Regeneration of a titanium containing zeolite

Abstract

The present invention relates to a process for the regeneration of a catalyst comprising a titanium-containing zeolite, said catalyst having been used in a process for the preparation of an olefin oxide and having phosphate deposited thereon, said process for the regeneration comprising the steps: (a) separating the reaction mixture from the catalyst, (b) washing the catalyst obtained from (a) with liquid aqueous system; (c) optionally drying the catalyst obtained from (b) in a gas stream comprising an inert gas at a temperature of less than 300? C.; (d) calcining the catalyst obtained from (c) in a gas stream comprising oxygen at a temperature of at least 300? C.

Claims

1. A process for the regeneration of a catalyst comprising a titanium containing zeolite as catalytically active material, said catalyst having been used in a process for the preparation of an olefin oxide comprising (i) providing a mixture comprising an organic solvent, an olefin, an epoxidation agent and an at least partially dissolved potassium comprising salt; (ii) subjecting the mixture provided in (i) in a reactor to epoxidation conditions in the presence of the catalyst, obtaining a mixture comprising the organic solvent and the olefin oxide, and obtaining the catalyst having a potassium salt deposited thereon; said process for the regeneration comprising (a) separating the mixture obtained from (ii) from the catalyst; (b) washing the catalyst obtained from (a) with a liquid aqueous system; which comprises less than 0.1 wt. -% of compounds with a pKa value of 8 or less; (c) optionally drying the catalyst obtained from (b) in a gas stream comprising an inert gas at a temperature of less than 300? C.; (d) calcining the catalyst obtained from (b) or (c) in a gas stream comprising oxygen at a temperature of at least 300? C.

2. The process of claim 1, wherein the liquid aqueous system used in (b) contains at least 75 weight water, based on a total weight of the liquid aqueous system.

3. The process of claim 1, wherein the washing (b) is performed at a pressure in a range of from 0.8 to 1.5 bar, and a temperature in a range of from 40 to 90? C.

4. The process of claim 1, wherein the washing (b) is performed until a potassium content of the liquid aqueous system after having been contacted with the catalyst is at most 1000 weight-ppm.

5. The process of claim 1, wherein the washing (b) is performed until a potassium content of the liquid aqueous system after having been contacted with the catalyst relative to the potassium content of the liquid aqueous system before having been contacted with the catalyst is at most 333:1.

6. The process of claim 1, wherein the process comprises the drying (c) and at least 90 volume-% of the gas stream comprising the inert gas consist of at least one inert gas selected from the group consisting of nitrogen, helium, and argon.

7. The process of claim 1, wherein the process comprises the drying (c), which is performed until a water content of the gas stream comprising the inert gas after having been contacted with the catalyst relative to a water content of the gas stream comprising the inert gas before having been contacted with the catalyst is at most 1.10:1.

8. The process of claim 1, wherein the process comprises the drying (c) and after (c), the dried catalyst is heated to the calcination temperature according to (d) with a rate in a range of from 0.5 to 5 K/min.

9. The process of claim 1, wherein the catalyst obtained from (d) has a potassium content of at most 0.5 weight-%, based on a total weight of the catalyst and determined via elemental analysis.

10. The process of claim 1, wherein the mixture provided in (i) has a potassium content with a molar range of potassium relative to the epoxidation agent comprised in the mixture in a range of from 10?10.sup.?6:1 to 1500?10.sup.?6:1.

11. The process of claim 1, wherein the at least partially dissolved potassium comprising salt in (i) is selected from the group consisting of an inorganic potassium salt, an organic potassium salt, and a combination thereof.

12. The process of claim 1, wherein the at least partially dissolved potassium comprising salt in (i) is selected from the group consisting of at least one inorganic potassium salt selected from the group consisting of potassium hydroxide, a potassium halide, potassium nitrate, potassium sulfate, potassium hydrogen sulfate, potassium perchlorate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate, a potassium pyrophosphate, and a potassium etidronate, at least one organic potassium salt selected from the group consisting of a potassium salt of an aliphatic saturated monocarboxylic acid, potassium carbonate, and potassium hydrogen carbonate, and a combination of the at least one inorganic potassium salt and the at least one organic potassium salt.

13. The process of claim 1, wherein the titanium containing zeolite has an MFI framework structure, an MEL framework structure, an MWW framework structure, an MWW-type framework structure, an ITQ framework structure, a BEA framework structure, a MOR framework structure, or a mixed structure of two or more thereof.

14. The process of claim 1, wherein the titanium containing zeolite comprises at least one of Al, B, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn, Ga, Ge, In, Sn, Pb, Pd, Pt, and Au.

15. The process of claim 1, wherein the titanium containing zeolite is an aluminum-free zeolitic material of MWW or MWW-type framework structure comprising titanium.

16. The process of claim 1, wherein the catalyst comprising the titanium containing zeolite is a micropowder.

17. The process of claim 16, wherein the molding further comprises at least one binder.

18. The process of claim 1, wherein the process for the regeneration is carried out in the reactor in which the mixture provided in (i) is subjected to epoxidation conditions according to (ii).

19. The process of claim 1, further comprising employing the catalyst obtained from (d) in an olefin epoxidation process comprising (i) providing a mixture comprising an organic solvent, an olefin, an epoxidation agent and an at least partially dissolved potassium comprising salt; and (ii) subjecting the mixture provided in (i) in a reactor to epoxidation conditions in the presence of the catalyst obtained from (d), obtaining a mixture comprising the organic solvent and the olefin oxide.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the amount of potassium and phosphor deposited on the spent catalyst relative to the overall silicon content. Fraction 1 is a sample taken from the first meter at the bottom of a reactor tube, fraction 2 is a sample taken 1 to 2 m away from the bottom of a reactor tube and fraction 3 is a sample taken 2 to 3 m away from the bottom of a reactor tube.

(2) FIG. 2 shows the amount of carbon and nitrogen deposited on the spent catalyst relative to the overall silicon content. Fraction 1 is a sample taken from the first meter at the bottom of a reactor tube, fraction 2 is a sample taken 1 to 2 m away from the bottom of a reactor tube and fraction 3 is a sample taken 2 to 3 m away from the bottom of a reactor tube.

(3) FIG. 3 shows the catalytic performance of spent catalyst regenerated according to a method of the prior art compared with the catalytic performance of fresh catalyst under otherwise identical epoxidation conditions. Indicated are the conversion rate based on hydrogen peroxide, the normalized selectivities based on hydrogen peroxide and propene of the spent catalyst and the fresh catalyst and further the reaction temperature (? C.) of the spent catalyst as well as the fresh catalyst.

(4) FIG. 4 shows an FT-IR spectrum of fresh catalyst. The x axis shows the wavenumber (wn) in cm.sup.?1, the y axis shows the absorbance (A).

(5) FIG. 5 shows an FT-IR spectrum of spent catalyst following after regeneration cycles, each cycle comprising steps (a) to (b) according to the invention. The x axis shows the wavenumber (wn) in cm.sup.?1, the y axis shows the absorbance (A).

(6) FIG. 6 shows the catalytic performance of spent catalyst having been submitted to five regeneration cycles comprising steps (a) to (b) according to the invention compared with the catalytic performance of fresh catalyst under otherwise identical epoxidation conditions. Indicated are the on hydrogen peroxide conversion rate, the normalized selectivities based on hydrogen peroxide and based on propene of the regenerated catalyst and the fresh catalyst and further the reaction temperature (? C.) applied when using the regenerated catalyst and the fresh catalyst.

(7) The present invention is further illustrated by the following reference examples, examples, and reference examples.

EXAMPLES

Reference Example 1

Preparation of a Catalyst Comprising a Titanium Containing Zeolite (ZnTiMWW);

(8) 1.1 Preparation of Boron-Containing MWW

(9) 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. 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. From said suspension, the B-MWW 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. The thus obtained filter cake was subjected to spray-drying in a spray-tower using technical nitrogen as drying gas. 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. %.

(10) 1.2 Preparation of Deboronated MWW

(11) Based on the spray-dried material obtained according to section 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 section 1.1 and 525 kg water were employed. In the fourth batch, 32 kg of the spray-dried material obtained according to section 1.1 and 480 kg water were employed. In total, 137 kg of the spray-dried material obtained according to section 1.1 and 2025 kg water were employed. 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. 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. 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. From the nitrogen-dried filter cake having a residual moisture content of 79% obtained 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 using technical nitrogen as drying gas. 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. %.

(12) 1.3 Preparation of TiMWW

(13) Based on the deboronated MWW material as obtained according to section 1.2, a zeolitic material of structure type MWW containing titanium (Ti) was prepared, referred to in the following as TiMWW. 54.16 kg of the deboronated zeolitic material of structure type MWW were transferred in to a first vessel A. 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. 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. 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. 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. 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. 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 using technical nitrogen as drying gas. 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. %.

(14) 1.4 Acid Treatment of TiMWW

(15) The spray-dried TiMWW material as obtained in section 1.3 above was subjected to acid treatment, followed by spray-drying and calcining as described below. 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. 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. 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. From the filter cake obtained, 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 using technical nitrogen as drying gas. 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. %. 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 66131 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.

(16) 1.5 Impregnation of TiMWW with Zn

(17) The acid-treated, spray-dried and calcined material as obtained according to 1.4 was then subjected to an impregnation stage. Impregnation was carried out in 3 batches a) to c) as follows:

(18) a) In a vessel equipped with a reflux condenser, a solution of 840 kg deionized water and 5.13 kg zinc acetate dihydrate was prepared within 30 min. Under stirring (40 r.p.m.), 28 kg of the calcined Ti-MWW material obtained according to 1.4 were suspended. Subsequently, the vessel was closed and the reflux condenser put into operation. The stirring rate was increased to 70 r.p.m.

(19) b) In a vessel equipped with a reflux condenser, a solution of 840 kg deionized water and 5.13 kg zinc acetate dihydrate was prepared within 30 min. Under stirring (40 r.p.m.), 28 kg of the calcined Ti-MWW material obtained according to 1.4 were suspended. Subsequently, the vessel was closed and the reflux condenser put into operation. The stirring rate was increased to 70 r.p.m.

(20) c) In a vessel equipped with a reflux condenser, a solution of 930 kg deionized water and 5.67 kg zinc acetate dihydrate was prepared within 30 min. Under stirring (40 r.p.m.), 31 kg of the calcined Ti-MWW material obtained according to 1.4 were suspended. Subsequently, the vessel was closed and the reflux condenser put into operation. The stirring rate was increased to 70 r.p.m.

(21) In all batches a) to c), the mixture in the vessel was heated to 100? C. within 1 h and kept under reflux for 4 h at a stirring rate of 70 r.p.m. Then, the mixture was cooled within 2 h to a temperature of less than 50? C. For each batch a) to c), the cooled suspension was subjected to filtration, and the mother liquor was transferred to waste water discharge. The filter cake was washed five 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. For batch a), 106.5 kg nitrogen-dried filter cake were finally obtained. For batch b), 107.0 kg nitrogen-dried filter cake were finally obtained. For batch c), 133.6 kg nitrogen-dried filter cake were finally obtained. The thus dried Zn-impregnated TiMWW material (ZnTiMWW), for each batch, had a Si content of 42 wt. %, a Ti content of 1.6 wt.-%, a Zn content of 1.4 wt. % and a TOC of 1.4 wt. %.

(22) 1.6 Preparation of a Molding

(23) Starting from the calcined spray-dried ZnTiMWW material obtained above, a molding was prepared, dried, and calcined. Therefor, 22 batches were prepared, each starting from 3.4 kg of the calcined spray-dried ZnTiMWW material obtained in Example 1, 0.220 kg Walocel? (Walocel MW 15000 GB, Wolff Cellulosics GmbH & Co. KG, Germany), 2.125 kg Ludox? AS-40 and 6.6 l deionized water, as follows: 3.4 kg ZnTiMWW and 0.220 kg Walocel were subjected to kneading in an edge mill for 5 min. Then, during further kneading, 2.125 kg Ludox were added continuously. After another 10 min, addition of 6 l of deionized water was started. After another 30 min, further 0.6 l of deionized water were added. After a total time of 50 min, the kneaded mass had become extrudable. Thereafter, the kneaded mass was subjected to extrusion under 65-80 bar wherein the extruder was cooled with water during the extrusion process. Per batch, the extrusion time was in the range of from 15 to 20 min. The power consumption per batch during extrusion was 2.4 A. A die head was employed allowing for producing cylindrical strands having a diameter of 1.7 mm. At the die head out outlet, the strands were not subjected to a cutting to length. The strands thus obtained were dried for 16 h at 120? C. in a drying chamber under air. In total (sum of the 22 batches), 97.1 kg white strands with a diameter of 1.7 mm were obtained. 65.5 kg of the dried strands were subjected to calcination in a rotary furnace at 550? C. for 1 h under air, yielding 62.2 kg calcined strands. Thereafter, the strands were sieved (mesh size 1.5 mm), and the yield, after sieving, was 57.7 kg.

(24) Characterization of the Strands Obtained:

(25) The thus obtained moldings exhibited a bulk density of 322 g/l (gram per liter) and had a Zn content of 1.2 wt. %, a Ti content of 1.4 wt. %, a Si content of 43 wt. %, and a C content of 0.13 wt. %. The sodium (Na) content was 0.07 wt. %. The mesopores of the micropowder had an average pore diameter (4V/A) of 20.1 nm as determined by Hg porosimetry according to DIN 66133. The macropores of the micropowder had an average pore diameter (4V/A) of 46.8 nm as determined by Hg porosimetry according to DIN 66133. The degree of crystallization determined via XRD was 74+/?%, the average crystallite size 38.0 nm+/?10%. The Langmuir surface are determined via nitrogen adsorption at 77 K according to DIN 66131 was 499 m.sup.2/g, the mulitpoint BET specific surface area determined via nitrogen adsorption at 77 K according to DIN 66131 was 361 m.sup.2/g. The total intrusion volume (please explain) determined according to Hg porosimetry according to DIN 66133 was 1.2 ml/g (milliliter/gram), the respective total pore area 92.2 m.sup.2/g.

(26) 1.7 Post-Treatment of the Molding

(27) Starting from the calcined strands obtained according to section 1.6, a post-treatment stage was performed as follows: 590 kg deioinized water were filled in a vessel. Then, 29.5 kg of the calcined moldings obtained according to Example 2 were added. The vessel was closed (pressure-tight), and the obtained mixture was heated to a temperature of 145? C. within 1.5 h and kept at this temperature under autogenous pressure (about 3 bar) for 8 h. Then, the mixture was cooled for 2 h. The water-treated strands were subjected to filtration and washed with deionized water. The obtained strands were heated in a drying chamber under air within 1 h to a temperature of 120? C. and kept at this temperature for 16 h. Subsequently, the dried material was heated under air to a temperature of 450? C. within 5.5 h and kept at this temperature for 2 h. Thereafter, the strands were sieved (mesh size 1.5 mm), and the yield, after sieving, was 27.5 kg.

(28) Characterization of the Strands Obtained:

(29) The thus obtained water-treated moldings exhibited a bulk density of 340 g/l (gram per liter) and had a Zn content of 1.3 wt. %, a Ti content of 1.4 wt. %, a Si content of 43 wt. %, and a C content of 0.10 wt. %. The mesopores of the micropowder had an average pore diameter (4V/A) of 20.2 nm as determined by Hg porosimetry according to DIN 66133. Thus, the inventive water treatment has practically no influence on the mesopore characteristics of the molding (cf. the molding as described above, having a respective average pore diameter of 20.1 nm). The macropores of the micropowder had an average pore diameter (4V/A) of 45.9 nm as determined by Hg porosimetry according to DIN 66133.Thus, the inventive water treatment has practically no influence on the macropore characteristics of the molding (cf. the molding as described above, having a respective average pore diameter of 46.8 nm). The degree of crystallization determined via XRD was 64%+/?10%, the average crystallite size 39.4 nm+/?10%. The Langmuir surface are determined via nitrogen adsorption at 77 K according to DIN 66131 was 418.1 m.sup.2/g, the multipoint BET specific surface area determined via nitrogen adsorption at 77 K according t DIN 66131 was 299.8 m.sup.2/g. The total intrusion volume determined according to Hg porosimetry according to DIN 66133 was 1.1322 ml/g (milliliter/gram), the respective total pore area 92.703 m.sup.2/g.

Reference Example 2

Production of Propylene Oxide at Large Scale Using the ZnTiMWW Catalyst

(30) An epoxidation of propene to propylene oxide using the ZnTiMWW catalyst obtained as described in Reference Example 1 was carried as described in Reference Example 3. The aqueous hydrogen peroxide feed was admixed with 390 micromol K.sub.2PO.sub.4 additive per 1 mol H.sub.2O.sub.2 to the stream (3). The reaction was further carried out under the condition that the conversion rate of hydrogen peroxide was at least 91% at all times, which required the reaction temperature to be gradually increased.

(31) Here, to compensate for the activity loss of the ZnTiMWW catalyst the initial water cooling temperature, i.e. the reaction temperature, of 30? C. was gradually increased to 55? C. while performing the reaction. The epoxidation was carried out for 2100 hours in total.

(32) After 2100 hours the ZnTiMWW catalyst was removed from the reactor tubes and 12 samples were taken for elemental analysis. A sample was taken of the catalyst located in every meter of the reactor.

(33) Samples 1 to 12 were analyzed using the Inductively Coupled Plasma (ICP) technique. FIG. 1 shows the amounts of potassium and phosphor deposited on the spent catalyst plotted as molar ratios relative to the silicon content, the latter which essentially does not change in the course of the reaction. This corresponds to approx. 0.5 to 2 weight-% potassium and approx. 0.5 to 2 weight-% phosphor relative to the total amount of catalyst. FIG. 2 shows the amounts of carbon and nitrogen deposited on the spent catalyst plotted as molar ratios relative to the silicon content.

Reference Example 3

Epoxidation Reaction Setup (Large-Scale)

(34) According to a large-scale setup, the epoxidation reaction was carried out as follows:

(35) a) Epoxidation in an Epoxidation Main Reactor (Epoxidation Unit A) The main reactor A was a vertically mounted tube-bundle reactor with 5 tubes (length of the tubes: 12 m, internal tube diameter: 38 mm), each tube being equipped with an axially placed multi-point thermocouple with 10 equally spaced measuring points encased in a suitable thermowell with a diameter of 18 mm. Each tube was charged with 17.5 kg of the ZnTiMWW catalyst moldings as prepared according to Reference Example 1, section 1.7 (post-treated moldings). Free space eventually remaining was filled with steatite spheres (diameter of 3 mm). The heat of reaction was removed by circulating a thermostatized heat transfer medium (water/glycol mixture) on the shell side in co-current to the feed. The flow rate of the heat transfer medium was adjusted so that the temperature difference between entrance and exit did not exceed 1? C. The reaction temperature referred to herein-below was defined as the temperature of the heat transfer medium entering the reactor shell. At the reactor exit, the pressure was controlled by a pressure regulator and kept constant at 20 bar. The reactor was fed from below with a liquid monophasic stream (1). Stream 1 was prepared by mixing three streams (2), (3), and (4). The temperature of stream (1) was not actively controlled, but was usually in the range from 20 to 40? C.: Stream (2) having a flow rate of 85 kg/h. At least 99.5 weight-% of stream (2) consisted of acetonitrile, propene and water. This stream (2) came from the bottoms of the acetonitrile recycle distillation unit (J). Stream (3) having a flow rate of 15 kg/h was an aqueous hydrogen peroxide solution having a hydrogen peroxide concentration of 40 weight-% (crude/washed grade from Solvay with a TOC in the range of 100 to 400 mg/kg. The aqueous hydrogen peroxide solution was supplied from a storage tank, allowing for a continuous feeding, and fed using a suitable metering pump. Stream (4) was a make-up stream of pure acetonitrile (chemical grade, from Ineos, purity about 99.9%, containing between 70-180 weight-ppm propionitrile, 5-20 weight-ppm acetamide and less than 100 weight-ppm water as impurities). Enough fresh acetonitrile was added to compensate for losses in the process. Under regular conditions, an average of from 100 to 150 g/h of make-up acetonitrile were added. The output stream leaving the epoxidation unit A was sampled every 20 minutes in order to determine the hydrogen peroxide concentration using the titanyl sulfate method and to calculate the hydrogen peroxide conversion. The hydrogen peroxide conversion was defined as 100?(1-m.sub.out/m.sub.in) wherein m.sub.in is the molar flow rate of H.sub.2O.sub.2 in the reactor feed and m.sub.out is the molar flow rate of H.sub.2O.sub.2 in the reactor outlet. Based on the respectively obtained hydrogen peroxide conversion values, the inlet temperature of the heat transfer medium was adjusted in order to keep the hydrogen peroxide conversion essentially constant in the range of from 90 to 92%. The inlet temperature of the heat transfer medium was set at 30? C. at the start of a given run with a fresh batch of the epoxidation catalyst and was increased, if necessary, to maintain the hydrogen peroxide conversion in the mentioned range. The required temperature increase was usually less than 1? C./d. b) Intermediate Removal of Propylene Oxide (Distillation Unit B) After pressure release, the effluent from the epoxidation unit A (stream (5)) was sent to an intermediate propylene oxide removing column (distillation unit B) operated at about 1.1 bar. The column was 6 m high, had a diameter of 200 mm and was equipped with 30 bubble trays, an evaporator, and a condenser. The feed to the column entered above bubble tray 25 (counted from the top). The overhead stream leaving the column with about 50? C. mainly contained propylene oxide, unconverted propene and small amounts of oxygen formed as byproduct. This stream was partly condensed (T=15-25? C.), and the condensed liquid served as an internal reflux stream whereas the gaseous part (stream (6)) was sent to the lights separation column (distillation unit D). The bottoms temperature of the intermediate propylene oxide removal column was about 80? C. The bottoms stream (stream (7)) was almost free of propylene oxide (<300 wt.-ppm) and was a mixture of acetonitrile (about 78-80 weight-%), water (about 18-20 weight-%), unconverted hydrogen epoxide and heavy boilers having a normal boiling point of above 100? C., the main heavy boiler being propene glycol. This bottoms stream (7) was subsequently cooled to 35? C. and pumped pump to the finishing reactor (epoxidation unit C; see section c) below) using a suitable metering pump. c) Epoxidation in a Finishing Reactor (Epoxidation Unit C) The total feed stream to the finishing reactor C was obtained by mixing stream (7) obtained according to section b) above with a stream (8) of polymer grade liquid propene containing propane (purity?about 99.5%, feed rate: 0.9 kg/h, at ambient temperature). Both streams (7) and (8) were mixed using a static mixer and fed to the bottom of the finishing reactor C. The finishing reactor C was a fixed bed reactor operated adiabatically. In this context, the term adiabatic refers to an operation mode according to which no active cooling is carried out and according to which the finishing reactor is suitably insulated in order to minimize heat losses). The finishing reactor C had a length of 4 m and a diameter of 100 mm. The reactor was filled with 9 kg of the same epoxidation catalyst which was used in the main epoxidation reactor A. Spare space was filled with steatite spheres (diameter of 3 mm). The operating pressure of the finishing reactor C was 10 bar which was kept constant by a suitable pressure regulator at the reactor exit. The output of the finishing reactor C was sampled every 20 min in order to determine the hydrogen peroxide concentration using the titanyl sulfate method. The effluent of the finishing reactor C, stream (9), was depressurized into a flash drum, and both the liquid and the gas from this drum were fed to a light boiler separation column (distillation unit D). The stream (6) obtained from the top of the intermediate propylene oxide removing column (distillation unit B) and the stream (9) obtained as effluent from the finishing reactor C (epoxidation unit C) together constitute the effluent stream of the epoxidation reaction.

Reference Example 4

Epoxidation Reaction Setup (Micro-Plant)

(36) A tubular reactor (length: 1.4 m, internal diameter: 7 mm) equipped with a jacket for thermostatization was charged with 15 g of the desired catalyst in the form of strands with a diameter of 1.5 mm as described in the examples below. The remaining reactor volume was filled with inert material (steatite spheres, 2 mm in diameter, to a height of ca. 5 cm at the lower end of the reactor and the remainder at the top end of the reactor). The reactor was thermostatized by flowing a heat transfer medium (a mixture of water and ethylene glycol) through the jacket. The heat transfer medium is fed at the lower end of the jacket so that it flows in cocurrent to the reactor contents. The temperature of the heat transfer medium at the entrance of the jacket is defined as being the reaction temperature. The flow rate of the heat transfer medium is adjusted so that the difference between entrance and exit temperature is not more than 1? C. Pressure in the reactor is controlled by a suitable pressure control valve and maintained constant at 20 bar (abs).

(37) The reactor feed stream is combined from three separate feed streams, that are metered by using separate metering pumps. The first stream consists of acetonitrile (flow rate: 68 g/h). The second stream consists of liquefied polymer grade propylene (flow rate: 11 g/h) and the third stream consists of an aqueous hydrogen peroxide solution with a concentration of 40 wt.-% (flow rate: 17 g/h). The potassium salt additive used in the experiments was dissolved in the hydrogen peroxide solution. The three feed streams were premixed before they were fed at ambient temperature to the bottom of the tubular reactor. Under the conditions used the feed is liquid and only one liquid phase is present.

(38) The experiments were performed in a continuous manner. At the start of the run (t=0 is defined at which the H.sub.2O.sub.2 metering pump is started) the reaction temperature was set to 30? C. With a fresh catalyst this results initially in a 100% conversion of hydrogen peroxide. After a certain period of time (usually within 100 hours on stream) the hydrogen peroxide conversion starts to fall. The temperature is then adjusted (usually once to twice a day is sufficient) in order to keep the hydrogen peroxide conversion between 85 and 95%. During most of the time on stream the conversion remains between 88 and 92%. The reactor effluent after the pressure control valve was collected, weighed and analyzed.

(39) Organic components (with the exception of hydroperoxypropanols) and O.sub.2 were analyzed in two separate gas-chromatographs. The hydrogen peroxide was determined colorimetrically using the titanyl sulfate method. The content of hydroperoxypropanols (a mixture of 1-hydroperoxypropanol-2 and 2-hydroperoxypropanol-1) was determined by measuring the total peroxide content (iodometrically) and then subtracting the hydrogen peroxide content. Additionally the hydroperoxypropanol concentration can also be cross checked by determining the amount of propylene glycol before and after reduction with an excess of triphenylphosphane. The difference between the two values gives the amount of hydroperoxypropanols present in the unreduced sample.

(40) The selectivity for propylene oxide given is relative to H.sub.2O.sub.2 and was calculated as 100 times the ratio of moles of propylene oxide in the reactor effluent divided by the sum of moles of propylene oxide plus propylene glycol plus twice the moles of hydroperoxypropanols and twice the moles of O.sub.2 (the factor two reflects the stoichiometry of the reactions leading to these products: 2 H.sub.2O.sub.2.fwdarw.2H.sub.2O+O.sub.2 and Propylene+2 H.sub.2O.sub.2.fwdarw.hydroperoxypropanol+H.sub.2O).

Comparative Example 1

Conventional Regeneration of the Zn TiMWW Catalyst

(41) Spent ZnTi-MWW catalyst of fractions 1 to 3 of Reference Example 2 was regenerated by submitting to a thermal treatment. Specifically, 30 g of the spent catalyst were transferred into an oven. The ZnTiMWW catalyst was contacted with nitrogen at a temperature of 120? C. to remove volatile reaction compounds after which the ZnTiMWW catalyst was calcinated in an oven in air at 450? C. for 5 hours.

Comparative Example 2

Catalytic Performance of Conventionally Regenerated ZnTiMWW Catalyst

(42) Following the regeneration according to Comparative Example 1, the catalytic performance of the regeneration ZnTiMWW catalyst was compared with the catalytic performance of fresh ZnTiMWW catalyst.

(43) Two separate epoxidation reactions were performed according to the setup as described in Reference Example 3 using 15 g fresh ZnTiMWW catalyst and with 15 g conventionally regenerated ZnTiMMW catalyst, respectively, at otherwise identical reaction conditions.

(44) The epoxidation using fresh ZnTiMWW catalyst was terminated after 405 hours, whereas the epoxidation using the conventionally regenerated ZnTiMWW catalyst was terminated after 500 hours. The reaction temperatures (i.e. cooling water temperatures) were adjusted in each experiment so that at all times the conversion rate of hydrogen peroxide was at least 91%.

(45) In FIG. 3, the selectivity based on hydrogen peroxide, the selectivity based on propene (C3), the conversion rate based on hydrogen peroxide and the reaction temperature required to maintain a conversion rate for hydrogen peroxide of at least 91% of the fresh ZnTiMWW catalyst and the conventionally regenerated ZnTiMWW were compared. The amounts of products obtained and the amount of educt converted were determined by gas chromatography.

(46) For the fresh ZnTiMWW catalyst, the reaction temperature could be kept at 35? C. for most of the reaction time to maintain a conversion rate based on hydrogen peroxide of at least 91%. Also, the selectivities based on hydrogen peroxide and propene remained above 98% during the time period the epoxidation was performed with fresh ZnTiMWW catalyst.

(47) The ZnTiMWW catalyst regenerated conventionally as described in Comparative Example 1 required a significant increase of the reaction temperature to up to 64? C. to maintain a conversion rate based on hydrogen peroxide of at least 91%. While the selectivity based on propene also remained above 98% similar to the fresh ZnTiMWW catalyst, the selectivity based on hydrogen peroxide dropped to 94% after 400 hours when using the ZnTiMWW catalyst regenerated by heating only.

Example 1

One-Time ZnTiMWW Catalyst Regeneration According to the Invention

(48) Two separate regenerations according to the invention were performed at two different washing temperatures. A regeneration was performed by washing the catalyst at 50? C. and another regeneration was performed by washing the catalyst at 70? C. For each experiment, 40 g spent ZnTiMWW catalyst from fractions 1 to 3 of Example 1 were used.

(49) The washing of the ZnTiMWW catalyst was performed in both experiments using a water cooled double mantle glass tube as reactor with a length of 1 m and an inner diameter of 20 mm. The water temperatures were controlled by a thermostat to keep the temperature constant during the respective washing procedure. The water was introduced into the reactor mantle via a pump with a flow rate of 4 ml/min (corresponding to a WHSV of 7 h.sup.?1) in upflow.

(50) At 50? C., the washing was performed for 420 min. At 70? C., the washing was performed 410 min. In both experiments, the washing was performed until the conductivity of the washing water leaving the reactor at the top was determined to be approx. 200 microSiemens/cm. The conductivity was determined using a conductometer (WTW, LF320) with a standard conductivity measuring cell (Tetra Con 325).

(51) Following the washing, the ZnTiMWW catalyst was dried in both experiments in the double mantle glass reactor in a nitrogen gas stream of 100 l/h at 40? C. for 16 hours, after which the ZnTiMWW catalyst was removed from the reactor and calcinated in an oven at 450? C. in air for 5 hours.

(52) After the regenerations of the ZnTiMWW catalyst at 50? C. and 70? C., the individual compositions were determined by elemental analysis. The elemental analysis was performed as indicated in Reference Example 2 and the results obtained are summarized in Table 1 below.

(53) TABLE-US-00001 TABLE 1 Results of Example 1 Washing at 50? C. Washing at 70? C. no. time/min K/g P/g Si/g Ti/g Zn/g time/min K/g P/g Si/g Ti/g Zn/g 1 0 0.34 0.27 13.5 0.45 0.41 0 0.34 0.27 13.5 0.45 0.41 2 180 0.14 0.11 0.04 0.006 0.008 170 0.20 0.14 0.06 0.005 0.010 3 300 0.04 0.03 0.03 0.003 0.005 290 0.05 0.02 0.04 <0.004 <0.004 4 420 0.03 0.01 0.02 0.002 0.004 410 0.03 0.01 0.03 <0.004 <0.004 5 residual wash 0.01 <0.01 <0.01 <0.001 0.001 residual wash 0.01 <0.01 0.03 <0.004 <0.004 6 calcinated 0.13 0.11 13.2 0.43 0.37 calcinated 0.06 0.09 13.2 0.39 0.36 In row no. 1, the amounts in g of the compounds K, P, Si, Ti and Zn in 40 g total amount of ZnTiMWW catalyst before the regeneration are given. In rows no. 2 to 4 the total amounts in g of the compounds K, P, Si, Ti and Zn in the collected wash water within different time periods are indicated (row no. 2: 0 to 180 min; row no. 3: 181 to 300 min; row no. 4: 301 to 420 min). The small losses of Si, Ti and Zn observed during washing are believed to be attributed to small fines formation. In row no. 5, the total amounts in g of these compounds in the residual water removed from the glass tube reactor after finished wash are given. In row no. 6, the total amounts in g of said compounds in the ZnTiMWW catalyst following the completed regeneration, i.e. washing, drying and calcining, are indicated.

(54) Consequently, after approx. 7 hours washing, followed by drying and calcining, the total amounts of K and P have been both reduced favorably by approx. 60% by washing at 50? C. and even more favorably by approx. 82% and 67%, respectively, by washing at 70? C.

(55) At both temperatures the removal of the deposits is satisfactory. However, it is evident that by washing at 70? C. potassium and phosphor deposited on the ZnTiMWW catalyst may be removed faster and more thoroughly.

Example 2

Repeated ZnTiMWW Catalyst Regeneration Performed According to the Invention

(56) 34.3 g spent ZnTiMWW of fractions 1 to 3 of Reference Example 2 were submitted to 5 subsequent regenerations as described in Example 1.

(57) The washing was performed each time at 70? C. After each cycle the exact ZnTiMWW catalyst composition and further properties, specifically, its surface, pore volume, crushing strength were determined. Further, a propylene oxide (PO) test was performed which is an indicator for the catalytic activity of the ZnTiMWW catalyst.

(58) The total amounts of K, P, Ti, Zn and Si of the ZnTiMWW catalyst were determined as described in Example 1 by elemental analysis.

(59) The Langmuir surface area was determined via nitrogen adsorption at 77 K according to DIN 66131. The pore volume was determined according to Hg porosimetry according to DIN 66133.

(60) 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 f?r die Material-Pr?fmaschine Z2.5/TS1S, version 1.5, December 2001 by Zwick GmbH & Co. Technische Dokumentation, August-Nagel-Strasse 11, D-89079 Ulm, Germany. The title page of the instructions handbook is shown in FIG. 9. With said machine, a ZnTiMWW catalyst pellet 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.

(61) In a PO test (propylene oxide test), the ZnTiMWW catalyst regenerated according to the process of the present invention is tested in a mini autoclave by reaction of propene with an aqueous hydrogen peroxide solution (30 wt.-%) to yield propylene oxide. In particular, 0.63 g of the ZnTiMWW catalyst are introduced together with 79.2 g of acetonitrile and 12.4 g of propene at room temperature, and 22.1 g of hydrogen peroxide (30 wt.-% in water) are introduced in a steel autoclave. After a reaction time of 4 hours at 40? C., the mixture was cooled and depressurized, 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 wt.-%) is the result of the PO test.

(62) The results are summarized in Table 2 below.

(63) TABLE-US-00002 TABLE 2 Results of Example 2 Langmuir pore crush PO K/ P/ Zn/ Ti/ Si/ Surface/ volume/ strength/ yield/ Cycle wt.-% wt.-% wt.-% wt.-% wt.-% m.sup.2/g ml/g N wt.-% Fresh 0 0 1.3 1.4 43 418 1.1 13 8.8 Catalyst Spent 1.10 0.78 1.2 1.3 40 n.d.* n.d. n.d. n.d. catalyst 1 0.22 0.30 1.2 1.3 42 412 1.3 n.d. 8.8 2 0.16 0.25 1.2 1.4 42 403 1.2 14 n.d. 3 0.08 0.19 1.2 1.4 42 414 1.4 13 n.d. 4 0.05 0.15 1.2 1.4 42 373 1.3 12 n.d. 5 0.02 0.11 1.2 1.4 42 416 1.4 13 8.3 n.d.*not determined

(64) The results in Table 2 show that the amounts of potassium and phosphor deposits may be further reduced when performing the regeneration process of the present invention subsequently several times.

(65) From Table 2 it becomes also evident that the Zn, Ti and Si contents of the ZnTiMWW catalyst did not change over a process comprising five regeneration cycles compared with the fresh ZnTiMWW catalyst. The slight variations determined are considered to be within the error of measurement.

(66) Further, Table 2 also shows that the Langmuir surface, the pore volume and the crushing strength of the ZnTiMWW catalyst did not change during the repeated regeneration process relative to fresh ZnTiMWW catalyst. Equally, the variations observed for the values determined are considered to be within the error of measurement.

(67) The PO test also showed that the yield of the repeatedly regenerated ZnTiMWW catalyst did not change significantly after five regeneration cycles.

(68) In addition, an IR spectrum of fresh ZnTiMWW catalyst shown in FIG. 4 may be compared with the IR spectrum recorded with the five times regenerated ZnTiMWW catalyst in FIG. 5. The spectra are largely identical except the band visible at approx. 3500 cm.sup.?1 in the spectrum of the regenerated ZnTiMWW catalyst. This is an indicator for a decrease of internal silanol nests following regeneration. However, such an alteration does not have an impact on the activity of a zeolitic catalyst as confirmed by the results summarized in Table 2.

(69) In summary, these results indicate consistently that the present process for the regeneration of a catalyst comprising a titanium zeolite as active material, is sufficiently effective, so that the catalytic activity original activity is restored, without even following several regeneration cycles the catalyst is not altered structurally in a significant way.

Example 3

Catalytic Performance of the Multiply Regenerated Catalyst According to the Invention

(70) Following the multiple regeneration according to Example 2, the catalytic performance of the regeneration ZnTiMWW catalyst was compared with the catalytic performance of fresh ZnTiMWW catalyst.

(71) Two separate epoxidation reactions were performed in a micro-plant with 15 g fresh ZnTiMWW catalyst and with 15 g multiply regenerated ZnTiMMW catalyst, respectively, at otherwise identical reaction conditions.

(72) The micro-plant comprised water cooled reactor tubes of 1.4 m length and an internal diameter of 7 mm. The feeds introduced in upflow were in each case 68 g/h ACN, 16 g/h H.sub.2O.sub.2 (40 weight-% in water), 10.8 g/h propene and a concentration of 130 micromol KH.sub.2PO.sub.4 per 1 mol H.sub.2O.sub.2was used. The epoxidation using fresh ZnTiMWW catalyst was terminated after 500 hours, whereas the epoxidation using the multiply regenerated ZnTiMWW catalyst was terminated after 310 hours. The reaction temperatures (i.e. cooling water temperatures) adjusted in each experiment so that at all times the conversion rate of hydrogen peroxide was at least 91%.

(73) In FIG. 6, the selectivity based on hydrogen peroxide, the selectivity based on propene, the conversion rate based on hydrogen peroxide and the reaction temperatures (i.e. cooling water temperatures) required to maintain a conversion rate of at least 91% obtained with fresh and multiply regenerated catalyst, respectively, are compared. The selectivities and the conversion rates were determined as indicated in Comparative Example 2 by gas chromatography.

(74) It is immediately evident that the reaction temperatures required to maintain the hydrogen peroxide conversion rate above 91% are favorably essentially identical when comparing the fresh ZnTiMWW catalyst and the five times regenerated ZnTiMWW catalyst. In both cases the conversion rate at approx. 45? C. remained well above 91%, with the exception of an outlier just below 90? C. after approx. 255 h observed for the multiply regenerated ZnTiMWW catalyst.

(75) Also, the selectivities based both on hydrogen peroxide and on propene remained essentially unchanged displaying a favorably high value of approx. 99% in the course of the epoxidation reaction when comparing ZnTiMWW catalyst regenerated five times according to the invention with fresh ZnTiMWW catalyst.

Example 4

In Situ Regeneration of Spent ZnTiMWW Catalyst According to the Invention

(76) A regeneration according to the present invention was performed on the ZnTiMWW catalyst inside the reactor used for epoxidation in Reference Example 2.

(77) Spent ZnTiMWW catalyst was washed in the 12 m reactor tubes with water at a flow rate of 130 l/h at 60? C. for 17.7 hours, followed by a wash with water at a flow rate of 130 l/h at 75? C. for 4.5 hours. The water was introduced in downflow at the top of the reactor tubes.

(78) Subsequently, the ZnTiMWW catalyst was dried in the reactor in a nitrogen gas stream also introduced at the bottom of the reactor tubes. The nitrogen was introduced with a flow rate of 12 m.sup.3/h at a temperature of 60? C. for 96 hours, followed by an introduction of nitrogen at a flow rate of 14 m.sup.3/h at 65? C. for 1 h, further followed by an introduction of nitrogen at a flow rate of 13 m.sup.3/h at 70? C. for 354.5 h. At the end of the drying step, the humidity of the nitrogen leaving the reactor as determined using a humidity sensor (GE, HygroPro) was 243 ppmV which corresponds to the humidity of the nitrogen gas before introduction in the reactor.

(79) Following the completed drying step, the catalyst was calcinated in the reactor for 6.5 hours at 450? C., wherein the calcining temperature was increased gradually with a rate of 0.5? C./minute.

(80) The properties of the catalyst following the regeneration when reused in an epoxidation procedure were similar to the results obtained in the Examples 1 and 3.

Reference Example 5

Characterization of the Catalyst

Reference Example 5.1

Determination of Dv10, Dv50, and Dv90 Values

(81) 1.0 g of the micropowder is suspended in 100 g deionized water and stirred for 1 min. The sample was subjected to the measurement in an apparatus using the following parameters: Master-sizer S long bed version 2.15, ser. No. 33544-325; supplier: Malvern Instruments GmbH, Herrenberg, Germany: focal width 300RF mm; beam length 10.00 mm; module MS17; shadowing 16.9%; dispersion model 3$$D; analysis model polydisperse correction none.

Reference Example 5.2

Determination of the Silanol Concentration of the Moldings of the Present Invention

(82) For the determination of the silanol concentration, the .sup.29Si MAS NMR experiments were carried out at room temperature on a VARIAN Infinityplus-400 spectrometer using 5.0 mm ZrO.sub.2 rotors. The .sup.29Si MAS NMR spectra were collected at 79.5 MHz using a 1.9 ?s ?/4 (microsecond pi/4) pulse with 10 s recycle delay and 4000 scans. All .sup.29Si spectra were recorded on samples spun at 6 kHz, and chemical shifts were referenced to 4,4-dimethyl-4-silapentane sulfonate sodium (DSS). For the determination of the silanol group concentration, a given .sup.29Si MAS NMR spectrum is deconvolved by the proper Gaussian-Lorentzian line shapes. The concentration of the silanol groups with respect to the total number of Si atoms is obtained by integrating the deconvolved .sup.29Si MAS NMR spectra.

Reference Example 5.3

Determination of the Crush Strength of the Moldings

(83) 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 f?r die Material-Pr?fmaschine 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 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 5.4

29Si Solid-State NMR Spectra Regarding Q3 and Q4 Structures

(84) The effect of the inventive water treatment on the molding related to Q.sup.3 and Q.sup.4 structures in the material was characterized by comparing the changes in .sup.29Si solid-state NMR spectra under comparable conditions. All .sup.29Si solid-state NMR experiments were performed using a Bruker Advance spectrometer with 300 MHz.sup.1H Larmor frequency (Bruker Biospin, Germany). Samples were packed in 7 mm ZrO.sub.2 rotors, and measured under 5 kHz Magic Angle Spinning at room temperature. .sup.29Si direct polarization spectra were obtained using (pi/2)-pulse excitation with 5 microsecond pulse width, a .sup.29Si carrier frequency corresponding to ?65 ppm in the spectrum, and a scan recycle delay of 120 s. Signal was acquired for 25 ms under 45 kHz high-power proton decoupling, and accumulated over 10 to 17 hours. Spectra were processed using Bruker Topspin with 30 Hz exponential line broadening, manual phasing, and manual baseline correction over the full spectrum width. Spectra were referenced with the polymer Q8M8 as an external secondary standard, setting the resonance of the trimethylsilyl M group to 12.5 ppm. The spectra were then fitted with a set of Gaussian line shapes, according to the number of discernable resonances. Relating to the presently assessed spectra, 6 lines in total were used, accounting for the five distinct peak maxima (at approximately ?118, ?115, ?113, ?110 and ?104 ppm) plus the clearly visible shoulder at ?98 ppm. Fitting was performed using DMFit (Massiot et al., Magnetic Resonance in Chemistry, 40 (2002) pp 70-76). Peaks were manually set at the visible peak maxima or shoulder. Both peak position and line width were then left unrestrained, i.e., fit peaks were not fixed at a certain position. The fitting outcome was numerically stable, i.e., distortions in the initial fit setup as described above did lead to similar results. The fitted peak areas were further used normalized as done by DMFit. After the water treatment of the invention, a decrease of signal intensity at the left hand side of the spectrum was observed, a region that includes Q.sup.3 silanol structures (here especially: around and above ?104 ppm, i.e. left of ?104 ppm). Further, an increase of signal at the right hand side of the spectrum (here: below ?110 ppm, i.e. right of ?110 ppm) was observed, which region comprises Q.sup.4 structures exclusively. For the quantification of spectrum changes, a ratio was calculated that reflects changes in the peak areas left hand and right hand, as follows. The six peaks were labeled with 1, 2, 3, 4, 5, and 6, and the ratio Q was calculated with the formula 100*{[a.sub.1+a.sub.2]/[a.sub.4+a.sub.5+a.sub.6]}/a.sub.3. In this formula, a.sub.i,i=1.6 represents the area of the fitted peak to which this number was attributed.

Reference Example 5.5

Water Adsorption/Desorption-Water Uptake

(85) The water adsorption/desorption isotherms measurements 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 were 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 N.sub.2 flow. After the drying program, the temperature in the cell was decreased to 25? C. and kept isothermal during the measurements. The microbalance was calibrated, and the weight of the dried sample was balanced (maximum mass deviation 0.01 wt. %). Water uptake by the sample was measured as the increase in weight over that of the dry sample. First, an adsorption curve was measured by increasing the relative humidity (RH) (expressed as weight-% water in the atmosphere inside of the cell) to which the samples was exposed and measuring the water uptake by the sample at equilibrium. The RH was increased with a step of 10 wt. % from 5 to 85% and at each step the system controlled the RH and monitored the sample weight until reaching the equilibrium conditions and recording the weight up-take. The total adsorbed water amount by the sample was taken after the sample was exposed to the 85 weight-% RH. During the desorption measurement the RH was decreased from 85 wt. % to 5 wt. % with a step of 10% and the change in the weight of the sample (water uptake) was monitored and recorded.

Reference Example 5.6

FT-IR Measurements

(86) The FT-IR (Fourier-Transformed-Infrared) measurements were performed on a Nicolet 6700 spectrometer. The molding was powdered and then 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 region were analyzed and for comparing multiple samples, as reference the band at 1880?5 cm.sup.?1 was taken.

Reference Example 5.7

Determination of Crystallinity Via XRD

(87) The crystallinity of the zeolitic materials according to the present invention were determined by XRD analysis. The data were collected using a standard Bragg-Brentano diffractometer with a Cu-X-ray source and an energy dispersive point detector. The angular range of 2? to 70? (2 theta) was scanned with a step size of 0.02?, while the variable divergence slit was set to a constant illuminated sample length of 20 mm.

(88) The data were then analyzed using TOPAS V4 software, wherein the sharp diffraction peaks were modeled using a Pawley fit containing a unit cell with the following starting parameters: a=14.4 Angstrom (1 Angstrom=10.sup.?10 m) and c=25.2 Angstrom in the space group P6/mmm. These were refined to fit the data. Independent peaks were inserted at the following positions. 8.4?, 22.4?, 28.2? and 43?. These were used to describe the amorphous content. The crystalline content describes the intensity of the crystalline signal to the total scattered intensity. Included in the model were also a linear background, Lorentz and polarization corrections, lattice parameters, space group and crystallite size.

CITED LITERATURE

(89) WO-A 98/55229 WO-A 2011/064191 EP-A 0 934 116 EP-A 0 790 07 EP-A 1 371 414 EP-A 1 221 442 WO-A 2005/000827 WO-A 2007/013739 EP-A 1 122 249 US 2003/0187284 A1 US 2012/142950 A1 WO 2011/115234 A1 US 2004/058798 A1 U.S. Pat. No. 5,916,835 A