EP3743381A1

EP3743381A1 - Process for synthesizing zeolite ssz-13

Info

Publication number: EP3743381A1
Application number: EP19712272.4A
Authority: EP
Inventors: Dhananjay Prabhakar SABDE; Arshia altaf LALJEE; Rajeshkumar Manubhai PATEL; Vijay Sopan Narkhede
Original assignee: Sued Chemie India Pvt Ltd
Current assignee: Sued Chemie India Pvt Ltd
Priority date: 2018-01-23
Filing date: 2019-01-23
Publication date: 2020-12-02
Also published as: CN111886202B; WO2019145869A1; CN111886202A

Abstract

A primary means by way of which SSZ-13 which is an aluminosilicate zeolite with a chabazite structure is synthesized. The synthesis employs quaternary ammonium salts i.e chloride or hydroxide salts of 3-chloro-2 – hydroxy propyl trimethyl ammonium ion [(CH3)3N+CH2-CHOH-CH2Cl] solution or 2,3-dihydroxy propyl trimethyl ammonium ion [(CH3)3N+CH2-CHOH-CH2OH] solution referred herein as Q1, silica, alumina and an alkali metal cation in addition to low amounts of NNN-Trimethyl adamantyl ammonium hydroxide referred herein as Q2 to synthesize the SSZ-13. An auxiliary means by way of which the SSZ-13 synthesized can further ion exchanged to Ammonium form and subsequently calcined to H-form.

Description

PROCESS FOR SYNTHESIZING ZEOLITE SSZ-13

Introduction:

Natural and synthetic zeolites are important and useful compositions. Many of these zeolites or Alumino-silicates are porous and have definite, distinct crystal structures and chemical compositions. Within the crystals are a large number of cavities and pores whose dimensions and shapes vary from zeolite to zeolite. Variations in chemical composition, pore dimensions and shapes cause variations in the adsorptive and catalytic properties of these zeolites. Because of their unique molecular sieving characteristics, as well as their potentially acidic nature, shape selectivity, ion exchange ability, zeolites are especially useful in hydrocarbon processing as adsorbents 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 wide array of applications, the search for new zeolites which can be used in hydrocarbon and chemical processing continues.

In the recent years, small pore zeolites have attracted attention due to their promising activity in wide array of applications, such as SCR, methanol to olefins. Among the many small pore zeolites, SSZ-13 one of the synthetic zeolite with Chabazite Structure (CHA topology) is found promising for SCR application due to high NOx conversions, higher N2 Selectivity, thermal and hydrothermal stability.

Due to growing concerns to protect the environment and human health from vehicular air pollutants, emission standards to control the pollutants from stationary as well as mobile engines such as CO, NOx, HC and PM have been continuously tightened over the years in the world. Particularly for mobile gasoline applications that operate at stoichiometric air/fuel ratio, the so called modern three-way catalytic converter which is now a standard component on vehicles has contributed to a remarkable drop in emissions of CO, HC and NOx. As a result, the introduction of the catalytic converter technology has dramatically improved air quality and, correspondingly, human health.

The catalytic converter technology of gasoline -based engines cannot be directly applied to the lean burn engines which operate at high air/fuel ratio. In the conventional diesel engine simultaneous control of both NOx and particulate matter (PM) emissions is challenging because of existing trade-off of NOx-PM. Furthermore reduction of NOx in oxygen rich environment increases the complexity of the emission control. To meet the stringent NOx and PM emission standards for diesel engines requires clean diesel technology and the application of highly efficient exhaust gas after treatment systems. Further to comply current and future regulations of light and heavy duty diesel engines, both NOx and PM must be greatly minimized for today’s state of the art diesel engine.

In order to control and regulate NOx few proven technologies such as vanadium-tungsten-titanium (VWT) catalyst and metals like Fe, Cu incorporated in zeolite catalysts for the SCR aftertreatment systems is commercially available in the market. The temperature window for the V-based catalysts is 180 to 450 °C with limited conversion in the low temperature region. The working temperature range for the base metal (Cu or Fe) zeolite catalysts differs. The Fe-based zeolite catalyst exhibit excellent activity in the high temperature regime, however the low temperature activity for the NOx conversion over Fe-zeolite is inferior. Recently the Cu-based zeolites, particularly Cu-SSZ-l3, has become more attractive due to its wide working temperature range and better durability.

Due to high sulfur level in the fuel till BS-IV, the main concerns of the base metal/zeolite catalysts for the SCR reaction were sulfur poisoning and thermal durability. The impact of sulfur is more severe, particularly on Cu-based catalysts than on Fe-based zeolite catalysts for the NOx activity. However, due to the availability of fuel that has less than 10 ppm sulfur for BS-VI application, the utilization of Cu-containing catalysts becomes feasible for the aftertreatment systems.

In recent literature several efforts have been reported to design and develop robust Cu-SSZ-l3 catalysts employing various preparation methodologies, such as chemical vapor deposition, liquid phase ion exchange methods, one-pot synthesis, etc. In particular, the catalysts prepared via wet chemical routes showed excellent deNOx activity and high selectivity to N2.

Field of invention

The present invention relates to the synthesis of SSZ-13 which is a zeolite with a chabazite structure. SSZ-13 is a small pore zeolite. SSZ-13 frame work consists of Si04 and A104 tetrahydra connected through corner sharing of oxygen atom to form CHA structure. SSZ-13 is porous material with pore opening of 0.38 x 0.38 nanometers and contains a definite and distinct crystalline structure which can be determined by X-ray diffraction. Since the crystalline structure of SSZ 13 contains a large number of cavities and pores with a distinct pore dimension and pore size, SSZ-13 can be used effectively in catalyst formulation for removing Nitrogen oxide emissions from the exhaust gases emitted by automobiles and manufacturing industries. SSZ- 13 is also promising for other applications such as converting methanol to olefins and in the production of methyl amine from methanol and ammonia.

The present invention is further related to the cost effective preparation of SSZ- 13 with different physicochemical properties. More particularly the invention relates to the synthesis of SSZ-13, aimed at meeting the specific requirement of diverse applications employing SSZ- 13 as catalyst, catalyst support and starting material.

Background of the invention

Unique physicochemical property or combination of properties of SSZ-13 zeolite are required in diverse applications. The individual properties such as Silica to Alumina molar ratio (Si02/Al203), SEM crystallite size, powder particle size, carbon content, phase purity, alkali content and surface area or combinations thereof are required for particular application. The Silica to Alumina molar ratio (Si02/Al203), SEM crystallite size, powder particle size, carbon content, phase purity, alkali content and surface area, which are directly concerned with the subject matter of the present invention are explained as follows.

Silica to Alumina molar ratio (Si02/Al203): The Si02/Al203 molar ratio of zeolite is determined by either wet chemical analysis method or instrument techniques such as XRF or ICP. The Si02/Al203 molar ratio of a particular zeolite influence the acidity of zeolite and exchange ability of active metal /elements at exchange sites. For SCR application, typically the zeolites are exchanged/loaded with Cu or Fe. The content of Cu and/or Fe at exchange position determine the NOx conversion activity of a particular Zeolite. Hence Si02/Al203 molar ratio is an important criteria of a zeolite to be considered for SCR or any other application.

SEM crystallite size: The crystallite size of zeolite is determined by Scanning Electron Microscope (SEM). SEM is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The crystallite size of zeolite of a particular zeolite is known to influence the aggregate particle size, stability under set of conditions and performance in a particular application

Particle size: The particle size of zeolite is determined by many techniques. One the common technique is by laser diffraction method. As far as SCR application is concerned, the particle size is known to influence the coating thickness of active component. Especially for filter application (SCRF), lower and narrow particle is desired as the same will influence the washcoat thickness. If the particle size distribution of wash coat is high, the same may block the pores of substrate (honey comb support), thus limiting the access of reactant molecules to active component. In an effective catalyst, there is no resistance to internal diffusion i.e reactant molecules diffuse through the pores of catalyst / catalyst support.

Carbon content: The carbon content is determined by CHN analyzers/combustion analyzers. The common source of carbon content in zeolite is attributed to incomplete calcination/removal of organic amine template from the zeolite pores. The present of Carbon content to some extent influence the activity of zeolite in particular application.

Alkali content: The alkali content in zeolite is determined by Flame photometer. The common alkali content in zeolites are Na and K. The presence of alkali content in zeolite beyond certain content influence the activity of zeolite.

Surface Area: Surface Area is important property of zeolite. The surface Area of zeolite is measured using N2 adsorption technique. Surface area of zeolite is related to porosity, particle morphology and size. Surface area in known to influence the catalytic activity.

Phase Purity: The Phase purity and crystallinity of zeolite are determined by XRD. The impurity content in zeolite is known to influence properties and activity for particular application. It follows therefore that an optimal Si02/Al203 molar ratio, alkali content, carbon content, SEM crystallite and particle size are required for particular application.

Conventional methods for synthesizing SSZ-13 are expensive as it involves the use of NNN Trimethyl adamantyl ammonium hydroxide as template. The subject invention employs quaternary ammonium salts i.e chloride or hydroxide salts of 3-chloro-2 - hydroxy propyl trimethyl ammonium ion [(CH3)3N+CH2-CHOH-CH2Cl] solution or 2,3-dihydroxy propyl trimethyl ammonium ion [(CH3)3N+CH2-CH0H-CH20H] solution referred herein as Ql, silica, alumina and an alkali metal cation in addition to low amounts of NNN-Trimethyl adamantyl ammonium hydroxide referred herein as Q2 to synthesize the SSZ-13. The synthesis optionally involves chloride or hydroxide salts of Ql. The synthesis also optionally involves the use of SSZ- 13 zeolite itself which can be used as seed material which may be added in to the aforementioned mixture of 3-chloro-2 - hydroxy propyl trimethyl ammonium salt solution and NNN-Trimethyl adamantyl ammonium hydroxide and silica, alumina and an alkali metal cation solution in desired molar gel composition. The addition of the seed material i.e SSZ-13 zeolite, helps in producing desired morphology and phase, and reduces the hydrothermal crystallization time. The aforementioned mixture when subjected to hydrothermal synthesis resultantly produces SSZ 13. The method is found to be more cost effective and the resultant SSZ- 13 produced effectively removes nitrogen oxide emissions from automobiles and manufacturing industries.

US 4544438 relates to a method of preparing SSZ- 13 from organic nitrogen-containing cations derived from l-adamantamine, 3-quinuclidinol, and 2-exo-aminonorbornane.The prior art employs a mixture of active material compounds such as sodium silicate, water, aluminium sulphate, sodium hydroxide and trimethyl adamantyl ammonium salt. The mixture is subjected to hydrothermal synthesis for 6 days.

US 4665110 relate to a method of preparing crystalline molecular sieve compositions requiring a reaction mixture for crystallization thereof which contains an adamantane compound as a templating agent. The prior art employs a mixture of active material compounds such as water and trimethyl adamantyl ammonium salt. Another mixture of Aluminium Sulphate and sodium hydroxide is prepared and then added to the trimethyl adamantyl ammonium salt solution. The mixture is subjected to hydrothermal synthesis for 6 days. US 20110251048 relates to the synthesis of a chabazite-type zeolite that is expected to have durability and thermal resistance, which are practical properties required of catalyst supports and adsorbents. The prior art employs a mixture of active material compounds such as sodium hydroxide or potassium hydroxide and NNN trimethyl adamantly ammonium salt. Solution of NNN trimethyl adamantly ammonium salt is made, KOH/NaOH solution is prepared and added to salt solution. Sodium Alumino-silicate is prepared separately using sodium silicate and Aluminium sulphate. The Alumino-silicate gel is added to the NNN trimethyl adamantly ammonium salt solution. The gel is mixed for some time then subjected to hydrothermal synthesis in an autoclave. The gel mixture is subjected to hydrothermal synthesis for 6 days. It is important to note that prior art aims at producing a chabazite type zeolite having a crystallite size of greater than 1.5 microns,

US 20140147378 relates to a process for preparing CHA-type molecular sieves using a colloidal aluminosilicate composition containing at least one cyclic nitrogen-containing cation suitable as structure directing agents for synthesizing CHA-type molecular sieves The prior art employs a mixture of active material compounds such as colloidal alumino silicate containing NNN trimethyl adamantly ammonium hydroxide, SSZ-13 seeds, to produce the SSZ-13. Whereas the prior art states that the invention should compulsorily contain a colloidal aluminosilicate composition containing at least one cyclic nitrogen cation, which will act as structure directing agent.

Prior art thus reveals, not only synthesis time are longer, but also the processes are resource intensive and cost prohibitive. The disadvantages against each of the prior art are mentioned below; a) US 4544438, US 4665110, US 20110251048 and US 20140147378 use NNN trimethyl adamantly ammonium salt as template, which is expensive

b) Further the synthesis time is longer i.e typically 6 days, making it resource intensive c) Further the product properties obtained are in narrow range i.e synthesis is aimed at producing SSZ-13 with Silica to Alumina ratio (Si02/Al203) and SEM crystallite size in narrow range.

d) The synthesis involves, colloidal aluminosilicate composition containing cyclic nitrogen cation as part of its active materials. Further the colloidal aluminosilicate composition are costly. There is therefore an urgent and long felt need for a versatile synthesis recipe and process that ensures economics in terms of synthesis time, resources and cost effective raw materials, and also provides tailor make process to get desired properties in terms of Silica to Alumina ratio (Si02/Al203) and SEM crystallite size by varying the synthesis recipe and synthesis conditions. The inventors after an extensive research, devised a) a synthesis recipe for preparing SSZ-13 with shorter synthesis time, b) a synthesis recipe which involves a cost effective structure directing agent, c) surprisingly provides versatility to the process to tailor make SSZ- 13 with desired physic- chemical properties, where by the attributes are not limited to narrow range of Silica to Alumina ratio (Si02/Al203) and SEM crystallite size. The individual or combination of properties can be tuned to suit the requirement of diverse industrial process employing SSZ-13.

To overcome the disadvantages of the prior art processes, alternate recipes comprising low cost template in addition to small amount of NNN trimethyl adamantly ammonium salt were explored by the inventors. After several trials of varied combinations including the common template used in the art, alternate template 3-chloro-2 hydroxy propyl trimethyl ammonium salt was tested. This compound to some extent is structurally similar to NNN trimethyl adamantly ammonium salt. Surprisingly the combination of 3-chloro - 2 hydroxy propyl trimethyl ammonium salt and lower amount of NNN trimethyl adamantly ammonium salt were found suitable for making SSZ- 13. The combination also provide advantage with respect to cost.

The present invention employs a mixture of compounds such as sodium hydroxide or potassium hydroxide, alumina and silica which is then added into the solution of 3-chloro-2 hydroxy propyl trimethyl ammonium salt solution and/or small amounts of NNN Trimethyl adamantyl ammonium salt solution or both. Optionally SSZ- 13 seeds are also added to gel to direct the synthesis to pure phase and reduce the crystallization time. This also shows that the SSZ- 13 producing using the present invention is distinct as the compounds employed to produce the crystalline molecular sieve composition is different from that of the prior art.

The present invention aims at producing SSZ- 13 crystallite size in wide range of crystallite size i.e from 0.1 to 5 microns. It may also be noted that the present invention does not contain such a colloidal aluminosilicate composition containing cyclic nitrogen cation as part of its active materials which are used for the effective synthesis of SSZ- 13 in prior art. Objects of the invention

The object of the present invention is to prepare SSZ-13, which can be used in producing catalyst formulations for the effective removal of nitrogen oxide emissions from the exhaust gases emitted by automobiles and manufacturing industries.

Another object of the present invention is to prepare SSZ-13 in a cost effective manner by employing relatively low cost template. The product obtained should be less resource intensive (economical) compared to competing processes in the art.

The main object of the present invention is to provide a recipe to make SSZ-13 with desired physico-chemical properties. The recipe involves fewer steps, more energy efficient and lower synthesis time and hydrothermal synthesis temperatures.

Another main object of the said invention is to provide a recipe to make SSZ-13 with custom make physico-chemical properties by varying synthesis recipe and process conditions during the synthesis of zeolite.

Summary of the invention

A primary means by way of which SSZ-13 which is an aluminosilicate zeolite with a chabazite structure is synthesized. The synthesis employs quaternary ammonium salts i.e chloride or hydroxide salts of 3-chloro-2 - hydroxy propyl trimethyl ammonium ion [(CH3)3N+CH2-CHOH- CH2C1] solution or 2,3-dihydroxy propyl trimethyl ammonium ion [(CH3)3N+CH2-CHOH- CH20H] solution referred herein as Ql, silica, alumina and an alkali metal cation in addition to low amounts of NNN-Trimethyl adamantyl ammonium hydroxide referred herein as Q2 to synthesize the SSZ-13. An auxiliary means by way of which the SSZ-13 synthesized can further ion exchanged to Ammonium form. Subsequently the ammonium form or Calcined H-form is further ion exchanged with Copper salt and /or iron salt. The ion exchanged zeolite is then employed as a catalyst to effectively remove nitrogen oxide emissions from exhaust gases emitted by automobiles and manufacturing industries. Detailed description of the invention

The invention relates to the synthesis of SSZ-13 which is an aluminosilicate zeolite with a chabazite structure. The H-SSZ-13 or NH4-SSZ-13 obtained after ion exchange with Ammonium and / or mineral acid has the following properties:

1. X-ray diffraction value: Phase pure with Chabazite Structure

2. Ratio of silica to alumina: 5 to 100

3. Total alkali content (Na20 and K20): < 5000 parts per million

4. Surface area: > 500 meter square per gram

5. Crystallite size: 0.1 to 5 microns

6. Carbon content: <0.5 weight %

The subject invention is synthesized using the following molar gel composition relative to one mole Alumina:

1. 0 to 4 moles 3-chloro - 2 hydroxy propyl trimethyl ammonium salt solution

2. 0.2 to 8 moles Trimethyl adamantyl ammonium hydroxide salt solution

3. 0 to 10 moles Potassium hydroxide or Sodium Hydroxide

4. 5 to 150 Silica

5. 200 to 2000 Water

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

Solution of 3-chloro-2-hydroxy-propyl trimethyl ammonium salt or solution of NNN- Trimethyl adamantyl ammonium hydroxide or a mixture of both is prepared Sodium hydroxide solution is added to the solution of 3-chloro-2-hydroxy-propyl trimethyl ammonium salt or Solution of NNN-Trimethyl adamantyl ammonium hydroxide or mixture of both to produce a mixture

Another aspect of the invention wherein potassium hydroxide solution can be alternatively added into the solution of 3-chloro-2-hydroxy-propyl trimethyl ammonium salt or Solution of NNN-Trimethyl adamantyl ammonium hydroxide or mixture of both instead of sodium hydroxide to produce a mixture. Another aspect of the invention wherein alternatively solution of 2,3 dihydroxy -propyl trimethyl ammonium salt can be used instead of 3-chloro-2-hydroxy-propyl trimethyl ammonium salt.

Alumina in the form of alumina sol or Aluminium metal or Aluminium hydroxide or pseudo boehmite alumina or aluminium alkoxide or aluminium sulphate or Aluminium nitrate is then added to the aforementioned mixture.

Silica in the form of precipitated silica or silica sol or fumed silica or silicon alkoxides, sodium silicate is then added to the aforementioned mixture into which alumina has been added to produce a gel based mixture.

Another aspect of the invention wherein addition sequence of Silica source and Alumina source can be reversed. Another aspect of the invention wherein the addition sequence of other raw materials can be changed.

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

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

The mixture obtained is then subjected to hydrothermal synthesis at a temperature range of 80 to 200 degree Celsius under autogenous pressure in an autoclave for 1/2 to 6 days to produce SSZ-13

The SSZ-13 thus obtained is calcined in Nitrogen and/or Air at 450 to 650 degree Celsius for 4 to 12 hours to remove the organic material associated with the SSZ-13 Zeolite.

The SSZ-13 obtained is then treated with ammonium salts or dilute mineral acids to obtain SSZ-13 in ammonium form or H form respectively.

The Ammonium form of SSZ-13 obtained by treating ammonium salt is calcined to obtain SSZ-13 in hydrogen form. In order to provide a clear understanding of the invention and without limitation to the scope of the invention, a few of the embodiments thereof are described herein below as examples along with a table to show variegated attributes of SSZ-13 zeolite product.

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

Take 40 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water), mix l3.36g of Hydroxide salt of 3-chloro-2-hydroxypropyltrimethylammonium chloride (HPTMAOH solution, 25 wt% in water) along with 137 g of water. Subsequently add solution of 8 g of KOH in 91 g water, mix for 10 minutes. 156.8 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 19.2 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 54.74 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour. The molar gel composition at this stage was as below

26 Si02: A1203: 2 K20: 1.57 TMADAOH: 0.65 HPTMAOH: 802 H20

Set the pH of the gel composition to pH 12 by adding KOH solution of 20 wt% concentration. Add 1.64 g of SSZ-13 seeds to above gel composition and mix thoroughly for 30 Minutes.

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 170 Deg C in 3 hours and subjected to hydrothermal synthesis at 170 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The total yield was 38 grams. The crystallite size by SEM was in the range of 0.2 to 1.0 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis.

2) Example 2: Synthesis of H-SSZ-13 with input SAR of 26 Take 26.7 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water), mix 26.7g of Hydroxide salt of 3-chloro-2- hydroxypropyltrimethylammonium chloride (HPTMAOH solution, 25 wt% in water) along with 137 g of water. Subsequently add solution of 8 g of KOH in 91 g water, mix for 10 minutes. 156.8 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 19.2 g of Aluminium sulphate.16H20 (16 wt .% A1203) in 54.74 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below

26 Si02: A1203: 2 K20: 1.0 TMADAOH: 1.3 HPTMAOH: 802 H20

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 170 Deg C in 3 hours and subjected to hydrothermal synthesis at 170 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The total yield was 35 grams. The crystallite size by SEM was in the range of 0.2 to 1.0 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis.

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

Take 52.4 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water) along with 134 g of water. Subsequently add solution of 7.9 g of KOH in 90 g water, mix for 10 minutes. 154 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 28.8 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 54 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below

17 Si02: A1203: 1.3 K20: 1.37 TMADAOH: 524 H20

Set the pH of the gel composition to pH 12 by adding KOH solution of 20 wt% concentration. Add 1.6 g of SSZ-13 seeds to above gel composition and mix thoroughly for 30 Minutes.

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 170 Deg C in 3 hours and subjected to hydrothermal synthesis at 170 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The crystallite size by SEM was in the range of 0.4 to 1.0 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis.

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

Take 54 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water) along with 99 g of water. Subsequently add solution of 8 g of KOH in 91 g water, mix for 10 minutes. 211 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 19.2 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 54.74 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below

35 Si02: A1203: 2 K20: 2 TMADAOH: 802 H20

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 170 Deg C in 3 hours and subjected to hydrothermal synthesis at 170 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The crystallite size by SEM was in the range of 0.6 to 1.2 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis.

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

Take 54 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water) along with 137 g of water. Subsequently add solution of 8 g of KOH in 91 g water, mix for 10 minutes. 156.8 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 19.2 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 54.74 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below

26 Si02: A1203: 2 K20: 2 TMADAOH: 802 H20

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 160 Deg C in 3 hours and subjected to hydrothermal synthesis at 160 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The crystallite size by SEM was in the range of 1 to 3 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis. 6) Example 6: Synthesis of H-SSZ-13 with input SAR of 17

Take 29.5 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water) along with 287 g of water. Subsequently add solution of 5.5 g of NaOH in 50 g water, mix for 10 minutes. 56.4 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 10.5 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 81 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below

17 Si02: A1203: 4.1 Na20: 2.1 TMADAOH: 1610 H20

Set the pH of the gel composition to pH 12 by adding NaOH solution of 20 wt% concentration. Add 0.64 g of SSZ-13 seeds to above gel composition and mix thoroughly for 30 Minutes.

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 170 Deg C in 3 hours and subjected to hydrothermal synthesis at 170 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The crystallite size by SEM was in the range of 0.1 to 0.4 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis.

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

Take 27.8 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water) along with 266 g of water. Subsequently add solution of 5.4 g of NaOH in 50 g water, mix for 10 minutes. 85.1 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 10.42 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 76 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below 26 Si02: A1203: 4.1 Na20: 2.0 TMADAOH: 1610 H20

Set the pH of the gel composition to pH 12 by adding NaOH solution of 20 wt% concentration and mix thoroughly for 30 Minutes.

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

Take 54 g of NNN TriMethyl Adamantyl Ammonium Hydroxide (TMADAOH) template solution (25 wt% in water) along with 137 g of water. Subsequently add solution of 8 g of KOH in 91 g water, mix for 10 minutes. 156.8 g of silica sol (30 wt% Si02) is added slowly to the above mixture and stirred further for 30 Minutes. Prepare separately Aluminium Sulphate solution by adding 5 g of Aluminium sulphate.16H20 (16 wt.% A1203) in 54.74 g water to obtain a clear solution. The Aluminium Sulphate solution is slowly added to the solution containing template, alkali and silica precursor. The gel mixture is stirred for 1 hour.

The molar gel composition at this stage was as below

100 Si02: A1203: 7.6 K20: 8 TMADAOH: 3080 H20

The molar gel composition is heated with stirring in an closed autoclave from Room Temperature to 170 Deg C in 3 hours and subjected to hydrothermal synthesis at 170 Deg C for 4 days. The crystallization is followed by XRD. After the hydrothermal synthesis the contents in the autoclave are cooled and subjected to filtration. The wet cake is washed with demineralized water to remove template and other soluble impurities. The washed wet cake is subjected to drying at 120 Deg C for 12 hours. Phase purity by XRD is confirmed. The crystallite size by SEM was in the range of 0.5 to 3.0 microns. The as-synthesized zeolite is calcined at 550 Deg C prior subjecting to ion exchange with mineral acids or ammonium salts solution to limit the alkali content in the zeolite to less than 500 ppm. Subsequently the H-form of zeolite is obtained by drying and calcination. The Si02/Al203 molar ratio for zeolite is confirmed by chemical analysis.

Table 1 :

Claims

We Claim:

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 of which least one such source of quaternary ammonium ion(Ql) is having the formula (CH3)3N+CH2-CHOH-CH2Cl or

(CH3 )3N+CH2-CH0H-CH20H ion, b) Stirring the resulting mixture for 30 minutes to 120 minutes, c) Then subjecting the mixture to hydrothermal synthesis at a temperature range of 80 to 200 degree Celsius under autogenous pressure in an autoclave for between 12 hours to 144 hours to produce SSZ-13 d) Filtering the zeolite slurry, washing the wet cake with demineralized water, drying the wet cake at 120 Degree Celsius for 6 to 12 hours and Calcining the resulting SSZ-13 in Nitrogen and/or Air at 450 to 650 degree Celsius for 4 to 12 hours to remove the organic material associated with the SSZ-13 Zeolite e) Treating the resulting SSZ-13 with ammonium salts to obtain SSZ-13 in ammonium form f) Calcining the resulting SSZ-13 in ammonium form to obtain SSZ-13 in hydrogen form

2. The process of claim 1 wherein the second Quaternary ammonium ion (Q2) is NNN Trimethyl Adamantyl ammonium ion 3. The process of claims 1 or 2 where in the aqueous reaction mixture of step (a) has a molar composition of (1 A1203): (5 to 150 Si02): (0.1 to 4 Ql): (0.2 to 8 Second Quaternary ammonium ion (Q2)): (0.1 to 10 Potassium Hydroxide and/or Sodium Hydroxide): (200 to 2000 water).

4. The process of claims 1 , 2 or 3 wherein the molar ratio of First Quaternary ammonium ion (Ql) to Second Quaternary ammonium ion (Q2) is 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 between 5 and 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 said SSZ-13 seed crystals are present in the amount of between 0.1 to 5 wt% of Si02 in the reaction mixture.

8. The process of claim 1 wherein said ammonium salts of step (e) comprise Ammonium Nitrate or Ammonium Sulphate or Ammonium Chloride with concentration less than 5 wt%

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

10. The process of claim 9 wherein said mineral acids comprise nitric acid or sulphuric acid or hydrochloric acid with concentration less than 3 wt%

11. The process of claims 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 claims 1 or 9 wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has surface area more than 500-meter square per gram.

13. The process of claims 1 or 9 wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has the carbon content less than 0.5 weight %.

14. The process of claims 1 or 9 wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has Si02/Al203 molar ratio in the range of 5 to 100

15. The process of claims 1 or 9 wherein the resulting SSZ-13 zeolite obtained at the end of step (f) has 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 source of silica, at least one source of alumina, at least one source of alkali metal hydroxide and at least one source of quaternary ammonium ion (Q2) which is NNN Trimethyl Adamantyl ammonium ion b) Stirring the resulting mixture for 30 minutes to 120 minutes c) Then subjecting the mixture to hydrothermal synthesis at a temperature range of 80 to 200-degree Celsius under autogenous pressure in an autoclave for between 12 hours to 144 hours to produce SSZ-13 d) Filtering the zeolite slurry, washing the wet cake with demineralized water, drying the wet cake at 120 Degree Celsius for 6 to 12 hours and Calcining the resulting SSZ-13 in Nitrogen and/or Air at 450 to 650 degree Celsius for 4 to 12 hours to remove the organic material associated with the SSZ-13 Zeolite e) Treating the resulting SSZ-13 with ammonium salts to obtain SSZ-13 in ammonium form f) Calcining the resulting SSZ-13 in ammonium form to obtain SSZ-13 in hydrogen form 17. The process of claim 16 wherein a second Quaternary ammonium ion (Ql) is added at step (a) having the formula (CH3)3N+CH2-CHOH-CH2Cl or (CH3)3N+CH2-CHOH- CH20H ion

18. The process of claim 16 in the aqueous reaction mixture of step (a) has a molar

composition of (1 A1203): (5 to 150 Si02): (0.1 to 4 Ql): (0.2 to 8 Q2): (0.1 to 10 Potassium Hydroxide and/or Sodium Hydroxide): (200 to 2000 water).

19. The process of claims 16, 17 or 18 wherein the molar ratio of First Quaternary

ammonium ion (Ql) to Second Quaternary ammonium ion (Q2) is 0.0125 to 20

20. The process of claims 16 or 17 wherein the aqueous reaction mixture of step (a)

comprises a silica to alumina molar ratio of between 5 and 150 21. The process of claims 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 said seed crystals are present in the amount of between 0.1 to 5 wt% of Si02 in the reaction mixture.

23. The process as claimed in claims 16 or 17, wherein the ammonium salt of step (e)

comprise Ammonium Nitrate or Ammonium Sulphate or Ammonium Chloride with concentration less than 5 wt%

24. The process of claims 16 or 17 wherein the resulting SSZ-13 obtained after step (d) is treated with dilute mineral acids to obtain the final SSZ-13 zeolite in hydrogen form

25. The process of claim 24 wherein said mineral acids comprise nitric acid or sulphuric acid or hydrochloric acid with concentration less than 3 wt% 26. The process of claims 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-meter square per gram.

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

29. The process of claim 16 or 17 wherein, the resulting SSZ-13 zeolite obtained at the end of step (f) has a Si02/Al203 molar ratio in the range of 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.