CN111886202A

CN111886202A - Process for synthesizing zeolite SSZ-13

Info

Publication number: CN111886202A
Application number: CN201980020854.7A
Authority: CN
Inventors: 达南杰·普拉巴卡尔·萨布德; 阿尔希亚·阿尔塔夫·拉勒吉; 拉杰什库马尔·马努拜·帕特尔; 维贾伊·索潘·纳赫德
Original assignee: Sade Chemicals India Private Ltd
Current assignee: Sade Chemicals India Private Ltd
Priority date: 2018-01-23
Filing date: 2019-01-23
Publication date: 2020-11-03
Anticipated expiration: 2039-01-23
Also published as: CN111886202B; WO2019145869A1; EP3743381A1

Abstract

By means of which a main process for the synthesis of aluminosilicate zeolite SSZ-13 having the chabazite structure. The synthesis uses a quaternary ammonium salt, i.e., a chloride or hydroxide salt of a 3-chloro-2-hydroxypropyl trimethylammonium ion [ (CH3)3N + CH2-CHOH-CH2Cl ] solution or a2, 3-dihydroxypropyl trimethylammonium ion [ (CH3)3N + CH2-CHOH-CH2OH ] solution (referred to herein as Q1), silica, alumina and alkali metal cations, and a small amount of NN N-trimethyl adamantyl ammonium hydroxide (referred to herein as Q2) to synthesize SSZ-13. The SSZ-13 synthesized by means of this can be further ion-exchanged into the ammonium form and then calcined to the H form.

Description

Process for synthesizing zeolite SSZ-13

Introduction:

natural and synthetic zeolites are important and useful compositions. Many of these zeolites or aluminosilicates are porous and have a well-defined, unique crystal structure and chemical composition. The crystals have a large number of cavities and pores, the size and shape of which vary from zeolite to zeolite. Changes in chemical composition, pore size and shape cause changes in the adsorption and catalytic properties of these zeolites. Due to their unique molecular sieve characteristics as well as their potential acidic properties, shape selectivity, ion exchange capacity, zeolites are particularly useful as adsorbents in hydrocarbon processing and as catalysts for cracking, reforming and other hydrocarbon conversion reactions and environmental applications. Although many different crystalline aluminosilicates have been prepared and tested for a wide range of applications, new zeolites useful in hydrocarbon and chemical processing are still being sought.

In recent years, small pore zeolites have attracted attention due to their promising activity in a wide range of applications such as SCR, methanol to olefins. Among many small pore zeolites, SSZ-13, one of the synthetic zeolites having the chabazite structure (CHA topology), has been found to be promising for SCR applications due to high NOx conversion, higher N2 selectivity, thermal stability and hydrothermal stability.

Due to growing concerns about protecting the environment and human health from vehicle air pollutants, the world has continuously tightened emission standards to control pollutants (such as CO, NOx, HC, and PM) from stationary and mobile engines over the years. So-called modern three-way catalytic converters (now standard components on vehicles) have helped dramatically reduce emissions of CO, HC and NOx, especially for mobile gasoline applications running at stoichiometric air/fuel ratios. Thus, the introduction of catalytic converter technology has significantly improved air quality and correspondingly improved human health.

Catalytic converter technology for gasoline-based engines cannot be directly applied to lean-burn engines operating at high air/fuel ratios. In conventional diesel engines, controlling both NOx and Particulate Matter (PM) emissions simultaneously is challenging due to existing NOx-PM tradeoffs. In addition, reducing NOx in an oxygen-rich environment can increase the complexity of emission control. In order to meet the stringent NOx and PM emission standards for diesel engines, clean diesel technology and the application of highly efficient exhaust after-treatment systems are required. To further comply with current and future regulations for light and heavy duty diesel engines, both NOx and PM must be greatly minimized for the most advanced diesel engines of today.

For the control and regulation of NOx, technologies such as vanadium-tungsten-titanium (VWT) catalysts and metals incorporated in zeolite catalysts like Fe, Cu for SCR aftertreatment systems are commercially available, which are rarely proven in the market. The temperature window of the V-based catalyst is 180 ℃ to 450 ℃, and the conversion in the low temperature region is limited. The base metal (Cu or Fe) zeolite catalysts operate in different temperature ranges. Fe-based zeolite catalysts show excellent activity in high temperature systems, however the low temperature activity of NOx conversion on Fe-zeolites is poor. Recently, Cu-based zeolites, particularly Cu-SSZ-13, have become more attractive due to their wide operating temperature range and better durability.

The primary concerns of base metal/zeolite catalysts for SCR reactions are sulfur poisoning and thermal durability due to high sulfur levels in the fuel prior to BS-IV. The effect of sulfur, particularly on Cu-based catalysts, is more severe for NOx activity than for Fe-based zeolite catalysts. However, due to the availability of fuels with less than 10ppm sulfur for BS-VI applications, it becomes feasible to use Cu-containing catalysts for aftertreatment systems.

In recent literature, several efforts to design and develop robust Cu-SSZ-13 catalysts using various preparation methods such as chemical vapor deposition, liquid phase ion exchange methods, one-pot synthesis, etc. have been reported. In particular, catalysts prepared via the wet chemical route show excellent deNOx activity and high selectivity to N2.

Technical Field

The present invention relates to the synthesis of zeolite SSZ-13 having the chabazite structure. SSZ-13 is a small pore zeolite. The SSZ-13 framework consists of SiO4 and AlO4 tetrahedra (tetrahydrodra) connected by a common corner of oxygen atoms to form the CHA structure. SSZ-13 is a porous material with pore openings of 0.38X 0.38 nanometers and contains a well-defined and unique crystalline structure that can be determined by X-ray diffraction. Because the crystalline structure of SSZ 13 contains a large number of cavities and pores having different pore sizes and pore diameters, SSZ-13 can be effectively used in catalyst formulations for the removal of nitrogen oxide emissions from exhaust gases emitted by automobiles and manufacturing industries. SSZ-13 is also promising for other applications, such as the conversion of methanol to olefins and the production of methylamine from methanol and ammonia.

The invention further relates to the cost-effective preparation of SSZ-13 having different physico-chemical properties. More particularly, the present invention relates to the synthesis of SSZ-13, intended to meet the specific requirements of various applications employing SSZ-13 as a catalyst, catalyst support and starting material.

Background

Unique physicochemical properties or combinations of properties of SSZ-13 zeolite are required in a variety of applications. Individual characteristics, such as silica to alumina molar ratio (SiO2/Al2O3), SEM grain size, powder particle size, carbon content, phase purity, alkali content, and surface area, or combinations thereof, are required for a particular application. The molar ratio of silica to alumina (SiO2/Al2O3), SEM grain size, powder particle size, carbon content, phase purity, alkali content, and surface area directly related to the subject matter of the present invention are explained as follows.

Silica to alumina molar ratio (SiO2/Al2O 3): the SiO2/Al2O3 molar ratio of the zeolite is determined by wet chemical analytical methods or instrumental techniques such as XRF or ICP. The SiO2/Al2O3 molar ratio of a particular zeolite affects the acidity of the zeolite and the exchange capacity of the active metal/element at the exchange sites. For SCR applications, the zeolite is typically exchanged/loaded with Cu or Fe. The Cu and/or Fe content at the exchange sites determines the NOx conversion activity of a particular zeolite. Thus, the SiO2/Al2O3 molar ratio is an important criterion to consider for zeolites for SCR or any other application.

SEM grain size: the crystallite size of the zeolite was determined by Scanning Electron Microscopy (SEM). An SEM is a type of electron microscope that produces an image of a sample by scanning a surface with a focused electron beam. The crystallite size of a zeolite of a particular zeolite is known to affect aggregate size, stability under a set of conditions, and performance in a particular application.

Granularity: the particle size of the zeolite is determined by a number of techniques. One common technique is by laser diffraction. For SCR applications, particle size is known to affect the coating thickness of the active component. Especially for filter applications (SCRF), smaller and narrow particles are required, as they will influence the elution coating thickness. If the particle size distribution of the eluting coating is high, the eluting coating may plug the pores of the substrate (honeycomb carrier), thereby limiting access of the reactant molecules to the active component. In an effective catalyst, there is no resistance to internal diffusion, i.e., the reactant molecules diffuse through the pores of the catalyst/catalyst support.

Carbon content: carbon content was determined by CHN analyzer/combustion analyzer. A common source of carbon content in zeolites is due to incomplete calcination/removal of the organoamine templating agent from the zeolite pores. In certain applications, the presence of carbon content affects the activity of the zeolite to some extent.

Alkali content: the alkali content in the zeolite was determined by flame photometry. The common alkali content in zeolites is Na and K. The presence of alkali levels in the zeolite above a certain level can affect the activity of the zeolite.

Surface area: surface area is an important characteristic of zeolites. The surface area of the zeolite was measured using the N2 adsorption technique. The surface area of the zeolite is related to porosity, particle morphology and size. Surface area is known to affect catalytic activity.

Phase purity: the phase purity and crystallinity of the zeolite was determined by XRD. It is known that the impurity content in zeolites can affect the properties and activity for a particular application.

It follows therefore that for a particular application, the optimum SiO2/Al2O3 molar ratio, alkali content, carbon content, SEM grain size and particle size are required.

The conventional method for synthesizing SSZ-13 is expensive because it involves the use of NNN trimethyladamantyl ammonium hydroxide as a templating agent. SSZ-13 is synthesized using a quaternary ammonium salt, i.e., a chloride or hydroxide salt of a 3-chloro-2-hydroxypropyl trimethylammonium ion [ (CH3)3N + CH2-CHOH-CH2Cl ] solution or a2, 3-dihydroxypropyl trimethylammonium ion [ (CH3)3N + CH2-CHOH-CH2OH ] solution (referred to herein as Q1), silica, alumina, and an alkali metal cation, and a small amount of NNN-trimethyladamantyl ammonium hydroxide (referred to herein as Q2). The synthesis optionally includes chloride or hydroxide salts of Q1. Synthesis also optionally involves the use of SSZ-13 zeolite itself (which may be used as a seed material) which may be added to a mixture of 3-chloro-2-hydroxypropyl trimethylammonium salt solution and NNN-trimethyladamantyl ammonium hydroxide with silica, alumina and alkali metal cation solutions of the desired molar gel composition described above. The addition of a seeding material, i.e., SSZ-13 zeolite, helps to produce the desired morphology and phase and reduces hydrothermal crystallization time. SSZ 13 is produced as a result when the above mixture is subjected to hydrothermal synthesis. The process was found to be more cost effective and the resulting SSZ-13 produced effectively removed nitrogen oxide emissions from automobiles and manufacturing.

US 4544438 relates to a process for the preparation of SSZ-13 from organic nitrogen-containing cations derived from 1-amantadine, 3-quinuclidinol and 2-exo-aminonorbornane. The prior art employs mixtures of active material compounds such as sodium silicate, water, aluminum sulfate, sodium hydroxide, and trimethyladamantyl ammonium salts. The mixture was subjected to hydrothermal synthesis for 6 days.

US 4665110 relates to a process for the preparation of a crystalline molecular sieve composition requiring a reaction mixture comprising an adamantane compound as template for its crystallization. The prior art employs mixtures of active material compounds such as water and trimethyladamantylammonium salts. Another mixture of aluminum sulfate and sodium hydroxide is prepared and then added to the trimethyladamantylammonium salt solution. The mixture was subjected to hydrothermal synthesis for 6 days.

US 20110251048 relates to the synthesis of chabazite-type zeolites which are expected to have durability and heat resistance, which are desirable practical characteristics for catalyst supports and adsorbents. The prior art uses mixtures of active material compounds such as sodium or potassium hydroxide with NNN trimethyladamantyl ammonium salts. A solution of NNN trimethyladamantyl ammonium salt was made, a KOH/NaOH solution was prepared and added to the salt solution. Sodium aluminosilicate was prepared using sodium silicate and aluminium sulphate, respectively. The aluminosilicate gel was added to the NNN trimethyladamantylammonium salt solution. The gel was mixed for some time and then subjected to hydrothermal synthesis in an autoclave. The gel mixture was subjected to hydrothermal synthesis for 6 days. It is important to note that the prior art is directed to producing chabazite-type zeolites having a crystallite size greater than 1.5 microns.

US 20140147378 relates to a method of preparing a CHA-type molecular sieve using a colloidal aluminosilicate composition comprising at least one cyclic nitrogen-containing cation suitable as a structure directing agent for the synthesis of the CHA-type molecular sieve. The prior art uses mixtures of active material compounds such as colloidal aluminosilicates containing NNN trimethyladamantyl ammonium hydroxide, SSZ-13 seeds to produce SSZ-13. Whereas the prior art shows that the present invention should mandatorily comprise a colloidal aluminosilicate composition comprising at least one cyclic nitrogen cation which will act as a structure directing agent.

Thus, the prior art reveals that not only is synthesis time longer, but the process is resource intensive and costly. The following mentions the disadvantages for each prior art;

a) US 4544438, US 4665110, US 20110251048 and US 20140147378 use NNN trimethyladamantyl ammonium salts as templating agents, which are expensive

b) Furthermore, the synthesis time is longer, i.e. typically 6 days, which makes it resource intensive

c) Furthermore, the range of product properties obtained is narrow, i.e. SSZ-13 is synthesized with the aim of producing silica to alumina ratios (SiO2/Al2O3) and SEM grain sizes within a narrow range.

d) The synthesis includes a colloidal aluminosilicate composition that includes cyclic nitrogen cations as part of its active material. Furthermore, colloidal aluminosilicate compositions are expensive.

Therefore, there is an urgent and long-felt need for a versatile synthesis formulation and method that ensures economy in terms of synthesis time, resources and cost-effective raw materials by varying the synthesis formulation and synthesis conditions, and also provides a tailored approach to achieve the desired characteristics in terms of silica to alumina ratio (SiO2/Al2O3) and SEM grain size.

The inventors have conducted extensive studies to design a) synthetic formulations for preparing SSZ-13 with shorter synthesis times, b) synthetic formulations comprising structure directing agents that are cost effective, c) surprisingly provide versatility to tailor-made methods of SSZ-13 with desired physicochemical properties, wherein the properties are not limited to a narrow range of silica to alumina ratios (SiO2/Al2O3) and SEM grain sizes. Individual characteristics or combinations of characteristics can be tailored to suit the requirements of various industrial processes employing SSZ-13.

To overcome the shortcomings of the prior art methods, the inventors sought alternative formulations that included low cost templating agents and small amounts of NNN trimethyladamantyl ammonium salt. After several trials of various combinations including common templating agents used in the art, the replacement templating agent, 3-chloro-2 hydroxypropyl trimethylammonium salt, was tested. The compound is structurally similar to NNN trimethyladamantylammonium salt to some extent. It has been unexpectedly found that a combination of 3-chloro-2 hydroxypropyl trimethylammonium salt and lesser amounts of NNN trimethyladamantylammonium salt is suitable for use in making SSZ-13. This combination also provides advantages in terms of cost.

The present invention employs a mixture of compounds such as sodium or potassium hydroxide, alumina and silica, which are then added to a solution of 3-chloro-2 hydroxypropyl trimethylammonium salt and/or a small amount of NNN trimethyladamantylammonium salt or both. SSZ-13 seeds are also optionally added to the gel to direct the synthesis to a pure phase and reduce crystallization time. This also shows that SSZ-13 produced using the present invention is unique in that the compounds used to produce the crystalline molecular sieve composition are different from the compounds of the prior art.

The present invention is directed to producing a wide range of grain sizes, i.e., SSZ-13 grain sizes of 0.1 to 5 microns. It may also be noted that the present invention does not comprise such colloidal aluminosilicate compositions comprising cyclic nitrogen cations as part of their active materials, which are used in the prior art for the efficient synthesis of SSZ-13.

Object of the Invention

It is an object of the present invention to prepare SSZ-13 which can be used to produce catalyst formulations for the efficient removal of nitrogen oxide emissions from exhaust gases emitted by automotive and manufacturing industries.

It is another object of the present invention to prepare SSZ-13 in a cost-effective manner by employing a relatively low cost templating agent. The resulting product should be less resource intensive (economical) than competing processes in the art.

It is a primary object of the present invention to provide a formulation for producing SSZ-13 having desirable physicochemical properties. The formulation involves fewer steps, is more energy efficient, and has lower synthesis times and hydrothermal synthesis temperatures.

It is another principal object of the described invention to provide a formulation for making SSZ-13 with tailored physicochemical properties by varying the synthesis formulation and process conditions during zeolite synthesis.

Disclosure of Invention

By means of which a main process for the synthesis of aluminosilicate zeolite SSZ-13 having the chabazite structure. The synthesis uses a quaternary ammonium salt, i.e., a chloride or hydroxide salt of a 3-chloro-2-hydroxypropyl trimethylammonium ion [ (CH3)3N + CH2-CHOH-CH2Cl ] solution or a2, 3-dihydroxypropyl trimethylammonium ion [ (CH3)3N + CH2-CHOH-CH2OH ] solution (referred to herein as Ql), silica, alumina and alkali metal cations, and a small amount of NNN-trimethyladamantyl ammonium hydroxide (referred to herein as Q2) to synthesize SSZ-13. The SSZ-13 synthesized by means of this can be further ion-exchanged into the ammonium form. Subsequently, the ammonium form or the calcined H form is further ion exchanged with copper and/or iron salts. Ion-exchanged zeolites are then used as catalysts to effectively remove nitrogen oxide emissions from exhaust gases emitted by automobiles and manufacturing industries.

Detailed Description

The present invention relates to the synthesis of aluminosilicate zeolite SSZ-13 having the chabazite structure. H-SSZ-13 or NH4-SSZ-13 obtained after ion exchange with ammonium and/or mineral acid has the following properties:

x-ray diffraction value: pure phase with chabazite structure

2. Silica to alumina ratio: 5 to 100

3. Total alkali content (Na2O and K2O): < 5000 parts per million

4. Surface area: 500 square meter/g

5. Grain size: 0.1 to 5 microns

6. Carbon content: < 0.5% by weight

The invention was synthesized using the following molar gel composition for one mole of alumina:

1.0 to 4 molar 3-chloro-2 hydroxypropyl trimethylammonium salt solutions

2.0.2 to 8 molar trimethyladamantyl ammonium hydroxide salt solution

3.0 to 10 mol potassium hydroxide or sodium hydroxide

4.5 to 150 silica

5.200 to 2000 parts of water

The method of synthesizing SSZ-13, which is an aluminosilicate zeolite having a chabazite structure, is used in catalyst formulations for the effective removal of nitrogen oxide emissions from exhaust gas emitted by automobiles and manufacturing industries.

Preparation of a solution of 3-chloro-2-hydroxypropyltrimethylammonium salt or a solution of NNN-trimethyladamantylammonium hydroxide or a mixture of the two.

Adding a sodium hydroxide solution to a solution of 3-chloro-2-hydroxypropyl trimethylammonium salt or a solution of NNN-trimethyladamantyl ammonium hydroxide or a mixture of both to produce a mixture.

In another aspect of the invention, wherein a potassium hydroxide solution can be added instead of sodium hydroxide to a solution of 3-chloro-2-hydroxypropyl trimethylammonium salt or a solution of NNN-trimethyladamantyl ammonium hydroxide or a mixture of both to produce a mixture.

Another aspect of the invention, wherein, instead, a solution of 2, 3-dihydroxypropyltrimethylammonium salt can be used instead of 3-chloro-2-hydroxypropyltrimethylammonium salt.

Then to the above mixture is added alumina sol or aluminium metal or aluminium hydroxide or pseudoboehmite alumina or aluminium alkoxide or aluminium sulphate or aluminium nitrate form of alumina.

Then adding to the above-mentioned mixture to which alumina has been added precipitated silica or silica sol or fumed silica or silica in the form of silicon alkoxide, sodium silicate to produce a gel-based mixture.

Another aspect of the invention, wherein the order of addition of the silica source and the alumina source may be reversed. In another aspect of the present invention, the order of addition of the other materials may be varied.

The gel-based mixture obtained above is then subjected to stirring for 30 to 120 minutes.

The above gel-based mixture is then optionally mixed with SSZ-13 seeds to accelerate the process of synthesizing the SSZ-13 zeolite mixture and/or to avoid other crystalline impurities. The above gel is subjected to homogeneous mixing for 5 to 30 minutes.

The resulting mixture is then subjected to hydrothermal synthesis in an autoclave at autogenous pressure at a temperature range of 80 to 200 degrees celsius for 1/2 to 6 days to produce SSZ-13.

Calcining the SSZ-13 thus obtained at 450 to 650 degrees celsius in nitrogen and/or air for 4 to 12 hours to remove organic materials associated with the SSZ-13 zeolite.

The SSZ-13 obtained is then treated with an ammonium salt or a dilute mineral acid to obtain SSZ-13 in the ammonium form or H form, respectively.

Calcination of SSZ-13 in ammonium form obtained by treatment of the ammonium salt to obtain SSZ-13 in hydrogen form.

In order to provide a clear understanding of the invention, and not to limit the scope thereof, some embodiments thereof are described below as examples and are annexed tables showing the various properties of the SSZ-13 zeolite product.

1) Example 1: synthesis of H-SSZ-13 with input SAR of 26

40g of NN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt.% in water) was taken and mixed with 13.6g of the hydroxide salt of 3-chloro-2-hydroxypropyltrimethylammonium chloride (HPTMAH solution, 25 wt.% in water) together with 137g of water. A solution of 8g KOH in 91g water was then added and mixed for 10 minutes. To the above mixture was slowly added 156.8g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. Aluminum sulfate solution was separately prepared by adding 19.2g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 54.74g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

26 SiO2:Al2O3:2 K2O:1.57 TMADAOH:0.65 HPTMAOH:802 H2O

The pH of the gel composition was set to pH 12 by adding a 20 wt% strength KOH solution. To the above gel composition, 1.64g of SSZ-13 seed crystals were added and mixed thoroughly for 30 minutes.

The molar gel composition was heated from room temperature to 170 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 170 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The total yield was 38 g. The grain size by SEM is in the range of 0.2 to 1.0 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

2) Example 2: synthesis of H-SSZ-13 with input SAR of 26

26.7g of NN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt.% in water) was taken and mixed with 26.7g of the hydroxide salt of 3-chloro 2-hydroxypropyltrimethylammonium chloride (HPTMAOH solution, 25 wt.% in water) together with 137g of water. A solution of 8g KOH in 91g water was then added and mixed for 10 minutes. To the above mixture was slowly added 156.8g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. Aluminum sulfate solution was separately prepared by adding 19.2g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 54.74g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

26 SiO2:Al2O3:2 K2O:1.0 TMADAOH:1.3 HPTMAOH:802 H2O

The molar gel composition was heated from room temperature to 170 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 170 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The total yield was 35 g. The grain size by SEM is in the range of 0.2 to 1.0 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

3) Example 3: synthesis of H-SSZ-13 with input SAR of 17

52.4g of NN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt% in water) was taken along with 134g of water. A solution of 7.9g KOH in 90g water was then added and mixed for 10 minutes. To the above mixture was slowly added 154g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. The aluminum sulfate solution was separately prepared by adding 28.8g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 54g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

17 SiO2:Al2O3:1.3 K2O:1.37 TMADAOH:524 H2O

The pH of the gel composition was set to pH 12 by adding a 20 wt% strength KOH solution. To the above gel composition, 1.6g of SSZ-13 seed crystals were added and mixed thoroughly for 30 minutes.

The molar gel composition was heated from room temperature to 170 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 170 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The grain size by SEM is in the range of 0.4 to 1.0 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

4) Example 4: synthesis of H-SSZ-13 with input SAR as 35

54g of NN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt% in water) was taken along with 99g of water. A solution of 8g KOH in 91g water was then added and mixed for 10 minutes. To the above mixture was slowly added 211g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. Aluminum sulfate solution was separately prepared by adding 19.2g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 54.74g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

35 SiO2:Al2O3:2 K2O:2 TMADAOH:802 H2O

The molar gel composition was heated from room temperature to 170 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 170 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The grain size by SEM is in the range of 0.6 to 1.2 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

5) Example 5: synthesis of H-SSZ-13 with input SAR of 26

54g of NN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt% in water) was taken along with 137g of water. A solution of 8g KOH in 91g water was then added and mixed for 10 minutes. To the above mixture was slowly added 156.8g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. An aluminum sulfate solution was separately prepared by adding 19.2g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 54.74g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

26 SiO2:Al2O3:2 K2O:2 TMADAOH:802 H2O

The molar gel composition was heated from room temperature to 160 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 160 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The grain size by SEM is in the range of 1 to 3 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

6) Example 6: synthesis of H-SSZ-13 with input SAR of 17

29.5g of NNN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt% in water) was taken together with 287g of water. A solution of 5.5g NaOH in 50g water was then added and mixed for 10 minutes. To the above mixture was slowly added 56.4g of silica sol (30 wt% SiO2) and stirred for further 30 minutes. The aluminum sulfate solution was separately prepared by adding 10.5g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 81g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

17 SiO2:Al2O3:4.1 Na2O:2.1 TMADAOH:1610 H2O

The pH of the gel composition was set to pH 12 by adding a 20 wt% strength NaOH solution. To the above gel composition 0.64g of SSZ-13 seed crystals were added and mixed thoroughly for 30 minutes.

The molar gel composition was heated from room temperature to 170 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 170 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The grain size by SEM is in the range of 0.1 to 0.4 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

7) Example 7: synthesis of H-SSZ-13 with input SAR of 26

27.8g of NNN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt% in water) was taken together with 266g of water. A solution of 5.4g NaOH in 50g water was then added and mixed for 10 minutes. To the above mixture was slowly added 85.1g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. The aluminum sulfate solution was separately prepared by adding 10.42g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 76g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

26 SiO2:Al2O3:4.1 Na2O:2.0 TMADAOH:1610 H2O

The pH of the gel composition was set to pH 12 by adding a 20 wt% strength NaOH solution and mixed thoroughly for 30 minutes.

8) Example 8: synthesis of H-SSZ-13 with input SAR as 100

54g of NN trimethyladamantyl ammonium hydroxide (TMADAOH) template solution (25 wt% in water) was taken along with 137g of water. A solution of 8g KOH in 91g water was then added and mixed for 10 minutes. To the above mixture was slowly added 156.8g of silica sol (30 wt% SiO2) and further stirred for 30 minutes. The aluminum sulfate solution was separately prepared by adding 5g of aluminum sulfate 16H2O (16 wt.% Al2O3) to 54.74g of water to obtain a clear solution. To the solution containing the templating agent, base and silica precursor, an aluminum sulfate solution is slowly added. The gel mixture was stirred for 1 hour.

The molar gel composition at this stage is as follows

100 SiO2:Al2O3:7.6 K2O:8 TMADAOH:3080 H2O

The molar gel composition was heated from room temperature to 170 ℃ over 3 hours with stirring in a closed autoclave and subjected to hydrothermal synthesis at 170 ℃ for 4 days. After crystallization, XRD was carried out. After hydrothermal synthesis, the contents of the autoclave were cooled and subjected to filtration. The wet cake is washed with desalted water to remove the templating agent and other soluble impurities. The washed wet cake was subjected to drying at 120 ℃ for 12 hours. Phase purity was confirmed by XRD. The grain size by SEM is in the range of 0.5 to 3.0 microns. Prior to ion exchange with a solution of an inorganic acid or ammonium salt, the as-synthesized zeolite is calcined at 550 ℃ to limit the base content in the zeolite to less than 500 ppm. The H form of the zeolite is then obtained by drying and calcination. The SiO2/Al2O3 molar ratio of the zeolite was confirmed by chemical analysis.

Table 1:

Claims

1. a process for producing SSZ-13 zeolite, the process comprising,

a) providing an aqueous reaction mixture comprising at least one source of silica, at least one source of alumina, at least one source of alkali metal hydroxide, and at least two sources of quaternary ammonium ions, wherein at least one such source of quaternary ammonium ions (Q1) has the formula (CH3)3N + CH2-CHOH-CH2Cl or (CH3)3N + CH2-CHOH-CH2OH ions,

b) the resulting mixture is stirred for 30 to 120 minutes,

c) the mixture is then subjected to hydrothermal synthesis in an autoclave at autogenous pressure at a temperature range of 80 to 200 degrees celsius for 12 hours to 144 hours to produce SSZ-13

d) Filtering the zeolite slurry, washing the wet cake with desalted water, drying the wet cake at 120 degrees Celsius for 6 to 12 hours, and calcining the resulting SSZ-13 at 450 to 650 degrees Celsius for 4 to 12 hours in nitrogen and/or air to remove organic material associated with the SSZ-13 zeolite

e) Treating the resulting SSZ-13 with an ammonium salt to obtain SSZ-13 in the ammonium form

f) The resulting ammonium form of SSZ-13 is calcined to obtain the hydrogen form of SSZ-13.

2. The method of claim 1, wherein the second quaternary ammonium ion (Q2) is an NNN trimethyladamantylammonium ion.

3. The process of claim 1 or 2, wherein the aqueous reaction mixture of step (a) has a molar composition of (1Al2O3): from (5 to 150SiO2): from (0.1 to 4Q1): from (0.2 to 8 second quaternary ammonium ion (Q2)): from 0.1 to 10 potassium hydroxide and/or sodium hydroxide): from 200 to 2000 water.

4. The method of claim 1, 2 or 3, wherein the molar ratio of first quaternary ammonium ion (Q1) to second quaternary ammonium ion (Q2) is from 0.0125 to 20.

5. The process of claim 1, wherein the aqueous reaction mixture of step (a) comprises a silica to alumina molar ratio of 5 to 150.

6. The process of claim 1, wherein SSZ-13 seed crystals are optionally added to the aqueous reaction mixture of step (a).

7. The process of claim 5, wherein the SSZ-13 seed crystals are present in the reaction mixture in an amount of 0.1 to 5 wt% of SiO 2.

8. The process of claim 1, wherein the ammonium salt of step (e) comprises ammonium nitrate or sulfate or chloride at a concentration of less than 5 wt%.

9. The process of claim 1, wherein the resulting SSZ-13 obtained after step (d) is treated with dilute mineral acid to obtain the final SSZ-13 zeolite in hydrogen form.

10. The method of claim 9, wherein the inorganic acid comprises nitric acid or sulfuric acid or hydrochloric acid at a concentration of less than 3 wt%.

11. The process of claim 1 or 9, wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has a total alkali content of less than 5000 parts per million.

12. The process of claim 1 or 9, wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has a surface area of more than 500 m/g.

13. The process according to claim 1 or 9, wherein the obtained SSZ-13 zeolite obtained at the end of step (f) has a carbon content of less than 0.5 wt.%.

14. The process according to claim 1 or 9, wherein the obtained SSZ-13 zeolite obtained at the end of step (f) has a SiO2/Al2O3 molar ratio ranging from 5 to 100.

15. The process of claim 1 or 9, wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has a crystallite size by SEM in the range of 0.1 to 5 microns.

16. A process for producing SSZ-13 zeolite, the process comprising,

a) providing an aqueous reaction mixture comprising at least one silica source, at least one alumina source, at least one alkali metal hydroxide source, and at least one source of quaternary ammonium ions (Q2) which are NNN trimethyl adamantyl ammonium ions

b) The resulting mixture is stirred for 30 to 120 minutes

17. The process of claim 16, wherein a second quaternary ammonium ion (Q1) having the formula (CH3)3N + CH2-CHOH-CH2Cl or (CH3)3N + CH2-CHOH-CH2OH ion is added in step (a).

18. The process of claim 16 wherein the aqueous reaction mixture of step (a) has a molar composition of (1Al2O3) (5 to 150SiO2) (0.1 to 4Q1) (0.2 to 8Q2) (0.1 to 10 potassium hydroxide and/or sodium hydroxide) (200 to 2000 water).

19. The method of claim 16, 17 or 18, wherein the molar ratio of first quaternary ammonium ion (Q1) to second quaternary ammonium ion (Q2) is from 0.0125 to 20.

20. The process of claim 16 or 17, wherein the aqueous reaction mixture of step (a) comprises a silica to alumina molar ratio of 5 to 150.

21. The process of claim 16 or 17, wherein SSZ-13 seed crystals are optionally added to the aqueous reaction mixture of step (a).

22. The process of claim 21, wherein the seed crystal is present in the reaction mixture in an amount of 0.1 to 5 wt% of SiO 2.

23. The method of claim 16 or 17, wherein the ammonium salt of step (e) comprises ammonium nitrate or sulfate or chloride at a concentration of less than 5 wt%.

24. The process according to claim 16 or 17, wherein the obtained SSZ-13 obtained after step (d) is treated with dilute mineral acid to obtain the final SSZ-13 zeolite in hydrogen form.

25. The method of claim 24, wherein the inorganic acid comprises nitric acid or sulfuric acid or hydrochloric acid at a concentration of less than 3 wt%.

26. The process of claim 16 or 17, wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has a total alkali content of less than 5000 parts per million.

27. The process of claim 16 or 17, wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has a surface area of more than 500 m/g.

28. The process according to claim 16 or 17, wherein the obtained SSZ-13 zeolite obtained at the end of step (f) has a carbon content of less than 0.5 wt.%.

29. The process as claimed in claim 16 or 17, wherein the obtained SSZ-13 zeolite obtained at the end of step (f) has a SiO2/Al2O3 molar ratio ranging from 5 to 100.

30. The process of claim 16 or 17, wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has a crystallite size by SEM in the range of 0.1 to 5 microns.