Patent Publication Number: US-9840423-B2

Title: Method for producing MTW-type zeolite

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 13/509,677, filed Mar. 1, 2013, now U.S. Pat No. 9,333,495, which application is the 35 U.S.C. §371 National Phase Application of International PCT Patent Application No. PCT/JP10/70663, filed Nov. 19, 2010, which application claims the benefit of priority to Japanese Patent Application No. JP 2009-264550, filed Nov. 20, 2009, the contents of each of which in their entirety are hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a method for producing an MTW-type zeolite from a reaction mixture in which an organic compound is not used, by adding an MTW-type zeolite which does not contain an organic compound, as a seed crystal. 
     BACKGROUND ART 
     Synthetic zeolite is a crystalline aluminosilicate and has uniform micropores in an angstrom size resulting from the crystal structure thereof. Taking advantage of this feature, the synthetic zeolite has been industrially used as a molecular sieve adsorbent which adsorbs only the molecules having a specific size, an adsorption separating agent which adsorbs molecules having high affinity, or a catalyst base agent. MTW is a designation representing the framework structure type given to zeolite ZSM-12, and zeolite having the same structure includes CZH-5, NU-13, TPZ-12, Theta-3, and VS-12. The MTW-type zeolite is used in a large amount all over the world at present as a catalyst in petrochemical industry. The feature of the MTW-type zeolite is in that it has 12 membered-ring one-dimensional micropores as described in the following Non Patent Literature 1. Further, the X-ray diffraction pattern showing the structural feature thereof is described in the following Non Patent Literature 2. 
     Since the MTW-type zeolite has been conventionally produced only by a method in which an organic ammonium ion is used as a structure-directing agent (hereinafter abbreviated as “SDA”), it has been considered that the use of SDA is essential in order to obtain the MTW-type zeolite. Further, since synthesized MTW-type zeolite contains SDA, it has been considered inevitable that the zeolite is fired to remove SDA before it is used. 
     Various methods for synthesizing the MTW-type zeolite are proposed. A common method is a method of using organic ammonium ions, such as tetraethylammonium ions, methyltriethylammonium ions, or benzyltriethylammonium ions, as SDA. Also, at the same time, addition of alkali metal ions, such as sodium or lithium, is essential. Such a method is for example described in the following Patent Literatures 1 to 3. According to these methods, an MTW-type zeolite having a SiO 2 /Al 2 O 3  ratio of 20 or more can be obtained. However, the SDAs as described above are expensive, and most SDAs in mother liquor may be decomposed after completion of the crystallization of the MTW-type zeolite. Further, since these SDAs are incorporated into the crystals of the zeolite to be produced, it is necessary to fire the zeolite to remove the SDAs when using the zeolite as an adsorbent or a catalyst. The exhaust gas from the firing causes environmental pollution, and further a large amount of chemicals is required for the detoxification treatment of the synthetic mother liquor containing decomposition products of SDAs. Thus, since the synthetic method of the MTW-type zeolite using SDA is not only expensive, but is a production method having a high environmental load, the realization of a production method in which SDA is not used and an MTW-type zeolite which is obtained by the production method and does not essentially contain organic matter is desired. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Patent Publication No. 52-16079 
         Patent Literature 2: Japanese Patent Publication No. 63-31406 
         Patent Literature 3: Japanese Patent Laid-Open No 60-264320 
         Non Patent Literature 1: Ch. Baerlocher, L. B. McCusker, D. H. Olson, Atlas of Zeolite Framework Types, Published on behalf of the Commission of the International Zeolite Association, 2007, p. 232-233 
         Non Patent Literature 2: M. M. J. Treacy and J. B. Higgins, Collection of Simulated XRD Powder Patterns for Zeolites, Published on behalf of the Commission of the International Zeolite Association, 2007, p. 300-301 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     An object of the present invention is to provide a method for producing an MTW-type zeolite which does not essentially contain organic matter, specifically a method which eliminates the prior art disadvantages as described above, can reduce an environmental load as much as possible, and can produce an MTW-type zeolite without using SDA and inexpensively. 
     Solution to Problem 
     A conventional method for producing an MTW-type zeolite is a method in which organic ammonium ions are used as SDA, and at the same time alkali metal ions are added, as described above. However, a method of producing an MTW-type zeolite by using only alkali metal ions without using SDA has not been known at all. The present inventors have found a method for producing an MTW-type zeolite in which SDA is not used, by firing an MTW-type zeolite which has been synthesized using SDA to remove SDA and using the fired MTW-type zeolite as a seed crystal. These findings have led to the completion of the present invention. 
     Specifically, the present invention provides a method for producing an MTW-type zeolite comprising:
     (1) mixing a silica source, an alumina source, an alkali source, a lithium source, and water so as to obtain a reaction mixture having a composition represented by the following molar ratios:   SiO 2 /Al 2 O 3 =12 to 200   Na 2 O/SiO 2 =0.1 to 0.3   Li 2 O/(Na 2 O+Li 2 O)=0.05 to 0.5   H 2 O/SiO 2 =10 to 50;   (2) adding an MTW-type zeolite which has a SiO 2 /Al 2 O 3  ratio of 10 to 500 and does not contain an organic compound, as a seed crystal, to the reaction mixture in a proportion of 0.1 to 20% by weight relative to the silica component in the reaction mixture; and   (3) airtightly heating the reaction mixture, to which the seed crystal has been added, at 100 to 200° C.   

     Advantageous Effects of Invention 
     As described above, in the present invention, since an MTW-type zeolite is produced from a reaction mixture which does not use SDA, by adding an MTW-type zeolite which does not contain organic matter, as a seed crystal, the resulting MTW-type zeolite does not essentially contain organic matter. Therefore, this MTW-type zeolite does not require firing treatment before it is used, does not require exhaust gas treatment because no organic matter is produced by dehydration treatment, has a small environmental load, and can be produced inexpensively. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an X-ray diffraction pattern of the MTW-type zeolite after firing for the seed crystal having a SiO 2 /Al 2 O 3  ratio of 50.6 synthesized in Reference Example 1. 
         FIG. 2  is an X-ray diffraction pattern of the MTW-type zeolite after firing for the seed crystal having a SiO 2 /Al 2 O 3  ratio of 101.2 synthesized in Reference Example 1. 
         FIG. 3  is an X-ray diffraction pattern of the MTW-type zeolite synthesized in Example 1. 
         FIG. 4  is an X-ray diffraction pattern of the MTW-type zeolite synthesized in Example 2. 
         FIG. 5  is an X-ray diffraction pattern of the MTW-type zeolite synthesized in Example 3. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, the present invention will be described based on preferred embodiments thereof. The MTW-type zeolite synthesized according to the present invention does not essentially contain organic matter in the state where it is not heat-treated. The ions which compensate the negative charge of 4-coordinate aluminum of the aluminosilicate framework and are present outside the framework are sodium ions and lithium ions, and others which are present in micropores are only water or a small amount of adsorbed gas. That is, since the MTW-type zeolite synthesized according to the present invention is obtained by a production method in which SDA to be described below is not used, it does not essentially contain organic matter. The ratio of SiO 2 /Al 2 O 3  of the aluminosilicate framework is preferably in the range of 12 to 200. Further, the X-ray diffraction pattern of the MTW-type zeolite synthesized according to the present invention is essentially the same as the X-ray diffraction pattern of the MTW-type zeolite described in Non Patent Literature 2 as described above. From this, it is determined that the structural feature of the MTW-type zeolite synthesized according to the present invention is the same as that of conventional MTW-type zeolite synthesized using SDA. 
     One of the features of the production method of the present invention is that a reaction mixture is prepared without adding SDA which is composed of an organic compound. Specifically, an aqueous aluminosilicate gel containing sodium ions and lithium ions is used as a reaction mixture. It is an essential condition that sodium ions and lithium ions are allowed to be present together with the reaction mixture of the aqueous aluminosilicate gel. Further, their mixing proportions are such that the ratio Li 2 O/(Na 2 O+Li 2 O) is in the range of 0.05 to 0.5, preferably in the range of 0.1 to 0.4. If the ratio is outside this range, impurities will be accompanied, or the crystallinity of the MTW-type zeolite will be reduced. 
     Another feature of the production method of the present invention is the use of a seed crystal. An MTW-type zeolite produced by a conventional method, that is, a method in which SDA is used is fired to remove organic matter and used as a seed crystal. A method for synthesizing an MTW-type zeolite in accordance with a conventional method is described, for example, in Patent Literatures 1 to 3 as described above, and is well known to those skilled in the art. The type of SDA to be used is not limited, in a method for synthesizing the MTW-type zeolite in accordance with a conventional method. That is, the type of SDA may be any of organic ammonium ions such as tetraethylammonium ions, methyltriethylammonium ions, and benzyltriethylammonium ions as described above, or may be any other type. 
     In the synthesis of a seed crystal, it is preferred to add alkali metal ions simultaneously with the addition of SDA. It is preferred to use sodium and/or lithium ions as the alkali metal ions. Thus, once an MTW-type zeolite is synthesized, it is required to fire the MTW-type zeolite, for example, at a temperature of 500° C. or more in the air to remove SDA which is incorporated into the crystal, before using the MTW-type zeolite as a seed crystal. If the method of the present invention is performed using a seed crystal from which SDA is not removed, organic matter will enter the discharge liquor after completion of the reaction. Further, the MTW-type zeolite to be produced may contain SDA, which is contrary to the spirit of the present invention. 
     In the production method of the present invention, the MTW-type zeolite obtained in accordance with the present invention can also be used as a seed crystal. The MTW-type zeolite obtained by the present invention does not essentially contain an organic compound. Therefore, it has an advantage that when it is used as a seed crystal, it needs not be subjected to firing treatment beforehand. 
     Both in the case of using the MTW-type zeolite obtained in accordance with a conventional method and in the case of using the MTW-type zeolite obtained in accordance with the present invention, the SiO 2 /Al 2 O 3  ratio of the seed crystal is in the range of 10 to 500, preferably in the range of 10 to 200. If the SiO 2 /Al 2 O 3  ratio of the seed crystal is smaller than 10, the synthesis of the MTW-type zeolite will be difficult by any methods. On the other hand, if the SiO 2 /Al 2 O 3  ratio is larger than 500, the crystallization rate of the MTW-type zeolite will be very slow, which is not efficient. 
     The amount of the seed crystal added is in the range of 0.1 to 20% by weight, preferably in the range of 1 to 10% by weight, relative to the silica component in the reaction mixture as described above. Provided that the amount added is within the above range, the amount of the seed crystal added is smaller the better, and the amount added is determined in consideration of a reaction rate, an effect of suppressing impurities, and the like. 
     The grain size of the MTW-type zeolite seed crystal used in the present invention is not critical and not particularly limited in the present invention. It may be a size of a nanometer order or may be a size of a micrometer order. The size of the crystal of the zeolite obtained by synthesis is generally not uniform and has a certain degree of grain size distribution. When the crystal grain size having the maximum frequency in the distribution is defined as the average grain size, the average grain size may have influence on a crystallization rate or the size of crystals produced, but the difference in the average grain size of seed crystals will not cause essential trouble to the synthesis of the MTW-type zeolite. 
     The reaction mixture to which the seed crystal is added is obtained by mixing a silica source, an alumina source, an alkali source, a lithium source, and water so as to obtain a composition represented by the following molar ratios. If the composition of the reaction mixture is outside the following range, a target MTW-type zeolite cannot be obtained as apparent from the results of Comparative Examples to be described below.
         SiO 2 /Al 2 O 3 =12 to 200   Na 2 O/SiO 2 =0.1 to 0.3   Li 2 O/(Na 2 O+Li 2 O)=0.05 to 0.5   H 2 O/SiO 2 =10 to 50       

     A more preferred range of the composition of the reaction mixture is as follows.
         SiO 2 /Al 2 O 3 =12 to 150   Na 2 O/SiO 2 =0.12 to 0.25   Li 2 O/(Na 2 O+Li 2 O)=0.1 to 0.4   H 2 O/SiO 2 =12 to 30       

     The silica source used for obtaining the reaction mixture having the above molar ratios includes silica itself and a silicon-containing compound which can produce silicate ions in water. Specific examples include wet-process silica, dry-process silica, colloidal silica, sodium silicate, and aluminosilicate gel. These silica sources can be used individually or in combination of two or more. Among these silica sources, it is preferred to use silica (silicon dioxide) in that target zeolite can be obtained without being accompanied by an unnecessary by-product. 
     As the alumina source, a water-soluble aluminum-containing compound can be used, for example. Specific examples include sodium aluminate, aluminum nitrate, and aluminum sulfate. Further, aluminum hydroxide is also one of the suitable alumina sources. These alumina sources can be used individually or in combination of two or more. Among these alumina sources, it is preferred to use sodium aluminate and aluminum hydroxide in that target zeolite can be obtained without being accompanied by unnecessary by-products (for example, sulfate, nitrate, and the like). 
     As the alkali source, sodium hydroxide can be used, for example. Note that when sodium silicateis used as a silica source or when sodium aluminate is used as an alumina source, sodium which is an alkali metal component contained therein is considered to be NaOH at the same time, which is also an alkali component. Therefore, the above Na 2 O is calculated as the sum of all the alkali components in the reaction mixture. 
     As the lithium ion source, lithium salts are suitably used, including halides such as chlorides, bromides, and iodides and inorganic acid salts such as nitrates and sulfates. In addition, soluble organic salts may be used. Further, lithium hydroxide may be used as one of the lithium ion sources. In this case, since lithium hydroxide acts not only as a lithium ion source but also as an alkali source, it is necessary to take not only the Li 2 O/(Na 2 O+Li 2 O) ratio but also the optimization of the total alkali amount into consideration. 
     Any method by which a uniform reaction mixture can be easily obtained may be employed as the order of adding each raw material for preparing the reaction mixture. For example, a uniform reaction mixture can be obtained by adding an alumina source and a lithium source to an aqueous sodium hydroxide solution to dissolve the sources at room temperature, followed by adding a silica source and stirring and mixing. A seed crystal is added before adding a silica source or added while being mixed with a silica source. Subsequently, they are stirred and mixed so that the seed crystal is uniformly dispersed. The temperature at which the reaction mixture is prepared is also not particularly limited, and the preparation may be generally performed at room temperature (20 to 30° C.). 
     The reaction mixture containing the seed crystal is put in an airtight container and heated to react it to crystallize the MTW-type zeolite. SDA is not included in this reaction mixture. Crystallization sufficiently proceeds even while the airtight container is left standing. When the reaction mixture is stirred to achieve equalization of the temperature thereof during heating, it may be subjected to mixing with an impeller or mixing by rotation of the container. The strength of stirring and the number of rotations may be controlled depending on the uniformity of temperature and the manner in which impurities are by-produced. Intermittent stirring may be employed instead of continuous stirring. 
     Both in the case of a stationary method and a stirring method, the reaction mixture is heated at a heating temperature of 100 to 200° C., preferably 120 to 180° C., under a spontaneous pressure. If the temperature is less than 100° C., a crystallization rate will be extremely slow, thereby reducing the production efficiency of the MTW-type zeolite. On the other hand, a temperature exceeding 200° C. is not economical because an autoclave having high pressure resistance is required, and it increases the rate of impurity production. Therefore, this temperature range is not preferred. The heating time is not critical in the present production method, and the reaction mixture may be heated until an MTW-type zeolite having a sufficiently high crystallinity is produced. An MTW-type zeolite having a satisfactory crystallinity can be generally obtained by heating for about 5 to 500 hours. 
     The crystal of the MTW-type zeolite is obtained by the heating as described above. After completion of the heating, the produced crystal powder is separated from mother liquor by filtration, and then washed with water or warm water, and dried. Since the MTW-type zeolite does not contain organic matter in the dried state, it does not require firing and can be used as an adsorbent or the like if it is subjected to dehydration. Further, when the MTW-type zeolite is used as a solid acid catalyst, it can be used as an H +  type, for example, by exchanging Na +  ions and Li +  ions in the crystal with NH 4   +  ions, followed by firing. 
     The MTW-type zeolite obtained by the present production method can be suitably used, for example, as an adsorption separating agent in various industrial fields and a catalyst in petrochemical industries, using the large micropore size and micropore volume and solid acid characteristics thereof. 
     EXAMPLES 
     Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited to these Examples. Unless otherwise specified, “%” means “% by weight”. Note that the analytical instruments used in the following Examples and Comparative Examples are as follows. 
     Powder X-ray diffractometer: A powder X-ray diffractometer MO3XHF 22  manufactured by Mac Science Co., Ltd., use of Cukα rays, voltage: 40 kV, current: 30 mA, scanning step: 0.02°, scanning speed: 2°/min Composition analyzer: ICP-AES LIBERTY Series II manufactured by Varian Inc. 
     Reference Example 1 
     A reaction mixture having a composition of 8TEA 2 O.3.5Li 2 O.Al 2 O 3 .40SiO 2 .640H 2 O was prepared by using tetraethylammonium hydroxide as SDA, aluminum hydroxide as an alumina source, lithium bromide as a lithium source, and fine powder silica (Cab-O-sil, M-5) as a silica source and further adding water. This reaction mixture was put in an airtight container and heated at 160° C. for 5 days. The product was an MTW-type zeolite. This was fired in an electric furnace at 550° C. for 10 hours while circulating air to synthesize a seed crystal 1 which does not contain organic matter. The SiO 2 /Al 2 O 3  ratio after firing was 50.6. The X-ray diffraction pattern of this MTW-type zeolite is shown in  FIG. 1 . 
     Reference Example 2 
     A reaction mixture having a composition of 9.8TEA 2 O.0.79Na 2 O.Al 2 O 3 .80SiO 2 .1040H 2 O was prepared by using tetraethylammonium hydroxide as SDA, sodium aluminate as an alumina source, and fine powder silica (Cab-O-sil, M-5) as a silica source and further adding water. This reaction mixture was put in an airtight container and heated at 160° C. for 8 days. The product was an MTW-type zeolite. This was fired in an electric furnace at 550° C. for 10 hours while circulating air to synthesize a seed crystal 2 which does not contain organic matter. The SiO 2 /Al 2 O 3  ratio after firing was 101.2. The X-ray diffraction pattern of this MTW-type zeolite is shown in  FIG. 2 . 
     Example 1 
     The reaction mixture having the composition described in Table 1 was prepared by dissolving 0.30 g of sodium hydroxide in 5.8 g of distilled water and adding thereto 0.31 g of lithium bromide monohydrate, 0.16 g of aluminum hydroxide, 0.12 g of the seed crystal 1, and 1.20 g of silica (Cab-O-Sil M5) in this order, followed by uniformly stirring. This reaction mixture was put in an airtight container and heated at 140° C. for 7 days. The product was separated by filtration, washed with water, and then dried at 60° C. This product was an MTW-type zeolite which does not contain impurities, as apparent from the X-ray diffraction pattern shown in  FIG. 3 . The results of the composition analysis were as shown in Table 1. 
     Example 2 
     The reaction mixture having the composition described in Table 1 was prepared using the same raw materials as in Example 1, and it was heated under the conditions as described in the same table. The product was an MTW-type zeolite which does not contain impurities, as apparent from the X-ray diffraction pattern shown in  FIG. 4 . The product was as described in Table 1. 
     Example 3 
     The reaction mixture having the composition described in Table 1 was prepared using the same raw materials as in Example 1 except that the MTW-type zeolite seed crystal 2 synthesized in Reference Example 2 was used, and it was heated under the conditions as described in the same table. The product was an MTW-type zeolite which does not contain impurities, as apparent from the X-ray diffraction pattern shown in  FIG. 5 . The composition of the product was as described in Table 1. 
     Example 4 
     The reaction mixture having the composition described in Table 1 was prepared using the same raw materials as in Example 1 except that the amount of the seed crystal 1 added was set at 1%, and it was heated under the conditions as described in the same table. As a result, the product and the composition thereof were as described in Table 1. 
     Examples 5 to 13 
     The reaction mixtures each having the composition described in Table 1 were prepared using the same raw materials as in Example 1, and they were heated under the conditions as described in the same table. As a result, the products and the compositions thereof were as described in Table 1. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                   
                   
                   
                   
                 Seed crystal 
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Composition of reaction mixture 
                   
                 Amount 
                 Heating 
                 Product 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 SiO 2 / 
                 Na 2 O/ 
                 Li 2 O/ 
                 H 2 O/ 
                 SiO 2 / 
                 added * 1   
                 Temperature 
                 Time 
                   
                 SiO 2 / 
                 Na 2 O/ 
                 Li 2 O/ 
               
               
                 Example 
                 Al 2 O 3   
                 SiO 2   
                 (Na 2 O + Li 2 O) 
                 SiO 2   
                 Al 2 O 3   
                 (wt %) 
                 (° C.) 
                 (day) 
                 Zeolite 
                 Al 2 O 3   
                 Al 2 O 3   
                 Al 2 O 3   
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 20 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type 
                 19.2 
                 0.42 
                 0.46 
               
               
                 2 
                 40 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type, 
                 36.6 
                 0.80 
                 0.47 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 very small amount 
                   
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 of layered silicate 
                   
                   
                   
               
               
                 3 
                 20 
                 0.188 
                 0.286 
                 16 
                 101.2 
                 10 
                 140 
                 7 
                 MTW-type 
                 17.8 
                 0.68 
                 0.34 
               
               
                 4 
                 20 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 1 
                 140 
                 24 
                 MTW-type 
                 19.0 
                 0.50 
                 0.49 
               
               
                 5 
                 60 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 14 
                 MTW-type 
                 — 
                 — 
                 — 
               
               
                 6 
                 100 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 14 
                 MTW-type, 
                 — 
                 — 
                 — 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 very small amount 
                   
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 of layered silicate 
                   
                   
                   
               
               
                 7 
                 15 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type 
                 17.8 
                 0.36 
                 0.50 
               
               
                 8 
                 30 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type 
                 33.0 
                 0.52 
                 0.60 
               
               
                 9 
                 40 
                 0.150 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 10 
                 MTW-type 
                 — 
                 — 
                 — 
               
               
                 10 
                 40 
                 0.225 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type, 
                 — 
                 — 
                 — 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 very small amount 
                   
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 of ZSM-5 
                   
                   
                   
               
               
                 11 
                 20 
                 0.188 
                 0.150 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type 
                 — 
                 — 
                 — 
               
               
                 12 
                 20 
                 0.188 
                 0.320 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type 
                 — 
                 — 
                 — 
               
               
                 13 
                 40 
                 0.188 
                 0.444 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 MTW-type, 
                 — 
                 — 
                 — 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 very small amount 
                   
                   
                   
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 of layered silicate 
                   
                   
                   
               
               
                   
               
               
                 * 1  Amount of silica relative to reaction mixture 
               
            
           
         
       
     
     Comparative Example 1 
     The reaction mixture having the composition described in Table 2 was prepared using the same raw materials as used in Example 1 and the seed crystal 1 except that lithium bromide monohydrate was not added, and it was heated under the conditions as described in the same table. As a result, the product was as described in Table 2. 
     Comparative Examples 2 and 3 
     The reaction mixtures each having the composition described in Table 2 were prepared using the same raw materials as used in Example 1 and the seed crystal 1, and they were heated under the conditions as described in the same table. As a result, the product was as described in Table 2. 
     Comparative Example 4 
     The reaction mixture having the composition described in Table 2 was prepared using the same raw materials as used in Example 1 except that a seed crystal was not added, and it was heated under the conditions as described in the same table. As a result, the product was as described in Table 2. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                   
                   
                   
                   
                   
                 Seed crystal 
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Composition of reaction mixture 
                   
                 Amount 
                 Heating 
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Comparative 
                 SiO 2 / 
                 Na 2 O/ 
                 Li 2 O/ 
                 H 2 O/ 
                 SiO 2 / 
                 added * 1   
                 Temperature 
                 Time 
                 Product 
               
               
                 Example 
                 Al 2 O 3   
                 SiO 2   
                 (Na 2 O + Li 2 O) 
                 SiO 2   
                 Al 2 O 3   
                 (wt %) 
                 (° C.) 
                 (day) 
                 Zeolite 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 40 
                 0.188 
                 0 
                 16 
                 50.6 
                 10 
                 150 
                 4 
                 ZSM-5 
               
               
                 2 
                 40 
                 0.188 
                 0.600 
                 16 
                 50.6 
                 10 
                 150 
                 4 
                 Lithium silicate 
               
               
                 3 
                 10 
                 0.188 
                 0.286 
                 16 
                 50.6 
                 10 
                 140 
                 7 
                 Mordenite 
               
               
                 4 
                 40 
                 0.188 
                 0.286 
                 16 
                 — 
                 0 
                 140 
                 7 
                 Layered silicate 
               
               
                   
               
               
                 * 1  Amount of silica relative to reaction mixture