MXPA06009055A - Synthesis of zsm-48 crystals with heterostructural, non zsm-48, seeding - Google Patents

Abstract

Pure phase, high activity ZSM-48 crystals having a SiO2/A12O3 ratio of less than about 150/1, substantially free from ZSM-50 and Kenyaite, and fibrous morphology crystals. The crystals may further have a specific cross morphology. A method for making such crystals using heterostructural, zeolite seeds, other than ZSM-48 and ZSM-50 seeds.

Description

SYNTHESIS OF ZSM-48 CRYSTALS WITH HETEROESTRUCTURAL SEED, OF NO ZSM-48 FIELD OF THE INVENTION This invention relates generally to novel ZSM-48 crystals and their method of preparation. More specifically, the invention relates to the use of non-ZSM-48 seeding to prepare high activity ZSM-48 crystals and to prepare ZSM-48 crystals of cross-morphology. BACKGROUND OF THE INVENTION Zeolitic materials can be both natural and synthetic materials. The zeolitic materials exhibit catalytic properties of various types of hydrocarbon reactions. Certain zeolitic materials are porous, ordered crystalline aluminosilicates having a defined crystalline structure as determined by X-ray diffraction. Within this structure there is a large number of smaller cavities that can be interconnected by a still smaller number of channels or pores. These cavities and pores have to be uniform in size within a specific zeolitic material. Since the dimensions of these pores are such as to accept molecules of adsorption of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as "molecular sieves" and are used in a variety of ways to take advantage of these properties . The zeolites typically have uniform pore diameters of about 3 angstroms to about 10 angstroms. The chemical composition of zeolites can vary widely and typically consist of SiO2 wherein some of the silica atoms can be replaced by tetravalent atoms such as Ti or Ge, by trivalent ions such as Al, B, Ga, Fe, or by divalent ions such as Be, or by a combination of any of the aforementioned ions. When there is substitution by bivalent or trivalent ions, cations such as Na, K, Ca. NH or H are also present. Zeolites include a wide variety of crystalline aluminosilicates containing positive ion. These aluminosilicates can be described as a rigid three-dimensional structure of SI04 and A104 where the tetrahedra are cross-linked because they share oxygen atoms, whereby the ratio of the total aluminum and silicon atoms to oxygen atoms is 1: 2. The electrovalence of the aluminum-containing tetrahedra is balanced by the inclusion in the crystal of a cation, for example, an alkali metal cation, an alkaline earth metal cation, or an organic species such as a quaternary ammonium cation. This can be expressed where the ratio of aluminum to the number of various cations, such as Ca / 2, Sr / 2, Na, K or Li is equal to unity. One type of cation can be exchanged either totally or partially by another type of cation using ion exchange techniques in a conventional manner. By means of said cation exchange, it has been possible to vary the properties of a given aluminosilicate by appropriate selection of the cation. The spaces between the tetrahedrons are usually occupied by water molecules before dehydration. The techniques of the previous branch have resulted in the formation of a large variety of synthetic aluminosilicates. These aluminosilicates have come to be designated by letter or other convenient symbols, as illustrated by zeolite A (U.S. Patent No. 2,882,243), zeolite W (U.S. Patent No. 2,882,244), Y zeolite (U.S. Patent No. 3,130,007), zeolite ZK-5 (Patent of E.U.A. No. 3,247,195), ZK-4 zeolite (U.S. Patent No. 3,314,752), ZSM-5 zeolite (U.S. Patent No. 3,702,886), ZSM-11 zeolite (U.S. Patent No. 3,709,979), and ZSM-12 zeolite ( U.S. Patent No. 3,832.44), just to name a few. The ratio of SIO2 / AI2O3 of a given zeolite is frequently variable. For example, zeolite X can be synthesized at a ratio of SIO2 / AI2O3 from about 2 to about 3.; the Y zeolite, from about 3 to about 6. In some zeolites, the upper limit of the ratio of SÍO2 / AI2O4 is unlimited. ZSM-5 is one such example where the ratio of SÍO2 / A.I2O3 is at least five. The Patent of E.U.A. No. 3,941,871 discloses a crystalline metal organosilicate essentially free of aluminum and eiting a characteristic X-ray diffraction pattern of aluminosilicates type ZSM-5. US Patents Nos. 4,061,724, 4,073,865 and 4,104,294 describe microporous, crystalline silica or organosilicates of variable content of alumina and metal. The Patent of E.U.A. No. 4,423,021 to Rollmann et al., Discloses a method for synthesizing silica-crystal ZSM-48 using a diamine having four to twelve carbons as the targeting agent. The composition is described as a silica-crystal and includes very little, if any, aluminum. The Patents of E.U.A. Nos. 4,397,827 and 4,448,675 to Chu also describe method for synthesizing a ZSM-48 crystal-silica including very little, if any, aluminum. The synthesis utilizes a mixture of an amine having two to twelve carbons and tetramethylammonium compound as the targeting agent.

The Patent of E.U.A. No. 5,075,269 to Degnan et al., Describes silica-cristal ZSM-48 prepared with organic linear diquaternary ammonium compound as a template. The crystal morphology is illustrated in Figures 3 and 4 of the '269 patent and is described as having platelet-like crystal morphology at high silica / alumina ratios and small crystal aggregates irregularly configured at silica / alumina ratios lower than 200. In the US Patent No. 5,075,269 this is compared to the crystal morphology of Roll ann et al. (Patent of E.U.A .. NO. 4,423,021) in Figure 1 and Chu (U.S. Patent No. 4,397,827) in Figure 2. Figures 1 and 2 show a rod-like or needle-like crystal morphology that is random and scattered. ZSM-48 is also described by R. Szostak, Handbook of Molecular Sieves, Van Nostrand Rheinhold, New York 1992, on p. 551-553. The organics are listed as dicuat-6-bis (N-methylpyridyl) ethylquin, diethylenetriamine, triethyl tetramine, tetraethylenepentamine, 1,4,8,1-tetra-aza-undecane, 1,5,9,13-tetra-aza-undecane, 1.5, 8, 12-tetra-aza-undecane, 1,3-diaminopropane, n-propylamine / TMA +, hexane-diamine and triethylamine. The Patent of E.U.A. No. 5,961,951 to Kennedy et al., Discloses a method for making ZSM-48 by crystallizing a reaction mixture consisting of a silica source, a trivalent metal oxide source, an alkali metal oxide, ethylenediamine, and water. ZSM-48 has been synthesized under a wide range of ratios of SÍO2 / AI2O3 that varies generally from around 150/1 to around 600/1. The synthesis of high activity non-fibrous ZSM-48 crystals with lower Si0 / Al203 ratios is desirable for the development of selective olefin isomerization catalysts, near linear olefin catalysts and lubricant deinking catalysts. However, generally previous attempts to develop pure phase ZSM-48 to a ratio of Sio2 / AI2O3 of less than 150/1 have been unsatisfactory for the most part and result in the formation of impurities, such as ZSM-50 and Kenyaite. It is known that the crystallization of some zeolites proceeds only in the presence of seeds. Adding seed crystals to a crystallization system has typically resulted in increased crystallization regimes. In other cases, the addition of seeds determines, to an important degree, the type of the crystallized zeolites and affects the resulting zeolite composition and changes the kinetics of the process. It is also known that pure phase ZSM-50 and crystals of ZSM-23 can be synthesized from hydrothermal reactions with the addition of heterostructural seeds including ZSM-5, silicalite, X, Y and Mordenite as described in EP 0 999 182 Al, US Patent 6,342,200 Bl, and Patent of E.U.A. 6,475,464. COMPENDIUM OF THE INVENTION The present invention overcomes some of the aforementioned problems of the previous branch. It provides a method for making crystals of pure phase, highly active ZSM-48 substantially without crystals of fibrous morphology or any other impurities. One aspect of the invention provides cross-morphology ZSM-48 crystals and a method for making them. The present invention is directed to a pure phase ZSM-48, high activity and a method for its preparation. The product can be prepared from a reaction mixture which includes sources of a tetravalent element such as a silica, a trivalent metal oxide, an alkali metal oxide, a template (or steering agent) and zeolite seeds, heterostructural, different to seeds of ZSM-48 and ZSM-50, in a solvent phase that includes water. The mixture, in terms of molar ratios of oxides, has the following composition: XO2 / Y2O3: 20/1 to 2500/1, OH- / XO2: 0.1 / 1 to 2.0 / 1, R / X02: 0. 001/1 to 5 . 0/1, M + / X02: 0. 1 to 2 0/1, and H20 / X02: 1/1 to 500/1, where Y is a trivalent metal, M + is an alkali metal, X is a tetravalent element, and R is an organic template. The reaction mixture is prepared and maintained under conditions effective for crystallization of the porous ZSM-48. The method employs zeolite seeds, heterostructural, other than ZSM-48 and ZSM-50, in a hydrothermal reaction. Examples of suitable seeds include hetero-structural zeolite ZSM-5, ZSM-11, ZSM-12, zeolites Beta, X and Y, and colloidal BEA seeds. It has been unexpectedly discovered that the use of heterostructural seeds in the reaction promotes more incorporation of aluminum into the crystal structure of ZSM-48. It also suppresses the formation of impurities and crystals of morphology -fibrous. The resulting product exhibits highly pure ZSM-48 crystals with a SiO2 / AI2O3 ratio of less than 150/1, preferably less than about 70/1, and more preferably less than about 50/1. The product is substantially free of impurities such as ZSM-50 and / or Kenyaite impurities typically found in products made using conventional methods. It is also substantially free of any crystals of fibrous morphology, another problem of the previous branch. It has also been found that when non-ZSM-48 seeds are colloidal BEA seeds, the inventive ZSM-48 crystals have a cross morphology. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an X-ray diffraction pattern of a ZSM-48 prepared in accordance with an embodiment of this invention. Figure 2 is an SEM of a ZSM-48 product having an SiO2 / Al203 of about 70/1 to about 150/1. The product is an agglomerate of irregularly shaped small crystals. Figure 3 is an SEM of a product ZSM-48 that has a SIO2 / AI2O3 <; 70/1. The product is a mixed needles agglomerate and small crystals. Figure 4 is an SEM of a cross morphology of crystals ZSM-48 made in accordance with one embodiment of the invention. Figure 5 is an SEM of the cross-morphology of crystals ZSM-48 shown in Figure 4, shown at higher amplification. DETAILED DESCRIPTION OF THE INVENTION The preparation process comprises mixing in an aqueous medium a source of an alkaline or alkaline earth metal M, preferably sodium; at least one source of at least one tetravalent element X, preferably selected from silicon, and germanium, at least one source of at least one trivalent element Y, preferably selected from aluminum, gallium, boron, iron, titanium, vanadium, and zirconium, at least one template material R selected from organic compounds containing nitrogen; and heterostructural seeds of zeolite not ZSM-48. Examples of suitable seeds are ZSM-5, ZSM-11, ZSM-12, beta zeolites, X and Y, and colloidal BEA. The effective amounts of the various components are added to form a reaction mixture having the following molar composition: TABLE 1 mol / mol Pre-Scale Pre-Scale Scale The Most Preferred Feride Feride X02 / Y203 20 - 1500/1 30 - 500/1 40 - 200/1 H20 / X02 1 - 500/1 10 - 100/1 15 - 60/1 0H- / X02 0 - 2.0 / 1 0.02 - 0.5 / 1 0.1 - 0.5 / 1 MVX02 0 - 2.0 / 1 0.02 - 0.8 / 1 0.1 - 0.6 / 1 R / SiOz 0.001 - 5.0 / 1 0.005 - 1.0 / 1 0.01 - 0.5 / 1 The seeds can be used in amounts of about 0.1 ppm by weight to about 5% by weight, preferably around 0.1 ppm by weight around of 2% by weight and more preferably from about 0.05 weight ppm to about 1% by weight, based on the total amount of the reaction mixture. When using colloidal BEA seeds it is especially preferred to use them in an amount ranging from about 0.01 wt. Ppm to about 0.1 wt.%. Examples of suitable template materials include organic linear nitrogen compounds, such as linear diamine alkanes, of which 1.6 diamino hexane and 1,8 diamino octane are representative examples and linear diquaternary alkylammonium compounds, of which the hexamethonium salts They are an example. The reaction mixture is heated to a preferred temperature of about 100 ° C (212 ° F) to about 250 ° C (482 ° F), more preferably from about 150 ° C (302 ° F) to about 170 ° C (338 ° F). The reaction pressure is preferably maintained from about 1 atm to about 15 atm, and more preferably around 3 atm to about 8 atm. The heating can be done using any conventional container, continuous or batch type, such as autoclaves or static or oscillating pump reactors. Preferably, the mixture is stirred during the heating step through conventional agitation means. Sufficient mixing energy can be used to effectively mix the various components of the reaction mixture to form a macroscopically homogeneous mixture. The mixture is maintained under conditions of effective crystallization until crystals of ZSM-48 are formed. The crystallization time may vary depending on a number of factors from a few minutes to many hours, typically around 20 to about 500 hours and more typically around 40 to about 240 hours, or until the reaction is completed and the zeolite crystals have formed. The product is filtered using appropriate conventional filter media and washed with deionized water (DI). Subsequent operations may include drying, calcination and ion exchange. The XRD analysis of the product shows a topology of pure phase ZSM-48 substantially free of any impurities. Scanning electron microscopy analysis of the product shows that it is composed of agglomerates of small crystals with an average crystal size of about 0.01 to about 1.0 microns, and more preferably about 0.01 to about 0.05 microns. Importantly, the SEM analysis shows that the product does not have detectable levels of fibrous morphology crystals. The method may further comprise converting the product crystals into their hydrogen form. For example, this can be done by contacting the crystals with an ammonium nitrate solution, preferably at room temperature, followed by drying and calcination steps. The drying and calcination steps include heating by conventional means at conventional temperatures. Preferably, the inventive product ZSM-48 crystals have a molar ratio of XO2 / Y2O3 typically less than about 150/1, preferably about 30-150, and more preferably about 40-90. X is Si and Y is Al. One embodiment of the invention is directed to a method for making highly active, pure phase ZSM-48 crystals. The method comprises mixing effective amounts of water, hexamethonium chloride, Ultrasil PM, sodium aluminate, sodium hydroxide solution and crystal seeds of non-ZSM-48 and non-ZSM-50. The effective amounts of the various components can be easily determined by a person skilled in the art to form a mixture having the desired composition. The seeds can be introduced at any point in the preparation. They can be introduced at the same time as silicon and aluminum sources, or as a template. They can also be introduced first into an aqueous mixture, or they can be introduced after introducing the silicon and aluminum sources and / or the template. Preferably, the seeds can be added after at least partial homogenization of the aqueous mixture containing the aluminum and silicon sources and the template. The particle size of the seed can have an influence on the synthesis process. The term "seed particle" means either a seed crystal or an agglomerate of seed crystals. In this way, the size of at least a larger portion of the seed particles introduced during the preparation of the zeolitic material is on the scale of about 0.01 to about 5.0, preferably on the scale of about 0.02 to about 1.0. um. Suitable sources of silicon can be any in normal use intended for synthesis of zeolite, for example, solid pulverized silica, silicic acid, colloidal silica or dissolved silica. The powdered silicas that can be used include precipitated silicas, in particular those obtained by precipitation of a solution of an alkali metal silicate such as "Zeosil" or "Tixosil" produced by Rhone-Poulenc, smoked silicas such as "Aerosil" produced by Degussa and "Cabosil" produced by Cabot, and silica gels. Colloidal silicas with a variety of granulometries can be used, such as those sold under the "LUDOX" brands of Dupont and "SYTON" of Monsanto. The appropriate dissolved silicas that can be used are commercially available soluble sodium silicates or sodium silicates containing 0.5 to 6.0, preferably 2.0 to 4.0 moles of SiO2 per mole of alkali metal oxide and silicates obtained by dissolving silica in an alkali metal hydroxide, an diquaternary hydroxide, ammonium hydroxide, ammonium halide or a mixture thereof. Suitable aluminum sources include sodium aluminates, aluminum salts, for example chloride, nitrate or aluminum sulfate salts, aluminum alcoholates or alumina preferably in a hydrated or hydratable form, such as colloidal alumina, pseudoboehemite, boehemite, alumina gamma or a trihydrate. Mixtures of the above-mentioned sources can be used, as well as combined sources of silicon and aluminum such as amorphous silica-aluminas or certain clays. The inventive ZSM-48 crystals can be used in many catalyst applications including: de-waxing, olefin isomerizations, or near-linear olefin catalyst systems. Its use is advantageous due to the high activity and its small, non-fibrous crystal morphology. The following Examples are provided to further illustrate the method and crystals invented and should not be considered as limiting the scope of the invention outlined in the appended claims. Example 1: Preparation of ZSM-48 by seeding with ZSM-12 A mixture of 1100 g of water, 32 g of hexamethonium chloride insole (56% solution), 225.5 g of Ultrasil PM, 14.2 of aluminum aluminate solution was prepared. sodium (45%), and 45.1 g of 50% sodium hydroxide solution. Then, 10 g of ZSM-12 seed (Si02 / Al203-49.2) was then added to the mixture. The mixture had the following molar composition: Si02 / Al203 = 89.9 HxO / SiO2 = 18.75 OHVSiOz = 0.178 Na + / SiO2 = 0.178 Stencil / SiO2 = 0.019 The mixture was reacted at 160 ° C (320 ° F) in an autoclave 2 liters with agitation at 250 RPM for 48 hours. The product was filtered, washed with deionized water (DI) and dried at 120 ° C (250 ° F). The X-ray diffraction pattern (XRD) of the material as synthesized shows pure phase ZSM-48 topology. The scanning electron microscope (SEM) of the material as synthesized shows that the sample consisted of agglomerates of small crystals (with an average crystal size of approximately 0.05 microns) and trace of crystals with needle morphology. The crystals as they are synthesized are converted to the hydrogen form by two ion exchanges with ammonium nitrate solution at room temperature, followed by drying at 120 ° C (250 ° F) and calcination at 540 ° C (1000 ° F) for 6 hours. The resulting crystals of ZSM-48 had a molar ratio Example 2: Preparation of ZSM-48 seeded with ZSM-11 A mixture of 1000 g of water, 25 g of hexamethonium chloride insole (56% solution), 190 g of Ultrasil PM, 10 g of sodium aluminate solution (45%), and 33.33 g of 50% sodium hydroxide solution.

Then 20 g of seed ZSM-11 (SÍO2 / AI2O3 - 27/1) was then added to the mixture. The mixture had the following molar composition: H20 / SiO2: = 20. 08 0H- / Si02 = 0. 165 Na + / Si02 = 0. 165 Template / Si02 = 0. 018 The mixture was reacted at 160 ° C (320 ° F) in a 2 liter autoclave with stirring at 250 RPM for 48 hours. The product was filtered, washed with deionized water (DI) and dried at 120 ° C (250 ° F). The XRD pattern of the material as synthesized shows pure phase ZSM-48 topology. The SEM of the material as synthesized shows that the material was composed of agglomerates of small crystals (with an average crystal size of about 0.05 microns). The crystals as synthesized were converted to the hydrogen form by two ion exchanges with ammonium nitrate solution at room temperature, followed by drying at 120 ° C (250 ° F) and calcination at 540 ° C (1000 ° F) for 6 hours. The resulting ZSM-48 crystals had a molar ratio of Si02 / Al203 of 78.8, Example 3: Preparation of ZSM-48 by seeding with Beta crystal A mixture of 1000 g of water, 25 g of hexamethonium chloride template (solution at 56%), 190 g of Ultrasil PM (a precipitated silica powder produced from Degussa), 10 g of sodium aluminate solution (45%), and 33.33 g of 50% sodium hydroxide solution. Then 10 g of Beta seed (Si02 / Al203-35/1) was added to the mixture. The mixture had the following molar composition: H2O / SIO2 = 20.08 ILO / SiOz = 0.165 Na + / Si02 = 0.165 Template / Si02 = 0.018 The mixture was reacted at 160 ° C (320 ° F) in a 2 liter autoclave with stirring at 250 RPM for 48 hours. The product was filtered, washed with deionized water (DI) and dried at 120 ° C (250 ° F). The XRD pattern of the material as synthesized shows pure phase topology of ZSM-48. The SEM of the material as synthesized shows that the material was composed of agglomerates of small crystals (with an average crystal size of about 0.05 microns). The crystals as synthesized are converted to the hydrogen form by two ion exchanges with ammonium nitrate solution at room temperature, followed by drying at 120 ° C (250 ° F) and calcination at 540 ° C (1000 ° F) for 6 hours. The resulting ZSM-48 crystals had a molar ratio of Si02 / Al203 of 87.2. Example 4: Preparation of ZSM-48 by seeding with Beta crystal A mixture of 11000 g of water, 320 g of hexamethonium chloride template (56% solution) was prepared, 2255 g of Ultrasil PM, 126 g of sodium aluminate solution (45%), and 521 g of 50% sodium hydroxide solution. The 100 g of Beta seed (Si02 / Al203 - 35/1) were then added to the mixture. The mixture had the following molar composition: Na + / Si02 = 0.175 Template / Si02 = 0.019 The mixture was reacted at 160 ° C (320 ° F) in a 18.925 liter (5 gallon) autoclave with agitation at 250 RPM for 28 hours. The product was filtered, washed with deionized water (DI) and dried at 120 ° C (250 ° F). The XRD pattern of the material as synthesized shows pure phase ZSM-48 topology. The SEM of the material as synthesized shows that the material was composed of agglomerates of small crystals (with an average crystal size of about 0.05 microns). The crystals as they are synthesized are converted to the hydrogen form by two ion exchanges with ammonium nitrate solution at room temperature, followed by drying at 120 ° C (250 ° F) and calcination at 540 ° C (1000 ° F) for 6 hours. The resulting ZSM-48 crystals had a molar ratio of SÍO2 / AI2O3 of 81.32. Example 5: Preparation of Beta Seed ZSM-48 A mixture of 1200 g of water, 40 g of hexamethonium chloride insole (56% solution), 228 g of Ultrasil PM, 16 g of sodium aluminate solution was prepared. (45%), 1.3 g of 98% H2SO4 solution, and 40 g of 50% sodium hydroxide solution. Then 10 g of Beta seed (Si02 / Al203 - 35/1) were added to the mixture. The mixture had the following molar composition: Si02 / Al203 = 81 H20 / Si02 = 20 Na + / Si02 = 0.165 Template / SiOz = 0.022 The mixture was reacted at 160 ° C (320 ° F) in a 2 liter autoclave with stirring at 250 RPM for 72 hours. The product was filtered, washed with deionized water (DI) and dried at 120 ° C (250 ° F). The XRD pattern of the material as synthesized shows the typical topology of ZSM-48 of pure phase. The SEM of the material as synthesized shows that the material was made up of agglomerates of mixed needle crystals and small irregular crystal. The crystals as synthesized were converted to the hydrogen form by two ion exchanges with ammonium nitrate solution at room temperature, followed by drying at 120 ° C (250 ° F) and calcination at 540 ° C (1000 ° F) for 6 hours. The resulting ZSM-48 crystals had a molar ratio of SÍO2 / AI2O3 of 67.7.

Example 6 (Comparative): Preparation of ZSM-48 Without Adding Beta Seed The same reagents and procedure of Example 5 were used, except that Beta crystal was not added as a seeding agent. The XRD pattern of the material as synthesized shows the typical ZSM-48 topology and the vestige of impurity of ZSM-50 was identified. The above examples show that crystals of high activity ZSM-48, pure phase with Si02 / Al203 < 150/1 can be prepared with the addition of heterostructural seed crystals without ZSM-48, such as ZSM-5, ZSM-11, ZSM-12, beta zeolites in hydrothermal reactions. These added seed crystals appear to change the kinetics of the crystallization process and promote crystallization of the desirable ZSM-48 structure, while suppressing the formation of impurities such as ZSM-50. Also, substantially no detectable amounts of crystals with fibrous morphology were observed in the synthesized products. The crystal morphology varied based on the Si02 / Al203 ratio. For crystals with ratios of about 70/1 to about 150/1, agglomerates of irregularly shaped small crystals were observed. Si02 / Al203 ratios less than 70 produced mixed needle agglomerates and irregularly formed small crystals.

Example 7: Preparation of crossed morphology ZSM-48 crystals A suspension of colloidal BEA was prepared by combining 210.8 g of tetraethylammonium hydroxide (40% solution) 13.88 g of A1 (N03) 3 9H20 and 68.66 g of silica acid ( 10.2% water). The mixture was boiled for 10 minutes and then heated at 70 ° C for 37 days. The product was washed with water at a pH of the last wash water of 11.2. After washing the crystals they were redispersed in demineralized water and stored as such. Before use as seeds, the suspension was diluted freshly with water. ZSM-48 crystals with cross morphology were prepared in three separate tests using very small and different seed levels of colloidal BEA seeds. The composition of the synthesis mixture was: 0.71 Na20 / 3 R * / 10 SiO? / 376 H20 where the template R * was 1, 6-diaminohexane. The different seeding, and the synthesis times that were used resulted in crystals of different size as shown in the following table. For comparative purposes a test was conducted without seeded BEA and was included in the table. Testing Seeding Level Synthesis Time Size (pesoppm) (1) at 150 ° C Crystal (um) 72 hours amorphous product 2 1.1 24 hours 3.5 3 0.56 30 hours 4.5 4 0.016 30 hours i2) 10 (1) suspension of colloidal BEA (2) still some amorphous material present. Figures 4 and 5 show the cross morphology of the crystals of ZSM-48. Example 8: Preparation of crossed morphology ZSM-48 crystals Three separate batches of ZSM-48 crystals with cross morphology were prepared using a mixture that was prepared from 10.51 g of NaOH, 2.26 g of A12 (S04) 2 18H20, 252.27 Ludox AS-40 (40% of Si02 in H20), 76.75 gr of 1,8-diamino octane template and 358.8 gr of H20. Then the colloidal BEA suspension as prepared in the Example was freshly diluted with water and added in the same amounts as in Example 7. After mixing for about 5 minutes, the gel was heated in an autoclave from room temperature to 150. ° C in 2 hours and then kept at that temperature for 20 hours. After cooling to room temperature, the product was washed with water until the wash water had a pH of about 9.5. The washed product was then dried at 120 ° C. XRD showed excellent crystallinity. Also, the crystal size varied in Example 7 depending on the amount of colloidal seeds used.

Claims (2)

1. CLAIMS 1.- Crystals of high activity, pure phase ZSM-48, having a ratio of X02 / Y203 of less than about 150/1 and substantially free of ZSM-50 and impurities of Kenyaite having a diameter of less than about 1 micron and that are substantially free of fibrous morphology.
2. 2. The crystals of ZSM-48 of high activity, of pure phase according to claim 1, having a ratio of XO2 / Y2O3 of about 40/1 to about 150/1 = 3.- The crystals of ZSM-48 of high activity, pure phase, according to claim 1, wherein X is at least one of Si and Ge and Y is at least one of Al, Ga, B, Fe, Ti, Va, and Fr 4. The high-phase, pure-phase ZSM-48 according to claim 1, wherein X is Si and Y is Al. 5.- A method for making crystals of ZSM-48, the method comprising: mixing effective amounts of zeolite seeds, heterostructural, zeolite seeds, selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, colloidal BEA, zeolites Beta, X and Y, at least one source of a tetravalent element X, at least one source of a trivalent element Y, an alkaline or alkaline earth metal M, and at least one organic template material R; to form a reaction mixture having, in terms of molar ratios of oxides, the following composition: HxO / X02 1/1 - 500/1 and maintaining the reaction mixture under effective crystallization conditions for a sufficient time to form crystals of ZSM-48. 6. The method according to claim 5, wherein the organic template is selected from organic linear diquaternary alkylammonium compounds and linear diaminoalkanes. 7. The method according to claim 6, wherein the effective amount of non-ZSM-48 seeds is in the escape from 0.01 wt. Ppm to about 5 wt.%, Based on the total weight of the reaction mixture. 8. The method according to claim 7, wherein the zeolite seeds, heterostructural, are selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, Beta, X and Y zeolites and mixtures thereof. . 9. The method according to claim 5, wherein the seeds of non-ZSM-48 are colloidal BEA seeds in an amount in the range of 0.01 weight ppm to about 0.1% by weight whereby the crystals of ZSM- 48 have cross morphology and crystal size of around 1 to 15 um. 10. A method for preparing a high-phase, high-activity ZSM-48, the method comprising: (a) preparing a reaction mixture comprising a source of silica, a source of alumina, an alkali metal or alkaline earth metal ( M), water, an organic template 8R), and heteroestructural zeolite seeds other than ZSM-48 and seeds ZSM-50, where the mixture, in terms of molar-oxide ratios, has the following composition: Si02 / Al203: 30/1 to 500/1, M7Si02: 0.02 / 1 to 0.8 / 1, OHVSÍO2: 0.02 / 1 to 0.5 / 1, and H20 / Si02: 10/1 to 100/1, R / Si02: = 0.005 / 1 to 1.0 / 1 where M + is an alkali metal; and R is the source of the organic structuring agents such as linear diquaternary ammonium compound, (b) maintaining the mixture under effective crystallization conditions until the ZSM-48 crystals are formed. 11. The method according to claim 10, wherein the mixture has the following composition scales: Si02 / Al203: 40/1 to 200/1, M + / Si02: 0.1 / 1 to 0.6 / 1 '0H' / Si02: 0.1 / 1 to 0.5 / 1, and H20 / Si02: 15/1 to 60/1. R / Si02 = 0.01 / 1 - 0.5 / 1