CZ18596A3 - PROCESS FOR PRODUCING Ti-, V- OR Zr- BETA ZEOLITE AND ZEOLITE PRODUCED IN SUCH A WAY - Google Patents

Abstract

In the manufacture of a substituted Beta zeolite, a high ethene pressure, is used advantageously accompanied by synthesis gel ageing and low aluminium content.

Description

Technical field

The present invention relates to a process for the production of zeolite, particularly a zeolite suitable for use as a catalyst, a process for the production of such a zeolite, and organic reactions, in particular by oxidation of the hydrocarbons which are thus catalysed.

BACKGROUND OF THE INVENTION

TS-1 and TS-2 containing titanium are catalysts for the oxidation of hydrocarbons with hydrogen peroxide. The disadvantage of these catalysts is that they have MFI and MEL structures whose rings are ten-membered with a diameter of the order of 0.5 nm, which limits the entry of bulky dosed molecules. For example, in the oxidation of alkanes, n-hexane reacts faster than cyclohexane, and in general, reactivity decreases in branching and molecular weight. In addition, the activity of the catalysts is high only for hydrogen peroxide, for organic hydroperoxides these catalysts are much less effective.

Quite recently, a zeolite-containing zeolite has been synthesized which is capable of effectively catalysing the oxidation of higher alkanes using hydrogen peroxide. This catalyst, β-β zeolite, has a pore diameter of about 0.75 nm and can be produced as described in J. Chem. Soc. Chem. Comm. 8, 589 (1992), using a process wherein low concentrations of aluminum are present in the synthetic composition.

Our co-pending patent application No. 93 07 910 describes a process for producing Ti-β zeolite by producing a synthetic blend containing a source of titanium -------------- (e.g. tetraethyl orthotitanate, also abbreviated as TEOT), an aluminum source (e.g., powdered aluminum), a silicon source (e.g., colloidal silica) and an organic nitrogen-containing base (especially tetraethylammonium hydroxide, also abbreviated as TEAOH), the mixture is aged, preferably in the presence of peroxide hydrogen and the aged mixture is hydrothermally treated.

The crystals formed during the hydrothermal treatment are isolated, washed, dried and calcined to remove the organic material from the structure. Conventional synthetic compositions providing Τί-β zeolite after hydrothermal treatment have an initial molar composition within the following range:

silica (1), titanium dioxide (0.0001 to 0.2), alumina (0.005 to 0.100), water (10 to 100), and tetraethylammonium hydroxide (0.1 to 1).

The preferred molar ratio of titanium to silicon to aluminum is in the range of from 10 to 200: 1. Hydrogen peroxide is preferably present in the synthetic composition, although it may decompose before or during hydrothermal treatment, preferably in a ratio of 10 to 200 moles hydrogen peroxide per mole of tetraethyl orthotitanate when used as a titanium source.

The catalyst produced by this process is activated to oxidations using organic peroxides, especially hydroperoxides, allowing the oxidation reaction to occur in a single organic phase and avoiding the use of an aqueous phase which is also present when hydrogen peroxide is used.

Although the process described above leads to the production of an active catalyst, yields in the absence of alkali cations.

in the metal are very low. In the article published by Camblor ......

et al. in Zeolites 202-210 (1991), however, it is recommended that alkali metal cations be considered essential for the formation of zeolite β alone, and therefore should not appear to cause Ti-β in this regard.

The present invention is based on the observation that when ethylene is present in contact with a synthetic Ti-, V- or Zr-β-forming mixture during hydrothermal treatment, the corresponding Ti-, V- or Zr-β-zeolite is obtained in good yields.

SUMMARY OF THE INVENTION

The present invention therefore provides, in a first aspect, a process for the production of Ti-, V- or Zr-β zeolite, wherein at least a portion of the hydrothermal treatment of the synthetic Ti-, V- or Zr-β-forming mixture is carried out in an ethylene containing atmosphere MPa and preferably at least 500 kPa at an ethylene partial pressure.

A second aspect of the invention relates to a process for the production of Ti-, V- or Zr-β zeolite, wherein at least a portion of the hydrothermal treatment of the synthetic Ti-, ν-, or Zr-β-forming mixture is carried out in the presence of at least 0.1 moles of ethylene cations. Preferably, the molar ratio of ethylene to tetraethyleneammonium is in the range of 0.1 to 1: 1.

For clarity, the remainder of the description will primarily relate to a feature of the invention wherein the product is Ti-β zeolite. It should be taken into account that for other products the same method is used mutatis mutandis. It is also to be understood that within the scope of the present invention products are produced which contain mixtures of two or more metals selected from titanium, vanadium and zirconium, as well as zeolites which contain two or more metals selected from titanium, vanadium and zirconium and a small proportion of other cations.

As a synthetic Ti-β-forming mixture, a mixture comprising a silicon source, a titanium source, an aluminum source, water and a source of tetraethylammonium cations is generally used.

Preferably, the synthetic mixture is substantially free of alkali metal cations, the term substantially free means that no more alkali metal is present than is obviously present in commercial supplies of the constituents. If alkali metal ions such as sodium or potassium ions are present, they are preferably present in a SiO ₂ : M ⁺ molar ratio corresponding to 1: (at most 0.5).

A preferred synthetic mixture has a molar composition in this range:

silica (1), titanium dioxide (0.0001 to 0.2), aluminum oxide (0.0005 to 0.1), water (10 to 100) and tetraethylammonium hydroxide (0.01 to 1).

The preferred molar ratio of titanium to silicon to aluminum is in the range of from 50 to 200: 1.

Preferred component sources are: for silicon, colloidal silica, preferably free of alkali metal cations or tetraalkylammonium ortho-silicate, for aluminum aluminum powder, and for titanium hydrolyzable titanium compound, for example TiOCl ₄ , TiOCl ₂ or tetraalkyl orthotitanate, especially tetraethyl orthotitanate. A preferred source of vanadium is vanadyl sulfate and zirconium is zirconium sulfate.

Tetraethylammonium cations are preferably supplied with tetraethyl 5 ammonium hydroxide.

preferably hydrogen peroxide is present in the synthetic composition at least for titanium. The hydrogen peroxide is preferably present in an amount of from 10 to 200 moles per mole of tetraethyl orthotitanate if it is a source of titanium.

Preferably, especially if the synthetic composition comprises hydrogen peroxide, it is aged between its formation and the hydrothermal treatment. The maturation may be carried out at room temperature or at elevated temperatures, for example from 60 to 90 ° C, preferably at a temperature of about 70 ° C, the maturation time being from 2 to 24 hours, depending indirectly on the temperature. A preferred maturation treatment comprises initially room temperature for a maturation of from 12 to 18 hours, and then maturation at elevated temperature, for example at 70 ° C, is performed for 2 to 4 hours.

The aging at elevated temperature also causes the water to evaporate from the synthetic mixture, thereby producing a synthetic gel at a concentration favorable for hydrothermal treatment. If appropriate or desired, the aged gel may be diluted prior to treatment, for example with ethanol. When ethanol is added, it is preferably present in the synthetic mixture subjected to hydrothermal treatment in an amount of at most 2 moles per mole of silica.

The synthetic mixture, preferably matured, is preferably subjected to a hydrothermal treatment at a temperature in the range of from 120 to 200 ° C, preferably from 130 to 150 ° C, under a pressure arrangement as described above, preferably for a period of from 1 hour to 30 ° C. days, preferably from 6 to 15 days, until crystals are formed. The hydrothermal treatment is preferably carried out in an autoclave. ''

While not wishing to be bound by theory, it is believed that under conditions prevailing in hydrothermal treatment, tetraethylammonium ions decompose and are unusable to produce a template effect in the zeolite formation. When carried out in the presence of ethylene, the decomposition product causes the decomposition reaction equilibrium to be shifted and more teraethylammonium ions remain usable to act as templates.

In another embodiment, wherein at least a portion of the hydrothermal treatment is carried out in the presence of ethylene, a higher zeolite yield may be achieved or a lower proportion of teraethylammonium ions in the synthetic composition may be present. Preferably, ethylene is present in the reaction vessel from the start of the hydrothermal treatment.

Preferably, the ethylene partial pressure is at least 500 kPa, preferably at least 2.0 MPa, and most preferably at least 3.0 MPa, at least during part of the hydrothermal treatment period. It is also preferred that the total pressure is at least 3.0 MPa and preferably is at least 4.0 MPa. The ethylene partial pressure is preferably at least 80%, preferably at least 90% of the total pressure.

After crystallization occurs, the synthetic mixture is cooled and the crystals are separated from the mother liquors, washed and dried.

In order to eliminate the organic base from the crystals, they are preferably heated to a temperature of from 200 to 600 ° C, preferably to a temperature of about 550 ° C, in air for 1 to 72 hours, preferably about 12 hours.

The resulting calcined product may either be used as such or subjected to further treatment, for example with an acid such as hydrochloric acid, or with a base, such as ammonium or sodium ions. The product may be post-processed, such as by steam treatment.

The β-β zeolite produced by the process of the present invention can be highly crystalline and exhibits infrared absorption at about 960 cm ^-1 and an absorption band at diffuse spectroscopy at 47,500 cm ^-1 . Diffuse reflectance spectroscopy is described in Chapter 4 Characterization of Heterogeneous Catalysts in Chemical Industries, Vol. 15, published by Manel Dekker Inc, New York, in 1984. The system used is shown in Figure 3 in this chapter and obtained using a Cary 5 spectrometer.

The zeolite produced by the process of the present invention is an active oxidation catalyst, particularly for reactions utilizing peroxide as an oxidizing agent, including organic peroxides, including hydroperoxides as well as hydrogen peroxide. Compared to TS-1 and TS-2 catalysts, Ti-β zeolite is more effective in oxidizing larger molecules, such as cycloalkanes and cycloalkenes. The use of organic hydroperoxides avoids the two-phase system necessarily associated with aqueous hydrogen peroxide.

Industrial applicability

The present invention therefore also provides the use of the product obtained by the process of the present invention as a catalyst for the oxidation of organic compounds, especially in a single phase wherein the oxidation is carried out with organic peroxide.

The catalyst of the invention is effective in oxidizing saturated hydrocarbons such as alkanes and cycloalkanes, and alkyl substituents in alkylaromatic hydrocarbons. In cycloalkanes, ring opening and acid formation can occur. For example, adipic acid is produced in the cyclohexane oxidation with tertiary butyl peroxide or hydrogen peroxide, and glutaric acid is produced in the cyclopentane oxidation. The catalyst is also effective in epoxidizing unsaturated hydrocarbons such as olefins and dienes and producing glycol ethers and diols, oxidizing alcohols, ketones or aldehydes to acids, and hydroxylating aromatic compounds.

In the oxidation process of the present invention, the oxidizing agent may be, for example, ozone, nitrous oxide, or preferably hydrogen peroxide or an organic peroxide including hydroperoxides. Examples of suitable organic hydroperoxides include diisopropylbenzene monohydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, cyclohexyl hydroperoxide, ethylbenzene hydroperoxide, tert-amyl hydroperoxide and tetralin hydroperoxide. Preferably, the compound to be oxidized is a liquid or is in a dense phase under the conditions used for the reaction. The reaction is preferably carried out in the presence of a suitable solvent.

The use of tertiary butyl hydroperoxide is particularly advantageous since the tert-butyl alcohol produced can be converted to a valuable isobutylene molecule.

The oxidation reaction can be carried out under batch conditions or on a solid bed, and the use of a heterogeneous catalyst facilitates a continuous reaction in a single-phase or two-phase system. The catalyst is stable under the reaction conditions and can be recovered and reused.

DETAILED DESCRIPTION OF THE INVENTION

The following examples illustrate the invention.

Example 1

Mixture A is prepared by dropping 3.4 ml of tetraethyl orthotitanate into 63.39 ml of distilled water.

The mixture was cooled to 5 ° C and 39 ml hydrogen peroxide (35% in water) was added. The resulting mixture was stirred at 5 ° C for 2 hours to give a clear yellow-orange liquid.

Mixture B was prepared by adding 0.0312 g of aluminum powder to 28.71 g of tetraethylammonium hydroxide (40% in water) and dissolving by heating to 90 ° C. After cooling, 31 ml of distilled water were added to the reaction mixture. The resulting mixture was cooled to 5 ° C and added to mixture A. The resulting mixture was stirred for an additional hour and then 12.23 g of colloidal silica (Ludox HS40, 40% in water, stabilized with sodium ions) was added. The synthetic mixture was stirred at room temperature overnight and then heated at 70 ° C for 4 hours. The resulting concentrated gel was diluted with 10 mL of ethanol, transferred to a stainless steel autoclave and adjusted to a volume of 100 mL with water.

After 6 days at 125 ° C, the contents of the autoclave are a milky white suspension. This suspension is centrifuged for 20 minutes at 4000 rpm to separate the solids. After drying at 60 ° C, the solids are calcined at 550 ° C in air for 12 hours and

Ti-0 zeolite. More details on the state of synthesis in this and the remaining examples are given in Table 1, while the characteristics of the zeolites produced are given in Table 2.

In Comparative Example 1, the procedure described above was followed except that after addition of the colloidal silica, the synthesis mixture was immediately placed in an autoclave and heated to 150 ° C for 7 days.

The result is an amorphous product.

Example 2

Mixture A is prepared by dropping 0.5 ml of tetraethyl orthotitanate into 63 ml of distilled water. The mixture was cooled to 5 ° C and then 39 mL of hydrogen peroxide (35% in water) was added. The resulting mixture was stirred at 5 ° C for 3 hours to give a clear yellow-orange liquid.

Mixture B was prepared by adding 0.0312 g of aluminum powder to 29.43 g of tetraethylammonium hydroxide (40% in water) and dissolving by heating to 90 ° C. 31 ml of distilled water are then added to the reaction mixture. The resulting mixture was cooled to 5 ° C.

Solutions A and B are mixed and the resulting solution is stirred at 5 ° C for 1 hour. 12.54 g of colloidal silica (Ludox AS40, 40% in water, stabilized with ammonium ions) are then added to the resulting solution. The mixture was stirred at room temperature for 18 hours and then at 70 ° C for a further 2 hours. The resulting gel was diluted with 10 mL of ethanol and transferred to a stainless steel autoclave.

The autoclave is placed in an oven and the crystallization is allowed to proceed at 125 ° C for 6 days. After this time, the autoclave was rapidly cooled to room temperature and the solids were separated from the liquid by centrifugation at 13,000 rpm. The organic template is then removed from the zeolite pores by calcination at 550 ° C in air for 12 hours.

Example 3 3 ml of distilled water are mixed with 1.5 ml of tetraethyl orthotitanate. The resulting mixture was cooled to 5 ° C and a white slurry formed while the mixture was maintained at this temperature. Then, 39 ml of pre-cooled hydrogen peroxide (35% by weight in water) was added to the resulting suspension. It becomes yellow when the suspension is added. The resulting solution (mixture A) was stirred at 5 ° C for 3 hours.

0.0315 g of aluminum powder and 29.42 g of tetraethylammonium hydroxide (40% in water) are placed in a beaker which is sealed to prevent evaporation and heated to 80 ° C for 3 hours. After all the aluminum had dissolved, distilled water (32.31 g) was added. The resulting solution (mixture B) was cooled to 5 ° C.

Mixtures A and B were combined and the resulting light yellow solution was kept under stirring at 5 ° C for an additional hour. Then, 12.53 g of colloidal silica (Ludox AS40, 40% in water) was added to the resulting solution. The mixture was stirred at room temperature for 18 hours, after which time the color of the weak opaque solution changed from light yellow to white. The solution was then held at 70 ° C for 2 hours, at which time the solution was cooled to room temperature. The resulting gel was diluted with 10 mL of ethanol and transferred to an autoclave.

The autoclave is held in a static oven at 135 ° C. After 6 days, the crystals were collected by centrifugation at 13,000 rpm. Finally, the resulting solids are dried at 60 ° C overnight. The organic template is then removed from the zeolite pores by calcination at 550 ° C in air for 12 hours.

Example 4

Mixture A is prepared by dropping 1.5 ml of tetraethyl orthotitanate into 63 ml of distilled water. The mixture was cooled to 5 ° C and then 39 mL of hydrogen peroxide (35% in water) was added. The resulting mixture was stirred at 5 ° C for 3 hours to give a clear yellow-orange liquid.

Mixture B was prepared by adding 0.910 g of aluminum powder to 29.43 g of tetraethylammonium hydroxide (40% in water) and dissolving by heating to 90 ° C. 31.08 ml of distilled water are then added to the reaction mixture. The resulting mixture was cooled to 5 ° C.

Solutions A and B were mixed and the resulting solution was stirred at 5 ° C for 1 hour. Then, 12.57 g of colloidal silica (Ludox AS40, 40% in water) was added to the resulting solution. The mixture was stirred at room temperature for 16 hours and then at 70 ° C for a further 2 hours. The resulting gel was diluted with 10 mL of ethanol and transferred to a stainless steel autoclave.

The autoclave is placed in an oven and the crystallization is allowed to proceed at 135 ° C without stirring for 10 days. After this time, the autoclave is rapidly cooled to room temperature and the solid is separated from the liquid by centrifugation at 13,000 rpm. After drying at 60 ° C, the organic template is removed from the zeolite pores by calcination at 550 ° C in air for 12 hours.

Example 5 5 ml of tetraethyl orthotitanate are mixed with 256 g of distilled water. The resulting mixture was cooled to 5 ° C and a slurry formed during the time the mixture was maintained at this temperature. Then 103 ml of hydrogen peroxide (35% by weight in water) were added to the resulting suspension. Upon addition of the suspension, it turns yellow. The resulting solution was stirred at 5 ° C for 3 hours.

An aluminum source of 0.3859 g of powdered aluminum and 366 g of tetraethylammonium hydroxide (40% in water) is contacted in a beaker that is sealed to prevent evaporation and heated at 80 ° C for 2 hours. After all the aluminum has dissolved, 183 ml of distilled water are added. The resulting solution was cooled to 5 ° C.

The two solutions were mixed to give a light yellow solution, which was kept under stirring at 5 ° C for an additional hour.

61 g of colloidal silicon dioxide (Aerosil, 200 m ² / g) are then added to the resulting solution. The mixture was stirred at room temperature for 18 hours, after which time the color of the weak opaque solution changed from light yellow to white. The solution was then maintained at 70 ° C for 2.5 hours, during which time the solution turned yellow again. The solution was allowed to cool to room temperature. 61 ml of ethanol are added before transferring the solution to a 1000 ml stainless steel autoclave coated with Teflon (poly (tetrafluoroethylene)). In the preceding examples, the synthetic mixture occupied no more than two-thirds of the volume of the autoclave. In this example, the synthetic composition occupies approximately 95% by volume.

Gas phase analysis shows a high ethylene content in the upper part of the space.

The autoclave is maintained at 140 ° C without stirring. After 11 days the pressure rises to 5.0 MPa. The crystals are separated from the mother liquors and washed by centrifugation at 13,000 rpm. After drying at 60 ° C, the organic template is removed from the zeolite pores by calcination at 550 ° C in air for 12 hours.

Example 6

The same method as described in Example 5 was used to make a synthetic gel except that all reagents were used in half. The gel is transferred to a 1000 ml Teflon-coated stainless steel autoclave and occupies approximately 50% by volume. After closing the autoclave, ethylene was introduced to achieve an ethylene pressure of 700 kPa. The autoclave is then heated to 140 ° C. After 18 hours the pressure rises to 1.4 MPa. Additional ethylene was introduced into the autoclave to increase the pressure to 3.4 MPa. Finally, after 3 days, the pressure that has risen to 3.6 MPa is increased to 4.4 MPa by addition of additional ethylene. At this stage, the molar ratio of ethylene to tetraethylammonium hydroxide is about 0.4: 1. After a total of 13 days at a pressure of 5.0 MPa, the autoclave was rapidly heated.

cools. The crystals are separated from the mother liquors and washed by centrifugation at 13,000 rpm. After drying at 60 ° C, the organic template is removed from the zeolite pores by calcination at 550 ° C in air for 12 hours.

Comparative example

The synthesis is carried out as described by M. A. Camblor et al. in J. Chem; Soc. Chem. Comm. 8, 589 (1992).

Dissolve 33.95 g of tetraethylammonium hydroxide (40% in water) with 40.00 g of distilled water to which 0.9 ml of tetraethyl orthotitanate is added. A white precipitate formed. Then 9.99 g of colloidal silicon dioxide (Aerosil 200 m ² / g) is added and finally 0.32 g of aluminum nitrate Al (NO ₃ ) ₃ .9H ₂ O in 6.01 g of distilled water is added.

The resulting gel was transferred to a Teflon-coated stainless steel autoclave and held at 135 ° C for 10 days, rotating at 50 rpm. The autoclave rapidly cools. The crystals are separated from the mother liquors and washed by centrifugation at 13,000 rpm. After drying at 60 ° C, the organic template is removed from the zeolite pores by calcination at 550 ° C in air for 12 hours.

Comparative example

Example 2 is repeated at a molar ratio of silica to alumina of 101: 1 and 1.49 moles of tetraethylammonium hydroxide per mole of silica.

There will be no solids.

Table 1

Conditions for synthesis

Example Gel composition (molar ratio)

No. SiO ₂ / SiO ₂ SiO ₂ / Al ₂ O ₃ OH "/ SiO ₂ EtOH / SiO ₂ H ₂ O / SiO ₂ ^a

comparative Example 1 5 143 0,94 2 ! 95 1 5 147 0.95 2 ! 98 2 35 145 0.96 '2 : 98 3 12 143 0,96 2 : 90 (43) 4 12 50 0,96 2 100 (24) 5 18 142 0.98 1 40 (24) 6 18 142 0.98 1 40 (24) comparative Example 2 38 385 0,55 0 22nd Example Conditions crystallization C. Evaporation time Upper part of the room Temperature Time at 70 Noc: 2 ° C (%) (° C) comparative Example 1 0 40 150 7 1 4 33 125 6 2 2 50 125 6 3 2 50 135 10 4 2 50 135 10 5 2.5 5 140 11 6 2.5 50 140 13 comparative Example 2 0 50 135 10 ^p

^a H ₂ O / SiO ₂ : The value in parentheses indicates the ratio of H ₂ O / SiO ₂ after evaporation ^b : Stirring at 50 rpm

Table 2

Product Characterization Example Notes

C.

Yield (%)

XRD

comparative Example 1 Ludox HS40 / H ₂ O ₂ / not mixed 0 amorphous 1 Ludox HS40 (H ₂ O ₂ ) stirred 4 Ti-β 2 Ludox AS40 / H ₂ 0 ₂ / stirred 20 May Ti-β 3 more Ti / elevated temperature and čas 35 Τΐ-β 4 more aluminum 75 -Ί-β 5 small upper part of the space 55 Ti-β 6 large upper part of the space / 55 high ethylene content Ti-β comparative Example 2 Camblor method 10 Camblor-β Example Ich (cm ¹ ) DRS (cm - ¹ ) 960 575 525 30 000 34 000 47 500 comparative Example 1 no no no yes (3) yes (3) No 1 yes (2) yes (3) yes (3) yes (1) yes (2) yes (3) 2 yes (3) yes (3) yes (3) No No yes (3) 3 yes (3) yes (3) yes (3) No No yes (3) 4 yes (3) yes (3) yes (3) No yes (3) yes (3) 5 yes (3) yes (3) yes (3) No No yes (3) 6 yes (3) yes (3) yes (3) No No yes (3) comparative example 2 yes (1) yes (3) yes (3) yes (2) yes (3) No

(1): very weak (2): weak (3): strong

The results in Tables 1 and 2 show, with reference to Comparative Example 1 and Example 1, the importance of maturation of the synthetic composition prior to hydrothermal treatment. The infrared spectrum of Comparative Example 1 shows neither the typical systemic vibration of O-zeolite at 575 and 525 cm ^-1 , nor the Ti = 0 vibration at 960 cm ^1, and X-ray diffraction (XRD) indicates the absence of crystallinity. In DRS testing, very strong bands are at - 1

800 cm, ascribed to agglomerated titanium dioxide, and at 34,000 cm @ ¹ , ascribed to finely dispersed titanium dioxide. In contrast, in the ripening example, all of the above infrared bands are present, although the band at 960 cm ¹ is weak, while the above DRS bands are present, are weak and are accompanied by a strong

- band at 47500 cm ¹ ascribable to the titanium of the zeolite. However, the yield of 4% is very low. The yield is calculated as follows:

weight of calcined zeolite recovered yield% = 100 x - ^: - weight of silica and alumina in gel

In Example 2, where an ammonium-stabilized silica source is used, a much higher yield of 20% is achieved, and the DRS bands attributed to the titanium dioxide phase are absent.

In Example 3, a higher yield (35%) is achieved with a higher titanium content, higher temperature and longer crystallization time.

In Example 4, a higher yield (75%) results from a higher aluminum content, but a thicker band at 34,000 cm ^-1 indicates the presence of titanium dioxide, which may be indicative of the common formation of β-aluminum, aluminum-enriched β-titanium and titanium dioxide. .

In Examples 5 and 6, high ethylene pressure was maintained, in Example 5 a small upper part of the space, and in Example 6 by the addition of ethylene during crystallization. High yields are obtained, which is not a sign of titanium dioxide contamination.

In Comparative Example 2, the bands are not present at 47,500 cm ^-1 and the presence of the other two DRS bands is indicative of a substantially different structure of the Ti-β zeolite in the process of the present invention as compared to the above processes.

Overall results show that optimal synthesis has the following characteristics:

high ethylene pressure, synthetic gel maturation, peroxide presence, absence of alkali metal cations and low aluminum content.

Claims (27)

PATENT TOOLS Process for the production of Ti-, V- or Zr-β zeolite, characterized in that at least part of the hydrothermal treatment of the synthetic Ti-, V- or Zr-β-forming mixture is carried out in an atmosphere containing ethylene at a pressure of at least 2.0 MPa. Process according to claim 1, characterized in that at least part of the hydrothermal treatment is carried out at an ethylene partial pressure of at least 500 kPa. Process according to claim 2, characterized in that the ethylene partial pressure is at least 2.0 MPa. The process according to claim 2, wherein the ethylene partial pressure is at least 3.0 MPa. Method according to one of Claims 1 to 3, characterized in that the total pressure is at least 3.0 MPa. 6. A process for the production of Ti-, V- or Zr-β zeolite, characterized in that at least part of the hydrothermal treatment of the synthetic Ti-, V- or Zr-β-forming mixture is carried out in the presence of at least 0.1 moles of ethylene per mole of tetraethyleneammonium cations. The method of claim 6, wherein the molar ratio of ethylene to tetraethyleneammonium is in the range of 0.1 to 1: 1. in - 21 Process according to any one of claims 1 to 7, characterized in that the synthetic mixture comprises water, a silicon source, a titanium source, an aluminum source and a tetraethylammonium ion source. The method of claim 8, wherein the synthetic composition has a molar composition within the following range: silica (1), titanium dioxide (0.0001 to 0.2), aluminum oxide (0.0005 to 0.1), water (10 to 100) and tetraethylammonium hydroxide (0.01 to 1). Method according to any one of claims 1 to 9, characterized in that the synthetic mixture comprises colloidal silica. The method of claim 10, wherein the colloidal silica is substantially free of alkali metals. Process according to any one of claims 1 to 9, characterized in that the synthetic mixture comprises tetraalkyl ortho-silicate. Process according to any one of claims 1 to 12, characterized in that the synthetic mixture comprises at least initially hydrogen peroxide. Method according to one of Claims 1 to 13, characterized in that the synthetic mixture is aged between its formation and the hydrothermal treatment. Method according to claim 14, characterized in that the ripening is carried out at room temperature. Method according to claim 14 or 15, characterized in that at least part of the ripening is carried out at elevated temperature. Method according to one of claims 1 to 16, characterized in that the synthetic mixture subjected to hydrothermal treatment contains ethanol, preferably in an amount of at most 2 moles per mole of silica. Process according to one of Claims 1 to 17, characterized in that the hydrothermal treatment is carried out at a temperature in the range of from 120 to 200 ° C. Process according to any one of claims 1 to 18, characterized in that the hydrothermal treatment is carried out within 1 hour to 30 days. Process according to any one of claims 1 to 19, characterized in that, after hydrothermal treatment, the resulting crystals are collected and heated in air at a temperature of from 200 to 600 ° C for a period of from 1 to 72 hours. 21. The method of claim 20, wherein the calcined product is treated with an acid or a base, or treated with steam. 22. A, V, or Zr-O zeolite obtainable by a process according to any one of claims 1 to 21. Use of an ethylene-containing atmosphere during hydrothermal treatment of the synthetic mixture to improve the yield of Ti-, V- or Zr-β zeolite. Use of a product according to any one of claims 1 to 21 or a product according to claim 22 as a catalyst for the oxidation of an organic compound. Use according to claim 24, wherein the oxidation is carried out using an organic peroxide. Use according to claim 24 or 25, wherein the organic compound is a saturated hydrocarbon. 27. Any new feature described herein or any combination of features described herein.