Method for synthesizing molecular sieves of the mww framework type

Abstract

Disclosed are methods of synthesizing molecular sieves of the MWW framework type and molecular sieves synthesized thereby. The methods include preparing a synthesis mixture for forming a molecular sieve of the MWW framework type, the synthesis mixture comprising water, a source of silicon, a source of a trivalent element X, a structure directing agent R, a source of an alkali or alkaline earth metal cation M, and a source of poly(diallyldimethylammonium) cations (PDDA).

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to U.S. Provisional Application No. 63 / 155990, filed March 3, 2021, and European Application No. 21167971.7, filed April 13, 2021, the entire contents of which are incorporated herein by reference. Invention Field

[0003] This invention relates to a novel method for synthesizing MWW framework-type molecular sieves and the molecular sieves prepared therefrom. Background of the Invention

[0005] In the past, both natural and synthetic molecular sieve materials have demonstrated catalytic properties for various types of hydrocarbon conversion reactions. Some molecular sieves, such as zeolites, AlPO, and mesoporous materials, are ordered porous crystalline materials with well-defined crystalline structures, as determined by X-ray diffraction (XRD). Some molecular sieves are ordered and produce specific, recognizable XRD patterns, but are not strictly crystalline. Numerous cavities may exist within some molecular sieve materials, which can be interconnected by several channels or pores. These cavities and pores are uniformly sized within a particular molecular sieve material. Because the size of these pores allows for the acceptance of adsorbed molecules of certain sizes while rejecting larger molecules, these materials are called "molecular sieves" and are used in various industrial processes.

[0006] Such molecular sieves (natural and synthetic) comprise a wide variety of ionic crystalline silicates. These silicates can be described as three-dimensional frameworks of SiO4 tetrahedra and tetrahedra of group 13 element oxides (e.g., AlO4). The tetrahedra are typically formed by the shared angle of oxygen atoms, and the valence of tetrahedra containing group 13 elements (e.g., aluminum, gallium, or boron) is balanced by the charges of cations, such as protons, alkali metals, or alkaline earth metals.

[0007] Typically, zeolite synthesis involves hydrothermal crystallization from a synthetic mixture containing all elemental sources present in zeolites, such as silica and alumina, and in many cases, a structure-directing agent and / or a source of hydroxide or fluoride ions. Often, the synthetic mixture is obtained by treating a solution of aluminate and silicate with a compound that breaks Si-O bonds, thereby providing grown crystals with Si and, in some cases, disrupting the amorphous structure. Often, hydroxide (OH-) ions are used. -Zeolite synthesis also often uses a structure directing agent (SDA) to help promote the formation of crystals having the desired structure, especially organic molecular structure directing agents. Typically, the zeolite crystals form around the structure directing agent, with the structure directing agent occupying the pores in the zeolite once crystallization is complete. A "as-synthesized" zeolite will thus contain the structure directing agent in its pores, such that after crystallization the "as-synthesized" zeolite is often subjected to a calcination step to remove the structure directing agent. For many catalytic applications, it is also desirable to include metal cations within the molecular sieve structure, for example metal cations of Groups 2 through 15 of the Periodic Table of the Elements. This is typically done by an ion exchange process. Formation of the desired zeolite structure can also be promoted by the addition of seeds to the synthesis mixture. The introduction of seeds to a molecular sieve synthesis mixture can have beneficial effects including, for example, controlling product particle size, accelerating synthesis, improving selectivity of the desired structure type, and sometimes avoiding the need for an organic structure directing agent.

[0008] Molecular sieve, such as zeolite, crystal structures have found widespread use in refining processes and other processes for treating petroleum streams. Some zeolite applications are catalytic in nature, while others focus on the ability of the zeolite to selectively adsorb molecules within a gas stream.

[0009] MWW-type molecular sieves are a class of zeolites that can be used in industrial processes, including for example catalysis. Some members of the MWW zeolite family are active components of commercially available catalysts for processes such as alkylation. MCM-22 has been successfully used on a commercial scale for the alkylation of benzene to produce cumene.

[0010] Zeolitic materials designated by IZA-SC as having the MWW topology are multilayer materials having a dual pore system resulting from the presence of 10-membered rings and 12-membered rings. As such, MWW-type molecular sieves can be microporous and mesoporous. As used herein, the term microporous is used to refer to materials having a pore diameter of less than 1.5 nm and mesoporous is used to refer to materials having a pore diameter of 1.5 nm to 50 nm. Based on their 10-ring internal pore system, MWW framework type zeolites are considered to be medium pore size zeolites, which generally have pore sizes from about to less than about However, the 12-ring surface pockets that are not in communication with the 10-ring internal pore system can impart some properties more similar to large pore zeolite alkylation catalysts such as mordenite.

[0011] Molecular sieves having the MWW framework structure are often referred to as "MWW family molecular sieve materials." As used herein, the term "MWW family molecular sieve materials" includes one or more of the following:

[0012] (i) a molecular sieve made from a common first order building block unit cell, wherein the unit cell has a MWW framework topology. (A unit cell is a spatial arrangement of atoms that, if packed in three-dimensional space, describes a crystal structure. Such crystal structures are discussed in "Atlas of Zeolite Framework Types", Fifth Edition, 2001, the entire contents of which are incorporated by reference.) ;

[0013] (ii) a molecular sieve made from a common second order building block, which is a two-dimensional packing of such MWW framework topology unit cells, thereby forming a single layer of unit cell thickness, preferably a c-unit cell thickness;

[0014] (iii) a molecular sieve made from a common second order building block, which is a layer of one or more than one unit cell thickness, wherein the layer of more than one unit cell thickness is made from stacking, packing or combining at least two single layers of unit cell thickness. Such stacking of second order building blocks can be in regular form, irregular form, random form or any combination thereof; and

[0015] (iv) a molecular sieve made from any regular or random two-dimensional or three-dimensional combination of unit cells having a MWW framework topology.

[0016] MWW family molecular sieve materials are characterized as having an XRD pattern (either calcined or as-synthesized) including d-spacing maxima at 12.4 ± 0.25, 3.57 ± 0.07, and 3.42 ± 0.07 Angstroms. MWW family molecular sieve materials can also be characterized as having an XRD pattern (either calcined or as-synthesized) including d-spacing maxima at 12.4 ± 0.25, 6.9 ± 0.15, 3.57 ± 0.07, and 3.42 ± 0.07 Angstroms. XRD data for characterizing the molecular sieve is obtained by standard techniques using copper K-alpha doublet as the incident radiation and a diffractometer equipped with a scintillation counter and computerized data acquisition system as the collection system. Materials belonging to the MWW family include, but are not limited to, MCM-22 (described in U.S. Patent No. 4,954,325), PSH-3 (described in U.S. Patent No. 4,439,409), SSZ-25 (described in U.S. Patent No. 4,826,667), ERB-1 (described in European Patent No. 0 293 032), ITQ-1 (described in U.S. Patent No. 6,077,498), ITQ-2 (described in International Patent Publication No. WO 97 / 17290), ITQ-30 (described in International Patent Publication No. WO 2005118476), MCM-36 (described in U.S. Patent No. 5,250,277), MCM-49 (described in U.S. Patent No. 5,236,575), MCM-56 (described in U.S. Patent Nos. 5,362,697, 5,827,491, and 5,453,554), EMM-10 (described in U.S. Patent No. 8,110,176), EMM-10-P (described in U.S. Patent No. 7,959,599), EMM-12 (described in International Patent Publication No. WO 2010 / 021795), EMM-13 (described in International Patent Publication No. WO 2010 / 014406), and MCM-22 family materials (described in U.S. Patent No. 7,842,277). Also UZM-8 (described in U.S. Patent No. 6,756,030) and UZM-8HS (described in U.S. Patent No. 7,713,513). The entire contents of the patents and applications are incorporated herein by reference. WO 2007 / 094937 discloses a method of making MCM-22 family molecular sieves. WO 2015 / 112293 discloses a method of making molecular sieves having MWW framework structures using precipitated aluminosilicates.

[0017] MWW-type zeolites have a layered three-dimensional structure, with each two-dimensional layer being approximately 1-2 nm thick. Within the MWW family, a number of individually defined materials represent different stacking arrangements of individual platelets. Various strategies for obtaining different members of the MWW family are reviewed in “Lamellar MWW-Type Zeolites: Toward Elegant Nanoporous Materials”, A. Schwanke et al., Appl. Sci. 2018, 8, 1636, the contents of which are incorporated herein by reference. For example, MCM-22 can be formed via a precursor (P)MCM-22 containing a structure directing agent (SDA) cyclohexylidene imine (HMI) sandwiched between individual platelets, with hydrogen bonds between the HMI molecules and silanol groups on the zeolite surface fixing the platelets. Calcination removes the HMI molecules and condenses the silanol groups, thereby forming three-dimensional MCM-22. A three-dimensional analogue of MCM-22, MCM-49, can be formed by direct crystallization from a gel mixture, again using HMI as the SDA, increasing the relative proportion of alkali metal (sodium) in the composition. “Zeolite MCM-49: A Three-Dimensional MCM-22 Analogue Synthesized by in situ Crystallization”, S. L. Lawton et al., J. Phys. Chem., 1996, 100, 3788-3798 discloses the synthesis and characterization of MCM-22, (P)MCM-22 and MCM-49. It discloses that (P)MCM-22 was synthesized when the reaction mixture had an organic template / inorganic cation (alkali metal) ratio greater than 2.0, whereas MCM-49 was formed when the molar ratio was less than 2.0. MCM-22 and MCM-49 were found to be very similar in structure, except that the unit cell c parameter of MCM-49 was larger, indicating an increase in the interlayer distance in the platelet structure. Increasing the proportion of alkali metal in the reaction mixture resulted in increased aluminium incorporation into the zeolite framework. For MCM-49, a crystallite framework Si / Al2ratio of 17-22 was reported using HMI as the SDA. “Synthesis of MCM-22 zeolites of different Si / Al ratio and their structural, morphological and textural characterisation”, C. Delitala et al., Microporous and Mesoporous Materials, Volume 118, Issues 1-3, 2009, Pages 1-10 discloses MCM-22 zeolites with Si / Al ratios in the range 9-46 (corresponding to Si / Al2ratios of 18-92).

[0018] The preparation of MCM-22 from a reaction mixture using NaOH or KOH as a mineralizing agent and HMI as SDA is disclosed in “Synthesis and characterization of MCM-22 and MCM-49 zeolites”, D. Vuono et al., Studies in Surface Science and Catalysis, 154, 2004, 203-210. MCM-49 zeolites were also reported in this study, but only using NaOH as a mineralizing agent (using KOH only yielded (p)MCM-22).

[0019] The preparation of nanosized MCM-22 zeolite from a synthetic mixture containing colloidal silica as the Si source and a cationic polymer (poly(diallyldimethylammonium)(PDDA) chloride) is disclosed in “Synthesis of the nanosized MCM-22zeolite and its catalytic performance in methane dehydro-aromatization reaction”, X. Yin et al., Catalysis Communications, Vol. 43, 2014, pp. 218-222. PDDA chloride is added to act as a protective agent to prevent self-aggregation of the synthesized colloid.

[0020] MCM-56 is a MWW group zeolite with partially lamellar disorder, which forms as an intermediate of MCM-49 (see A. Schwanke et al.). Each layer in MCM-56 is porous and has a skeletal structure closely related to that of MCM-22 and other members of the MCM-22 group. MCM-56 is isolated by intervening in the reaction for the formation of MCM-49 during the crystallization process. If crystallization is allowed to continue, the initially peeled-off, randomly stacked MCM-56 sheets (with an MCM-22 topology and a...) Thick unit cells gradually organize into an ordered three-dimensional framework in the c-direction, which is in the form of zeolite MCM-49. The formation of MCM-56 presents unique challenges, especially on a large scale, because it is a transient product and undergoes further changes during the manufacturing process. For example, while careful control of crystallization conditions can be controllable on a laboratory scale, determining the correct time to stop crystallization and thus isolate a usable amount of intermediate zeolite is problematic on a commercial scale. WO2013 / 048636 discloses a method for manufacturing high-quality porous crystalline MCM-56 materials.

[0021] MWW zeolites are characterized by high aluminum content. High aluminum content is important for high activity in catalytic processes. Each aluminum center on the accessible portion of the zeolite provides an acid site, which can provide catalytic activity. Higher aluminum content makes the zeolite more acidic and thus provides higher activity. When aluminum centers are located in the pores of the zeolite, the size and shape of the pores can affect selectivity and activity. For example, reactant molecules that can more easily access the pores can preferentially undergo catalytic reactions over molecules that have a size and / or shape that prevents access to the pores. This can present advantages and limitations in zeolite catalysts. For example, in the case of sites where aluminum centers are incorporated in relatively small pores, the resulting zeolite catalyst can provide high selectivity for reactions with small reactant molecules, as well as relatively low activity (even with smaller molecules, for example, due to the slowing of the time taken for the reaction by the reactant molecules to enter and exit the pores). Such catalysts can not be effective in catalysis of reactions involving larger reactant molecules, for example, aromatic molecules. In MWW-type zeolites, aluminum centers located in the 12-ring surface pores provide potential catalytic sites accessible to relatively large molecules, while aluminum centers located in the 10-ring internal pore network can be accessible only to smaller molecules. The mixed 10-ring / 12-ring structure of MWW zeolites can provide a catalyst suitable for use with a relatively wider variety of reactant molecules, depending on the location of aluminum incorporation into the zeolite framework.

[0022] There are many methods of synthesizing molecular sieves of the MWW framework type, but there remains a need for additional MWW zeolites having improved properties or improved combinations of properties, such as high external surface area (high mesoporosity) along with high micropore volume. SUMMARY

[0023] The present invention provides a method of synthesizing a molecular sieve of the MWW framework type, the method comprising preparing a synthesis mixture capable of forming a molecular sieve of the MWW framework type, the synthesis mixture comprising water, a source of silicon, a source of a trivalent element X, a structure directing agent R, a source of an alkali or alkaline earth metal cation M, a source of poly(diallyldimethylammonium) cations (PDDA), optionally a source of a pentavalent element Z, optionally a source of hydroxide ions, and optionally a seed crystal. The synthesis mixture has the following molar ratio composition: Si:X2 = 8 to less than 30, H2O:Si = 5 to less than 50, M:Si = 0.05 to 1.0, R:Si = 0.05 to 1.0. The synthesis mixture comprises the source of PDDA in an amount from 0.01 to less than 1.0 wt.%, based on the weight of the synthesis mixture. The method further comprises heating the synthesis mixture under crystallization conditions comprising a temperature of 80 °C to 225 °C for a time sufficient to form crystals of the molecular sieve of the MWW framework type, and recovering the crystals of the molecular sieve of the MWW framework type from the synthesis mixture.

[0024] It has been found that the presence of PDDA in the synthesis mixture of the zeolite helps to form a MWW-type molecular sieve with a high external surface area in combination with a high micropore volume. In particular, the resulting MWW-type molecular sieve shows an external surface area in the range of the previously known MCM-56 zeolite, however, it has a higher micropore volume close to the micropore volume of the previously known MCM-49 zeolite. Without wishing to be bound by theory, the inventors believe that the PDDA used in the synthesis mixture acts as a zeolite growth modifier. The increased external surface area is especially advantageous because the accessibility of the surface depressions of MWW-type molecular sieves is of considerable importance for their catalytic performance, for example in applications such as alkylation, while maintaining or increasing microporosity is of paramount importance for shape selective catalysis using molecular sieves.

[0025] The present invention also provides a MWW framework type molecular sieve obtainable or made by the synthesis method according to the present invention.

[0026] The present invention also provides a MWW framework type molecular sieve having in its calcined and anhydrous form a composition comprising the molar relationship: (n) Si02: X203, wherein X is a trivalent element selected from the group consisting of aluminum, boron, gallium and mixtures thereof, and n is the number of moles of Si02per mole of X203, and varies from 8 to less than 30; an external surface area (S 2 ) of at least 125 m ext / g and a micropore volume (V 3 ) of more than 0.13 cm micro / g.

[0027] The present invention also provides a catalyst comprising the MWW framework type molecular sieve of the present invention.

[0028] The present invention also provides a hydrocarbon chemical conversion process comprising the step of contacting a hydrocarbon feedstock with the catalyst of the present invention. In one embodiment, the catalytic process is alkylation, for example aromatic compound alkylation.

[0029] These and other features and attributes of the present disclosure and its advantageous applications and / or uses will become apparent with regard to the following detailed description. It will be appreciated that features described with regard to one aspect of the present invention can be incorporated into other aspects of the invention.

[0030] BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 XRD patterns of Comparative Examples 1-2 and Examples 3-5 are shown in their as-synthesized form.

[0032] Figures 2a-2e Scanning electron microscopy (SEM) images of each of Comparative Examples 1-2 and Examples 3-5 are shown.

[0033] Figure 3 N2physisorption isotherms showing Comparative Examples 1-2 and Example 4. 27 Al NMR spectra.

[0034] Figure 4 N2physisorption isotherms showing Comparative Examples 1-2 and Example 4.

[0035] Figure 5 Thermogravimetric analysis showing Comparative Example 1 and Example 4 in as-prepared state.

[0036] Detailed description

[0037] The method of synthesizing a molecular sieve of the MWW framework type according to the present invention comprises preparing a synthesis mixture according to conventional techniques, with the difference that the synthesis mixture comprises at least a source of poly(diallyldimethylammonium) cations (PDDA) and the synthesis mixture has a Si:X2molar ratio of less than 30 and a H2O:Si molar ratio of less than 50. The method of synthesizing a molecular sieve according to the present invention further comprises crystallizing the molecular sieve according to conventional techniques, and isolating the molecular sieve according to conventional techniques.

[0038] Synthesis mixture

[0039] As mentioned above, the synthesis mixture can be prepared according to conventional methods. The components of the synthesis mixture can be combined in any order.

[0040] The synthesis mixture of the present invention comprises a source of polymeric cations, in particular poly(diallyldimethylammonium) cations (PDDA). The source of PDDA is present in the synthesis mixture of the present invention in an amount from 0.01 to less than 1.0 wt.%, typically 0.02-0.7 wt.%, preferably from 0.04 to less than 0.7 wt.%, for example 0.05-0.5 wt.%, based on the weight of the synthesis mixture. Without wishing to be bound by theory, the inventors believe that the PDDA acts as a zeolite growth modifier, leading to a modified structure of the zeolite. More particularly, the inventors surprisingly found that the presence of PDDA in the zeolite synthesis mixture of the present invention helps to form a MWW-type molecular sieve with a high external surface area in combination with a high micropore volume, the resulting MWW-type molecular sieve having an external surface area in the range of the previously known MCM-56 zeolite, however with a micropore volume that is close to the micropore volume of the previously known MCM-49 zeolite. This combination of a high external surface area in combination with a high micropore volume is especially advantageous, as it leads to a higher accessibility to the surface depressions of the MWW-type molecular sieve (which is of considerable importance for their catalytic performance, for example in applications such as alkylation), while maintaining selectivity.

[0041] The source of PDDA can for example be selected from at least one of a PDDA chloride and / or a PDDA hydroxide, for example a PDDA chloride. The source of PDDA typically has a molecular weight (Mw) in the range of 50,000-1,000,000 g / mole, preferably 100,000-800,000, for example 150,000-600,000 or 200,000-500,000, with specific examples including a source of PDDA having a Mw of 200,000-350,000 or 400,000-500,000.

[0042] The synthesis mixture further comprises a structure directing agent R. It will be appreciated that any structure directing agent suitable for forming a MWW-type molecular sieve can be used. Suitable structure directing agents include cyclopentylamine, cyclohexylamine, cycloheptylamine, cyclohexyl imine (HMI), cycloheptyl imine, homopiperazine, and combinations thereof. Additionally or alternatively, the structure directing agent can be a salt or hydroxide of diquat, for example a pentamethonium salt or hydroxide (e.g. pentamethonium bromide or hydroxide), a hexamethonium salt or hydroxide (e.g. hexamethonium bromide or hydroxide), and / or a heptamethonium salt or hydroxide (e.g. heptamethonium bromide or hydroxide). Additionally or alternatively, the structure directing agent can be a diethyl-dimethylammonium salt or hydroxide, or a N,N,N-trimethyl-1 -adamantylammonium salt or hydroxide, or a N,N,N-trimethyl-2-adamantylammonium salt or hydroxide, for example a chloride, bromide or hydroxide. Preferably, the structure directing agent R is cyclohexyl imine (HMI). The structure directing agent R is present in a molar ratio R:Si relative to silicon of 0.05 to 1.0, optionally 0.08 to 0.8, for example 0.1 to 0.5 or 0.1 to 0.3, for example 0.15 to 0.25 or even 0.16 to 0.20.

[0043] The synthetic mixture contains one or more sources of a trivalent element X, such as aluminum, boron, and / or gallium, preferably X contains Al, and more preferably X is Al. Suitable sources of the trivalent element X that can be used to prepare the synthetic mixture depend on the selected element X. In embodiments where X is aluminum, suitable sources of Al (e.g., aluminum oxides) for use in the method include aluminum salts, particularly water-soluble salts such as aluminum sulfate, aluminum nitrate, aluminum hydroxide, sodium aluminate, and aluminum alkoxides such as aluminum isopropoxide, as well as hydrated aluminum oxides such as boehmite, gibbsite, and boehmite, and mixtures thereof. In embodiments where X is boron, sources of B include boric acid, sodium tetraborate, and potassium tetraborate. Boron sources tend to be more soluble in hydroxide-mediated synthetic mixtures than aluminum sources. In embodiments where X is gallium, Ga sources include sodium gallate, potassium gallate, and gallium salts such as gallium chloride, gallium sulfate, and gallium nitrate. Preferably, X is Al and the source of aluminum in the synthetic mixture contains Al₂O₃, for example, where the source of aluminum is sodium aluminate. The synthetic mixture has a Si:X2 molar ratio of at least 8, preferably at least 10, more preferably at least 12, most preferably at least 13, for example at least 15, at least 16, or at least 17. The synthetic mixture has a Si:X2 molar ratio of less than 30, particularly at most 28 or even at most 25. The synthetic mixture has a Si:X2 molar ratio of 8 to less than 30, for example 10 to less than 30 or from 12 to less than 30, for example 15-25. In a particularly preferred embodiment, X is Al.

[0044] Suitable sources of Si (e.g., silicon oxides) for use in the method include silicates, such as tetraalkyl orthosilicates such as tetramethyl orthosilicate, and fumed silica, such as... (Available from Degussa) and (Available from DMS), precipitated silica, for example and 340 (available from Evonik), aqueous colloidal suspensions of alkali metal silicates such as potassium silicate and sodium silicate, and silica, such as those produced by EIdu Pont deNemours under the trade name For sale, silicates, fumed silica, precipitated silica, and alkali metal silicates are preferred. In particular embodiments, the silicon source comprises SiO2, preferably SiO2, for example in the form of an aqueous colloidal suspension of fumed silica, precipitated silica, or silica, most often fumed silica or precipitated silica.

[0045] Alternatively or in addition to the sources of Si and Al mentioned previously, sources containing both Si and Al can also be used as sources of Si and Al. Examples of suitable sources containing both Si and Al include amorphous silica-alumina gels or dried silica alumina powders, silica alumina, clays such as kaolin, metakaolin and zeolites, in particular aluminosilicates such as synthetic faujasites and ultrastable faujasites, for example USY, beta or other large to medium pore zeolites.

[0046] Optionally, the synthesis mixture comprises one or more sources of a pentavalent element Z, such as phosphorus. Suitable sources of the pentavalent element Z depend on the element Z selected. Preferably, Z is phosphorus. Suitable sources of phosphorus include phosphoric acid, organic phosphates such as triethyl phosphate and triethylammonium phosphate and aluminophosphates. Alternatively, the synthesis mixture does not contain any pentavalent element Z.

[0047] The synthesis mixture comprises one or more sources of an alkali or alkaline earth metal cation M, wherein M is preferably selected from sodium, potassium, lithium, rubidium, calcium, magnesium and mixtures thereof, preferably sodium and / or potassium, more preferably sodium. The source of sodium (when present) can be sodium hydroxide, sodium aluminate, sodium silicate, sodium aluminate or a sodium salt such as NaCI, NaBr or sodium nitrate. The source of potassium (when present) can be potassium hydroxide, potassium aluminate, potassium silicate, a potassium salt such as KCI or KBr or potassium nitrate. The source of lithium (when present) can be lithium hydroxide or a lithium salt such as LiCI, LiBr, LI, lithium nitrate or lithium sulfate. The source of rubidium (when present) can be rubidium hydroxide or a rubidium salt such as RbCI, RbBr, RBI or rubidium nitrate. The source of calcium (when present) can be, for example, calcium hydroxide. The source of magnesium (when present) can be, for example, magnesium hydroxide. The alkali or alkaline earth metal cation M can also be present in one or more sources of the trivalent element X, such as sodium aluminate, sodium tetraborate, potassium tetraborate, sodium gallate, potassium gallate and / or one or more sources of Si, such as potassium silicate and sodium silicate. The synthesis mixture comprises the source of alkali or alkaline earth metal cation M in a M:Si molar ratio of 0.05 to 1.0, preferably 0.08 to 0.5, more preferably 0.1 to 0.3, for example 0.1 to 0.25, or greater than 0.1 to less than 0.18.

[0048] Optionally, the synthetic mixture contains one or more sources of hydroxide ions, such as those selected from alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxide, and mixtures thereof; for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, calcium hydroxide, magnesium hydroxide, ammonium hydroxide, and mixtures thereof; more often, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, and mixtures thereof; most often, sodium hydroxide and / or potassium hydroxide. The hydroxide may also serve as a counterion to the structure-directing agent R, as a counterion to the PDDA cationic polymer, or as a source of Al by using aluminum hydroxide. Alternatively, the synthetic mixture may be free of hydroxide sources. Optionally, the synthetic mixture contains OH... - The / Si molar ratio is 0.05-1.0, optionally 0.08 to 0.5, for example 0.1 to 0.3, or 0.1 to 0.25, or greater than 0.1 to less than 0.18, containing a source of hydroxide ions. Preferably, the source of hydroxide ions is KOH and / or NaOH.

[0049] Optionally, the synthetic mixture contains 0.05-2, for example 0.1-1.5, for example 0.15-1 g. 晶种 / g (硅来源+三价元素X的来源)Seed crystals. Optionally, the seed crystals may have a framework type MWW or any other framework type, wherein the synthetic mixture is capable of forming a molecular sieve of the MWW framework type. Optionally, the seed crystals comprise a molecular sieve of the MWW framework type, for example, wherein the seed crystals comprise MCM-49 and / or MCM-56 zeolite, preferably composed of MCM-49 and / or MCM-56 zeolite. Optionally, the seed crystals are included in the synthetic mixture in the form of a colloidal suspension in a liquid medium such as water. As used herein, the expression "colloidal suspension" refers to a suspension containing discrete fine particles dispersed in a continuous liquid phase; preferably, it refers to a stable suspension at ambient temperature (23°C) for a time sufficient for its intended use, advantageously at least 10 hours, more advantageously at least 20 hours, preferably at least 100 hours, and more preferably at least 500 hours, in a sense, without visible separation or precipitation formation. The maximum size of particles for which a suspension remains stable (colloidal) will depend in part on their shape and on the properties and pH of the continuous medium, as well as on the time during which the suspension must remain usable. Particles can be spherical or have other shapes. When the particles are not spherical, the size mentioned is their minimum size. Colloidal seeds typically have an average diameter (or minimum size, corresponding to the number-average primary particle size determined by SEM for 100 or more particles) of 300 nm or less, specifically 200 nm or less, and more particularly 100 nm or less, provided that the colloidal seeds form a stable suspension within a time sufficient for intended use, in a sense that no visible separation or precipitation occurs. The preparation of colloidal seed suspensions and their use in the synthesis of molecular sieves are disclosed, for example, in International Patent Application Publications WO00 / 06493 and WO 00 / 06494.

[0050] The synthetic mixture contains H2O and SiO2 in a molar ratio of H2O:SiO2 ranging from 5 to less than 50, specifically 5-40, and more particularly 10-30, for example 15-25.

[0051] In a preferred embodiment, the synthetic mixture contains a structure-directing agent R and an alkali metal or alkaline earth metal cation M source with an R:M molar ratio of less than 2.5, preferably less than 2.0.

[0052] Crystallization and recycling

[0053] The crystallization conditions in step (b) include temperatures of 80°C-225°C, preferably 100°C-200°C, more preferably 140°C-180°C, for example 150°C-170°C, for example 155°C-165°C.

[0054] The time required for crystallization to occur will vary. For example, at higher temperatures, the crystallization time can be reduced. Optionally, the crystallization conditions in process step (b) include heating for a time period of from 1 to about 800 hours, for example from about 10 to less than 600 hours, particularly about 24 to 140 hours, for example about 40 to about 90 hours. The crystallization time can be determined by methods known in the art, for example by sampling the synthesis mixture at different times and determining the yield of precipitated solids and X-ray crystallinity.

[0055] The crystallization can be carried out in any suitable reactor vessel, for example a polypropylene jar or bottle, acid digestion vessel, stainless steel autoclave, plow shear mixer or reaction kettle, preferably a polypropylene jar, bottle or stainless steel autoclave, plow shear mixer or reaction kettle, preferably a polypropylene jar,

[0056] Optionally, the synthesis mixture is subjected to agitation during step (b), for example the conditions in step (b) include stirring. Optionally, at least a portion of step (b), for example the synthesis mixture is stirred throughout step (b). Alternatively, the synthesis mixture is not stirred during step (b), i.e. the crystallization is carried out under static conditions. Optionally, during step (b), the synthesis mixture is heated using agitation provided by a mixing device that moves the mixture in a turbulent fashion, for example as occurs using a pitch blade turbine mixer. Other means of introducing agitation can be used, as known to those skilled in the art, for example pumping the synthesis mixture around the vessel containing the mixture. The purpose of the agitation is to assist mass and heat transfer through the synthesis mixture in a uniform manner. The degree of agitation should be low enough so that shear-induced seed formation in the synthesis mixture is minimized. Optionally, the agitation is stopped once the synthesis mixture has reached a predetermined set time. Optionally, the synthesis mixture is continued to be heated after the agitation is stopped. Alternatively, the temperature can be maintained at the temperature reached when the agitation is stopped. It will be appreciated that the synthesis mixture can be optionally agitated (e.g. stirred) after step (b). Optionally, the synthesis mixture is subjected to discrete periods of agitation while being heated, according to which the synthesis mixture can be subjected to multiple static crystallization steps separated by agitation crystallization steps. For example, step (b) of the process can be repeated after a step of heating the synthesis mixture under stirred crystallization conditions, including a temperature of from 80°C to 225°C.

[0057] Optionally, the crystallization conditions of step (b) comprise a temperature equal to or greater than the effective nucleation temperature of the synthesis mixture. The effective nucleation temperature can be understood as the temperature at which continuous stirring of a heated zeolite synthesis mixture will result in a significant decrease in the mass average crystal diameter of the product zeolite crystals, for example a decrease in the mass average crystal diameter of the product crystals of 15% or greater. Preferably, the temperature of process step (b) is a temperature at which, if the synthesis mixture is stirred, the stirring will result in a decrease in the mass average crystal diameter of the product zeolite crystals of less than 10%, more preferably less than 5%, compared to the product zeolite crystals obtained from the corresponding un-stirred synthesis mixture. It will be appreciated that the effective nucleation temperature of the synthesis mixture will depend on the composition of the synthesis mixture, which in turn will be controlled by the zeolite being made. The effective nucleation temperature can be confirmed by procedures known in the art, for example by detecting the presence of crystals greater than any seed level by X-ray. Changes in the viscosity of the synthesis mixture during the first time period can also be used to determine the onset of crystallization. The effective nucleation temperature will be a function of the zeolite type being made and can often be expressed as a range of temperatures rather than a single, well-defined temperature.

[0058] Generally, the molecular sieve product is formed in solution and can be recovered by standard means, for example by centrifugation or filtration. The isolated product can also be washed, recovered by centrifugation or filtration, and dried.

[0059] Processing the molecular sieve

[0060] As a result of the crystallization process, the recovered molecular sieve product contains at least a portion of the structure directing agent used in the synthesis within its pores. Preferably, the process additionally includes activating the molecular sieve to remove the structure directing agent from the molecular sieve, opening active sites within the microporous channels of the molecular sieve for contact with the feedstock. The activation process is generally accomplished by calcination, or substantial heating, of the template-containing molecular sieve in the presence of an oxygen-containing gas. In some cases, it can be desirable to heat the molecular sieve in an environment having a low or zero oxygen concentration. This type of process can be used to partially or completely remove the structure directing agent from the intracrystalline pore system. Generally, the recovered molecular sieve is subjected to a calcination step, including heating the material at a temperature of at least about 200°C, preferably at least about 300°C, more preferably at least about 370°C, for at least 1 minute and generally no longer than 20 hours. Although sub-atmospheric pressures can be employed for the heat treatment, atmospheric pressure is generally desired for convenience reasons. The heat treatment can be carried out at a temperature of up to about 925°C. For example, the heat treatment can be carried out in the presence of an oxygen-containing gas, for example in air and / or ozone, at a temperature of 300-600°C, for example 400-550°C, for example 500-550°C.

[0061] The molecular sieve can also be subjected to ion exchange treatment, for example using aqueous ammonium salts such as ammonium nitrate, ammonium chloride and ammonium acetate, in order to remove remaining alkali metal cations and / or alkaline earth metal cations and replace them with protons, thereby producing the acid form of the molecular sieve. To the extent desired, the original cations of the as-synthesized material, for example alkali metal cations, can be replaced by ion exchange with other cations. Preferred replacement cations can include hydrogen ions, hydrogen precursors, for example ammonium ions, and mixtures thereof. The ion exchange step can be carried out after drying the as-prepared molecular sieve. The ion exchange step can be carried out before or after the calcination step.

[0062] The molecular sieve can also be subjected to other treatments, for example washing with a solvent and / or steaming. Such treatments are well known to the skilled person and are carried out in order to modify the properties of the molecular sieve as desired.

[0063] Once the molecular sieve has been synthesised, it can be formulated into a product composition by combination with other materials, for example binders and / or matrix materials, which provide additional hardness to the finished product. These other materials can be inert or catalytically active materials.

[0064] In particular, it can be desirable to incorporate the molecular sieve of the present application or manufactured by the method of the present application with another material which is resistant to the temperatures and other conditions employed during use. Such materials include synthetic or naturally occurring zeolites as well as inorganic materials such as clays, silicas and / or metal oxides such as alumina, yttria, zirconia, gallia, zinc oxide and mixtures thereof. The metal oxides can be naturally occurring or in the form of a gelatinous precipitate or gel, including mixtures of silica and metal oxides. Naturally occurring clays which can be used include the montmorillonite and kaolin families, which include sub-groups of bentonite and kaolin commonly referred to as Dixie, McNamee, Georgia and Florida clays or other kaolin in which the predominant mineral constituent is halloysite, kaolinite, dickite, nacrite or illite. Such clays can be used in the raw state as mined in the raw state or after being subjected to calcination, acid treatment or chemical modification. These binder materials are resistant to the temperatures and other conditions found in various hydrocarbon separation processes, for example mechanical attrition. The molecular sieve of the present application or manufactured by the method of the present application can therefore be used in the form of an extrudate having a binder. They are typically combined by forming pellets, spheres or extrudates. The extrudates are often formed by extruding the molecular sieve, optionally in the presence of a binder, and drying and calcining the resulting extrudate. Additional treatments such as steaming and / or ion exchange can be carried out as desired. The molecular sieve can optionally be combined with a binder having a surface area of at least 100 m 2 / g, for example at least 200 m 2 / g, optionally at least 300 m 2 / g.

[0065] These materials can be incorporated into naturally occurring clays, such as bentonite and kaolin, to improve the crush strength of the product under commercial operating conditions.

[0066] In addition to the foregoing materials, the molecular sieve of the present application can also be combined with porous matrix materials such as silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-berylia, silica-titania, and ternary compositions such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia, and silica-magnesia-zirconia.

[0067] The relative proportions of the molecular sieve and inorganic oxide matrix can vary widely, with the molecular sieve content ranging from about 1 to about 100 percent by weight of the composite material, and more often, particularly when the composite material is prepared in the form of an extrudate, in the range of about 2 to about 95, optionally about 20 to about 90 percent by weight of the composite material.

[0068] Molecular sieve

[0069] The present application also provides a MWW framework type molecular sieve obtainable by or made by the process according to the present application.

[0070] In a further embodiment, the present application also provides a MWW framework type molecular sieve in its calcined and amorphous form having a composition comprising the following molar relationship:

[0071] (n) Si02:X203

[0072] wherein X is a trivalent element selected from aluminum, boron and / or gallium, preferably wherein X comprises at least aluminum, more preferably wherein X is aluminum, and n is the number of moles of Si02per mole of X203, and varies from 8 to less than 30, in particular at least 10, such as at least 12 or at least 14, up to less than 30, such as up to 26 or up to 24. It will be understood that the Si:X2 molar ratio is the molar ratio in the molecular sieve framework. The composition of the molecular sieve material can be verified using any suitable method, such as Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis. Preferably, when X is Al, Al NMR spectroscopy can be used to determine whether the Al detected in the molecular sieve sample is Al incorporated in the molecular sieve framework or Al deposited on the material as an impurity. It will be appreciated that extra-framework aluminum can be expected to be visible by Al NMR spectroscopy with a signal having a chemical shift (δ) of about 0 ppm. Framework Al is visible by Al NMR spectroscopy with a signal having a shift (δ) of close to 50 ppm. 27 Al NMR spectroscopy to determine whether the Al detected in the molecular sieve sample is Al incorporated in the molecular sieve framework or Al deposited on the material as an impurity. It will be appreciated that extra-framework aluminum can be expected to be visible by Al NMR spectroscopy with a signal having a chemical shift (δ) of about 0 ppm. Framework Al is visible by Al NMR spectroscopy with a signal having a shift (δ) of close to 50 ppm. 27 Al NMR spectroscopy to determine whether the Al detected in the molecular sieve sample is Al incorporated in the molecular sieve framework or Al deposited on the material as an impurity. It will be appreciated that extra-framework aluminum can be expected to be visible by Al NMR spectroscopy with a signal having a chemical shift (δ) of about 0 ppm. Framework Al is visible by Al NMR spectroscopy with a signal having a shift (δ) of close to 50 ppm. 27 Al NMR spectroscopy to determine whether the Al detected in the molecular sieve sample is Al incorporated in the molecular sieve framework or Al deposited on the material as an impurity. It will be appreciated that extra-framework aluminum can be expected to be visible by Al NMR spectroscopy with a signal having a chemical shift (δ) of about 0 ppm. Framework Al is visible by Al NMR spectroscopy with a signal having a shift (δ) of close to 50 ppm.

[0073] The MWW framework-type molecular sieve of the present invention is characterized by a high external surface area and a high micropore volume.

[0074] Advantageously, the MWW framework-type molecular sieve of the present invention has a molecular weight greater than 0.13 cm⁻¹ in its calcined and ion-exchange form. 3 / g, preferably at least 0.14cm 3 / g, more preferably at least 0.15cm 3 / g micropore volume (V micro Micropore volume (V) of MWW framework-type molecular sieves micro It is usually at most 0.2cm 3 / g, and more specifically, up to 0.19cm 3 / g, for example, at most 0.18cm 3 / g.

[0075] Advantageously, the MWW framework-type molecular sieve of the present invention has a molecular weight of at least 125 m in its calcined and ion-exchange form. 2 / g, preferably at least 130m 2 / g, more preferably at least 135m 2 / g, with a minimum of 140m 2 / g, for example, at least 145m 2 / g of nitrogen surface area (S) ext (Also often referred to as mesoporous surface area). The nitrogen external surface area (S) of MWW framework-type molecular sieves. ext (Usually up to 200m) 2 / g, and more specifically, up to 180m 2 / g, most special up to 165m 2 / g, for example, up to 160m 2 / g.

[0076] Obtain S ext and V micro A suitable approach is to apply the t-plot pattern to the N2 isotherm, as mentioned in “Analytical Methods in Fine Particle Technology, PAWebb and C. Orr, Micrometrics Instrument Corporation, ISBN 0-9656783-0-X”, the contents of which are incorporated herein by reference.

[0077] Optionally, the MWW framework-type molecular sieve of the present invention has a molecular sieve with a molecular sieve size of 250-600, for example 300-550, or for example 400-550 μm in the form of calcination and ion exchange. 2nitrogen Brunauer-Emmett-Teller (BET) total surface area (S tot ).

[0078] Optionally, the MWW framework type molecular sieve of the present application has a S ext / S tot ratio of greater than 20, preferably 22 to 50, more preferably 25 to 35, in its calcined and ion exchanged form.

[0079] The MWW framework type molecular sieve of the present application is characterized as having an XRD pattern (either calcined or as-synthesized) comprising d-spacing maxima at 12.4 ± 0.25, 3.57 ± 0.07 and 3.42 ± 0.07 Angstroms. The MWW family of molecular sieve materials can also be characterized as having an XRD pattern (either calcined or as-synthesized) comprising d-spacing maxima at 12.4 ± 0.25, 6.9 ± 0.15, 3.57 ± 0.07 and 3.42 ± 0.07 Angstroms.

[0080] Optionally, the MWW framework type molecular sieve of the present application has the X- ray diffraction pattern characteristics of MCM-49 in its as-synthesized form, as shown in Table 1 below.

[0081] Table 1

[0082]

[0083] Optionally, the MWW framework type molecular sieve of the present application has the X- ray diffraction pattern characteristics of MCM-49 in its calcined form, as shown in Table 2 below.

[0084] Table 2

[0085]

[0086] Relative intensities are indicated by the symbols vs = very strong (60-100), s = strong (40-60), m = medium (20-40) and w = weak (0-20).

[0087] Those skilled in the art will understand that the MWW framework-type molecular sieves of the present invention may contain impurities, such as amorphous materials; unit cells with non-MWW framework topologies (e.g., MFI, MTW, MOR, FER, quartz, tridymite, or other dense phases that may or may not affect the performance of the resulting catalyst); and / or other impurities (e.g., heavy metals and / or organic hydrocarbons). Typical examples of non-MWW framework-type molecular sieves coexisting with the MWW framework-type molecular sieves of the present invention are hydrated hydroxysilicate, EU-1, ZSM-50, ZSM-12, ZSM-48, ZSM-5, magnesium alkali zeolite, mordenite, sodalite, and / or analcime. Other examples are molecular sieves with EUO, MTW, FER, MOR, SOD, ANA, and / or MFI framework types. The MWW framework-type molecular sieves of the present invention are preferably substantially free of impurities. The term "substantially free of impurities" as used herein means that the MWW framework-type molecular sieves of the present invention preferably contain a small proportion (less than 50% by weight), preferably less than 20% by weight, more preferably less than 10% by weight, even more preferably less than 5% by weight, and most preferably less than 1% by weight of such impurities (or "non-MWW framework-type molecular sieves"), the weight percentage (wt%) value being based on the total weight of the impurities and the pure phase MWW framework-type molecular sieves. The amount of impurities can be appropriately determined by powder XRD, rotating electron diffraction, and / or SEM / TEM (e.g., different crystal morphologies).

[0088] Applications of molecular sieves

[0089] The MWW framework-type molecular sieve of the present invention can be used as an adsorbent, for example, to separate at least one component from a mixture of components in a gaseous or liquid phase that have different adsorption properties relative to the molecular sieve. Therefore, at least one component can be partially or substantially completely separated from a mixture of components with different adsorption properties relative to the molecular sieve by contacting the mixture with the molecular sieve to selectively adsorb one component.

[0090] The molecular sieves of this invention can be used to catalyze a wide variety of chemical conversion methods, including many that are currently of commercial / industrial importance. Examples of chemical conversion methods effectively catalyzed by molecular sieves (either alone or in combination with one or more other catalytically active substances, including other crystalline catalysts) include those requiring acidic catalysts. Specific examples include:

[0091] (1) Alkylation of aromatic hydrocarbons such as benzene with long-chain olefins such as C14 olefins, wherein the reaction conditions include a temperature of about 340°C to about 500°C, a pressure of about atm to about 200 atm, and a reaction time of about 2 hours. -1 - Approximately 2000 hours -1 The weight hourly space velocity and the aromatic hydrocarbon / olefin molar ratio of about 1 / 1 to about 20 / 1 are used to provide long-chain alkyl aromatic compounds, which can then be sulfonated to provide synthetic cleaners;

[0092] (2) alkylation of aromatic hydrocarbons with gaseous olefins to provide short chain alkyl aromatic compounds, e.g., alkylation of benzene with ethylene to provide vinyl benzene, wherein the reaction conditions include a temperature of about 170°C to about 260°C, a pressure of about 20 to about 55 atmospheres, and a total WHSV of about 0.1 hr -1 - about 20 hr -1 -1 to about 30 atmospheres, and a total WHSV of about 5 hr -1 - about 50 hr -1 -1 to about 30 atmospheres, and a total WHSV of about 5 hr

[0093] (3) alkylation of reformate containing substantial amounts of benzene and toluene with fuel gas containing C5 olefins to provide, inter alia, monoalkylate and dialkylate, wherein the reaction conditions include a temperature of about 315°C to about 455°C, a pressure of about 2860 to about 3550 kPa (about 400 to about 800 psig), a WHSV-olefin of about 0.4 hr -1 - about 0.8 hr -1 -1 to about 30 atmospheres, and a total WHSV of about 5 hr -1 - about 2 hr -1 -1 to about 30 atmospheres, and a total WHSV of about 5 hr

[0094] (4) alkylation of aromatic hydrocarbons, e.g., benzene, toluene, xylene, and naphthalene, with long chain olefins, e.g., C14 olefins, to provide alkylated aromatic lube base stocks, wherein the reaction conditions include a temperature of about 160°C to about 260°C and a pressure of about 2515 to 3205 kPa (350 to 450 psig);

[0095] (5) alkylation of phenols with olefins or equivalent alcohols to provide long chain alkyl phenols, wherein the reaction conditions include a temperature of about 200°C to about 250°C, a pressure of about 1480 to 2170 kPa (200 to 300 psig), and a total WHSV of about 2 hr -1 - about 10 hr -1 -1 to about 30 atmospheres, and a total WHSV of about 5 hr

[0096] (6) alkylation of isoalkanes, e.g., isobutane, with olefins, e.g., 2-butene, wherein the reaction conditions include a temperature of about -25°C to about 400°C, e.g., 75°C to 200°C, a pressure of less than atmospheric to about 35000 kPa (5000 psig), e.g., 100 to 7000 kPa (1 to 1000 psig), and a WHSV of about 0.01 hr -1 - about 100 hr -1 -1 to about 30 atmospheres, and a total WHSV of about 5 hr-1 -20 hr -1 an olefin-based weight hourly space velocity of about 0.1 to about 100 hr1, and a molar ratio of total isoalkanes to total olefins of about 1 :2 to about 100: 1, for example 3: 1 to 30: 1. Examples

[0097] The application is further illustrated below without limiting its scope.

[0098] In these examples, x-ray diffraction (XRD) patterns of as-synthesized materials were recorded on an X-ray powder diffractometer (Bruker, D8 Discover or STOE, Stadi P Combi) using copper K-alpha radiation over a 2 theta range of 2 to 40 degrees.

[0099] Scanning electron microscopy (SEM) images of as-synthesized materials were obtained on a FEI Company, Helios Nanolab G3 UC scanning electron microscope.

[0100] The zeolite framework types of as-synthesized materials were confirmed by comparing their XRD patterns to those of known zeolite materials. SEM images were used to aid in the evaluation of product purity - the presence of distinctly different crystal morphologies in the SEM images can point to the presence of other crystalline material in the form of impurities. Such approximate analysis can be particularly useful in confirming the presence of relatively small amounts of crystalline impurities that can not be confirmable on the product XRD pattern.

[0101] Solid state29Si MAS NMR spectra were recorded on a Bruker Avance III-HD 500 spectrometer (11.7 T) operating at 130.3 MHz. The measurements were done using a 4 mm outer diameter zirconia rotor spinning at 14 kHz. The MAS NMR spectra were obtained using a π / 12 pulse and a recycle delay of 1 s. Chemical shifts were referenced to a 1 M AI(N03)3solution. The samples were hydrated overnight prior to analysis. 27 Al MAS NMR spectra (1 pulse). The measurements were done using a 4 mm outer diameter zirconia rotor spinning at 14 kHz. The MAS NMR spectra were obtained using a π / 12 pulse and a recycle delay of 1 s. Chemical shifts were referenced to a 1 M AI(N03)3solution. The samples were hydrated overnight prior to analysis.

[0102] A pycnometer was used to measure the density of the powder materials in as-synthesized and dried form. The empty weight of the pycnometer was weighed, then filled with water to determine the precise volume. A precise known amount of material was added to the pycnometer, which was then filled with water. Air trapped between the powder material was removed by placing the pycnometer in an ultrasonic bath. The material was allowed to settle until the top liquid was clear. The pycnometer was then filled with water and weighed. The volume of the powder was determined based on the weight difference and the density was calculated based on the weight and volume.

[0103] The following measurements were made on ion exchanged and calcined samples. For each sample subjected to ion exchange and calcination, the procedure used was as follows: the as-prepared sample was washed twice with 1 M ammonium nitrate solution and then calcined at 537°C for 10 hours.

[0104] The Si02:Al203molar ratio of the material was determined by inductively coupled plasma (ICP) methods.

[0105] The total BET surface area (S tot ) of the material was determined by the BET method as described by S. Brunauer, P. H. Emmett and E. Teller, J. Am. Chem. Soc, 1938, 60, 309 (incorporated herein by reference) using nitrogen adsorption-desorption at liquid nitrogen temperature.

[0106] The micropore volume (V micro ) of the material was determined by applying the t-plot model to the N2isotherm as referenced in "Analytical Methods in Fine Particle Technology, P. A. Webb and C. Orr, Micromeritics Instrument Corporation, ISBN 0-9656783-0-X", the contents of which are incorporated herein by reference.

[0107] The physical adsorption isotherm was collected according to the method disclosed in "Analytical Methods in Fine Particle Technology, P. A. Webb and C. Orr, Micromeritics Instrument Corporation, ISBN 0-9656783-0-X", the contents of which are incorporated herein by reference.

[0108] Comparative Examples 1 and 2 illustrate the preparation of MCM-49 and MCM-56 zeolites, respectively. Examples 3 to 5 illustrate the preparation of molecular sieves of MWW framework type according to the method of the present application using various amounts of PDDA. Comparative Examples 6 and 7 were prepared according to the synthesis method of Example 3 but in the presence of higher amounts of PDDA.

[0109] Comparative Example 1 - MCM-49 zeolite

[0110] A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (23.5 wt% alumina, 19.4 wt% sodium oxide). 18891.0 mg of water, 1192.4 mg of sodium aluminate solution, 89.6 mg of sodium hydroxide solution (40.0 wt%), 3779.3 mg of precipitated silica (Aerosil® 200, 20 wt% Si02) were combined in a beaker and stirred for 10 minutes. VN3) and 1047.7 mg of a cyclohexylamine solution (99.0 wt.%) were added to The mixture was stirred for 5 min after each addition and for 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160 °C for 60 h while stirring with a U-blade. Thereafter the solid material was recovered, washed several times with water, and dried at 120 °C.

[0111] The synthesis mixture was as follows (synthesis mixture / mole ratio):

[0112] Si / AI2: 19.01, M / Si: 0.14, R / Si: 0.11, H2O / Si: 18.94.

[0113] XRD was used to confirm that the recovered material was MCM-49.

[0114] Comparative Example 2 - MCM-56 zeolite

[0115] A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (23.5 wt.% aluminum oxide, 19.4 wt.% sodium oxide). 18986.0 mg of water, 1332.1 mg of the sodium aluminate solution, 183.8 mg of MCM-56 seeds (20.0 wt.%), 3846.5 mg of precipitated silica (30.0 wt.%), 1047.7 mg of a cyclohexylamine solution (99.0 wt.%), and 651.6 mg of a cyclohexylamine solution (99.0 wt.%) were added to VN3) and 651.6 mg of a cyclohexylamine solution (99.0 wt.%) were added to The mixture was stirred for 5 min after each addition and for 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160 °C for 60 h while stirring with a U-blade. Thereafter the solid material was recovered, washed several times with water, and dried at 120 °C.

[0116] The synthesis mixture was as follows (synthesis mixture / mole ratio, excluding seeds):

[0117] Si / AI2: 19.01, M / Si: 0.14, R / Si: 0.11, H2O / Si: 18.94.

[0118] The amount of seeds used was 0.95 wt.% [g 晶种 (g SiO2+ g Al2O3 ) -1 ].

[0119] XRD was used to confirm that the recovered material was MCM-56.

[0120] Example 3 - MWW type zeolite (0.10 wt.% PDDA chloride)

[0121] A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (10.1 wt% aluminum oxide, 7.3 wt% sodium oxide). 17097.3 mg water, 2784.5 mg of the sodium aluminate solution, 172.5 mg of a sodium hydroxide solution (40.0 wt%), 125.0 mg PDDA chloride (average Mw 200,000-350,000, 20 wt%), 3774.4 mg precipitated silica (Aerosil® VN3) and 1046.3 mg of a cyclohexylamine solution (99.0 wt%) were added to the inner liner. The mixture was stirred for 5 min after each addition, except for 15 min after the addition of PDDA and 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160°C for 60 h while stirring with a U-blade. Thereafter the solid material was recovered, washed several times with water and dried at 120°C.

[0122] The synthesis mixture was as follows (synthesis mixture / mole ratio):

[0123] Si / Al2: 20.84, M / Si: 0.15, R / Si: 0.18, H2O / Si: 19.02.

[0124] The amount of PDDA chloride used was 0.10 wt%, based on the weight of the synthesis mixture.

[0125] XRD was used to confirm that the recovered material was a MWW type zeolite.

[0126] Example 4 - MWW type zeolite (0.30 wt% PDDA chloride)

[0127] A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (10.0 wt% aluminum oxide, 7.3 wt% sodium oxide). 16468.8 mg water, 2797.8 mg of the sodium aluminate solution, 172.1 mg of a sodium hydroxide solution (40.0 wt%), 750.3 mg PDDA chloride (average Mw 200,000-350,000 g / mol, 10 wt%), 3766.8 mg precipitated silica (Aerosil® VN3) and 1044.2 mg of a cyclohexylamine solution (99.0 wt%) were added to the inner liner. The mixture was stirred for 5 min after each addition, except for 15 min after the addition of PDDA and 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160°C for 60 h while stirring with a U-blade. Thereafter the solid material was recovered, washed several times with water and dried at 120°C.

[0128] The synthesis mixture was as follows (synthesis mixture / mole ratio):​​

[0129] Si / AI2: 20.84, M / Si: 0.15, R / Si: 0.18, H2O / Si: 19.02.

[0130] The amount of PDDA chloride used was 0.30 wt.%, based on the weight of the synthesis mixture.

[0131] XRD was used to confirm that the recovered material was a MWW type zeolite.

[0132] Example 5 - MWW type zeolite (0.70 wt.% PDDA chloride)

[0133] A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (10.1 wt.% aluminum oxide, 7.3 wt.% sodium oxide). 16394.0 mg water, 2767.8 mg of the sodium aluminate solution, 171.4 mg of a sodium hydroxide solution (40.0 wt.%), 875.0 mg PDDA chloride (average Mw 200,000-350,000, 20 wt.%), 3751.7 mg precipitated silica (Aerosil® VN3) and 1040.0 mg of a cyclohexylideneimine solution (99.0 wt.%) were added to the inner liner. The mixture was stirred for 5 min after each addition, except for 15 min after the addition of PDDA and 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160 °C for 60 h while stirring with a U-blade. The solid material was recovered thereafter, washed several times with water and dried at 120 °C. XRD was used to confirm that the recovered material was a MWW type zeolite.

[0134] The synthesis mixture was as follows (synthesis mixture / mole ratios):

[0135] Si / AI2: 20.84, M / Si: 0.15, R / Si: 0.18, H2O / Si: 19.02.

[0136] The amount of PDDA chloride used was 0.70 wt.%, based on the weight of the synthesis mixture.

[0137] XRD was used to confirm that the recovered material was a MWW type zeolite.

[0138] Comparative Example 6 (1.00 wt.% PDDA chloride)

[0139] ​A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (10.1 wt% aluminum oxide, 7.3 wt% sodium oxide). 16042.3 mg water, 2759.4 mg of sodium aluminate solution, 170.9 mg of sodium hydroxide solution (40.0 wt%), 1250.0 mg PDDA chloride (average Mw 200,000-350,000, 20 wt%), 3740.4 mg precipitated silica (Ludox® VN3) and 1036.9 mg of cyclohexylideneimine solution (99.0 wt%) were added to an inner liner. The mixture was stirred for 5 min after each addition, except for 15 min after addition of PDDA and 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160°C for 60 h while stirring with a U-blade. Thereafter the solid material was recovered, washed several times with water and dried at 120°C.

[0140] The synthesis mixture was as follows (synthesis mixture / mole ratio):

[0141] Si / Al2: 20.84, M / Si: 0.15, R / Si: 0.18, H2O / Si: 19.02.

[0142] The amount of PDDA chloride used was 1.00 wt%, based on the weight of the synthesis mixture.

[0143] The MWW phase did not crystallize at a PDDA chloride concentration of 1.00 wt%.

[0144] Comparative Example 7 (2.00 wt% PDDA chloride)

[0145] A sodium aluminate solution was prepared by dissolving sodium aluminate powder in water (10.1 wt% aluminum oxide, 7.3 wt% sodium oxide). 14870.2 mg water, 2731.6 mg of sodium aluminate solution, 169.2 mg of sodium hydroxide solution (40.0 wt%), 2500.0 mg PDDA chloride (average Mw 200,000-350,000, 20 wt%), 3702.6 mg precipitated silica (Ludox® VN3) and 1026.4 mg of cyclohexylideneimine solution (99.0 wt%) were added to an inner liner. The mixture was stirred for 5 min after each addition, except for 15 min after addition of PDDA and 10 min after the last addition. The mixture was then treated under hydrothermal conditions at 160°C for 60 h while stirring with a U-blade. Thereafter the solid material was recovered, washed several times with water and dried at 120°C.

[0146] The synthesis mixture was as follows (synthesis mixture / mole ratio):​​

[0147] Si / AI2: 20.84, M / Si: 0.15, R / Si: 0.18, H2O / Si: 19.02.

[0148] The amount of PDDA chloride used was 2.00 wt.%, based on the weight of the synthesis mixture.

[0149] The MWW phase did not crystallize at a PDDA chloride concentration of 2.00 wt.%.

[0150] Synthesis of Crystalline Material Product

[0151] Figure 1 XRD patterns of Comparative Examples 1-2 and Examples 3-5 are shown in their as-synthesized state. The XRD pattern of Comparative Example 1 shows peaks typical of MCM-49; the XRD pattern of Comparative Example 2 shows peaks typical of MCM-56; and the XRD patterns of Examples 3-5 show peaks typical of MWW framework type molecular sieves. In comparison to the XRD pattern of Comparative Example 1 (MCM-49), the XRD pattern of Comparative Example 2 (MCM-56) shows broader (often merged) peaks. Without wishing to be bound by theory, it is believed that these differences indicate that disordered lamellae predominate in MCM-56 as compared to the more regularly stacked layers present in MCM-49. Most notably, the XRD pattern of MCM-49 material shows two separate peaks that can be clearly identified at about 8 and 10 (2 theta), while the XRD pattern of MCM-56 shows broad, merged peaks in the same region (as shown by comparison of the XRD patterns of Comparative Examples 1 and 2). For a more detailed discussion of the characteristic XRD pattern of MCM-56 as compared to, for example, MCM-49, see U.S. Patent Nos. 5,362,697, 5,827,491, and 5,453,554, the contents of which are incorporated herein by reference. The XRD patterns of Examples 3 and 4 are similar to the XRD pattern of MCM-49 (Comparative Example 1). The XRD pattern of Example 5 shows broader peaks as compared to Examples 3-4. The XRD patterns of Comparative Examples 1-2 and Examples 3-5 also show that no impurity phases were detected.

[0152] Figures 2a-2e Scanning electron micrograph (SEM) images of each of Comparative Examples 1-2 and Examples 3-5 are shown. The SEM patterns show that the morphology of Examples 3 and 4 is similar to the morphology of MCM-49 (Comparative Example 1). For Example 5, the SEM images show some minor amorphous phase, so without wishing to be bound by theory, it is believed that the higher PDDA concentration can inhibit or slow crystallization, such that the crystallization time should be extended at higher PDDA concentrations. Changes in morphology, such as resulting from the presence of impurities and / or amorphous phase, are not visible in the SEM images of any of the examples. Thus, for all of the examples, the SEM analysis indicates the formation of a single zeolite structure.

[0153] Figure 3 N2physisorption isotherms of Comparative Example 1-2 and Example 4 showing 27 Al NMR spectra. In all spectra, a peak of a species was observed at about 50 ppm. The chemical shift (δ) near 50 ppm is characteristic of Al incorporated into the zeolite framework. No spectra showed a peak in the range of about 0 ppm, which would indicate Al outside the framework. Thus, 27 The Al NMR spectroscopy analysis indicates that the Al detected by ICP-OES analysis is framework Al, indicating that the method of the present application successfully incorporated Al into the zeolite framework.

[0154] Figure 4 N2physisorption isotherms of Comparative Example 1-2 and Example 4 showing 0 the re-adsorption of N2from the zeolite is significantly delayed) is evidence that MCM-56 has a different mesopore shape than MCM-49. As can be seen from 0 the re-adsorption of N2from the zeolite is significantly delayed) is evidence that MCM-56 has a different mesopore shape than MCM-49. As can be seen from Figure 4 It can be seen that the N2physisorption isotherm of Example 4 is more similar to that of MCM-56 (Comparative Example 2). Thus, it is believed that the mesopore shape of the MWW molecular sieve of Example 4 is more similar to that of MCM-56.

[0155] Figure 5 Thermogravimetric analysis of Comparative Example 1 and Example 4 showing the as-prepared state. It can be seen that Example 4 has a weight loss of about 2 wt% higher than Comparative Example 1, which can be attributed to the decomposition of PDDA at 400-600°C. Figure 5 Thermogravimetric analysis of Comparative Example 1 and Example 4 showing the as-prepared state. It can be seen that Example 4 has a weight loss of about 2 wt% higher than Comparative Example 1, which can be attributed to the decomposition of PDDA at 400-600°C.

[0156] Table 3 shows the Si:Al2molar ratio after ion exchange and calcination and the textural and chemical properties (total surface area, mesopore surface area, ratio of mesopore surface area to total surface, and micropore volume) of Comparative Examples 1-2 and Examples 3-5.

[0157] Table 3

[0158]

[0159] As indicated by the results in Table 3, Examples 3-4 are characterized by high external surface area (or mesopore surface area) along with high micropore volume. More particularly, Examples 3-4 have a total surface area (S tot ) and external surface area (S extThe total surface area and external surface area of ​​Examples 3-4 were significantly higher than those of MCM-49 and MCM-56 (Comparative Examples 1-2), while the S of Examples 3-4 were significantly higher. ext / S tot Compared to S, which is close to MCM-56 (Comparative Example 2) ext / S tot Furthermore, the micropore volume of Examples 3-4 was maintained and more closely approximated the micropore volume of MCM-49 (Comparative Example 1). Example 5 yielded a lower V... micro The value may be due to the presence of some minor amorphous phases in the product. As already mentioned, without being bound by theory, it is believed that higher PDDA concentrations can inhibit or slow down crystallization, thus requiring a longer crystallization time at higher PDDA concentrations.

[0160] In summary, the presence of PDDA in the synthetic mixture, accompanied by changes in total surface area, external surface area (or mesoporous surface area), and microporosity, provides MWW-type molecular sieves with a layered structure, exhibiting increased total surface area and increased external surface area (or mesoporous surface area), while maintaining or increasing microporosity. This is particularly advantageous because the accessibility to surface depressions of MWW-type molecular sieves is quite important for their catalytic performance, for example in applications such as the alkylation of aromatic compounds, while maintaining or increasing microporosity is crucial for shape-selective catalysis using molecular sieves.

[0161] Comparative Examples 8 and 9 - Formulation extrudates comprising the molecular sieves prepared according to Comparative Examples 1 and 4

[0162] The portions of Comparative Example 1 and Example 4 were formed into 1 / 20-inch quadruple lobes, corresponding to Comparative Example 8 and Example 9, according to the following method. Eighty (80) parts by weight of zeolite (Comparative Example 1 and Example 4, respectively) were combined with 20 parts of Versal-300 alumina to form a dry powder on a dry weight basis. The dry powder was placed in a mill or mixer and mixed for about 5 to 15 minutes. Sufficient water was added to the powder during the mixing process to produce an extrudable slurry. The extrudable slurry was formed into 1 / 20-inch quadruple lobes using a plunger extruder. After extrusion, the 1 / 20-inch quadruple lobes were dried at a temperature of about 120°C. The dried extrudate was then calcined in nitrogen to a temperature between 454°C and 593°C and cooled under a nitrogen flow. The extrudate was then loaded into an exchange column, wetted, and exchanged with ammonium nitrate. After washing the extrudate with water, they were calcined under a gas flow between 454°C and 593°C.

[0163] The dry extrudates were tested for pyridine uptake according to the following method. The pyridine uptake of the extrudate zeolite composition was determined as the micromoles of pyridine (a class of catalyst poisons) absorbed per gram of the composition sample dried at 200°C for 60 minutes under a nitrogen stream on a thermogravimetric analyzer. After the dried catalyst sample, pyridine was purged over the catalyst sample at a partial pressure of 3 torr for 60 minutes. The sample was then flushed with nitrogen for 60 minutes. The pyridine uptake was calculated from the following equation: (sample weight after purging with pyridine - dried catalyst sample weight) ÷ (molecular weight of pyridine X dried catalyst sample weight). When the sample weight and dried sample weight are measured in grams, the molecular weight of pyridine is 121.2 x 10 -4 grams / micromole.

[0164] Table 4 shows the measured pyridine uptake of the extrudates of Comparative Example 8 and Example 9. Pyridine (2,4,6-trimethylpyridine) is a relatively large molecule with an aromatic ring core, and thus the uptake of pyridine can provide an indication of the proportion of acid sites located in mesopores accessible to larger molecules. Catalysts exhibiting high pyridine uptake are believed to be potentially effective in the alkylation of larger molecules, especially monocyclic aromatic molecules. Having a greater amount of surface acid sites accessible to larger molecules can allow the catalyst to continue to provide acceptable levels of activity for a longer period of time.

[0165] Table 4

[0166]

[0167] As shown by the results in Table 4, the pyridine uptake in Example 9 is significantly higher relative to Comparative Example 8. This can be related to the greater mesoporosity of the MWW framework type molecular sieve of the present application (as illustrated by Example 4) compared to the MCM-49 material (as illustrated by Comparative Example 1). This also represents an increase in the proportion of acid sites located in mesopores accessible to larger molecules and an improvement in the alkylation activity of larger molecules, especially monocyclic aromatic molecules.

[0168] The dried extrudates were also tested for benzene alkylation activity and selectivity according to the following method. 0.5 g of the catalyst extrudate was charged to an isothermally mixed Parr autoclave reactor under a nitrogen atmosphere with a mixture comprising 156 g of benzene and 28 g of propylene. The reaction was carried out at 130°C and 2170 kPa (300 psig) under a nitrogen atmosphere for 4 hours. Small samples of product were withdrawn at constant intervals and analyzed by gas chromatography. Catalyst performance was evaluated by the kinetic activity rate constant based on propylene conversion and the isopropylbenzene (cumene) selectivity at 100% propylene conversion.

[0169] Table 5 shows the catalytic properties of the extrudates from Comparative Example 8 and Example 9, specifically the pseudo-second-order rate constant (k), the selectivity of diisopropylbenzene to isopropylbenzene (cumene) (S). DIPB / IPB ) and the selectivity of triisopropylbenzene with isopropylbenzene (cumene) (S TIPB / IPB ).

[0170] Table 5

[0171]

[0172] As can be seen from Table 5, the extrudate of the present invention in Example 9 shows significantly lower selectivity for undesirable diisopropylbenzene and triisopropylbenzene byproducts compared to the extrudate of Comparative Example 8 based on MCM-49, while the second-order rate constant (k) remains similar.

[0173] Although the invention has been described and illustrated with reference to specific embodiments, those skilled in the art will appreciate that the invention is applicable to many different variations not specifically described herein.

[0174] In the foregoing description, when references are made to integers or elements having known, obvious, or foreseeable equivalents, these equivalents are incorporated herein as if set forth separately. Reference should be made to the claims used to define the true scope of the invention, which should be interpreted as including any such equivalents. The reader will also appreciate that integers or features of the invention described as preferred, advantageous, convenient, etc., are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that such optional integers or features, while potentially beneficial in some embodiments of the invention, may be undesirable in other embodiments and may therefore be absent. All numerical values ​​described herein are modified by the term "about" and take into account experimental errors and biases expected by those skilled in the art.

[0175] Alternatively, the present invention relates to:

[0176] Implementation Scheme 1: A method for synthesizing MWW framework-type molecular sieves, comprising the following steps:

[0177] a) Prepare a synthetic mixture capable of forming a molecular sieve of the MWW framework type, said synthetic mixture comprising water, a silicon source, a trivalent element X source, a structure directing agent R, an alkali metal or alkaline earth metal cation M source, a poly(diallyldimethylammonium) cation (PDDA) source, an optional pentavalent element Z source, an optional hydroxide ion source, and an optional seed crystal, said synthetic mixture having the following molar ratio composition:

[0178] Si:X2 = 8 to less than 30,

[0179] H2O:Si = 5 to less than 50

[0180] M: Si = 0.05 to 1.0,

[0181] R: Si = 0.05 to 1.0,

[0182] wherein a source of PDDA is added in an amount from 0.01 to less than 1.0 wt.%, based on the weight of the synthesis mixture;

[0183] b) heating the synthesis mixture under crystallization conditions including a temperature of from 80 °C to 225 °C for a time sufficient to form crystals of the MWW framework type molecular sieve; and

[0184] c) recovering the crystals of the MWW framework type molecular sieve from the synthesis mixture.

[0185] Embodiment 2: The method of embodiment 1, wherein the source of PDDA is selected from at least one of PDDA chloride and PDDA hydroxide, particularly PDDA chloride.

[0186] Embodiment 3: The method of embodiment 1 or 2, wherein the synthesis mixture contains the source of PDDA in an amount of from 0.05 to 0.7 wt.%, preferably from 0.05 to less than 0.7%, based on the weight of the synthesis mixture.

[0187] Embodiment 4: The method of any preceding embodiment, wherein the structure directing agent R is selected from the group consisting of cyclopentylamine, cyclohexylamine, cycloheptylamine, cyclohexyl imine (HMI), cycloheptyl imine, homopiperazine, pentamethonium bromide or hydroxide, hexamethonium bromide or hydroxide, heptamethonium bromide or hydroxide, and combinations thereof, preferably wherein the structure directing agent R is cyclohexyl imine (HMI).

[0188] Embodiment 5: The method of any preceding embodiment, wherein X is selected from the group consisting of aluminum, boron, gallium, and mixtures thereof, preferably wherein X comprises at least aluminum, more preferably wherein X is aluminum.

[0189] Embodiment 6: The method of any preceding embodiment, wherein the source of trivalent element X comprises AI2O3, preferably wherein the source of trivalent element X is AI2O3.

[0190] Embodiment 7: The method of any preceding embodiment, wherein the source of silicon comprises SiO2, preferably wherein the source of silicon is SiO2.

[0191] Embodiment 8: The method of any preceding embodiment, wherein Z, if present, is phosphorus.

[0192] Embodiment 9: The method of any one of embodiments 1 to 7, wherein the synthesis mixture does not contain any pentavalent element Z.

[0193] Embodiment 10: The process of any preceding embodiment, wherein M is selected from sodium, potassium, lithium, rubidium, calcium, magnesium and mixtures thereof, preferably sodium and / or potassium, more preferably sodium.

[0194] Embodiment 11 : The process of any preceding embodiment, wherein the synthesis mixture comprises a source of alkali or alkaline earth metal cations M in a M:Si molar ratio of 0.08-0.5, more particularly 0.1-0.3, for example from greater than 0.1 to less than 0.18.

[0195] Embodiment 12: The process of any preceding embodiment, wherein OH - , if present, comprises an alkali metal hydroxide, an alkaline earth metal hydroxide, an ammonium hydroxide, an aluminum hydroxide, a hydroxide form of a structure directing agent R, a hydroxide form of PDDA, or a combination thereof.

[0196] Embodiment 13: The process of any preceding embodiment, wherein the synthesis mixture comprises a source of hydroxide ions in an OH - :Si molar ratio of 0.05-1.0, preferably 0.08-0.5, more preferably 0.1-0.3, for example 0.1-0.25.

[0197] Embodiment 14: The process of any preceding embodiment, wherein the synthesis mixture comprises R and M in a R:M molar ratio of less than 2.5, preferably less than 2.0.

[0198] Embodiment 15: The process of any preceding embodiment, wherein the synthesis mixture comprises molecular sieve seeds in an amount of 0.05-2 g 晶种 / g (硅来源+三价元素X的来源) of the synthesis mixture.

[0199] Embodiment 16: The process of embodiment 15, wherein the seeds comprise a molecular sieve of MWW framework type, preferably MCM-49 and / or MCM-56.

[0200] Embodiment 17: The process of any preceding embodiment, wherein the crystallization conditions in step (b) comprise a temperature of 100°C-200°C, preferably 140°C-180°C.

[0201] Embodiment 18: The process of any preceding embodiment, wherein the crystallization conditions in step (b) comprise a time period of heating of 1-800 hours, especially from 10 to less than 600 hours, in particular 24-140 hours, for example 60-90 hours.

[0202] Embodiment 19: A molecular sieve of MWW framework type, obtainable by the process of any one of embodiments 1 to 18.

[0203] Embodiment 20: A molecular sieve of MWW framework type, in its calcined and anhydrous form having:

[0204] It includes the following molar relationships:

[0205] (n)SiO2:X2O3

[0206] Wherein X is a trivalent element selected from aluminum, boron, gallium and mixtures thereof, preferably wherein X contains at least aluminum, more preferably wherein X is aluminum, and n is the number of moles of SiO2 per mole of X2O3, varying from 8 to less than 30;

[0207] At least 125m 2 / g of external surface area (S) ext );and

[0208] Greater than 0.13cm 3 / g micropore volume (V micro ).

[0209] Implementation Scheme 21: The molecular sieve of Implementation Scheme 19 or 20 has a ratio (Souter surface area) greater than 20%, preferably 22-50%, more preferably 25-35% to the total BET surface area. ext / S tot ).

[0210] Implementation Scheme 22: Use of the molecular sieve of any one of Implementation Schemes 19 to 21 in a hydrocarbon chemical conversion method, particularly wherein the hydrocarbon chemical conversion method is an alkylation reaction, and more particularly an alkylation of aromatic compounds.

Claims

1. A method of synthesizing a molecular sieve of the MWW framework type, the method comprising the steps of: a) preparing a synthesis mixture capable of forming a molecular sieve of the MWW framework type, the synthesis mixture comprising water, a source of silicon, a source of a trivalent element X, a structure directing agent R, a source of an alkali or alkaline earth metal cation M, a source of poly(diallyldimethylammonium) cations (PDDA), optionally a source of a pentavalent element Z, optionally a source of hydroxide ions, and optionally seeds, the synthesis mixture having the following molar ratio composition: Si:X2 = 8 to less than 30, H20:Si = 5 to less than 50, M:Si = 0.05 to 1.0, R:Si = 0.05 to 1.0, wherein the source of PDDA is added in an amount from 0.01 to less than 1.0 weight percent, based on the weight of the synthesis mixture; b) heating the synthesis mixture under crystallization conditions comprising a temperature of 80 °C to 225 °C for a time sufficient to form crystals of the molecular sieve of the MWW framework type; and c) recovering the crystals of the molecular sieve of the MWW framework type from the synthesis mixture.

2. The method of claim 1, wherein the source of PDDA is selected from at least one of PDDA chloride and PDDA hydroxide, and wherein the source of PDDA is added to the synthesis mixture in an amount of 0.05 to 0.7 weight percent, based on the weight of the synthesis mixture.

3. The method of claim 1 or 2, wherein the structure directing agent R is selected from the group consisting of cyclopentylamine, cyclohexylamine, cycloheptylamine, cyclohexylamine (HMI), cycloheptylamine, homopiperazine, pentamethonium bromide or hydroxide, hexamethonium bromide or hydroxide, heptamethonium bromide or hydroxide, and combinations thereof.

4. The method of claim 3, wherein the structure directing agent R is cyclohexylamine (HMI).

5. The method of claim 1 or 2, wherein X is selected from the group consisting of aluminum, boron, gallium, and mixtures thereof.

6. The method of claim 5, wherein the source of trivalent element X comprises AI2O3.

7. The method of claim 1 or 2, wherein the source of silicon comprises SiO2.

8. The method of claim 1 or 2, wherein Z, if present, is phosphorus.

9. The method of claim 1 or 2, wherein the synthesis mixture is free of any pentavalent element Z.

10. The method of claim 1 or 2, wherein M is selected from the group consisting of sodium, potassium, lithium, rubidium, calcium, magnesium, and mixtures thereof.

11. The method of claim 1 or 2, wherein the synthesis mixture comprises the source of alkali or alkaline earth metal cation M in a molar ratio of M:Si of 0.08 to 0.

5.

14. The method of claim 1 or 2, wherein the synthesis mixture comprises R and M in a molar ratio of R:M of less than 2.

5.

16. The method of claim 1 or 2, wherein the crystallization conditions in step (b) comprise a temperature of 100 °C to 200 °C, and wherein the crystallization conditions in step (b) comprise a period of heating of 1 to 800 hours.

17. A molecular sieve of the MWW framework type, obtainable by the method of any one of claims 1 to 16. ​ ​ ​ ​ ​ 12. The method of claim 1 or 2, wherein the synthesis mixture comprises a source of hydroxide ions, wherein OH - the source comprises an alkali metal hydroxide, an alkaline earth metal hydroxide, an ammonium hydroxide, an aluminum hydroxide, a hydroxide form of a structure directing agent R, a hydroxide form of PDDA, or a combination thereof.

13. The method of claim 1 or 2, wherein the synthesis mixture comprises a source of hydroxide ions at an OH - :Si molar ratio of 0.05 to 1.

0. ​ 15. The method of claim 1 or 2, wherein the synthesis mixture comprises molecular sieve seeds in an amount of 0.05-2 g 晶种 / g (硅来源+三价元素X的来源) . ​ ​ 18. A molecular sieve of the MWW framework type having, in its calcined and anhydrous form, a composition comprising the following molar relationship: (n) Si02 : X203 wherein X is a trivalent element selected from the group consisting of aluminum, boron, gallium and mixtures thereof, and n is the number of moles of SiO2per mole of X2O3, and n varies from 8 to less than 30; at least 125 m 2 / g and up to 200 m 2 / g external surface area (S ext ); and a micropore volume (V micro ) of greater than 0.13 cm 3 / g and up to 0.2 m 2 / g.

19. The molecular sieve of claim 17 or 18, having a ratio of external surface area to BET total surface area (S ext / S tot ) of greater than 20%.

20. Use of a molecular sieve according to claim 17 or 18 in a hydrocarbon chemical conversion process, wherein the hydrocarbon chemical conversion process is the alkylation of aromatic compounds.

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