EP2646367A2

EP2646367A2 - Mechanochemical production of zeolites

Info

Publication number: EP2646367A2
Application number: EP11788450.2A
Authority: EP
Inventors: Josef SCHÖNLINNER; Jürgen Ladebeck; Jürgen Koy; Stephan Wellach; Götz BURGFELS
Original assignee: Sued Chemie IP GmbH and Co KG
Current assignee: Sued Chemie IP GmbH and Co KG
Priority date: 2010-12-01
Filing date: 2011-11-28
Publication date: 2013-10-09
Also published as: ZA201303567B; JP2014501683A; CN103269978A; WO2012072527A2; WO2012072527A3; DE102010053054A1; US20130266507A1

Abstract

The invention relates to a process for the synthesis of zeolites, which comprises the following steps: a) provision of a silicon source; b) provision of an aluminium source; c) optionally provision of at least one template; d) mixing of the silicon source, the aluminium source and the optional template to produce a synthesis gel; e) milling of the synthesis gel; f) treatment of the milled synthesis gel under hydrothermal conditions to produce crystalline zeolite, and also zeolites which can be obtained by this process. The products obtained by the process can be used as catalysts or catalyst supports.

Description

Mechanochemical production of zeolites

description

The invention relates to a process for the preparation of zeolites, as well as zeolites obtainable by this process

Background of the invention

Zeolite materials can be prepared by hydrothermal synthesis, that is, by synthesis in an aqueous medium under pressure and at elevated temperature. About the

hydrothermal synthesis become synthesis gels

Crystallization of the corresponding zeolites brought. The synthesis gels usually comprise a silicon source (e.g., silica), an aluminum source (e.g., sodium aluminate, aluminum hydroxide, aluminum sulfate, etc.), a template

(preferably, a quaternary ammonium compound serving as a structure-directing agent) and water.

However, the known synthesis processes have the disadvantage that the crystallization time of the zeolites in the

hydrothermal synthesis is relatively long and the resulting zeolites often are not uniform substances, but mixtures.

The invention therefore an object of the invention to provide a method that makes it possible with a simple

Process and short crystallization times to obtain crystalline zeolite, especially those with high phase purity.

There have been numerous attempts by the inventors

carried out to find such a method. It was surprisingly found that an additional Milling step, which is carried out following the preparation of the synthesis gel, the crystallization time is shortened and leads to zeolites of high phase purity.

Alternatively, this additional process step allows the reduction of the amount of template used without the

Phase damage to damage, which significantly reduces the manufacturing cost. Based on this finding, the present invention has been realized.

The invention relates to a method for the synthesis of

Zeolites comprising the following steps: a)

Providing a silicon source; b) providing an aluminum source; c) optionally providing at least one template; d) mixing the silicon source, the

Aluminum source and optional template for generating a synthesis gel; e) grinding the synthesis gel; f)

Treatment of the ground synthetic gel under hydrothermal conditions to produce crystalline zeolite.

In another aspect, the present invention relates to zeolites obtainable by the process of the invention. Preferred is the preparation of beta zeolite and MFI zeolite; more preferably of beta zeolite having a molar ratio Si: Al of 10 to 400, more preferably 20 to 50, of MFI zeolite having a molar ratio Si: Al of 12 to 800, more preferably 24 to 500, and particularly preferred from 75 to 250.

In addition, the present invention teaches the use of at least one grinding apparatus for treating a

Synthetic gels comprising a silicon source, an aluminum source, and optionally at least one template, prior to the generation of crystalline zeolite under hydrothermal conditions

Conditions.

Furthermore, the present invention teaches the use of the zeolites obtainable by the process according to the invention as catalysts or catalyst supports, in particular for acid-catalyzed reactions, oxidations, reductions and adsorptions. Particularly preferred is the use for catalytic cracking of hydrocarbons (cracking) and hydrogenating cracking of hydrocarbons (hydrocracking, mild hydrocracking and / or dewaxing); Alkylation of

Aromatics with olefins, alcohols or halogenated

paraffins; Alkylation of aromatics; Alkylation of

Isoparaffins with olefins; Transalkylation (especially of aromatics); disproportionation; isomerization;

hydroisomerization; dimerization; oligomerization;

polymerization; etherification; esterification; hydration;

dehydration; Adsorption; Condensation; Oxidation;

acetylation; Dealkylation and cyclization.

The invention relates generally to a method for

Production of zeolites, wherein initially from a silicon source, an aluminum source and optionally at least one template, a synthesis gel is prepared. Generation of synthesis gel by mixing silicon source,

Aluminum source and optionally one or more

Template may be made in a manner known to those skilled in the art based on the teachings of the present invention.

Silicon source, aluminum source and the one or more templates can be mixed together as such or in the form of a fluid, for example as a solution, suspension or gel, or added to a solvent or solvent mixture. Preferably, the solvent used is water or an aqueous solvent mixture. In particular, the silicon source, the

Aluminum source, the optional template and / or the

Synthesis gel in aqueous medium.

Preferably, in the step of mixing

Silicon source, aluminum source and optionally one or more templates mixing or homogenizing. Particularly good results can be achieved if the silicon source is a silicon source selected from the group consisting of precipitated

Silica, colloidal silica and mixtures thereof. In particular, the silicon source may comprise or consist of precipitated silica. The aluminum source may be an aluminum source selected from the group consisting of aluminates (especially sodium aluminate), aluminum hydroxide, aluminum sulfate and mixtures thereof. As template, any template based on the general knowledge or teaching of the present invention may be used, preferably quaternary ammonium compounds which may serve as structure-directing agents are used as a template. Examples of templates that can be used are

Tetraalkylammonium salts. Preference is given to the use of tetraalkylammonium hydroxides and / or

Tetraalkylammonium bromides, wherein it is in the

Alkyl groups preferably by the same or different, straight-chain or branched alkyl groups having one to ten

(preferably one to four) carbon atoms. Particularly preferred is the use of tetraethylammonium hydroxide

(TEAOH) or tetrapropylammonium bromide (TPABr). The template is used, for example, in an amount of from 1 to 50 mol%,

in particular in an amount of 10 to 30 mol%, preferably in an amount of 4 to 20 mol%, based on the molar amount of Si used in the silicon source. It can be one

Template or multiple templates can be used, preferred is the use of a template.

In the synthesis of MFI zeolite (zeolite ZSM-5), the synthesis gel can have a molar ratio of Al to Si

for example in the range of 0.00125: 1 to 0.0833: 1, preferably in the range of 0.002: 1 to 0.0416: 1,

particularly preferably in the range from 0.004: 1 to 0.0133: 1 and / or a molar ratio of Na to Si in the range from 0.01: 1 to 0.2: 1, preferably from 0.02: 1 to 0.15 : 1, more preferably 0.04: 1 to 0.14: 1.

Preferably, the synthesis gel comprises at least 10 moles of water per mole of S1O2, more preferably 18-30 moles of water.

In the synthesis of beta zeolite (BEA), the synthesis gel may have a molar ratio of Al to Si, for example, in the range of 0.0025: 1 to 0.1: 1, preferably in the range of

0.02: 1 to 0.08: 1 and / or a molar ratio of Na to Si in the range of 0.001: 1 to 0.1: 1, preferably in the range of 0.01: 1 to 0.08: 1 , Preferably, the synthesis gel comprises at least 5 moles of water per mole of S1O2, more preferably 10 to 50 moles of water.

After the synthesis gel has been generated, the synthesis gel is ground, as explained in detail below. The term "synthesis gel" in the context of the present invention comprises both synthesis gels, which are in the form of a gelatinous or gelatinous mass, as well as in fluid form,

for example in the form of a suspension. The ground synthesis gel is then transferred under hydrothermal conditions in the crystalline zeolite, whereupon the crystalline zeolite can be separated from the aqueous phase and optionally dried and calcined.

The process of the present invention is illustrated below with reference to the synthesis of beta zeolite and MFI zeolite, but is not limited to the synthesis of these zeolites.

Obtainable by the process according to the invention

Zeolites preferably have a phase purity of more than 80%, preferably more than 90%, preferably more than 95%, in particular more than 98%. The phase purity is determined by measuring an X-ray diffractogram and based on a 100% pure sample. The grinding of the synthesis gel before treatment under

hydrothermal conditions can lead to an increase in the dispersion of the silicon source used, e.g. a precipitated silica, which in turn accelerates the

Crystallization process can lead. Surprisingly, moreover, the formation of foreign phases can be inhibited or

be suppressed. In this way, if necessary, the amount of template required for the synthesis can also be reduced, which leads to a reduction of the production costs.

Furthermore, according to a preferred embodiment, the colloidal silicic acids can be formed on the basis of the

Synthesis gel preparation subsequent milling partially or completely replaced by the much cheaper precipitated silicas. This can be a further significant reduction in manufacturing costs

those zeolites can be achieved, in their preparation as a raw material usually colloidal silica sources are used. Furthermore, preferably none

Zeolite seed crystals, in particular the production of beta-zeolite, which can also reduce the production costs.

In addition, mother liquors can be used instead of high-purity starting materials in the preparation of the synthesis gel. As the mother liquor, the first filtrate after the

Separation of the solid from the synthesis gel according to

Termed completion of zeolite synthesis. This first

Filtrate still contains raw materials during the

Zeolite synthesis were not implemented, as well as a share of solid.

A grinding is preferably carried out such that the

average particle size ds o of the synthesis gel after completion of the grinding by at least 10%, more

preferably at least 15%, preferably at least 20%, is less than the average particle size ds o of the synthesis gel at the beginning of the milling.

The grinding can be done generally with any suitable

Grinding done. During grinding, a high amount of energy (for example about 0.5 to 10 kW / liter, preferably about 1 to 10 kW / liter) is introduced into the system via the mechanical energy. In the final stage of the

Milling, according to a preferred embodiment, the amount of energy can be reduced, for example to 2 to 5 kW / liter.

During grinding, a significant decrease in the

Viscosity, wherein according to a preferred

In accordance with the invention, the viscosity of the invention

Synthetic gel after completion of grinding, for example, at least 10%, preferably at least 15%, more

preferably at least 20% less than the viscosity of the synthesis gel at the beginning of the milling.

According to another embodiment, the

Starting materials, in particular the starting materials insoluble in the aqueous phase, also before

Production of the synthesis gel subjected to intensive grinding. It is further preferred that prior to preparation of the synthesis gel, the silicon source and / or the aluminum source, unless they are in the form of a solution, are subjected to grinding.

In the production of the synthesis gel by mixing and until the beginning of the grinding, optionally also during a part or during the entire duration of the milling, the

Synthesis gel preferably under a pressure of not more than 2.4 bar, more preferably under a pressure of not more than 1.9 bar, more preferably under a pressure of not more than 1.5 bar, most preferably under a pressure of not more set as 1.1 bar and / or preferably to a Temperature of not more than 128 ° C, more preferably not more than 110 ° C, even more preferably not more than 100 ° C, most preferably not more than 70 ° C, and most preferably not more than 35 ° C heated.

The grinding is preferably at a temperature

carried out between about 0 ° C and 100 ° C, in particular between about 0 ° C and 50 ° C, wherein the synthesis gel is pumped, for example, by a grinding chamber filled with grinding chamber.

According to a preferred embodiment, the grinding is carried out in a mill comprising a grinding chamber filled with grinding balls, for example in a ball mill, in an annular gap mill, a bead mill, a Manton-Gaulin mill or in a grinding device combination comprising one or more comprising these grinding devices. Preferably, a multi-stage grinding apparatus, for example a multi-stage ball or annular gap mill, may be used in which the coarse fractions from the last stage are returned to the first stage. More preferably, the one or more milling devices may comprise at least one grinding device selected from the group consisting of mills comprising a grinding chamber filled with grinding balls, in particular selected from ball mills, annular gap mills, bead mills, Manton-Gaulin mills and

Combinations thereof. A Manton Gaulin mill is

for example, in US 4,664,842 explained in detail, wherein the relevant disclosure of the document by

Reference is incorporated in the present application.

Alternative grinders can be selected by one skilled in the art based on his general expertise. If desired, several different or the same

Grinding devices are used sequentially or simultaneously. Higher temperatures, ie more than 100 ° C may also be possible if the grinding process is carried out at overpressure. In this case, the inlet and outlet of the synthesis gel must be regulated in or out of the grinding chamber.

The pH of the synthesis ^{gel is} adjusted according to the synthesis ^¬ conditions and is generally about 9 to 14. In particular, the milling at a pH in the range of about 9 to 14, preferably from about 10 to 13 are performed. Adjustment of the pH can be carried out according to a procedure known to the person skilled in the art, for example by addition of acids, bases and / or buffer salt mixtures.

The synthesis gel or the resulting

Reaction mixture can be conveyed through the grinding chamber in several passes or with a longer residence time. The synthesis gel or the reaction mixture formed therefrom may additionally contain zeolite precursors as crystallization nuclei and may then be subjected to a hydrothermal aftertreatment, the resulting product optionally being separated from the reaction mixture, dried and

optionally calcined. In particular, one can separate the resulting crystalline zeolite after production under hydrothermal conditions, dry and

optionally calcine.

According to another embodiment, the grinding is carried out twice or more frequently, eg. B. twice, three times or four times.

By grinding the starting materials or the

Crystallization nuclei formed are the course of the hydrothermal zeolite synthesis in terms of synthesis time, flexibility in the selection of the reactants, yield,

Crystallization degree and phase purity optimized. The

Introduction of the milling process allows for one preferred execution form zeolite synthesis with low template use.

The synthesis gel or the resulting

Reaction mixture can be pumped through the grinding chamber. The obtained after grinding suspension with the

Crystallization seeds are then further processed according to an imple mentation in a conventional manner under hydrothermal conditions and worked up the finished product. After a possible implementation form become

Precipitation process and an aging process (crystallization of the catalyst precursor) through the use of

Crystallization germs optimized.

In the method according to the invention, for example, the raw materials (a silicon source, an aluminum source and an alkali source) are stirred together with a template and demineralized water to form a suspension. The

Suspension is passed through one or more milling devices as indicated herein.

The mechanically activated fines act as

Crystallization nuclei during the subsequent hydrothermal treatment. After this treatment, the crystalline becomes

Separated zeolite from the suspension, dried and

optionally calcined. The drying can at a

Temperature of about 60 to 200 ° C, preferably from about 80 to 150 ° C, for z. B. 0.5 to 10 hours, and the

Calcination, if provided, at about 250 to 750 ° C, preferably at 300 to 550 ° C, for z. B. 1 to 10 hours.

The product thus obtained can be used as a catalyst or

Catalyst supports are used.

In particular, the present invention teaches the use of at least one grinding apparatus for treating a Synthetic gels comprising a source of silicon, an aluminum source, and optionally at least one template, in one step prior to the production of crystalline zeolite under hydrothermal conditions. This use can for

To improve the phase purity and / or the crystallinity of the zeolite produced serve.

In a further aspect, the present invention provides a zeolite which is suitable for the invention

Method is available. In particular, the zeolite may be an MFI zeolite, in particular having a molar Si: Al ratio in the range from 12 to 800, preferably from 24 to 500, particularly preferably from 75 to 250 or a zeolite beta.

Catalytically active forms of the zeolites, for example of the beta zeolite and of the MFI zeolite, may additionally contain metals of the groups IA, IIA, IIIA to VI IIA, IB, IIB or HIB of the Periodic Table and B, Al, Ga, Si, Ge or P, preferably Li, Na, K, Mg, Ca, Ba, La, Ce, Ti, Zr, Nb, Ta, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu, Zn , B, Al, Ga, Si, Ge or P. More preferably, the catalytically active zeolites contain one or more of Pt, Pd, Cu, Fe, Rh, Ru, P, and Ni. For example, the exchange by means of ion exchange, impregnation or

physical mixing process done. Further methods for replacing the original cations are familiar to the person skilled in the art and are therefore not explained in more detail here

Depending on the desired use, the after the

zeolites obtained according to the invention are mixed or further processed with further components.

Preferred further processing of the zeolite relate to aqueous ion exchange, solid-state ion exchange (as described, for example, in EP 0 955 080 A),

Dealumination, for example, by treatment with dilute mineral acid or a dilute organic acid, and by hydrothermal treatment (see eg R. Szostak, Studies in Surface Science Catalysis, 137 (2001) 261-297), producing moldings of any size and shape by conventional methods such as extrusion, tabletting or spray drying, optionally with the aid of binder, or coating Moldings, in particular honeycombs, with a suspension of zeolite and binder as so-called

Washcoat.

The synthetic zeolites of the invention are particularly useful as catalysts, for example, the zeolites in the H form (with or without occupancy of base metals and / or precious metals) as catalysts for acid-catalyzed reactions, oxidations, reductions and adsorptions

can be used.

These reactions include i.a. catalytic cracking (FCC additive) and hydrogenating cracking of hydrocarbons (mild hydrocracking, dewaxing, hydrocracking); Alkylations e.g. of aromatics with olefins, alcohols or halogenated paraffins; Alkylation of aromatics; Alkylation of

Isoparaffins with olefins; Transalkylation (of aromatics); Disproportionation (e.g., toluene disproportionation, etc.); Isomerization and hydroisomerization (e.g., of paraffins, olefins, aromatics, xylene isomerization, isodewaxing, etc.); Dimerization and oligomerization; polymerizations;

Etherification and esterification; Hydration and

dehydration; Adsorption; Condensation; Oxidation;

acetylation; Dealkylation and cyclization; Alkylation and hydrodealkylation (ethylbenzene to benzene); emission control; Acid-catalyzed reactions are also disclosed, for example, in DE-A-4 405 876, wherein a catalyst based on a particulate acid-activated phyllosilicate is used whose particle is bound by a binder

connected to each other. The process according to the invention is explained below by way of examples in a non-restrictive manner.

Methods a) Viscosity detection

The viscosity of the pastes or suspensions or dispersions was measured according to DIN 53019 / ISO 3219. A Rheostress 600 rheometer from Haake was used according to the manufacturer's instructions. b) Average particle diameter

The mean diameter dso is defined so that 50% of the total particle volume consists of particles with a smaller particle size

Diameter exist. A suitable method for determining the particle size distribution is, for example, the laser diffraction according to ISO 13320-1. c) loss on ignition

The loss on ignition is determined as follows: Clean

Porcelain crucibles are annealed at 600 ° C and then stored in a desiccator until use. The homogenized sample is weighed into a porcelain crucible and the crucible is then calcined for 3 h at 1000 ° C. in a laboratory muffle furnace. The crucible is then placed in a desiccator for cooling. By comparing the weight and weight, the loss on ignition can be calculated. The loss on ignition is always determined by a double determination. d) Chemical composition of the zeolites

To determine the chemical composition of the zeolites zeolites are used, the previously at 1000 ° C to the

Constant weight heated and then cooled to 20 ° C. To determine the content of Si and Al, a conventional elemental analysis can be performed. The value n5j_ / n7 ^] _ indicates the ratio of the molar amount of Si in mol to the molar amount of Al in mol, wherein the respective zeolite was previously subjected to heating at 1000 ° C to constant weight.

If there are several versions of a standard (for example, DIN, ISO, ASTM standard, etc.), this application refers to the current standard on October 1, 2008, unless another version is explicitly stated otherwise. e) Determination of phase and / or crystallization of zeolites This method is used to study crystalline solids with respect to their lattice structure. Of the sample to be examined and the corresponding reference sample is in each case a

X-ray diffraction log, recorded in direct temporal sequence. The comparison of the reflexes of the whole

Spectrum, in particular on the basis of the line width of the reflex at about 22.4 ° 2Theta gives a statement about the

Phase purity and / or degree of crystallization of the sample. To determine the X-ray diffractogram, a D4 Endeavor instrument from Bruker was used.

Examples a) Provision of the aluminum source

As the aluminum source, sodium aluminate was used, whereby an aqueous aluminum source was dissolved by dissolving

Sodium aluminate (and in the case of Ex. Or Comp. -Bsp. 4 additional NaOH beads) was prepared in water. To completely dissolve the sodium aluminate, the mixture was heated to 60-100 ° C. After the solid had dissolved, the yellowish, slightly turbid fluid was cooled to room temperature and the loss of mass by adding

Corrected demineralized water. b) providing the silicon source and the (at least one) template

In the preparation of the silicon source, the template tetraethylammonium hydroxide (TEAOH, SACHEM) was first mixed with water at room temperature in the case of the beta zeolite (BEA) or, in the case of the MFI zeolite, the template

Tetrapropylammonium bromide (TPABr, SACHEM) dissolved in water. The templated tetraethylammonium hydroxide used was used as a 35 wt.% TEAOH solution. The

Tetrapropylammonium bromide was used as solid with> 99 wt.% TPABr. Subsequently, precipitated silica (FK320, Degussa) was slurried. c) mixing the source of aluminum and silicon and preparing the synthesis gel

In this synthesis step, the aluminum source was steadily added to the silicon source in a reaction vessel at room temperature (20 ° C) with mixing. The resulting suspension was mixed for a further 140 minutes (in the preparation of beta zeolite) and 30 minutes (in the preparation of MFI zeolite) at room temperature (20 ° C).

Up to this step all 10 ran

Synthesis experiments identical. The synthetic approaches according to Examples 1 to 4 was in contrast to the

Comparative Examples 1 to 4 another

Production step, the grinding in one

Agitator ball mill subjected. d) grinding in the stirred ball mill

These were the appropriate synthesis rules with a

Hose pump into the grinding chamber of the ball mill (type Fryma M32) promoted. After the grinding chamber was filled, the rotor of the mill was started and the complete synthesis gel through the Grinding chamber pumped while the rotor is running. The ground product was collected in one container and a second

Subjected to milling passage. The pumping rate was 3 liters / minute (BEA and MFI).

It was observed that the viscosity of the synthesis gel changed dramatically with beta-zeolite. In the case of beta-zeolite, a medium-viscosity suspension was started and a lower viscosity suspension was obtained after milling. e) filling the autoclave and crystallization

To synthesize the zeolites, a 1 O-liter autoclave was filled with 9 kg each of the synthesis gels. The autoclave was then closed, the stirrer started and the heating of the synthesis gels started. f) crystallization conditions

The syntheses were in the autoclave under dynamic

Conditions carried out at 150 ° C. The

Crystallization times were depending on the approach between 1 h and 160 h.

BEA MFI

Heating time (h): 10 12

Stirring speed (rpm): 73 73

Synthesis pressure (bar):> 10 3,7-4,5

Crystallization temperature (° C): 150 150

Crystallization time (h): 10-160 1-10

Stirrer type: Anchor Anchor g) Processing of the synthesis products

All synthesis products were prepared by repeated washing with demineralized water on the Buchner funnel, Resuspend (conductivity <90 S / cm) and worked up at 120 ° C for 16 h.

Results

Table I gives an overview of the different template contents of the ground or unmilled synthetic gels and the products obtained.

Molar composition of the synthetic gels used: BEA:

(0.08 to 0.18) TEAOH: 0.04 Na ₂ 0: A1 ₂ 0 0.04 _3: 1 Si0 _2: 12 H ₂ 0

MFI:

0.055 TPABr: 0.0675 Na ₂ 0: A1 ₂ 0 0.0014 _3: 1 Si0 _2: 24.5 H ₂ 0

Table I

Template content of the synthesis gels and products

The molar template content, as indicated in Table I, is given based on the molar Si content. A molar Template content of 0.18, for example, indicates that the

Ratio of the amount of template in moles to the amount of Si in moles 0.18: 1 = 0.18 d. H. 18 mol%.

^** Beta-zeolite with low impurities of MFI zeolite, determined by measurement of an X-ray diffractogram.

Syntheses with milled synthesis gels resulted

phase-pure zeolites. The zeolites from the unground synthesis gels contained impurities in one case. The syntheses according to Examples 1 to 4 or

Comparative Examples 2 to 4 led to each

desired synthesis products BEA and MFI. For beta zeolite, the use of unground synthesis gel in one case gave little MFI zeolite impurity (Comp. Ex. 1).

Fig. 1 shows a significant reduction in

Crystallization time when using ground

Synthetic gel (Example 4) compared to unground

Synthesis gel (Comparative Example 4) of 1 h compared with 9 h in the synthesis of MFI zeolite. The course of the

Crystallization was determined by measuring the peak intensity of a synthesis gel or reaction mixture sample by measuring the X-ray diffractogram. The product of Example 4 (MFI zeolite) further shows a marked reduction in crystallite size

Primary crystallites. Although the shape of the primary crystallites is retained, the crystallite length decreases from about 3.8 μπι to about 1.2 μπι, i. to about 32%. This effect can be attributed to the fact that the grinding of the synthesis gel a larger number of seed crystals is formed, to which the actual zeolite in the

Growing crystal growth phase.

The chemical composition of the products obtained is given in Table II. Table II Chemical composition of the products

^a) Weight loss at 1000 ° C

b ⁾ based on weight loss at 1000 ° C.

From the results obtained, it is clear that both the grinding and the template content in the synthesis gel have a significant influence on the crystallization times of the zeolites. By grinding the synthesis gels, as well as by a higher template content, a shortening of the crystallization time can be achieved. By grinding the synthesis gels can be compared to the direct synthesis without grinding process, for example, by 5 to 80% lower, often at least 50% lower crystallization time can be achieved. Fig. 2 shows a comparison of the crystallization times in syntheses with ground (Example 1) and unmilled (Comparative Example 1) synthesis gels (molar template content based on the molar Si content = 0.08) and Fig. 3 shows a comparison of the crystallization times at Syntheses with milled (Example 2) and unmilled

(Comparative Example 2) Synthesis gels (molar template content based on the molar Si content = 0.12).

The course of the crystallization was determined by recording the peak number of a synthesis gel sample by measuring the X-ray diffractogram.

When using a precipitated silica (FK320), almost as good results can be achieved as when using a colloidal silica (LUDOX® from Dupont). As a result of the grinding process, zeolites with precipitated rather than colloidal silicic acids can be used, which leads to significant cost reductions, because precipitated silicas are cheaper than colloidal silicic acids.

Claims

claims

A process for the synthesis of zeolites, comprising the following steps:

a) providing a silicon source;

b) providing an aluminum source;

c) optionally providing one or more

Template;

d) mixing the silicon source, the aluminum source and the optional at least one template to produce a synthesis gel;

e) grinding the synthesis gel;

f) treatment of the ground synthetic gel under

hydrothermal conditions for the production of crystalline zeolite.

2. The method according to claim 1, characterized in that the silicon source, the aluminum source, the optional at least one template and / or the synthesis gel in an aqueous medium, preferably water.

3. The method according to claim 1 or 2, characterized in that the silicon source comprises precipitated silica or consists of this.

4. The method according to any one of the preceding claims, characterized in that subjecting the silicon source and / or the aluminum source to a grinding.

5. The method according to any one of the preceding claims, characterized in that the grinding is carried out with at least one grinding device, wherein the at least one grinding device is preferably selected from the group consisting of a mill which comprises a grinding chamber filled with grinding chamber, in particular a ball mill one

Annular gap mill, a pearl mill, and a Manton-Gaulin Mill; and combinations thereof.

6. The method according to any one of the preceding claims, characterized in that one carries out the milling at a pH in the range of about 9 to 14.

7. The method according to any one of the preceding claims, characterized in that the template in an amount of 1 to 50 mol%, in particular from 10 to 30 mol%, more preferably from 4 to 20 mol%, based on the molar amount of Si of the silicon source, uses.

8. The method according to any one of the preceding claims, characterized in that separating the crystalline zeolite obtained after the production under hydrothermal conditions, dried and optionally calcined.

9. The method according to claim 8, characterized in that the drying at a temperature of about 60 to 200 ° C, preferably at a temperature of 80 to 150 ° C and the optional calcination at 250 to 750 ° C, preferably at 300 up to 550 ° C.

10. The method according to any one of the preceding claims, characterized in that the average particle size dso of the synthesis gel after completion of the milling at least 10%, preferably at least 15%, preferably at least 20%, less than the average particle size dso of the synthesis gel before Milling is.

11. The method according to any one of the preceding claims, characterized in that the synthesis gel has a molar ratio of Al to Si in the range of 0.00125: 1 to 0.1: 1 and / or a molar ratio of Na to Si in the range of 0.001 : 1 to 0.2: 1, preferably a molar ratio of Al to Si in the range of 0.00125: 1 to 0.1: 1 and a molar

Ratio of Na to Si in the range of 0.001: 1 to 0.2: 1 having .

12. Use of the method according to any one of

Claims 1 to 11 obtainable zeolites as catalysts or catalyst support, in particular for acid-catalyzed reactions, oxidations, reductions and adsorptions, particularly preferably for catalytic cracking of

hydrocarbons; Hydrogenating catalytic cracking of hydrocarbons; Alkylation of aromatics with olefins, alcohols and / or halogen-containing paraffins; Alkylation of aromatics; Alkylation of isoparaffins with olefins; Transalkylation, in particular of aromatics; Hydrogenating isomerizing dewaxing of higher

hydrocarbons; disproportionation; isomerization; hydroisomerization; dimerization; oligomerization;

polymerization; etherification; esterification; hydration; dehydration; Adsorption; Condensation; Oxidation;

acetylation; Dealkylation and / or cyclization.

13. Use of at least one grinding device for

Treatment of a synthesis gel comprising a silicon source, an aluminum source and optionally at least one template, wherein the grinding device is preferably

is selected from the group consisting of a mill comprising a grinding chamber filled with grinding balls, in particular a ball mill, an annular gap mill, a bead mill, and a Manton-Gaulin mill, and combinations thereof.

14. A zeolite obtainable by a process according to any one of claims 1 to 11, in particular MFI zeolite and BETA zeolite.