JPH0249246B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing crystalline silicates. Molecule sieve type crystalline zeolites are well known and important commercial products. As a group of compounds, molecular sieve zeolites are SiO ₄ and AlO ₄ ^-tetrahedral rigid compounds bonded by covalent oxygen atoms such that the ratio of total aluminum and silicon atoms to oxygen atoms is 1:2. It is an aluminosilicate with a tertiary network structure. The AlO ₄ ^-tetrahedron is usually valence-equilibrated by bonding with a cation, and the cation is an alkali or alkaline earth metal cation in most naturally occurring zeolites, but in synthetic zeolites or In those that have undergone ion exchange treatment, essentially any metal cation,
It can be hydrogen, ammonium or an organic cation of appropriate atomic or molecular size. In all of these zeolite compositions, the AlO ₄ ^-tetrahedron is a crystallographically significant part of the crystal structure and clearly contributes to the acidic character of the overall structure. Until recently, it was not possible to synthesize zeolites with SiO ₄ /Al ₂ O ₃ ratios greater than 12. And natural zeolites never have a SiO ₂ /Al ₂ O ₃ ratio of 12 or more. However, this problem has recently been overcome and the conversion of methanol and other oxygenated organic compounds to aromatic hydrocarbons with high SiO ₂ /Al ₂ O ₃ ratio, stability and extremely high acidity points has been A series of zeolites have become available that have catalytic ability for reactions. This has been achieved by adding organic cations such as tetraalkylammonium during zeolite synthesis. For example, organic compounds containing quaternary ammonium (Japanese Patent Publication No. 46-10064, JP-A No. 51-67298,
No. 67299), those containing tertiary amines (Japanese Patent Application Laid-open No. 1983-
25097), those containing primary amines having 2 to 10 carbon atoms (Japanese Patent Application Laid-Open No. 50-54598), those containing alcohol (Japanese Patent Application Laid-Open No. 52-43800), and those containing alcohol and ammonia (Japanese Patent Application Laid-open No. 52-43800). 54-151600), monoethanolamine, monopropanolamine or derivatives (JP-A-54-107499), and organic sulfur compounds (JP-A-54-137500). It is being As mentioned above, zeolite consists of a hard three-dimensional network structure of SiO ₄ and AlO ₄ ^{-tetrahedrons} bonded by covalent oxygen atoms, and the AlO ₄ ^{-tetrahedrons} are bonded to exchangeable cations. They are usually balanced in terms of valence. It is well known in conventional zeolite synthesis technology that Ge can be used instead of Si and Ga can be used instead of Al. However, according to the research conducted by the present inventors, it was found that even if a transition metal is used instead of Al, a transition metal-centered tetrahedron is formed in the same form as the SiO ₄ tetrahedron in the zeolite structure. We have previously proposed a new crystalline transition metal organosilicate (hereinafter referred to as crystalline silicate) and a method for producing the same. (Patent application 1982-82293, 82294, 83684
issue). In these proposals, the organic compounds added during the synthesis of crystalline silicate are limited to alcohols, organic amines, ethers, ketones, or organic sulfur compounds. However, depending on the type of transition metal, the crystalline silicate synthesized using the above-mentioned organic compounds may have low crystallinity and a decrease in catalyst activity when the transition metal content increases during hydrothermal synthesis. It turns out that there is something. As a result of intensive experimental studies to solve the above problems, the present inventors found that when diglycolamine is used instead of the above organic compound, the crystallinity is high regardless of the type of transition metal, and the catalyst The activity of
I have confirmed that it will improve further. In the method of the present invention, in the dehydrated form, expressed in molar ratio of oxides (0.1 to 2.0) R _{2 /o} O.[aM ₂ O ₃ • bAl ₂ O ₃ ] • ySiO ₂ in the above formula R; Production of a crystalline silicate having the following chemical composition: species or more monovalent or divalent cations n; valence M of R; one or more trivalent transition metal cations a+b=1, a0, b0, y12 It is about the method. In the method for producing crystalline silicate, the present invention prepares a reaction mixture containing a silica source, a transition metal and/or alumina source, an alkali source, water, and diglycolamine, and converts this mixture into a reaction mixture to produce a crystalline silicate. It is characterized by being produced by heating for a certain amount of time and temperature. The silica source can be any silica compound commonly used in zeolite synthesis, such as solid silica powder, colloidal silica, or silicates such as water glass. . As the transition metal source, compounds such as transition metal sulfates, nitrates, and chlorides are used. In addition, trivalent transition metal ions (M) in this specification include iron, nickel, cobalt, rhodium,
Group elements such as ruthenium and palladium, rare earth elements such as lanthanum and cerium, and elements such as titanium, vanadium, chromium, niobium, and tantalum.
Refers to the valence cation. The alumina source is most preferably sodium aluminate, but compounds such as chlorides, nitrates, sulfates, oxides or hydroxides can be used. As the alkali source, a hydroxide of an alkali metal such as sodium or an alkaline earth metal such as calcium, or a compound with aluminic acid or silicic acid is used. Furthermore, the monovalent or divalent cation (R) in this specification refers to ions such as alkali metal ions, alkaline earth metal ions, diglycolamine ions, or hydrogen ions formed by treatments such as calcination and ion exchange. point to The crystalline silicate used in the present invention is one in which part or all of Al in the structure of conventional zeolite is replaced with a transition metal, and
It is characterized by a SiO ₂ /(M ₂ O ₃ +Al ₂ O ₃ ) ratio of 5 or more, and is produced starting from an aqueous reaction mixture having the following molar composition. SiO ₂ /(M ₂ O ₃ + Al ₂ O ₃ )
5-3000 (preferably 10-200) OH ^- / _SiO2 0-1.0 (preferably 0.2-0.8) _H2O / _SiO2 10-1000 (preferably 20-200) Organic compound/( _M2 O ₃ + Al ₂ O ₃ )
1 to 100 (preferably 5 to 50) The crystalline silicate used in the present invention is synthesized by heating the raw material mixture at a temperature and time sufficient to generate crystalline silicate.
Hydrothermal synthesis temperature is 80~300℃ preferably 130~200℃
The hydrothermal synthesis time is from 0.5 to 14 days, preferably from 1 to 10 days. Although the pressure is not particularly limited, it is preferable to carry out the test under its own pressure. The hydrothermal synthesis reaction is continued by heating the raw material mixture to the desired temperature, with stirring if necessary, until crystalline silicate is formed. After crystals have formed, the reaction mixture is cooled to room temperature, filtered, and washed with water to separate the crystals. Furthermore, drying is usually performed at 100°C or higher for about 5 to 24 hours. The crystalline silicate produced by the method described above can be used as a catalyst as it is or by mixing it with a binder etc. that has been conventionally used for catalyst molding and molding it into an appropriate size using well-known techniques. . Preferably, the crystalline silicate is activated by heating in air at a temperature ranging from 400 to 700°C for 2 to 48 hours before use as a catalyst. The alkali metal present in the crystalline silicate may be exchanged with one or more other cations by conventional methods to give the crystalline silicate in the H form or in the form of other metal cations such as iron, rhodium, ruthenium, etc. . For example, methods for ion exchange into H-type include baking the crystalline silicate produced by the method described above to remove organic compounds, and then immersing it in a strong acid such as hydrochloric acid to directly convert it into H-type. by immersing it in an aqueous solution of the compound.
There is a method of converting it into NH ₄ type and then converting it into H type by firing. Furthermore, the crystalline silicates can be impregnated with one or more metal compounds for catalytic purposes. Suitable metals include copper, zinc, chromium, lead, antimony, bismuth, titanium, vanadium, manganese, iron, cobalt, nickel, ruthenium, rhodium, palladium, platinum, lanthanum or cerium. The impregnated silicate is preferably 0.1 to 5.0% by weight.
Contains metal oxides of. The metal compounds used are suitably those which decompose on application of heat to give the corresponding oxides and which are soluble in water, such as nitrates or chlorides. Mixtures of crystalline silicates and metal oxides are thus prepared by impregnation with an aqueous solution of the compound of the desired metal and dry calcination. The catalyst obtained as described above can be used for polymerization, alkylation, isomerization of organic compounds, etc. as shown in the examples.
It exhibits high catalytic activity not found in conventional catalysts for reactions such as disproportionation, especially reactions for synthesizing aromatic compounds or lower olefins from alcohols or ethers. Hereinafter, the present invention will be specifically explained with reference to Examples. Example 1 160 g of water glass (Na ₂ O 17.5%,
Solution A was prepared by dissolving 37% SiO ₂ and 45.5% H ₂ O. Next, in a mixture of 90 g of water and 15 g of hydrochloric acid,
Solution B was prepared by dissolving 6.8 g of ferric chloride and 4 g of aluminum sulfate. First, solution A was put into a 500 c.c. stainless steel autoclave, and solution B was added while stirring to obtain a gel-like mixture. Add diglycolamine to this mixture
22g was added to form a reaction mixture. While stirring this mixture at approximately 500 rpm,
The reaction was carried out at ℃ for 2 days. The cooled solid content was separated, washed until the electrical conductivity of the washing solution became 100 μV/cm or less, and dried at 110° C. for 12 hours. The crystal grain size of this product was about 1 μ, and the composition excluding organic compounds and water of crystallization was 0.6Na ₂ O.0.45Fe ₂ O _{3.0.55Al 2 O} 3.77SiO ₂ . This is called crystalline silicate 1. When synthesizing this crystalline silicate 1, sulfuric acid or nitric acid may be used instead of hydrochloric acid among the raw materials, or ferric sulfate or ferric nitrate may be used instead of ferric chloride. A similar silicate was also obtained. Moreover, similar silicates were obtained by reacting at 160°C for 4 days, 170°C for 3 days, or 180°C for 4 days instead of reacting at 180°C for 2 days as hydrothermal synthesis conditions. Crystalline silicate 1 except that the following transition metal chloride or sulfate was added instead of ferric chloride in solution B during the preparation of crystalline silicate 1.
A crystalline silicate was prepared by repeating the preparation procedure.

[Table] In the case of crystalline silicates 7 to 9, sulfuric acid was used instead of hydrochloric acid. The composition of the above crystalline silicates (Nos. 1 to 9) excluding organic compounds and crystal water is (0.6 to 0.8) Na ₂ O (0.4 to 0.5) M ₂ O ₅ (0.5 to 0.8)
0.6) _{Al2O3 .} (70-85) _SiO2 . (M: V, Ti, La, Nd, Ce, Co, Cr, Sb) Example 2 Same as in Example 1 except that the added amounts of vanadium chloride and aluminum sulfate in crystalline silicate 2 in Example 1 were changed. The operation was repeated.

[Table] Similar crystalline silicates were obtained even when the proportion of V was changed as described above. Comparative Example Crystalline silicates 14 to 17 were prepared by repeating the procedure of Example 1, except that 10 g of ethanol was added in place of the diglycolamine added during the synthesis of crystalline silicates 10 to 13 in Example 2. . When the crystalline silicates prepared in Example 2 and Comparative Example were subjected to X-ray diffraction analysis, results as shown in the following table regarding crystallinity were obtained.

【table】

[Table] Experimental example 1 Crystalline silicates 1 to 1 synthesized in Examples 1 and 2
13 and crystalline silicates 14 to 17 synthesized in comparative examples
was immersed in 1N hydrochloric acid and treated at 80°C for 7 days.
After washing and filtering, the catalyst was compression molded and calcined at 550°C for 3 hours, and reacted with methanol at a relatively low temperature to see the difference in activity.
The reaction conditions were normal pressure, 330°C, WHSV1hr ^-1 ,
The results shown in the table below were obtained.

[Table] As shown above, crystalline silicates 1 to 13 synthesized using diglycolamine showed high activity in the methanol conversion reaction even at relatively low temperatures, but crystalline silicates 14 to 13 synthesized using ethanol 16
The activity decreased as the V content increased. Experimental Example 2 Using a catalyst in which the crystalline silicate 1 synthesized in Example 1 was activated in the same manner as in Experimental Example 1, an experiment was conducted for the following reaction, and the following results were obtained.

【table】

【table】

Claims (1)

[Claims] 1 silica source, transition metal and/or alumina source,
A method for producing a crystalline silicate comprising forming a reaction mixture containing an alkali source, water and diglycolamine, and heating this mixture for a time and at a temperature that results in the formation of a crystalline silicate.