DESC:
TECHNICAL FIELD
[0001] The present disclosure relates generally to the field of zeolites. Particularly, the present disclosure provides a new crystalline family of MRE type zeolite containing an additional phase of EUO in an amount of more than 5% by weight of total zeolite that exhibits unique pore geometry and distinctive XRD pattern. Aspects of the present disclosure also relates to a method of preparation of a new crystalline family of MRE type zeolite (MRE/EUO) containing an additional phase of EUO in an amount of more than 5% by weight of total zeolite. The synthesized MRE/EUO zeolites exhibit aspect ratio of less than 8.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Zeolites are crystalline aluminosilicates, either of natural or synthetic origin with highly ordered structures (i.e. periodical building units in all the three dimensions) or sometime disordered structures (periodical building block in less than three dimensions). Essentially, they consist of SiO4 and AlO4- tetrahedra, which are interlinked through shared oxygen atoms to give a three dimensional network. They have an internal pore structure, channels, and in some cases cavities. These properties are unique for each and individual zeolite frameworks. The crystalline zeolites and its unique crystal structures or frameworks are determined through its distinctive X-ray diffraction patterns using powder XRD technique.
[0004] Zeolites are designated as ‘molecular sieves’ owing to its ability to sieve of molecules with various shapes and size and are very popular in the field of heterogeneous catalysis. Due to its unique properties such as porous structure in molecular dimensions, high adsorption capacities, high surface area, molecular shape selectivity for reactants or products, tunable acidity etc., the crystalline zeolite and natural zeolites have gained much commercial value in the field of adsorption or gas drying & separation, catalysis for hydrocarbon and chemical conversion.
[0005] Today, the zeolites are in high demand due to its widespread application such as an adsorbents, ion exchange materials, detergent builders and catalysts, especially in petroleum refining as Fluidized Catalytic Cracking (FCC) and hydro-processing catalysts and in the production of petrochemicals.
[0006] At present, heightening environmental concerns and its stringent norms led to mounting pressure on refiners to generate clean fuels. Hydroprocessing of petroleum feedstocks has become crucial, wherein hydrogen is used for processing of petroleum feed stocks to produce clean and valuable products useful either in transportation fuels or in base stock production for lubricating oil. Hydroisomerization is one of the hydroprocessing routes, wherein catalytic dewaxing reaction is carried out by converting waxy n-parrafin molecules to branched chained iso-paraffin molecules. The route is routinely adopted in oil refineries for production of motor spirit with desired Research Octane Number (RON), winter grade diesel and Lube Oil Base Stock (LOBS) [Recent Advances and Future Aspects in the Selective Isomerization of High n-Alkanes, Catalysis Reviews: Science and Engineering, 49:1, 33-139 (2007)]. The bifuncational mechanism of hydroisomerization catalyst is discussed in detail in Fischer-Tropsch Waxes Upgrading via Hydrocracking and Selective Hydroisomerization, Oil & Gas Science and Technology – Rev. IFP, Vol. 64, No. 1, 91-112 (2009).
[0007] Bi-functional zeolite catalyst is most widely used catalyst for achieving skeletal branching in normal alkanes’ structure. According to the bi-functional mechanism, n-alkane is adsorbed in hydrogenation (HD)/dehydrogenation (DHD) site of metal in the catalyst body and then it gets dehydrogenated to a corresponding n-olefin. Olefin diffuses to Bronsted acid site and gets protonated to form carbocation. The carbocation then isomerizes into a branched form and gets deprotonated to olefinic product. Olefin diffuses back to an HD/DHD site for hydrogenation and finally desorbs from the catalyst to give isomerized product. While skeletal rearrangement of alkyl carbocation, cracking also happens through ß-scission leading to hydrocracked product. Thus, maximum isomerization yields can only be achieved if there is significant reduction of hydrocracking activities. An ideal balance of dispersed metal and acid function is required for minimizing hydrocracking reaction. Catalyst made of zeolite materials having smaller particle size (low length/width ratio or aspect ratio) also inhibits hydrocrackingreaction. Till date, various acid supports have been reported that includes SiO2-Al2O3, ZrO2 and zeolites containing Y, Beta, ZSM-5, ZSM-22, ZSM-23, ZSM-12, ZSM-48, SAPO-11 and SAPO-41 for bifunctional hydroisomerization. However, one-dimensional 10-membered ring channel structure zeolites namely ZSM-23, ZSM-22, ZSM-48, ZSM-12 and SSZ-32 are found to be suitable candidates offering maximized yield in long chain n-paraffins (C12 or more) isomerization as reported in Studies on Wax Isomerization for Lubes and Fuels, Stud. Surf. Sci. Catal. 84C, 2319-2326. This literature demonstrates the importance of one-dimensional zeolite framework in favoring isomerization selectivity owing to its unique pore geometry allowing the concept of pore-mouth/key-lock catalysis, wherein reaction occurs at the external surface. Thus zeolites having submicron crystal size with optimal surface area is desirable for better isomerization selectivity at maximum conversion yield during n-paraffin to isoparaffin reaction as reported in Monomethyl-Branching of Long n-Alkanes in the range from Decane to Tetracosane on Pt/H-ZSM-22 Bifunctional Catalyst, J. Catal. 190, 1, 39-48. Catalyst that converts waxy straight chain molecules to branched molecules through hydroisomerization reaction should provide desirable properties with regard to viscosity index (VI) and pour point. ZSM-48 (MRE framework) is an example of such zeolite candidate of hydroisomerization catalyst. ZSM-48 is a 10-membered ring, non-interpenetrating linear channels zeolite having molecular pore dimension of 0.53 X 0.556 nm as reported by Schlenker et al in Zeolites 5, 355 (1985). The detail study by Kirschhok et al in Ordered End-member of ZSM-48 Zeolite Family, Chem. Mater. 2009, 21, 371-380 indicated that ZSM-48 forms channels with the interconnection of pores leading to prolonged channeling perpendicular to the long axis of the needles. This arrangement leads to open up the channel at the short end of the needle structure. Thus, the retention time of the hydrocarbon feeds tends to increase owing to lengthening of diffusion path if the length to diameter (aspect ratio) of the needle increases. Hydrocarbon feeds with higher retention time favor ß-scission leading to hydrocracked products. The concept is also reflected in Shape Selectivity in Hydroisomerization of Hexadecane over Pt-Supported on 10-Rin g Zeolites: ZSM-22, ZSM-23, ZSM-35 and ZSM-48, Ind. Eng. Chem. Res. 2016, 55, 6069-6078. Thus, ZSM-48 zeolite with low aspect ratio is desirable as well as in current need for hydroisomerization application. Miao Zhang and co-workers reported a series EU-1 (EUO)/ZSM-48 (MRE) intergrowth zeolites by varying SiO2 to Al2O3 ratios as described in Catal. Sci. Technol. 2013, 00, 1-3. Successful hydrothermal synthesis utilizing hexamethonium bromide (HMBr2) as structure directing agent (known as template ) gave co-crystalline zeolite varying SiO2/Al2O3 ratio 100, 150, 200 and 250 respectively. They also synthesized pure ZSM-48 phase with SiO2/Al2O3 ratio 200. The comparative results obtained during catalyst evaluation of the prepared zeolites using n-hexadecane as the model feed indicates that co-crystallize EU-1/ZSM-48 for SiO2/Al2O3 of 200 showed superior isomer selectivity over pure ZSM-48 phase or the mechanical mixture of ZSM-48 and EU-1. However, the best result obtained for EU-1/ZSM-48 at SiO2/Al2O3 ratio of 200 does not provide sufficient selectivity (< 60 %) and conversion (< 70%) at 300oC. Stephen J. Muller et al. described in Determining the strength of Bronsted Acid Sites for Hydrodewaxing over shape-selective catalysts, Ind. Eng. Chem. Res. 2016, 55, 6760-6767 that hydrodewaxing requires higher conversion (>90%) with higher selectivity (>80%) for processing waxy paraffinic feeds. Here, in case of the co-crystallized catalysts, the possible reasons for causing higher percentage hydrocracked product are - a) use of high template to SiO2 molar ratio which leads the production of zeolite framework with higher aspect ratio as described in US7625478B2 and eventually favors cracking (described in US publication US20170056868) b) use of reaction condition which restrict the formation co-crystallized frame work in low SiO2/Al2O3 ratios (SiO2/Al2O3 =150) which favor hydroisomerization (as described in US7625478B2). Accordingly, there remains a need to develop new co-crystallite zeolite of ZSM-48 and EU-1 (more than 5%) which exhibits unique pore structure. Crystallization also needs to be performed at low SiO2/Al2O3 ratio with a desired morphology of low aspect ratio (<5).
[0008] So far, several synthetic methods have been reported for preparing ZSM-48 type zeolites, wherein hydrothermal synthesis has been performed using gel composition (reaction mixture) consisting of silica, alumina, alkali metal oxide, water and structure directing agents. Various structure directing agents, typically organic amines are reported for the synthesis ZSM-48 type zeolites. Choice as well as content of directing agents is found to be crucial in forming ZSM-48 material of desired morphology, acidity and textural properties. For instance, the first synthesis of ZSM-48 reported by Rollmann et al (US patent No. 4423021) carried out using a C4 to C12 organic diamine as structure directing agent. However, there was no significant alumina incorporation in framework and the resulting zeolite contained little acidity. In US patent 4397827, a mixed template (structure directing agent) system containing one C2 to C12 alkyl amine and another C3 to C5 tetramethylammonium compound was employed for ZSM-48 synthesis. In US Patent US4585747, ZSM-48 was synthesized using bis(N-methylpyridyl)ethylinium cations based directing agent. However, in both the cases synthesis results in high silica to alumina molar ratio leading to less acidic zeolites. The disclosure in US Pat. No. 5961951 described the synthesis, wherein high silica to alumina molar ratio zeolite was produced. Moreover, the synthesis was carried out in presence of high amount of template (template to silica molar ratio was 2 to 5) leading to undesired morphology. In US pat. No. 6923949, synthesis of ZSM-48 crystal was disclosed for various silica to alumina ratio. Synthesis was performed using heterostructural zeolite seeds such as ZSM-5, ZSM-11, ZSM-12, colloidal BEA, Beta, X and Y zeolites and in presence of multi directing agent selected from organic linear diquaternary alkyl ammonium compounds and liner diamino alkanes. In WO2007/070521, synthesis of ZSM-48 crystal was disclosed using hexamethonium salt as a template system. For the synthesis, template (hexamethonium salt) to silica molar ratio was used in the range of 0.01 to 0.05. The article by Song-Ho et al in Reinvestigation into the synthesis of zeolites using diquaternary alkylammonium ions (CH3)3N+(CH2)nN+(CH3)3 with n=3-10 as structure directing agents, Microporous and Mesoporous Materials, 68 (2004), 97-104 inferred that Me6-Dquat-5 favors the formation of ZSM-48 in presence of certain OH-/SiO2 concentration (molar ratio less than 0.33). The synthesis disclosed in US patent No. 8003074 indicated that use of combined template system of Me6-diquat-5 and Me6-diquat-6 can be applied in controlling morphology of highly active ZSM-48 crystals. In another US publication US20160121315, the synthesis of ZSM-48 crystal was reported using the combination of two directing agents, one is used as ‘dominant’ and another is used as secondary directing agent. Hexamethonium salt is used as dominant directing agent and alkyl ammonium hydroxide based salt such as tetraethyl ammonium hydroxide and tetramethyl ammonium hydroxide salt is used as secondary directing agent. The use of secondary directing agent is to improve the isomerization selectivity and thereby improving catalytic performance. According to abovementioned reports, attempts were made for synthesis of pure ZSM-48 based zeolites, however, in US publication US20170056868, new family of zeolite SSZ-91 was disclosed. SSZ-91 is almost similar to ZSM-48 family having similar XRD pattern with ZSM-48 type zeolites. SSZ-91 is the pure phase of ZSM-48 family zeolites having low EU-1 content of maximum 3%, low aspect ratio ranging 1 to 8 and containing at least 70% polytype 6 of total ZSM-48 materials. This stringent synthesis criteria is imposed in order to reduce the hydrocracking characteristic and thereby to improve hydroisomerization selectivity. Thus a flexible synthesis criteria with good isomerization selectivity (>88 % selectivity at 90% conversion of n-hexadecane in ~300oC) can be advantageous to develop new family of zeolites for bulk scale synthesis and commercialization. In the disclosure, SSZ-91 synthesis reported using hexamethonium chloride as structure directing agent. As discussed in the literature reports and disclosures, it is noticeable that use of secondary directing agent has a crucial role on controlling morphology, and hence the isomerization selectivity. Interestingly, the comparative report of catalyst evaluation published in Catal. Sci. Technol. 2013, 00, 1-3, showed that catalyst prepared using EU-1/ZSM-48 co-crystallized zeolite has a potential in the field hydroisomerization reaction.
[0009] In view of the state of the art discussed hereinabove, it is evident that the prior art for pure ZSM-48 or EU1/ZSM-48 family zeolite synthesis methods lack combine characteristics of i) low silica to alumina ratio ii) low aspect ratio iii) proper balance of metal to acid function leading to lower hydro-isomerization selectivity in n-paraffin’s conversion.
[0010] In view of above stated shortcomings, there exists a need for the zeolite that exhibits smaller crystal size and low aspect-ratio than that of a conventional zeolite. Need is also felt of zeolites that can find utility in preparation of a catalyst with high hydro-isomerization activity and selectivity.

OBJECTS OF THE INVENTION
[0011] An object of the present invention to provide a method of preparation of a MRE (ZSM-48) type of zeolite having EUO phase.
[0012] Another object of the present invention to provide a method of preparation of a family of ZSM-48 type of zeolite with an additional phase of EU-1.
[0013] Another object of the present invention to provide a catalyst containing MRE/EUO zeolite that exhibits mixed template based synthesis.
[0014] Another object of the present invention to provide a catalyst containing MRE/EUO zeolite that utilizes mixed template based synthesis for the preparation of zeolite with desired crystal size.
[0015] Another object of the present invention to provide a catalyst containing MRE/EUO zeolite that exhibits optimum acidity and high surface area.
[0016] Another object of the present invention to provide a catalyst comprising EU-1 phase containing ZSM-48 family zeolite that exhibits desired crystal size, optimum acidity and high surface area.
[0017] Another object of the present invention to provide a catalyst comprising ZSM-48 family zeolite with additional phase of EU-1 that exhibits high hydro-isomerization activity and selectivity.
[0018] Another object of the present invention to provide a catalyst containing MRE/EUO zeolite that exhibits high hydroisomerization activity and selectivity.
[0019] Another object of the present invention to provide a method for preparation of a MRE/EUO zeolite with low aspect ratio.
[0020] Another object of the present invention to provide a method for preparation of a ZSM-48 family zeolite with additional phase of EU-1 with low aspect ratio.
[0021] Another object of the present invention to provide a method for preparation of a catalyst containing MRE/EUO zeolite that exhibits desired crystal size, optimum acidity and high surface area.
[0022] Another object of the present invention to provide a method for preparation of a catalyst containing MRE/EUO zeolite that exhibits high hydroisomerization activity and selectivity.

SUMMARY
[0023] The present disclosure relates generally to the field of zeolites. Particularly, the present disclosure provides a new crystalline family of MRE type zeolite containing an additional phase of EUO (alternatively and synonymously referred to as “MRE/EUO zeolite” throughout the present disclosure) in an amount of more than 5% by weight of total zeolite, which exhibit unique pore geometry and distinctive XRD pattern. Aspects of the present disclosure also relates to a method of preparation of a new crystalline family of MRE type zeolite containing an additional phase of EUO in an amount of more than 5% by weight of total zeolite. The synthesized MRE/EUO zeolites exhibit aspect ratio of less than 8.
[0024] An aspect of the present disclosure provides a MRE/EUO zeolite, wherein said zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, said zeolite comprises EU-1 phase in an amount ranging from 5% to 23% by weight of said zeolite. In an embodiment, said zeolite comprises silica and alumina in a molar ratio ranging from 80 to 200. In an embodiment, said zeolite exhibits surface area ranging from 70 m2/gm to 350 m2/g. In an embodiment, said zeolite exhibits external surface area ranging from 30 m2/gm to 140 m2/g. In an embodiment, said zeolite exhibits crystal size of less than 1 micron. In an embodiment, said zeolite exhibits aspect ratio of less than 4.
[0025] Another aspect of the present disclosure provides a catalyst comprising: at least one MRE/EUO zeolite; and at least one noble metal supported thereon, wherein said MRE/EUO zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, the catalyst includes the at least one noble metal in an amount ranging from 0.05 wt% to 3 wt%. In an embodiment, the at least one noble metal is a metal of Group-VIII. In an embodiment, the catalyst exhibits dispersion of the at least one noble metal over at least 5% of total surface area thereof.
[0026] Further aspect of the present disclosure relates to a method of preparation of a MRE/EUO zeolite, the method comprising the step of - effecting hydrothermal crystallization of a reaction mixture comprising at least one silica precursor, at least one alumina precursor, at least one alkali and a combination of structure directing agents, wherein at least one of said combination of structure directing agents imparts, at least in part, a MRE framework to said zeolite, and wherein the other structure directing agent of said combination of structure directing agents imparts, at least in part, an EUO framework to said zeolite, wherein the method effects preparation of the MRE/EUO zeolite having EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, said zeolite exhibits aspect ratio of less than 3. In an embodiment, the step of effecting hydrothermal crystallization is conducted at a temperature ranging from 130°C to 200°C and for a time period ranging from 10 hours to 96 hours. In an embodiment, the at least one silica precursor is selected from a group comprising silica sols, tetraalkylorthosilicates and silicon dioxides. In an embodiment, the at least one alumina precursor is anhydrous NaAlO2. In an embodiment, the at least one alkali source is sodium hydroxide. In an embodiment, the combination of structure directing agents comprises pentamethonium bromide (Diquat-5) and hexamethonium bromide (Diquat-6). In an embodiment, molar ratio of pentamethonium bromide/SiO2 ranges from 0.01 to 0.05, molar ratio of hexamethonium bromide/SiO2 ranges from 0.0006 to 0.05, molar ratio of OH-/SiO2 ranges from 0.10 to 0.50, and molar ratio of H2O/SiO2 ranges from 15 to 35. In an embodiment, said zeolite comprises silica and alumina in a molar ratio ranging from 80 to 200.
[0027] Still further aspect of the present disclosure relates to a method for preparation of a catalyst comprising at least one MRE/EUO zeolite and at least one noble metal, the method comprising the steps of: effecting conversion of said at least one MRE/EUO zeolite to acidic form thereof; and contacting said acidic form of the at least one MRE/EUO zeolite with at least one precursor of the at least one noble metal to effect preparation of the catalyst, wherein said zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, the step of effecting conversion of said at least one MRE/EUO zeolite to acidic form thereof comprises: effecting ion-exchange by contacting said at least one MRE/EUO zeolite with an ammonia precursor. In an embodiment, the step of contacting said acidic form of the at least one MRE/EUO zeolite with the at least one precursor of the at least one noble metal comprises: effecting ion-exchange by contacting said acidic form of the at least one MRE/EUO zeolite with the at least one precursor of the at least one noble metal. In an embodiment, said ammonia precursor is ammonium nitrate. In an embodiment, the precursor of the at least one noble metal is tetra-ammonium platinum nitrate complex. In an embodiment, said acidic form of the at least one MRE/EUO zeolite exhibits surface area ranging from 70 m2/gm to 300 m2/gm, crystal size of less than 1 micron, external surface area ranging from 20 m2/gm to 150 m2/g, and titrable acidity ranging from 50 µmol/g to 300 µmol/g. In an embodiment, the method further comprises the steps of: drying the catalyst; effecting mixing of an appropriate amount of the dried catalyst with an appropriate amount of at least one binder to form a coherent mass; and effecting extrusion of said mixture to prepare an extruded mixture. In an embodiment, the extruded mixture comprises the catalyst in an amount ranging from 30% to 70% by weight of the extruded mixture. In an embodiment, the binder is selected from any or a combination of a clay, silica, alumina and a metal oxide. In an embodiment, the method further comprises the step of effecting calcination of the said extruded mixture. In an embodiment, the calcinations is effected at a temperature ranging from 250°C to 400°C and under constant air flow.

BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0029] FIG. 1 through FIG. 8 illustrate exemplary snippets depicting x-ray diffraction patterns for ZSM-48 family of co-crystallite zeolites, realized in accordance with embodiments of the present disclosure.
[0030] FIG. 9A and 9B illustrate exemplary snippets depicting x-ray diffraction patterns for ZSM-48 family of co-crystallite zeolites, realized in accordance with embodiments of the present disclosure, with characteristics peak of EU-1 at the 2-theta of 7.92, 8.75 and 20.53 degrees, respectively.
[0031] FIG. 10A through FIG. 10C illustrate exemplary snippets depicting X-ray diffraction patterns of physical mixture of ZSM-48 and EU-1 (PM-25, PM-50 and PM-75), respectively.
[0032] FIG. 11A and FIG. 11B illustrate exemplary snippets depicting Scanning Electron Microscope (SEM) images of ZSM-48 family of co-crystallite zeolites, realized in accordance with embodiments of the present disclosure.
[0033] FIG. 12 illustrates an exemplary snippet depicting Transmission Electron Microscope (TEM) image of ZSM-48 family of co-crystallite zeolite (Z4), realized in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0034] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0035] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0036] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0037] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0038] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0039] The present disclosure relates generally to the field of zeolites. Particularly, the present disclosure provides a new crystalline family of MRE type zeolite containing an additional phase of EUO in an amount more than 5% by weight of total zeolite that exhibits unique pore geometry and distinctive XRD pattern. Aspects of the present disclosure also relates to a method of preparation of a new crystalline family of MRE type zeolite (MRE/EUO) containing an additional phase of EUO in an amount more than 5% by weight of total zeolite. The synthesized MRE/EUO zeolites exhibit aspect ratio of less than 8.
[0040] An aspect of the present disclosure provides a MRE/EUO zeolite, wherein said zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, said zeolite comprises EU-1 phase in an amount ranging from 5% to 23% by weight of said zeolite. In an embodiment, the zeolite comprises silica and alumina in a molar ratio of less than 300. In an embodiment, said zeolite comprises silica and alumina in a molar ratio ranging from 80 to 200. In an embodiment, said zeolite exhibits surface area ranging from 70 m2/gm to 350 m2/g. In an embodiment, said zeolite exhibits external surface area ranging from 30 m2/gm to 140 m2/g. In an embodiment, said zeolite exhibits crystal size of less than 1 micron. In an embodiment, said zeolite exhibits aspect ratio of less than 4.
[0041] Another aspect of the present disclosure relates to a method of preparation of a MRE/EUO zeolite, the method comprising the step of - effecting hydrothermal crystallization of a reaction mixture comprising at least one silica precursor, at least one alumina precursor, at least one alkali and a combination of structure directing agents, wherein at least one of said combination of structure directing agents imparts, at least in part, a MRE framework to said zeolite, and wherein the other structure directing agent of said combination of structure directing agents imparts, at least in part, an EUO framework to said zeolite, wherein the method effects preparation of the MRE/EUO zeolite having EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, said zeolite exhibits aspect ratio of less than 3. In an embodiment, the step of effecting hydrothermal crystallization is conducted at a temperature ranging from 130°C to 200°C and for a time period ranging from 10 hours to 96 hours. In an embodiment, the at least one silica precursor is selected from a group comprising silica sols, tetraalkylorthosilicates and silicon dioxides. In an embodiment, the at least one alumina precursor is anhydrous NaAlO2. In an embodiment, the at least one alkali source is sodium hydroxide. In an embodiment, the combination of structure directing agents comprises pentamethonium bromide (Diquat-5) and hexamethonium bromide (Diquat-6). In an embodiment, molar ratio of pentamethonium bromide/SiO2 ranges from 0.01 to 0.05, molar ratio of hexamethonium bromide/SiO2 ranges from 0.0006 to 0.05, molar ratio of OH-/SiO2 ranges from 0.10 to 0.50, molar ratio of H2O/SiO2 ranges from 15 to 35, and molar ratio of silica to alumina ranges from 50 to 100.
[0042] Further aspect of the present disclosure provides a catalyst comprising: at least one MRE/EUO zeolite; and at least one noble metal supported thereon, wherein said MRE/EUO zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, the catalyst includes the at least one noble metal in an amount ranging from 0.05 wt% to 3 wt%. In an embodiment, the catalyst includes the at least one noble metal in an amount ranging from about 0.1 wt% to about 1 wt%. In an embodiment, the at least one noble metal is a metal of Group-VIII. In an embodiment, the catalyst exhibits dispersion (impregnation) of the at least one noble metal over at least 5% of total surface area thereof. In an embodiment, the catalyst is a hydroisomerization catalyst for effecting hydroisomerization of C12 to C40 n-paraffins fraction in a hydrocarbon mixture.
[0043] Still further aspect of the present disclosure relates to a method for preparation of a catalyst comprising at least one MRE/EUO zeolite and at least one noble metal, the method comprising the steps of: effecting conversion of said at least one MRE/EUO zeolite to acidic form thereof; and contacting said acidic form of the at least one MRE/EUO zeolite with at least one precursor of the at least one noble metal to effect preparation of the catalyst, wherein said zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, the step of effecting conversion of said at least one MRE/EUO zeolite to acidic form thereof comprises: effecting ion-exchange by contacting said at least one MRE/EUO zeolite with an ammonia precursor. In an embodiment, the step of contacting said acidic form of the at least one MRE/EUO zeolite with the at least one precursor of the at least one noble metal comprises: effecting ion-exchange by contacting said acidic form of the at least one MRE/EUO zeolite with the at least one precursor of the at least one noble metal. In an embodiment, said ammonia precursor is ammonium nitrate. In an embodiment, the precursor of the at least one noble metal is tetra-ammonium platinum nitrate complex. In an embodiment, said acidic form of the at least one MRE/EUO zeolite exhibits surface area ranging from 70 m2/gm to 300 m2/gm, crystal size of less than 1 micron, external surface area ranging from 20 m2/gm to 150 m2/g, and titrable acidity ranging from 50 µmol/g to 300 µmol/g. In an embodiment, the method further comprises the steps of: drying the catalyst; effecting mixing of an appropriate amount of the dried catalyst with an appropriate amount of at least one binder to form a coherent mass; and effecting extrusion of said mixture to prepare an extruded mixture. In an embodiment, the extruded mixture comprises the catalyst in an amount ranging from 30% to 70% by weight of the extruded mixture. In an embodiment, the binder is selected from any or a combination of a clay, silica, alumina and a metal oxide. In an embodiment, the method further comprises the step of effecting calcination of the said extruded mixture. In an embodiment, the calcinations is effected at a temperature ranging from 250°C to 400°C and under constant air flow.
[0044] In an embodiment, a method for preparing a noble metal loaded zeolite catalyst comprises following steps: (a) converting the zeolite to its acidic form by ion-exchanging with precursor salts which release ammonia; (b) treating the acidic form with a metal by the process of ion-exchange with a metal precursor salt to obtain noble metal loaded acidic form of the zeolite; (c) drying the metal loaded acidic form of the zeolite to obtain a dried material; (d) extrusion of dried material with a binder selected from the group consisting of clays, silicas, aluminas, metal oxides, and mixtures thereof to obtain an extruded catalyst; and (e) calcining the extruded catalyst under constant air flow to obtain a metal-containing catalyst zeolite. In an embodiment, the acidic form in step (a) is H-form, which is obtained by exchanging Na+ form of zeolite with ammonium nitrate and followed by calcination. In still another embodiment, the Na-form has a surface area in the range of 70-300 m2/gm, preferably more than 200 m2/gm and external surface area in the range of 10-150 m2/gm (Table-1) and crystal size of <1 micron. In yet another embodiment, the acidic H-form has acidity in the range of 50-300 µmol/g (Table-1). In still another embodiment, the step (a and b) are carried out at 550°C. In another embodiment, said metal containing catalyst has metal dispersion ranging from 10 to 95%. In yet another embodiment, the acidic H-form is loaded with Group-VIII metal by ion-exchange using a precursor salt, preferably Platinum salt or palladium salt, more preferably, platinum. In still another embodiment, said platinum salt used for ion-exchange is tetra-ammonium platinum nitrate complex. In another embodiment, wt% of platinum in the metal containing catalyst is 0.05-3 wt%, preferably 0.1 to 1.0 wt%. In yet another embodiment, said binder is in the percentage of 30 to 70%, and preferably 35-50%. In still another embodiment, in step (d) 35% w/w to 65 % w/w of the dried material is extruded with 65 % w/w to 35 % w/w of binder. In another embodiment, in step (e) calcination of the extruded catalyst is at 250-400 °C under constant air flow. In yet another embodiment, the crystallization temperature is in the range of 130 °C to 200 °C. In still another embodiment, the crystallization time is in range between 10-96 hrs depending on the silica to alumina molar ratio. In an embodiment, the noble metal loaded zeolite catalyst is a hydroisomerization catalyst for effecting hydroisomerization of C12 to C40 n-paraffins fraction in a hydrocarbon mixture.
[0045] Still further aspect of the present disclosure provides a catalyst for effecting hydroisomerization of C12 to C40 n-paraffins, the catalyst comprising: at least one MRE/EUO zeolite; and at least one noble metal supported thereon, wherein said MRE/EUO zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite. In an embodiment, the at least one noble metal is selected from a metal of Group-VIII. In an embodiment, the at least one noble metal includes any or a combination of platinum and palladium. In an embodiment, the MRE/EUO zeolite is a ZSM-48 family of zeolite containing an additional phase of EU-1, wherein said ZSM-48 family of zeolite exhibits low aspect ratio. In an embodiment, the MRE/EUO zeolite includes silica and alumina in a molar ratio of less than 100. In an embodiment, the MRE/EUO zeolite includes silica and alumina in a molar ratio ranging from about 50 to about 100. In an embodiment, the catalyst includes the at least one noble metal in an amount ranging from about 0.05 wt% to about 3 wt%. In an embodiment, the catalyst includes the at least one noble metal in an amount ranging from about 0.1 wt% to about 1 wt%. In an embodiment, the catalyst effects hydroisomerization of C12 to C40 n-paraffins to mid-branched isomers thereof in a yield ranging from about 10% to about 60% by weight of the C12 to C40 n-paraffins. In an embodiment, the catalyst effects hydroisomerization of C12 to C40 n-paraffins to mid-branched isomers thereof in a yield ranging from about 20% to about 45% by weight of the C12 to C40 n-paraffins.
[0046] The present invention also provides a method for preparing a zeolite of pure EU-1 phase. The said zeolite is prepared with varied SiO2 to Al2O3 molar ratio in the range from 100 to 200 using hexamethonium bromide as structure directing agent, sodium aluminate as alumina precursor, precipitated silica as silica source and sodium hydroxide as an alkali source.
[0047] The MRE/EUO zeolite of the present disclosure is a new family of ZSM-48 type zeolite that contains more than 5% of EU-1 phase. The MRE/EUO zeolite of the present disclosure is co-crystallized MRE/EUO zeolite. There are three characteristics peaks indexed for EUO type of zeolites (according to book chapter Stucture Commision of the International Zeolite Association by M. M. J. Treacy et al.) at 2? values around 7.92°, 8.75° and 20.53° respectively and accordingly the peak at 2? ~ 20.53°, is considered for EUO% calculation in the co-crystallized MRE/EUO zeolite. The wt% of EUO phase in the zeolites of present disclosure is more than 5 wt% of MRE/EUO zeolite. The EU-1 phase containing ZSM-48 type of zeolites of the present disclosure exhibits characteristic peaks (2 theta degree) at the 2-theta of 7.92, 8.75 & 20.53 (for EU-1) and 7.77, 8.95, 21.25 & 22.85. The zeolites exhibit aspects ratios in the range of 2.5 to 8 with average aspect ratio less than 5
[0048] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0049] EXAMPLE 1: Zeolite Z1
[0050] Table 1 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z1). About 8.5 g of sodium hydroxide was dissolved in about 600 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 13 g of diquat-5 (pentamethonium bromide) and about 15 g of diquat-6 (hexamethonium bromide) were added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 2.5 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally, about 85.5 g of amorphous precipitated silica (Hi-Sil) was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.1 with concentrated sulfuric acid, and transferred to a one liter autoclave for hydrothermal reaction. The hydrothermal reaction was carried out at 180oC at 500 rpm for 24 hrs. The reaction mixture was cooled down and the product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 1 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z1). The synthesized Zeolite Z1 exhibited ZSM-48 framework with additional 44.19 % of EU-1 phase.
Table 1: Composition for preparation of Zeolite Z1
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 88
NaOH/SiO2 0.15
Diquat-5/SiO2 0.026
Diquat-6/SiO2 0.029
H2O/SiO2 23.42

[0051] EXAMPLE 2: Zeolite Z2
[0052] Table 2 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z2). About 15 g of sodium hydroxide was dissolved in about 600 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 20 g of diquat-6 (hexamethonium bromide) was added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 9.7 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally, about 128 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.1 with concentrated sulfuric acid and transferred to a one liter autoclave for hydrothermal reaction. The hydrothermal reaction was carried out at 180oC at 500 rpm for 24 hrs. The reaction mixture was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 2 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z2). The synthesized Zeolite Z2 exhibited ZSM-48 framework with additional 100 % of EU-1 phase.
Table 2: Composition for preparation of Zeolite Z2
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 42
NaOH/SiO2 0.176
Diquat-6/SiO2 0.026
H2O/SiO2 23.42

[0053] EXAMPLE 3: Zeolite Z3
[0054] Table 3 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z3). About 8.5 g of sodium hydroxide was dissolved in about 600 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 6.3 g of diquat-5 (pentamethonium bromide) and 3.5 g of diquat-6 (hexamethonium bromide) were added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 2.5 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally, about 85.5 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.0 with concentrated sulfuric acid and transferred to a one liter autoclave for hydrothermal reaction. The hydrothermal reaction was carried out at 180oC at 500 rpm for 19 hrs. The reaction mixture was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 3 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z3). The synthesized Zeolite Z3 exhibited ZSM-48 framework with no additional phase of EU-1.
Table 3: Composition for preparation of Zeolite Z3
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 88
NaOH/SiO2 0.15
Diquat-5/SiO2 0.0127
Diquat-6/SiO2 0.0068
H2O/SiO2 23.42

[0055] EXAMPLE 4: Zeolite Z4
[0056] Table 4 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z4). About 8.5 g of sodium hydroxide was dissolved in about 600 g of distilled water and allowed to stir to cool down for 30 minutes. About 7.5 g of diquat-5 (pentamethonium bromide) and 3.5 g of diquat-6 (hexamethonium bromide) were added to the alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 2.75 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally 85.5 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.0 with concentrated sulfuric acid and transferred to a one liter autoclave for hydrothermal reaction. The hydrothermal reaction was carried out at 180oC at 500 rpm for 40 hrs. The reaction mixture was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 4 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z4). The synthesized Zeolite Z4 exhibited ZSM-48 framework with additional >7% of EU-1 phase.
Table 4: Composition for preparation of Zeolite Z4
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 80
NaOH/SiO2 0.15
Diquat-5/SiO2 0.015
Diquat-6/SiO2 0.0068
H2O/SiO2 23.42

[0057] EXAMPLE 5: Zeolite Z5
[0058] Table 5 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z5). About 40 g of sodium hydroxide was taken to dissolve in 2700 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 50 g of diquat-5 (pentamethonium bromide) and 5 g of diquat-6 (hexamethonium bromide) were added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 18.3 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally 427.5 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.0 with concentrated sulfuric acid and transferred to a five liter autoclave for hydrothermal reaction. The reaction hydrothermal was carried out at 180oC at 500 rpm for 48 hrs. The reaction mixture was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 5 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z5). The synthesized Zeolite Z5 exhibited ZSM-48 framework with additional 23.55% of EU-1 phase.
Table 5: Composition for preparation of Zeolite Z5
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 60
NaOH/SiO2 0.14
Diquat-5/SiO2 0.020
Diquat-6/SiO2 0.0013
H2O/SiO2 21.08

[0059] EXAMPLE 6: Zeolite Z6
[0060] Table 6 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z6). About 38.5 g of sodium hydroxide was taken to dissolve in 2700 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 50 g of diquat-5 (pentamethonium bromide) and about 5 g of diquat-6 (hexamethonium bromide) were added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 18.3 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally 427.5 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.0 with concentrated sulfuric acid and transferred to a five liter autoclave for hydrothermal reaction. The reaction hydrothermal was carried out at 180oC at 500 rpm for 47 hrs. The reaction was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 6 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z6). The synthesized Zeolite Z6 exhibited ZSM-48 framework with additional x10.68% of EU-1 phase.
Table 6: Composition for preparation of Zeolite Z6
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 60
NaOH/SiO2 0.135
Diquat-5/SiO2 0.020
Diquat-6/SiO2 0.0013
H2O/SiO2 21.08

[0061] EXAMPLE 7: Zeolite Z7
[0062] Table 7 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z7). About 37 g of sodium hydroxide was taken to dissolve in 2700 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 52 g of diquat-5 (pentamethonium bromide) and about 3 g of diquat-6 (hexamethonium bromide) were added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, about 20.2 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally 427.5 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the final was adjusted to about 12.0 with concentrated sulfuric acid and transferred to a five liter autoclave for hydrothermal reaction. The hydrothermal reaction was carried out at 180oC at 500 rpm for 64 hrs. The reaction mixture was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 7 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z7). The synthesized Zeolite Z7 exhibited ZSM-48 framework with additional 53.66% of EU-1 phase.
Table 7: Composition for preparation of Zeolite Z7
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 54
NaOH/SiO2 0.13
Diquat-5/SiO2 0.021
Diquat-6/SiO2 0.0011
H2O/SiO2 21.08

[0063] EXAMPLE 8: Zeolite Z8
[0064] Table 8 shows the composition used for the preparation of EU-1 phase containing ZSM-48 (Zeolite Z8). About 8.5 g of sodium hydroxide was taken to dissolve in about 600 g of distilled water and allowed to cool down for about 30 minutes under constant stirring to form an alkaline solution. About 8.5 g of diquat-5 (pentamethonium bromide) was added to the above alkaline solution under constant stirring to obtain a completely dissolved solution. To this solution, 2.25 g of anhydrous sodium aluminate was added and stirred again until a clear solution was obtained. Finally, about 85.5 g of Hi-Sil was added slowly and stirred at least for another 2 hours to obtain a homogenized gel mixture. The pH of the homogenized gel mixture was adjusted to about 12.0 with concentrated sulfuric acid and transferred to a one liter autoclave for hydrothermal reaction. The hydrothermal reaction was carried out at 180oC at 500 rpm for 19 hrs. The reaction mixture was cooled down and product was washed with distilled water, filtered off and dried at 120oC in oven for 6-8 hrs. FIG. 8 illustrates an exemplary snippet depicting X-ray diffraction pattern for ZSM-48 family of co-crystallite zeolite (Z8). The synthesized Zeolite Z8 exhibited ZSM-48 framework with additional 5.33 % of EU-1 phase
Table 8: Composition for preparation of Zeolite Z8
Ingredient/
Component Amount
(in ratio)
SiO2/Al2O3 98
NaOH/SiO2 0.15
Diquat-5/SiO2 0.017
H2O/SiO2 23.42

[0065] METHOD FOR THE DETERMINATION OF WEIGHT % OF EUO PHASE IN MRE/EUO TYPE OF ZEOLITES
[0066] Determination of weight % of EUO (EU-1) phase in EUO phase containing MRE type of zeolite was carried out by preparing different sets of physically mixed zeolites (ZSM-48 and EU-1) and subjecting them to XRD to measure characteristic x-ray diffraction patterns thereof vis-à-vis the EUO phase containing MRE zeolite. FIG. 9A and FIG. 9B illustrate exemplary snippets depicting x-ray diffraction patterns for ZSM-48 family of co-crystallite zeolites showing characteristics peak of EU-1 at the 2-theta of 7.92, 8.75 and 20.53 degrees. FIG. 10A through FIG. 10C illustrate exemplary snippets depicting X-ray diffraction patterns of physical mixtures of ZSM-48 and EU-1 - PM-25, PM-50 and PM-75, respectively. It is evident that the x-ray diffraction pattern of EUO containing ZSM-48 sample is different from EUO and ZSM-48. The peak centered at 2? ~ 20.53° clearly indicates the presence of EUO phase. There are three peaks indexed for EUO type zeolites by M.M.J. Treacy et al (in book chapter, at 2? values around 7.92°, 8.75° and 20.53° respectively. Additionally, Dougnier et al in “Synthesis, characterization, and catalytic properties of silica-rich faujasite-type zeolite (FAU) and its hexagonal analog (EMT) prepared by using crown-ethers as template, Zeolites, 1992, 12, 160-166” also determined/calculated the amount FAU in the FAU/EMT co-crystallized/intergrowth samples by comparing the x-ray diffraction pattern of physically mixed FAU and EMT zeolites. In order to verify the main characteristic peak of EUO phase, the x-ray diffraction pattern for a set of physically mixed/admixture (25-75 wt % of EUO in ZSM-48, denoted as PM-25, PM-50 and PM-75) samples were measured. It was observed that the intensity of X-ray diffraction peak at 20.53° linearly increases with increasing amount of EUO in ZSM-48 and the peak at 2? ~ 20.53°, was considered for EUO% calculation in the co-crystallized EUO and ZSM-48. It is interesting to note that low silica to alumina ratio (SAR) required higher C-5 template (pentamethonium) concentration and C-6 template control morphological aspect resulting in low aspect ratio co-crystallite zeolites. FIG. 11A and FIG. 11B illustrate an exemplary snippets depicting Scanning Electron Microscope images of ZSM-48 family of co-crystallite zeolites (Z8 and Z4). FIG. 12 illustrates an exemplary snippet depicting Transmission Electron Microscope images of ZSM-48 family of co-crystallite zeolite Z4 with aspect (length/diameter) ratio of about 2.86.
[0067] PREPARATION OF ACIDIC FORM OF ZEOLITE
[0068] The above crystallized samples (Z1 through Z8) were filtered, washed several times with de-ionized water and dried overnight at 110 °C. The samples were calcined in air at 550°C for 12 h. The proton (acidic) form of the sample was obtained by exchanging the samples with ammonium nitrate three times under refluxing at 90°C for about 3 to 4 h followed by calcination at 550°C for 4 h.
[0069] CHARACTERISATION OF ZEOLITE AND ITS CATALYST SAMPLE
[0070] All the zeolites (Z1 through Z8) were characterized by several physiochemical techniques (shown in Table 9).
Table 9: Textural properties of zeolites samples (Z1 through Z8)
Example
No. SiO2/Al2O3
Ratio BET
(m2/g) SAmeso
(m2/g) Acidity
(µmol/g) Wt % of EU-1
Z1 88 315 47 135 44.19
Z2 42 315 69 130 100
Z3* 88 209 74 165 -
Z4** 80 258 107 130 >7
Z5 60 215 68 190 23.55
Z6 60 230 136 180 10.68
Z7 55 258 62 262 53.66
Z8 98 211 97 130 5.33
*No peak was observed at 2 theta value of 20.53
** The exact value cannot be calculated due to low intensity peak (low crystallinity leads to high noise to signal ratio, hampering intensity calculation at 2-theta value of 20.53).

[0071] Platinum loading, binding and extruding the EU-1 phase containing ZSM-48 type of zeolite catalyst
[0072] The proton/acidic form of the above samples (Z1, Z2, Z3, Z4, Z5 and Z8) were used to make extruded Pt-loaded catalyst. About 0.086 g of tetra-ammonium platinum nitrate complex was dissolved in around 50 ml of distilled water. The above solution was taken into a flask and about 3.5 g of H-ZSM-48 (proton/acidic form of the samples Z1, Z2, Z3, Z4, Z5 and Z8) was added on to it. The pH of the solution was adjusted to be maintained in the range of 9 to 10 using tetra butyl ammonium hydroxide. The product obtained was filtered and dried at 100°C. About 65 parts of the above dried Pt/H-ZSM-48 crystal were mixed with 35 parts of pseudoboehmite alumina binder in a muller and sufficient amount of about 5% acetic acid solution was added to produce an extrudable dough type mass on a 1'' diameter extruder. The dough was extruded into 1/16'' diameter cylindrical extrudate and dried overnight in an oven at 130°C. The dried extrudate was calcined in oxygen at 400°C. Accordingly, six catalyst samples were prepared and named as CAT-1 (prepared using Z1), CAT-2 (prepared using Z2), CAT-3 (prepared using Z3), CAT-4 (prepared using Z4), CAT-5 (prepared using zeolite Z5) and CAT-6 (prepared using Z8).
The final catalyst composition is shown below:
Components Approx. Weight %
Zeolite 65 %
Binder 35%
Platinum 0.4%

[0073] Activity and Selectivity of the Catalyst (CAT-1, CAT-2, CAT-3, CAT-4, CAT-5 and CAT-6)
[0074] The above synthesized catalysts (CAT-1, CAT-2, CAT-3, CAT-4, CAT-5 and CAT-6) were tested for hydroisomerization selectivity using n-hexadecane as a standard feed. About 5 g of calcined catalyst extrudate diluted with inert material (quartz) was packed in a stainless steel fixed bed reactor. The catalyst was then dried overnight at 130°C under nitrogen flow and reduced at 320°C under a constant H2 flow of 100 ml/min at 60 bar pressure for 5 h. After reduction of the metal, the catalyst was used for hexadecane isomerization reaction. The reaction was carried out at a temperature range of 280-320°C, WHSV of 0.8-1.2 h-1, with H2/ HC ratio of 600 at 60 bar pressure. The activity and selectivity data for different catalysts is shown in Table 10.
Table 10: Comparison of activity and selectivity of different catalysts (CAT-1, CAT-2, CAT-3, CAT-4, CAT-5 and CAT-6) for n-C16 hydro-isomerization
Catalyst Zeolite used for synthesis of catalyst Temperature (°C) Conversion
(%) Isomer yield (%) Selectivity
(%)
CAT -1 Z1 302 74 40 54
CAT -2 Z2 310 86 13 15
CAT -3 Z3 309 89 79.21 89
CAT -4 Z4 302 89.37 80.77 90.38
CAT -5 Z5 302 90.07 80 89
CAT -6 Z8 310 90 76.5 85

[0075] CAT-3, CAT-4, CAT-5 and CAT-6 prepared using the MRE/EUO zeolite showed better selectivity for isomers as compared to CAT-1 (prepared using 44% of EU-1 phase containing ZSM-48 with bulk molar ratio of SiO2/Al2O3 = 88) and CAT-2 (prepared using EU-1 with bulk molar ratio of Si/Al = 42). However, zeolite, CAT-4 and CAT-5, with bulk molar ratio of SiO2/Al2O3 = 80 and SiO2/Al2O3 = 60 respectively showed comparable or even better activity and isomer selectivity compared to pure ZSM-48 type of zeolite CAT-3. It was interesting to note that CAT-4 and CAT-5 consist of >7% and 23.5 % of EU-1 phase containing ZSM-48 type of zeolites. The obtained isomerization results clearly indicate as well as demonstrate that ZSM-48 type of zeolite that contain substantial amount of EU-1 phase (> 5 to less than 23 %) can be an alternate choice of zeolite family having excellent hydro-isomerization applicability. Superior performances of CAT-4 and CAT-5 for n-C16 hydro-isomerization were attributed to its smaller zeolite crystal size, better surface area, higher external surface area and moderate acidity. Among CAT-4, CAT-5 and CAT-6, CAT-6 showed lower isomer selectivity due to its higher crystallization size (Fig 11A, SEM image for Z8) as it was synthesized using single template based zeolite synthesis (Example-8). Whereas the SEM image for Z4 (example 4) exhibited smaller particle size (FIG. 11B). Thus, the present invention clearly demonstrate the advantage of utilizing EU-1 phase containing ZSM-48 type zeolite with smaller particle size (obtained by using mixed template based synthesis method) in the preparation of hydro-isomerization catalyst.
[0076] Although the subject matter has been described herein with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein. Furthermore, precise and systematic details on all above aspects are currently being made. Work is still underway on this invention. It will be obvious to those skilled in the art to make various changes, modifications and alterations to the invention described herein. To the extent that these various changes, modifications and alterations do not depart from the scope of the present invention, they are intended to be encompassed therein.
ADVANTAGES OF THE INVENTION
[0077] The present disclosure provides a method of preparation of a MRE (ZSM-48) type of zeolite having EUO phase.
[0078] The present disclosure provides a method of preparation of a family of ZSM-48 type of zeolite with an additional phase of EU-1.
[0079] The present disclosure provides a catalyst containing MRE/EUO zeolite that exhibits mixed template based synthesis.
[0080] The present disclosure provides a catalyst containing MRE/EUO zeolite that exhibits mixed template based synthesis for the preparation of zeolite with desired crystal size.
[0081] The present disclosure provides a catalyst containing MRE/EUO zeolite that exhibits optimum acidity and high surface area.
[0082] The present disclosure provides a catalyst comprising EU-1 phase containing ZSM-48 family zeolite that exhibits desired crystal size, optimum acidity and high surface area.
[0083] The present disclosure provides a catalyst comprising ZSM-48 family zeolite with additional phase of EU-1 that exhibits high hydro-isomerization activity and selectivity.
[0084] The present disclosure provides a catalyst containing MRE/EUO zeolite that exhibits high hydro-isomerization activity and selectivity.
[0085] The present disclosure provides a method for preparation of a MRE/EUO zeolite with low aspect ratio.
[0086] The present disclosure provides a method for preparation of a ZSM-48 family zeolite with additional phase of EU-1 with low aspect ratio.
[0087] The present disclosure provides a method for preparation of a catalyst containing MRE/EUO zeolite that exhibits desired crystal size, optimum acidity and high surface area.
[0088] The present disclosure provides a method for preparation of a catalyst containing MRE/EUO zeolite that exhibits high hydro-isomerization activity and selectivity.
,CLAIMS:
1. A MRE/EUO zeolite, wherein said zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite.
2. The zeolite as claimed in claim 1, wherein said zeolite comprises EU-1 phase in an amount ranging from 5% to 23% by weight of said zeolite, and wherein said zeolite comprises silica and alumina in a molar ratio ranging from 80 to 200.
3. The zeolite as claimed in claim 1, wherein said zeolite exhibits surface area ranging from 70 m2/gm to 350 m2/g, external surface area ranging from 30 m2/gm to 140 m2/g, crystal size of less than 1 micron, and aspect ratio of less than 4.
4. A catalyst comprising:
at least one MRE/EUO zeolite; and
at least one noble metal supported thereon,
wherein said MRE/EUO zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite.
5. The catalyst as claimed in claim 4, wherein the catalyst includes the at least one noble metal in an amount ranging from 0.05 wt% to 3 wt%, and wherein the at least one noble metal is a metal of Group-VIII, further wherein the catalyst exhibits dispersion of the at least one noble metal over at least 5% of total surface area thereof.
6. A method for preparation of a MRE/EUO zeolite, the method comprising the step of: effecting hydrothermal crystallization of a reaction mixture comprising at least one silica precursor, at least one alumina precursor, at least one alkali and a combination of structure directing agents, wherein at least one of said combination of structure directing agents imparts, at least in part, MRE framework to said zeolite, and wherein the other structure directing agent of said combination of structure directing agents imparts, at least in part, EUO framework to said zeolite,
wherein the method effects preparation of the MRE/EUO zeolite having EU-1 phase in an amount of more than 5% by weight of said zeolite.
7. The method as claimed in claim 6, wherein said zeolite exhibits aspect ratio of less than 3.
8. The method as claimed in claim 6, wherein the step of effecting hydrothermal crystallization is conducted at a temperature ranging from 130°C to 200°C and for a time period ranging from 10 hours to 96 hours.
9. The method as claimed in claim 6, wherein the at least one silica precursor is selected from a group comprising silica sols, tetraalkylorthosilicates and silicon dioxides, and wherein the at least one alumina precursor is anhydrous NaAlO2, and wherein the at least one alkali source is sodium hydroxide, further wherein the combination of structure directing agents comprises pentamethonium bromide (Diquat-5) and hexamethonium bromide (Diquat-6).
10. The method as claimed in claim 9, wherein molar ratio of pentamethonium bromide/SiO2 ranges from 0.01 to 0.05, molar ratio of hexamethonium bromide/SiO2 ranges from 0.0006 to 0.05, molar ratio of OH-/SiO2 ranges from 0.10 to 0.50, molar ratio of H2O/SiO2 ranges from 15 to 35, and molar ratio of silica/alumina ranges from 50 to 100.
11. A method for preparation of a catalyst comprising at least one MRE/EUO zeolite and at least one noble metal, the method comprising the steps of:
effecting conversion of said at least one MRE/EUO zeolite to acidic form thereof; and
contacting said acidic form of the at least one MRE/EUO zeolite with at least one precursor of the at least one noble metal to effect preparation of the catalyst,
wherein said zeolite comprises EU-1 phase in an amount of more than 5% by weight of said zeolite.
12. The method as claimed in claim 11, wherein the step of effecting conversion of said at least one MRE/EUO zeolite to acidic form thereof comprises: effecting ion-exchange by contacting said at least one MRE/EUO zeolite with an ammonia precursor, and wherein the step of contacting said acidic form of the at least one MRE/EUO zeolite with the at least one precursor of the at least one noble metal comprises: effecting ion-exchange by contacting said acidic form of the at least one MRE/EUO zeolite with the at least one precursor of the at least one noble metal.
13. The method as claimed in claim 12, wherein said ammonia precursor is ammonium nitrate, and wherein the precursor of the at least one noble metal is tetra-ammonium platinum nitrate complex.
14. The method as claimed in claim 11, wherein said acidic form of the at least one MRE/EUO zeolite exhibits surface area ranging from 70 m2/gm to 300 m2/gm, crystal size of less than 1 micron, external surface area ranging from 20 m2/gm to 150 m2/g, and titrable acidity ranging from 50 µmol/g to 300 µmol/g.
15. The method as claimed in claim 11, wherein the method further comprises the steps of: drying the catalyst; effecting mixing of an appropriate amount of the dried catalyst with an appropriate amount of at least one binder to form a coherent mass; and effecting extrusion of said coherent mass to prepare an extruded mixture.
16. The method as claimed in claim 15, wherein the extruded mixture comprises the catalyst in an amount ranging from 30% to 70% by weight of the extruded mixture.
17. The method as claimed in claim 15, wherein the binder is selected from any or a combination of clay, silica, alumina and a metal oxide.
18. The method as claimed in claim 15, wherein the method further comprises the step of effecting calcination of the said extruded mixture, wherein the calcinations is effected at a temperature ranging from 250°C to 400°C and under constant air flow.