Process for preparation of zeolitic material

Abstract

The present invention relates to a process for process for the preparation of a zeolitic material which process comprises (i) providing a boron-containing zeolitic material and (ii) deboronating the boron-containing zeolitic material by treating the boron-containing zeolitic material with a liquid solvent system thereby obtaining a deboronated zeolitic material, which liquid solvent system does not contain an inorganic or organic acid, or a salt thereof.

Claims

1. A process for the preparation of a zeolitic material, comprising: (i) providing a boron-containing zeolitic material of a structure MWW or BEA; (ii) deboronating the boron-containing zeolitic material with a liquid solvent system at a temperature in the range of from 50 to 125 C. thereby obtaining a deboronated zeolitic material of the structure MWW or BEA; wherein the liquid solvent system is water, and wherein said liquid solvent system does not contain an inorganic or organic acid or a salt thereof, the acid being selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, propionic acid, oxalic acid, and tartaric acid.

2. The process of claim 1, wherein in (i), the boron-containing zeolitic material is provided by a process comprising (a) hydrothermally synthesizing the boron-containing zeolitic material from a synthesis mixture containing at least one silicon source, at least one boron source, and at least one template compound, to obtain the boron-containing zeolitic material in its mother liquor; (b) separating the boron-containing zeolitic material from its mother liquor; (c) drying the boron-containing zeolitic material separated according to (b); (d) calcining the boron-containing zeolitic material obtained from (b) or (c).

3. The process of claim 2, wherein according to (d), the boron-containing zeolitic material obtained from (b) or (c) is calcined at a temperature in the range of from 500 to 700 C.

4. The process of claim 1, wherein the boron-containing zeolitic material provided in (i) is an aluminum-free zeolitic material.

5. The process of claim 1, wherein the boron-containing zeolitic material provided in (i) has a boron content in the range of from 0.5 to 5.0 weight-%, calculated as element and based on the total weight of the boron-containing zeolitic material.

6. The process of claim 1, wherein the boron-containing zeolitic material provided in (i) is provided in the form of a spray-powder or a spray-granulate.

7. The process of claim 1, wherein the deboronating according to (ii) is carried out for a time in the range of from 6 to 20 h.

8. The process of claim 1, wherein in the deboronating according to (ii), the weight ratio of boron-containing zeolitic material relative to the liquid solvent system is in the range of from 1:5 to 1:40.

9. The process of claim 1, wherein during the deboronation according to (ii), the liquid solvent system is stirred.

10. The process of claim 1, wherein the deboronating according to (ii) is carried out at a temperature in the range of from 95 to 105 C. for a time in the range of from 8 to 15 h, wherein the deboronating according to (ii) is carried out under reflux.

11. The process of claim 1, and wherein the deboronated zeolitic material obtained in (ii) has a boron content of at most 0.2 weight-%, calculated as element and based on the total weight of the deboronated zeolitic material.

12. The process of claim 1, further comprising (iii) post-treating the deboronated zeolitic material obtained from (ii) by a process comprising (iii.1) separating the deboronated zeolitic material from the liquid solvent system; (iii.2) drying the separated deboronated zeolitic material.

13. The process of claim 12, wherein in (iii.2), the separated deboronated zeolitic material is dried by spray-drying.

14. The process of claim 12, further comprising (iii.3) calcining the deboronated zeolitic material obtained from (iii.2) at temperatures in the range of from 500 to 700 C.

Description

EXAMPLES

Example 1

Preparation of a Deboronated MWW

(1) 1.1 Preparation of Boron-Containing MWW

(2) 470.4 kg de-ionized water were provided in a vessel. Under stirring at 70 rpm (rounds per minute), 162.5 kg boric acid were suspended in the water. The suspension was stirred for another 3 h. Subsequently, 272.5 kg piperidine were added, and the mixture was stirred for another hour. To the resulting solution, 392.0 kg Ludox AS-40 were added, and the resulting mixture was stirred at 70 rpm for another hour.

(3) The finally obtained mixture was transferred to a crystallization vessel and heated to 170 C. within 5 h under autogenous pressure and under stirring (50 rpm). The temperature of 170 C. was kept essentially constant for 120 h; during these 120 h, the mixture was stirred at 50 rpm. Subsequently, the mixture was cooled to a temperature of from 50-60 C. within 5 h. The aqueous suspension containing B-MWW had a pH of 11.3 as determined via measurement with a pH electrode.

(4) From said suspension, the B-MWW precursor was separated by filtration. The filter cake was then washed with de-ionized water until the washing water had a conductivity of less than 700 microSiemens/cm

(5) From the thus obtained filter cake, an aqueous suspension was prepared having a solid content of 15 weight-%. This suspension was subjected to spray-drying in a spray-tower with the following spray-drying conditions:

(6) TABLE-US-00001 drying gas, nozzle gas: technical nitrogen temperature drying gas: temperature spray tower (in): 288-291 C. temperature spray tower (out): 157-167 C. temperature filter (in): 150-160 C. temperature scrubber (in): 40-48 C. temperature scrubber (out): 34-36 C. pressure difference filter: 8.3-10.3 mbar nozzle: top-component nozzle supplier Gerig; size 0 nozzle gas temperature: room temperature nozzle gas pressure: 2.5 bar operation mode: nitrogen straight apparatus used: spray tower with one nozzle configuration: spray tower - filter - scrubber gas flow: 1,900 kg/h filter material: Nomex needle-felt 20 m.sup.2 dosage via flexible tube pump: SP VF 15 (supplier: Verder)

(7) 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.

(8) The spray-dried material was then subjected to calcination at 650 C. for 2 h. The calcined material had a boron (B) content of 1.9 wt.-%, a silicon (Si) content of 41 wt.-%, and a total organic carbon (TOC) content of 0.18 wt.-%.

(9) 1.2 Preparation of Deboronated MWW

(10) a) Deboronation

(11) Based on the spray-dried material obtained according to Example 1.1 above, 4 batches of deboronated zeolite MWW were prepared. In each of the first 3 batches, 35 kg of the spray-dried material obtained according to Example 1.1 and 525 kg water were employed. In the fourth batch, 32 kg of the spray-dried material obtained according to Example 1.1 and 480 kg water were employed. In total, 137 kg of the spray-dried material obtained according to Example 1.1 and 2025 kg water were employed.

(12) For each batch, the respective amount of water was passed into a vessel equipped with a reflux condenser. Under stirring at 40 r.p.m., the given amount of the spray-dried material was suspended into the water. Subsequently, the vessel was closed and the reflux condenser put into operation. The stirring rate was increased to 70 r.p.m. Under stirring at 70 r.p.m., the content of the vessel was heated to 100 C. within 10 h and kept at this temperature for 10 h. Then, the content of the vessel was cooled to a temperature of less than 50 C.

(13) The resulting deboronated zeolitic material of structure type MWW was separated from the suspension by filtration under a nitrogen pressure of 2.5 bar and washed four times with deionized water. After the filtration, the filter cake was dried in a nitrogen stream for 6 h.

(14) The deboronated zeolitic material obtained in 4 batches (625.1 kg nitrogen-dried filter cake in total) had a residual moisture content of 79%, as determined using an IR (infrared) scale at 160 C.

(15) b) Spray-Drying of the Nitrogen-Dried Filter Cake

(16) From the nitrogen-dried filter cake having a residual moisture content of 79% obtained according to section a) above, an aqueous suspension was prepared with deionized water, the suspension having a solid content of 15 wt.-%. This suspension was subjected to spray-drying in a spray-tower with the following spray-drying conditions:

(17) TABLE-US-00002 drying gas, nozzle gas: technical nitrogen temperature drying gas: temperature spray tower (in): 304 C. temperature spray tower (out): 147-150 C. temperature filter (in): 133-141 C. temperature scrubber (in): 106-114 C. temperature scrubber (out): 13-20 C. pressure difference filter: 1.3-2.3 mbar nozzle: top-component nozzle: supplier Niro, diameter 4 mm nozzle gas throughput: 23 kg/h nozzle gas pressure: 2.5 bar operation mode: nitrogen straight apparatus used: spray tower with one nozzle configuration: spray tower - filter - scrubber gas flow: 550 kg/h filter material: Nomex needle-felt 10 m.sup.2 dosage via flexible tube pump: VF 10 (supplier: Verder)

(18) 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.

(19) 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.

(20) The spray-dried MWW material obtained had a B content of 0.08 wt.-%, an Si content of 42 wt.-%, and a TOC of 0.23 wt.-%.

Example 2

Preparation of Het1MWW, with Het1=Ti

(21) Based on the deboronated MWW material as obtained according to Example 1, a zeolitic material of structure type MWW containing titanium (Ti) was prepared, referred to in the following as TiMWW. The synthesis was performed in two experiments, described in the following as a) and b):

(22) a) First Experiment

(23) TABLE-US-00003 Starting materials: deionized water: 244.00 kg piperidine: 118.00 kg tetrabutylorthotitanate: 10.90 kg deboronated zeolitic material: 54.16 kg

(24) 54.16 kg of the deboronated zeolitic material of structure type MWW were transferred in to a first vessel A.

(25) In a second vessel B, 200.00 kg deionized water were transferred and stirred at 80 r.p.m. 118.00 kg piperidine were added under stirring, and during addition, the temperature of the mixture increased for about 15 C. Subsequently, 10.90 kg tetrabutylorthotitanate and 20.00 kg deionized water were added. Stirring was then continued for 60 min.

(26) The mixture of vessel B was then transferred into vessel A, and stirring in vessel A was started (70 r.p.m.). 24.00 kg deionized water were filled into vessel A and transferred to vessel B.

(27) The mixture in vessel B was then stirred for 60 min at 70 r.p.m. At the beginning of the stirring, the pH of the mixture in vessel B was 12.6, as determined with a pH electrode.

(28) After said stirring at 70 r.p.m., the frequency was decreased to 50 r.p.m., and the mixture in vessel B was heated to a temperature of 170 C. within 5 h. At a constant stirring rate of 50 r.p.m., the temperature of the mixture in vessel B was kept at an essentially constant temperature of 170 C. for 120 h under autogenous pressure. During this crystallization of TiMWW, a pressure increase of up to 10.6 bar was observed. Subsequently, the obtained suspension containing TiMWW having a pH of 12.6 was cooled within 5 h.

(29) The cooled suspension was subjected to filtration, and the separated mother liquor was transferred to waste water discharge. The filter cake was washed four times with deionized water under a nitrogen pressure of 2.5 bar. After the last washing step, the filter cake was dried in a nitrogen stream for 6 h.

(30) From 246 kg of said filter cake, an aqueous suspension was prepared with deionized water, the suspension having a solid content of 15 wt.-%. This suspension was subjected to spray-drying in a spray-tower with the following spray-drying conditions:

(31) TABLE-US-00004 drying gas, nozzle gas: technical nitrogen temperature drying gas: temperature spray tower (in): 304 C. temperature spray tower (out): 147-152 C. temperature filter (in): 133-144 C. temperature scrubber (in): 111-123 C. temperature scrubber (out): 12-18 C. pressure difference filter: 1.8-2.8 mbar nozzle: top-component nozzle: supplier Niro, diameter 4 mm nozzle gas throughput: 23 kg/h nozzle gas pressure: 2.5 bar operation mode: nitrogen straight apparatus used: spray tower with one nozzle configuration: spray tower - filter - scrubber gas flow: 550 kg/h filter material: Nomex needle-felt 10 m.sup.2 dosage via flexible tube pump: VF 10 (supplier: Verder)

(32) 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.

(33) The spray-dried TiMWW material obtained from the first experiment had a Si content of 37 wt.-%, a Ti content of 2.4 wt.-%, and a TOC of 7.5 wt.-%.

(34) b) Second Experiment

(35) The second experiment was carried out in the same way as the first experiment described in section a) above. The spray-dried TiMWW material obtained from the second experiment had a Si content of 36 wt.-%, a Ti content of 2.4 wt.-%, a TOC of 8.0 wt.-%

(36) Acid Treatment of TiMWW

(37) Each of the two spray-dried TiMWW materials as obtained in the first and the second experiment described in Example 2, sections a) and b) above was subjected to acid treatment as described in the following in sections a) and b). In section c) hereinunder, it is described how a mixture of the materials obtained from a) and b) are spray-dried. In section d) hereinunder, it is described how the spray-dried material is calcined.

(38) a) Acid Treatment of the Spray-Dried Material Obtained According to Example 2, Section a)

(39) TABLE-US-00005 Starting materials: deionized water: 690.0 kg nitric acid (53%): 900.0 kg spray-dried Ti-MWW a): 53.0 kg

(40) 670.0 kg deionized water were filled in a vessel. 900 kg nitric acid were added, and 53.0 kg of the spray-dried TiMWW were added under stirring at 50 r.p.m. The resulting mixture was stirred for another 1 5 min. Subsequently, the stirring rate was increased to 70 r.p.m.

(41) Within 1 h, the mixture in the vessel was heated to 100 C. and kept at this temperature and under autogenous pressure for 20 h under stirring. The thus obtained mixture was then cooled within 2 h to a temperature of less than 50 C.

(42) The cooled mixture was subjected to filtration, and the filter cake was washed six times with deionized water under a nitrogen pressure of 2.5 bar. After the last washing step, the filter cake was dried in a nitrogen stream for 10 h. The washing water after the sixth washing step had a pH of about 2.7. 225.8 kg dried filter cake were obtained.

(43) b) Acid Treatment of the Spray-Dried Material Obtained According to Example 2, Section b)

(44) TABLE-US-00006 Starting materials: deionized water: 690.0 kg nitric acid (53%): 900.0 kg spray-dried Ti-MWW b): 55.0 kg

(45) The acid treatment of the spray-dried material obtained according to Example 2, section b) was carried in the same way as the acid treatment of the spray-dried material obtained according to Example 2, section a) as described above. The washing water after the sixth washing step had a pH of about 2.7. 206.3 kg dried filter cake were obtained.

(46) c) Spray-drying of the mixture of the acid-treated materials obtained from a) and b)

(47) From 462.1 kg of the mixture of the filter cakes obtained from a) and b), an aqueous suspension was prepared with deionized water, the suspension having a solid content of 15 wt.-%. This suspension was subjected to spray-drying in a spray-tower with the following spray-drying conditions:

(48) TABLE-US-00007 drying gas, nozzle gas: technical nitrogen temperature drying gas: temperature spray tower (in): 304-305 C. temperature spray tower (out): 151 C. temperature filter (in): 141-143 C. temperature scrubber (in): 109-118 C. temperature scrubber (out): 14-15 C. pressure difference filter: 1.7-3.8 mbar nozzle: top-component nozzle: supplier Niro, diameter 4 mm nozzle gas throughput: 23 kg/h nozzle gas pressure: 2.5 bar operation mode: nitrogen straight apparatus used: spray tower with one nozzle configuration: spray tower - filter - scrubber gas flow: 550 kg/h filter material: Nomex needle-felt 10 m.sup.2 dosage via flexible tube pump: VF 10 (supplier: Verder)

(49) 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.

(50) The spray-dried acid-treated TiMWW material had a Si content of 42 wt.-%, a Ti content of 1.6 wt-%, and a TOC of 1.7 wt.-%.

(51) D) Calcination of the spray-dried material obtained according to c)

(52) The spray-dried material was then subjected to calcination at 650 C. in a rotary furnace for 2 h. The calcined material had a Si content of 42.5 wt.-%, a Ti content of 1.6 wt.-% and a TOC content of 0.15 wt.-%. The Langmuir surface are determined via nitrogen adsorption at 77 K according to DIN 66134 was 612 m.sup.2/g, the multipoint BET specific surface area determined via nitrogen adsorption at 77 K according to DIN 66131 was 442 m.sup.2/g. The total intrusion volume determined according to Hg porosimetry according to DIN 66133 was 4.9 ml/g (milliliter/gram), the respective total pore area 104.6 m.sup.2/g. The degree of crystallization determined via XRD was 80%, the average crystallite size 31 nm. The XRD of the material is shown in FIG. 1.

Example 3

Preparation of B-MWW Zeolitic Materials

(53) 3.1 22.050 kg Deionized Water and 8.515 kg Piperidine were Mixed in a Stirred Tank. 5.076 kg boric acid were added under stirring, and stirring was continued for 30 min. Then, 4.900 kg fumed silica (Aerosil 200) were added, and stirring was continued for 2 h. The stirring rate was 150 r.p.m. Subsequently, the resulting suspension was heated within 2 h to a temperature of 170 C. and kept at this temperature for 120 h. The pressure increase was 8.9 bar.

(54) After the synthesis, the suspension was subjected to filtration using a suction filter. The filter cake was washed with deionized water, and the pH of the filtrate was 8.5. The thus washed filter cake was dried at 100 C. by subjecting it to nitrogen which was applied with a flow rate of 6 m.sup.3/h for 24 h. Thereafter, the filter cake obtained was subjected to further drying for 2 h and calcined at 600 C. for 10 h.

(55) The obtained B-MWW had a B content of 2.2 weight-%, a Si content of 41 weight-%, and a C content (TOC (total organic carbon) of less than 0.2 weight-%, in each case calculated as element and based on the total weight of the B-MWW. The XRD of the obtained B-MWW is shown in FIG. 2, an SEM picture (secondary electrons) is shown in FIG. 3.

(56) 3.2 In a beaker, 203.1 g boric acid were dissolved in 340.6 g piperidine and 588.0 g water. The mixture was stirred for 20 min. Then, under stirring, 490.0 g ammonia-stabilized colloidal silica (Ludox AS 40) were added. The resulting mixture was stirred for 1 h. The liquid gel was then passed into an autoclave. In the autoclave, the gel was heated to a temperature of 170 C. within 1 h and kept at this temperature for 120 h. A white suspension was obtained.

(57) The suspension was subjected to filtration and washed with deionized water. The washed filter cake was dried at 100 C. for 16 h. The temperature was then increased to 600 C. with a temperature rate of 2 C./min, and calcination was performed at this temperature of 600 C. for 10 h in air.

(58) The obtained B-MWW had a B content of 1.3 weight-%, and a Si content of 42 weight-%.

(59) 3.3 In a beaker, 181.3.1 g boric acid were dissolved in 304.1 g piperidine and 525.0 g water. The mixture was stirred for 20 min. Then, under stirring, 437.5 g ammonia-stabilized colloidal silica (Ludox AS 40) were added. The resulting mixture was stirred for 1 h. The liquid gel was then passed into an autoclave. In the autoclave, the gel was heated to a temperature of 170 C. within 1 h and kept at this temperature for 120 h. A white suspension was obtained.

(60) The suspension was subjected to filtration and washed with deionized water. The washed filter cake was dried at 100 C. for 16 h. The temperature was then increased to 600 C. with a temperature rate of 2 C./min, and calcination was performed at this temperature of 600 C. for 10 h in air.

(61) The obtained B-MWW had a B content of 1.3 weight-%, and a Si content of 42 weight-%. The XRD of the obtained B-MWW is shown in FIG. 4, an SEM picture (secondary electrons) is shown in FIG. 5.

Example 4

Deboronation of B-MWW Zeolitic Materials

(62) 4.1 A suspension of 100 g of the material obtained according to Example 3.1 in 1000 g deionized water was refluxed for 2 h under stirring. Thereafter, stirring was stopped, and the suspension subjected to filtration. From the solid obtained, a sample was taken and subjected to drying at 120 C. For the sample, the B content was determined. The remaining solid was suspended in 1000 g deionized water and heated at 100 C. fore 1 h. The process was repeated 4 times in total. The finally obtained solid was subjected to drying at 100 C. for 24 h. In the following table, the B content of the samples and the finally obtained solid is shown:

(63) TABLE-US-00008 time/h B content (in weight-%, (subjecting to heating calculated as element and at 100 C. under reflux) based on total weight of solid) 0 2.0 1 not determined 2 0.37 3 0.18 4 0.13 5 0.12
4.2 A suspension of 166 g of the B-MWW obtained from Example 3.2 in 4,980.0 g deionized water was refluxed at 100 C. under stirring at 160 r.p.m. for 20 h. The white suspension was subjected to filtration and washed with deionized water. The obtained solid was subjected to drying at 100 C. for 16 h. The B content of the obtained solid, calculated as element, was less than 0.05 weight-%, the Si content, calculated as element, was 44 weight-%.
4.3 A suspension of 30.0 g of the B-MWW obtained from Example 3.2 in 900.0 g methanol was refluxed at 64 C. under stirring at 200 r.p.m. for 20 h. The white suspension was subjected to filtration and washed with deionized water. The obtained solid was subjected to drying at 100 C. for 16 h. The B content of the obtained solid, calculated as element, was 0.39 weight-%, the Si content, calculated as element, was 42 weight-%.

(64) Compared to the deboronation with water according to 4.2, a higher B content of the deboronated material was obtained. Nevertheless, it could be shown that a liquid solvent system consisting of a monohydric alcohol, namely methanol, can be used for considerably decreasing the B content of a B-MWW zeolitic material, and thus for deboronating a B-MWW zeolitic material.

Comparative Example

(65) The B-MWW zeolitic material as obtained from Example 3.3 was subjected to deboronation making use of the prior art teaching, i.e. a liquid solvent system containing nitric acid was employed as deboronating agent. This B-MWW zeolitic material is essentially identical to the B-MWW zeolitic material as obtained from Example 3.2; therefore, the results according this comparative example can be easily compared with the results of the deboronation according to Example 4.2.

(66) A suspension of 150 g of the B-MWW obtained from Example 3.3 in 4500 ml of 6 mol/1 nitric acid (aqueous solution) was refluxed at 100 C. under stirring at 200 r.p.m. for 20 h. The white suspension was subjected to filtration and washed with deionized water. The obtained solid was subjected to drying at 100 C. for 16 h. The B content of the obtained solid, calculated as element, was 0.09 weight-%, the Si content, calculated as element, was 40 weight-%.

(67) Thus, under otherwise identical conditions (deboronation time: 20 h; deboronation temperature: 100 C.; deboronation stirring rate: 200 r.p.m., drying time: 16 h; drying temperature: 100 C.), it was found that the inventive deboronation with water as liquids solvent system leads to a deboronated material having a lower B content (less than 0.05 weight-%) than the material deboronated according to the prior art (0.09 weight-%).

Example 5

Deboronation of B-MWW Zeolitic Materials

(68) 5.1 Preparation of a B-MWW Material (Zeolitic Material of Framework Structure MWW)

(69) 480 kg de-ionized water were provided in a vessel. Under stirring at 70 rpm (rounds per minute), 166 kg boric acid were suspended in the water at room temperature. The suspension was stirred for another 3 h at room temperature. Subsequently, 278 kg piperidine were added, and the mixture was stirred for another hour. To the resulting solution, 400 kg Ludox AS-40 were added, and the resulting mixture was stirred at 70 rpm for another hour at room temperature. The finally obtained mixture was transferred to a crystallization vessel and heated to 170 C. within 5 h under autogenous pressure and under stirring (50 rpm). The temperature of 170 C. was kept essentially constant for 120 h. During these 120 h, the mixture was stirred at 50 rpm. Subsequently, the mixture was cooled to a temperature of from 50-60 C. The aqueous suspension containing B-MWW precursor had a pH of 11.3 as determined via measurement with a pH-sensitive electrode. From said suspension, the B-MWW precursor 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 700 microSiemens/cm.

(70) The filter cake was then mixed with water to obtain a suspension having a solid content of 15 weight-%. This suspension was subjected to spray-drying in a spray-tower with the following spray-drying conditions:

(71) TABLE-US-00009 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)

(72) 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.

(73) The spray-dried material was then subjected to calcination at 600 C. for 10 h. The obtained B-MWW had a B content, calculated as element, of 1.9 weight-%, and a Si content, calculated as element, of 41 weight-%.

(74) 5.2 Deboronation

(75) 9 kg of de-ionized water and 600 g of the spay-dried material obtained according to Example 5.1 were refluxed at 100 C. under stirring at 250 r.p.m. for 10 h. The resulting deboronated zeolitic material was separated from the suspension by filtration and washed with 8 l deionized water at room temperature. After the filtration, the filter cake was dried at a temperature of 120 C. for 16 h. The obtained B-MWW had a B content, calculated as element, of 0.07 weight-%, and a Si content, calculated as element, of 42 weight-%.

Example 6

Deboronation of B-BEA Zeolitic Materials

(76) 6.1 Preparation of a B-BEA Material (Zeolitic Material of Framework Structure BEA)

(77) 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.

(78) 640 kg of the thus obtained filter cake were suspended in water to obtain a suspension having a solid content of 35 weight-%. This suspension was subjected to spray-drying in a spray-tower with the following spray-drying conditions:

(79) TABLE-US-00010 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)

(80) 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.

(81) The spray-dried material was then subjected to calcination at 500 C. for 5 h. The B content of the obtained solid, calculated as element, was 1.5 weight-%, the Si content, calculated as element, was 43 weight-%.

(82) 6.2 Deboronation

(83) 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 material obtained according to 6.1 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.

(84) The resulting deboronated zeolitic material of framework structure type BEA 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. Then, the filter cake was mixed with water to obtain a suspension having a solid content of 40 weight-%. Thus suspension was subjected to spray-drying under the conditions as described in

(85) The spray-dried material was then subjected to calcination at 550 C. for 5 h (heating ramp 2 K/min). The B content of the obtained solid, calculated as element, was less than 0.03 weight-%, the Si content, calculated as element, was 45 weight-%.

Example 7

Deboronation of B-CHA Zeolitic Materials

(86) 7.1 Preparation of a B-CHA Material (Zeolitic Material of Framework Structure CHA)

(87) Based on a synthesis mixture of 1414 g de-ionized water were provided in a vessel, 203.8 g of a 25 weight-% aqueous tetramethylammonium hydroxide solution, 765.7 g of a 13.26 weight-% aqueous trimethyl-1-adamantylammonium hydroxide solution, 31.0 g boric acid, 999.6 g Ludox AS40, and 20 g seed material, a B-CHA zeolite was synthesized under hydrothermal conditions at a temperature of 160 C. for 72 h under stirring at 200 r.p.m. In the autoclave used, the pressure was 5 bar. At the end of the synthesis procedure, the pH of the synthesis mixture was 11.8.

(88) 3,340 g of the suspension obtained from crystallization were subjected to filtration and washed with deionized water until the conductivity of the washing water water was less than 50 microSiemens/cm. 853 g of the wet filter cake were dried for 5 h at 120 C. The B content of the obtained solid, calculated as element, was 1.1 weight-%, the Si content, calculated as element, was 42 weight-%.

(89) 7.2 Deboronation

(90) 750 g de-ionized water were provided in a vessel equipped with a reflux condenser. Under stirring at 40 rpm, 50 kg of the dried material obtained according to 7.1 were employed. Subsequently, the vessel was closed and the reflux condenser put into operation. Under stirring, the content of the vessel was heated to 100 C. within 1 h and kept at this temperature for 10 h. Then, the content of the vessel was cooled to a temperature of less than 50 C.

(91) The resulting deboronated zeolitic material of framework structure type CHA was separated from the suspension by filtration and washed with deionized water until the washing water had a conductivity of less than 10 microSiemens/cm. After the filtration, the filter cake was dried at 120 C. overnight. The B content of the obtained solid, calculated as element, was 0.09 weight-%, the Si content, calculated as element, was 44 weight-%.

(92) The XRD pattern of the calcined sample (calcination of the dried material at 600 C. under air) is shown in FIG. 6.

SHORT DESCRIPTION OF THE FIGURES

(93) FIG. 1 shows the X-ray diffraction pattern (copper K alpha radiation) of the acid-treated, spray-dried and calcined TiMWW material as obtained according to Example 2. On the x axis, the degree values (2 Theta) are shown, on the y axis, the intensity (Lin (Counts)).

(94) FIG. 2 shows the X-ray diffraction pattern (copper K alpha radiation) of the B-MWW zeolitic material obtained according to Example 3.1. On the x axis, the degree values (2 Theta) are shown, on the y axis, the intensity (Lin (Counts)).

(95) FIG. 3 shows an SEM (Scanning Electron Microscopy) picture (secondary electron (SE) picture at 5 kV (kiloVolt)) of a representative sample of the B-MWW zeolitic material obtained according to Example 3.1. The scale is indicated in the lower right hand corner by the rule having a length of 2 micrometer.

(96) FIG. 4 shows the X-ray diffraction pattern (copper K alpha radiation) of the B-MWW zeolitic material obtained according to Example 3.3. On the x axis, the degree values (2 Theta) are shown, on the y axis, the intensity (Lin (Counts)).

(97) FIG. 5 shows an SEM (Scanning Electron Microscopy) picture (secondary electron (SE) picture at 5 kV (kiloVolt)) of a representative sample of the B-MWW zeolitic material obtained according to Example 3.3. The scale is indicated in the lower right hand corner by the rule having a length of 2 micrometer.

(98) FIG. 6 shows the X-ray diffraction pattern (copper K alpha radiation) of the B-CHA zeolitic material obtained according to Example 7.2. On the x axis, the degree values (2 Theta) are shown, on the y axis, the intensity (Lin (Counts)).

CITED PRIOR ART

(99) EP 1 485 321 A1 P. Wu et al., Studies in Surface Science and Catalysis, vol. 154 (2004), pp. 2581-2588 WO 02/057181 A2 EP 1 490 300 A1 P. Wu et al., Chemical Communications (2002), pp. 1026-1027 L. Liu et al., Microporous and Mesoporous Materials vol. 94 (2006) pp. 304-312. EP 1 324 948 A1 U.S. Pat. No. 4,954,325 M. E. Leonowicz, J. A. Lawton, S. L. Lawton, M. K. Rubin, Science, vol. 264 (1994) pp. 1910, S. L. Lawton et al., Micropor. Mesopor. Mater., Vol. 23 (1998) pp. 109. P. Wu et al., Hydrothermal Synthesis of a novel Titanosilicate with MWW Topology, Chemistry Letters (2000), pp. 774-775 WO 02/28774 A2