120° C. for 4 h and calcined in air at a temperature of 490° C. for 5 h. The crushing strength of the strands determined as described hereinabove was 1.4 N.

[0265] Water treatment: 36 g of these strands were mixed in four portions of each 9 g with 180 g deionized water per portion. The resulting mixtures were heated to a temperature of 145° C. for 8 h in an autoclave. Thereafter, the obtained water-treated strands were separated and sieved over a 0.8 mm sieve. The obtained strands were then washed with deionized water and subjected to a stream of nitrogen at ambient temperature. The respectively washed strands were subsequently dried in air at a temperature of 120° C. for 4 h and then calcined in air at a temperature of 450° C. for 2 h.

[0266] The resulting material had a TOC of less than 0.1 g/100 g, a Si content of 44 g/100 g, and a Ti content of 1.4 g/100 g. The crushing strength of the strands determined as described hereinabove was 8 N, and the total pore volume determined as described hereinabove was 0.83 mL/g. The tortuosity parameter relative to water was 1.60. The BET specific surface area was 356 m.sup.2/g, the C value was −356.

EXAMPLE 3: PREPARING A MOLDING USING A COLLOIDAL SILICA BINDER PRECURSOR WITH A PARTICLE SIZE DISTRIBUTION ACCORDING TO THE INVENTION

[0267] Shaping: The particles of the zeolitic material of Example 1 (105.3 g) and carboxymethyl cellulose (4.0 g; Walocel™, Mw=15,000 g) were mixed in a kneader for 5 min. Then, an aqueous polystyrene dispersion (100.7 g; 33.7 g polystyrene) was continuously added. After 10 min, polyethylene oxide (1.33 g) was added. After 10 min, an aqueous colloidal silica binder precursor (70 g; 40 weight-% SiO.sub.2; Dv10=68 nm; Dv50=97 nm; Dv90=151 nm; from Nalco Chemical Co.) was added. After a further 10 min, 20 mL water were added. The total kneading time was 35 min. The resulting formable mass obtained from kneading was extruded at a pressure of 150 bar through a matrix having circular holes with a diameter of 1.9 mm. The obtained strands were dried in air in an oven at a temperature of 120° C. for 4 h and calcined in air at a temperature of 490° C. for 5 h. The crushing strength of the strands determined as described hereinabove was 1.0 N.

[0268] Water treatment: 36 g of these strands were mixed in four portions of each 9 g with 180 g deionized water per portion. The resulting mixtures were heated to a temperature of 145° C. for 8 h in an autoclave. Thereafter, the obtained water-treated strands were separated and sieved over a 0.8 mm sieve. The obtained strands were then washed with deionized water and subjected to a stream of nitrogen at ambient temperature. The respectively washed strands were subsequently dried in air at a temperature of 120° C. for 4 h and then calcined in air at a temperature of 450° C. for 2 h.

[0269] The resulting material had a TOC of less than 0.1g/100 g, a Si content of 44 g/100 g, and a Ti content of 1.4. g/100 g. The crushing strength of the strands determined as described hereinabove was 11 N, and the total pore volume determined as described hereinabove was 0.84 mL/g. The tortuosity parameter relative to water was 1.71. The BET specific surface area was 352 m.sup.2/g, the C value was −500.

EXAMPLE 4: PREPARING A MOLDING USING A COLLOIDAL SILICA BINDER PRECURSOR WITH A PARTICLE SIZE DISTRIBUTION ACCORDING TO THE INVENTION

[0270] Shaping: The particles of the zeolitic material of Example 1 (105.3 g) and carboxymethyl cellulose (4.0 g; Walocel™, Mw=15,000 g) were mixed in a kneader for 5 min. Then, an aqueous polystyrene dispersion (100.7 g; 33.7 g polystyrene) was continuously added. After 10 min, polyethylene oxide (1.33 g) was added. After 10 min, an aqueous colloidal silica binder precursor (70 g; 50 weight-% SiO.sub.2; Dv10=56; Dv50=81 nm; Dv90=129 nm; from Nalco Chemical Co.) was added. After a further 10 min, 20 mL water were added. The total kneading time was 35 min. The resulting formable mass obtained from kneading was extruded at a pressure of 150 bar through a matrix having circular holes with a diameter of 1.9 mm. The obtained strands were dried in air in an oven at a temperature of 120° C. for 4 h and calcined in air at a temperature of 490° C. for 5 h. The crushing strength of the strands determined as described hereinabove was 1.5 N.

[0271] Water treatment: 36 g of these strands were mixed in four portions of each 9 g with 180 g deionized water per portion. The resulting mixtures were heated to a temperature of 145° C. for 8 h in an autoclave. Thereafter, the obtained water-treated strands were separated and sieved over a 0.8 mm sieve. The obtained strands were then washed with deionized water and subjected to a stream of nitrogen at ambient temperature. The respectively washed strands were subsequently dried in air at a temperature of 120° C. for 4 h and then calcined in air at a temperature of 450° C. for 2 h.

[0272] The resulting material had a TOC of less than 0.1 g/100 g, a Si content of 44 g/100 g, and a Ti content of 1.4 g/100 g. The crushing strength of the strands determined as described hereinabove was 12 N, and the total pore volume determined as described hereinabove was 0.82 mL/g. The tortuosity parameter relative to water was 1.67. The BET specific surface area was 353 m.sup.2/g, the C value was −395.

Comparative Example 1: Preparing a Molding using a Colloidal Silica Binder Precursor with a Particle Size Distribution not According to the Invention

[0273] Shaping: The particles of the zeolitic material of Example 1 (105.3 g) and carboxymethyl cellulose (4.0 g; Walocel™, Mw=15,000 g) were mixed in a kneader for 5 min. Then, an aqueous polystyrene dispersion (100.7 g; 33.7 g polystyrene) was continuously added. After 10 min, polyethylene oxide (1.33 g) was added. After 10 min, an aqueous colloidal silica binder precursor (70 g; 40 weight-% SiO.sub.2; Dv10=28 nm; Dv50=37 nm; Dv90=52 nm; Ludox® AS-40) was added. After a further 10 min, 20 mL water were added. The total kneading time was 35 min. The resulting formable mass obtained from kneading, having a plasticity of 3321 N, was extruded at a pressure of 100 bar through a matrix having circular holes with a diameter of 1.9 mm. The obtained strands were dried in air in an oven at a temperature of 120° C. for 4 h and calcined in air at a temperature of 490° C. for 5 h. The crushing strength of the strands determined as described hereinabove was 1.6 N.

[0274] Water treatment: 36 g of these strands were mixed in four portions of each 9 g with 180 g deionized water per portion. The resulting mixtures were heated to a temperature of 145° C. for 8 h in an autoclave. Thereafter, the obtained water-treated strands were separated and sieved over a 0.8 mm sieve. The obtained strands were then washed with deionized water and subjected to a stream of nitrogen at ambient temperature. The respectively washed strands were subsequently dried in air at a temperature of 120° C. for 4 h and then calcined in air at a temperature of 450° C. for 2 h.

[0275] The resulting material had a TOC of less than 0.1 g/100 g, a Si content of 44 g/100 g, and a Ti content of 1.5 g/100 g. The crushing strength of the strands determined as described hereinabove was 5 N, and the total pore volume determined as described hereinabove was 0.89 mL/g. The tortuosity parameter relative to water was 1.73. The BET specific surface area was 389 m.sup.2/g, the C value was −547.

Summary of the Crushing Strength Values

[0276] In the following Table 1, the crushing strength values of the moldings as prepared above are summarized. Obviously, the moldings of the present invention exhibit significantly higher and therefore highly advantageous values. Moreover, as can be derived from the table, the improvement of the crushing strength values achieved by the water treatment according to step (v) of the process of the invention is significantly better than the respective improvement as regards the process of the prior art.

TABLE-US-00001 TABLE 1 Results for catalytic testing according to Reference Example 9 crushing crushing strength/N strength/N Molding (non water- (water- improvement/ according to # treated) treated) (100%) *.sup.) Example 2 1.4 8 +4.7 Example 3 1.0 11 +10.0 Example 4 1.5 12 +7.0 Comparative 1.6 5 +2.1 Example 1 *.sup.) improvement of the crushing strength from non-water treated molding to water-treated molding

EXAMPLE 5: TESTING THE MOLDINGS AS CATALYSTS FOR EPOXIDIZING PROPENE

Example 5.1: Preliminary Test—PO Test

[0277] Moldings of the examples were preliminarily tested with respect to their general suitability as expoxidation catalysts according to the PO test as described in Reference Example 9. The respective resulting values of the propylene oxide activity are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Results for catalytic testing according to Reference Example 9 Molding propylene oxide pressure drop according to # activity/% rate/(bar/min) Example 2 5.0 0.013 Example 3 4.8 0.008 Example 4 4.7 0.011 Comparative 4.7 0.021 Example 1

[0278] Obviously, the moldings according to the present invention exhibit a very good propylene oxide activity according to the PO test and are promising candidates for catalysts in industrial continuous epoxidation reactions.

Example 5.2: Catalytic Characteristics of the Moldings in a Continuous Epoxidation Reaction

[0279] The characteristics of moldings of the present invention were compared with moldings of the prior art in a continuous epoxidation reaction as described in Reference Example 10. After a significant time on stream (TOS), the hydrogen peroxide conversions of the moldings according to Example 3 and 4 were compared with the respective moldings according to the prior art (Comparative Examples 1).The following results according to Table 3 were obtained:

TABLE-US-00003 TABLE 3 Results for catalytic testing according to Reference Example 10 Molding T (cooling hydrogen peroxide according to TOS/h medium)/° C. conversion/% Example 3 500 54 95 ± 2 Example 4 385 55 90 ± 2 Comparative 500 56 91 ± 2 Example 1

CITED LITERATURE

[0280] US 2016/250624 A1 [0281] U.S. Pat. No. 6,551,546 B1 [0282] DE 19859561 A1 [0283] U.S. Pat. No. 7,825,204 B2