JPH0249245B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel crystalline bismuth silicate and a method for producing the same. Molecule sieve type crystalline zeolites are well known and important commercial products. As a group of compounds, molecular sieve zeolites are composed of SiO4 and _SiO4 , which are all aluminum and silicon atoms bonded by covalent oxygen atoms such that the ratio of oxygen atoms is 1:2.
AlO ₄ ^-It is an aluminosilicate consisting of a rigid three-dimensional network structure of tetrahedrons. 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 It can be essentially any metal cation, hydrogen, ammonium, or organic cation of appropriate atomic or molecular size that has been subjected to ion exchange treatment. 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 ₂ /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 it has a high SiO ₂ /Al ₂ O ₃ ratio, high stability and extremely high acidity points, and the ability to convert methanol and other oxygenated organic compounds into aromatic hydrocarbons. A series of zeolites with catalytic ability for conversion reactions have become available. This has been achieved by adding organic cations such as tetraalkylammonium during zeolite synthesis. For example, those containing quaternary ammonium as an organic cation (Japanese Patent Publication No. 46-10064,
67298, 67299), those containing tertiary amines (JP-A-47-25097), those containing primary amines having 2 to 10 carbon atoms (JP-A-50-54598), and those containing alcohol ( JP-A-52-43800), those containing alcohol and ammonia (JP-A-54-151600), monoethanolamine, monopropanolamine or derivatives (JP-A-54-107499), and organic sulfur compounds (Japanese Patent Application Laid-Open No. 54-137500
It is known to use methods such as As mentioned above, zeolite consists of a rigid three-dimensional network structure of SiO ₄ and AlO ₄ ^{-tetrahedrons} bonded by covalent oxygen atoms, and the AlO ₄ ^{-tetrahedrons} are bonded with cations that can exchange ions. Usually balanced in terms of valence by Ge instead of Si,
It is also well known in conventional zeolite synthesis technology that Ga can be used instead of Al. However, according to research by the present inventors, even if Bi and other transition metals are used instead of Al, 3-SiO4 tetrahedra can be formed in the same form as the SiO ₄ tetrahedron in the zeolite structure.
It was found that tetrahedrons of valent cations are formed. This trivalent cation is different from a simple ion-exchangeable cation in that it cannot be ion-exchanged with ions such as H ⁺ and NH ₄ ⁺ , and that it cannot be ion-exchanged with ions such as H + and NH 4 +, and that it cannot be ion-exchanged with ions such as H + and NH 4 +. This is also inferred from the fact that almost no elution occurs. Surprisingly, by using the crystalline bismuth silicate obtained in the present invention instead of aluminosilicate, commonly called zeolite,
Significant changes in catalyst performance were found. For example, in the conversion reaction of methanol and other oxygenated organic compounds to aromatic hydrocarbons, conventional Mobil
Zeolite called ZSM-5 (Japanese Patent Publication No. 46-10064, Japanese Patent Publication No. 52-8005) by Oil Company, etc.
There is a problem in that several percent of durene (mp79℃), which causes blockage of the engine's carburetor, is produced as a by-product. However, when using the crystalline bismuth silicate obtained in the present invention, C ₁₀
An epoch-making result was obtained in which almost no aromatic hydrocarbons were produced. This suppresses the formation of carbon and extends the life of the catalyst.This phenomenon is caused by the fact that some or all of the Al is replaced by Bi and other transition metals, assuming that the active sites are around the Al atoms. This is presumed to be because the reaction of the substituted aromatic compound to further increase the number of substituents is suppressed or due to a change in the pore diameter. In the dehydrated form, the method of the present _invention is expressed as _the molar ratio of oxides: (1.0 _± 0.4)R _{2 /o} O.
ySiO ₂ {In the above formula, R; one or more monovalent or divalent
Valence cation, n; valence of R, M: one or more trivalent transition metal ions and/or aluminum ions, a+b=1, a>0, b0, y
The present invention relates to a crystalline bismuth silicate (hereinafter referred to as crystalline silicate) characterized by having a chemical composition of 5} and a method for producing the same. The method for producing crystalline silicate of the present invention involves preparing a reaction mixture containing a silica source, a bismuth source, a transition metal and/or alumina source, an alkali metal source, water, and a special organic compound, and converting this mixture into a crystalline silicate. It is characterized in that it is produced by heating for a time and at a temperature that results in formation. 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 bismuth source or transition metal source, compounds such as bismuth or transition metal sulfates, nitrates, chlorides, etc. 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. The alkaline source is
Hydroxides of alkali metals such as sodium or alkaline earth metals such as calcium, or compounds with aluminic acid or silicic acid are used. As a special organic compound that is one of the raw materials for hydrothermal synthesis of crystalline silicate, the following can be used. (1) Alcohols alone or mixtures with ammonia Monoalcohols such as ethanol Diols such as ethylene glycol Triols such as glycerin or mixtures of the above alcohols and ammonia (2) Organic amines n-propylamine, monoethanolamine Primary amines such as, secondary amines such as dipropylamine, diethanolamine, tertiary amines such as tripropylamine, triethanolamine, or quaternary amines such as ethylenediamine, diglycolamine, etc., and other tetrapropylammonium salts. Ammonium salts, etc. (3) Ethers Ethyl ether, di-n-butyl ether, etc. (4) Ketones Diethyl ketone, di-iso-butyl ketone, etc. (5) Organic nitrogen compounds other than organic amines Pyridine, pyrazine, pyrazole, etc. Various types of these The organic compounds are examples, and the present invention is not limited thereto. In addition, the monovalent or divalent cation (R) in this specification refers to an alkali metal ion, an alkaline earth metal ion, an ion of the above-mentioned organic compound, or
Refers to ions such as hydrogen ions formed through processes such as calcination and ion exchange. The crystalline silicate used in the present invention has a conventional zeolite structure in which part or all of the Al is replaced with bismuth or other transition metals, and further has a structure of SiO ₂ /(Bi ₂ O ₃ + M ₂ O ₃ ) It is characterized by a ratio of 5 or more, and is produced starting from an aqueous reaction mixture having the following molar composition. SiO ₂ /(Bi ₂ O ₃ +M ₂ O ₃ )
5-3000 (preferably 10-200) OH ^- /SiO ₂ 0-1.0 (preferably 0.2-0.8) H ₂ O / SiO ₂ 5-1000 (preferably 10-200) Organic compound / (Bi ₂ O ₃ +M _{2O3 )}
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 above-mentioned method can be used as a catalyst as it is or by mixing it with a binder or the like 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, as a method for ion exchange to H type, after removing organic compounds by firing the crystalline silicate produced by the method described above,
Directly convert it into H form by immersing it in a strong acid such as hydrochloric acid, or _NH4 by immersing it in an aqueous solution of an ammonium compound.
There is a method of forming the material into an H shape by baking it after forming it into a mold. 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. As shown in the examples, the catalysts obtained as described above can be used for reactions such as polymerization, alkylation, isomerization, and disproportionation of organic compounds, especially reactions for synthesizing aromatic compounds or lower olefins from alcohols or ethers. In contrast, it exhibits high catalytic activity not found in conventional catalysts. The crystalline silicate of the present invention has extremely excellent catalytic activity for organic reactions using carbonium ions as intermediates. Generally, organic compounds or raw materials containing organic compounds are heated at a temperature of 40℃ to 700℃,
It is contacted with a crystalline silicate-containing catalyst at a pressure of less than 200 atm and a weight hourly space velocity (hereinafter abbreviated as WHSV) of 0.1 h ^-1 to 1000 h ^-1 . More particularly, when the conversion involves polymerization of an olefin-containing feedstock, the temperature is between 260°C and 500°C.
℃, pressure is below 50atm, WHSV is 0.5h ^-1 ~ 50h ^-1
It is. When the conversion reaction is alkylation of an aromatic compound such as benzene or toluene with an olefin or alcohol, the reaction conditions are
Temperature of 200℃ ~ 550℃, pressure of 60atm, 0.5h ^-1 ~
WHSV of 50h ^-1 , aromatics/alkylating agent molar ratio of 2-200. When the conversion is isomerization of an aromatic compound such as xylene, the reaction conditions are a temperature of 150°C to 500°C;
Pressure below 60atm, WHSV between 0.2h ^-1 and 100h ^-1 . When the conversion is isomerization of paraffin or olefin, the reaction conditions are 40°C to 400°C, 60atm.
The pressure is below, WHSV of 0.1h ^-1 to 2h ^-1 . When the conversion is a disproportionation of an aromatic compound such as toluene, the reaction conditions are a temperature of 300°C to 600°C;
The WHSV is between 0.5h ^-1 and 20h ^-1 . Furthermore, the crystalline silicate obtained in the present invention has extremely high activity in the reaction for synthesizing aromatic compounds or lower olefins from alcohols or ethers, and the reaction conditions in this case are 300 to 600°C.
Temperature, pressure below 100atm, 0.1h ^-1 ~200h ^-1
It is WHSV. 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,
A solution B was prepared by dissolving 1 g of bismuth chloride. First, put A into a 500 c.c. stainless steel autoclave.
liquid was added thereto, and while stirring, liquid B was added to obtain a gel-like mixture. Diglycolamine 22 in this mixture
g was added to form a reaction mixture. This mixture was heated to 180°C while stirring at approximately 500 rpm.
The mixture was allowed to react for 2 days. After cooling, the 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 was 0.7Na ₂ O.Bi ₂ O _{3.7SiO 2.18H 2} O. This is called crystalline silicate 1. When synthesizing this crystalline silicate 1, even if sulfuric acid or nitric acid is used instead of hydrochloric acid among the raw materials,
Further, similar silicates were obtained even when bismuth sulfate or bismuth nitrate was used instead of bismuth chloride, and when silica sol was used instead of water glass. In addition, instead of reacting at 180°C for 2 days as the hydrothermal synthesis conditions, we conducted a reaction at 160°C for 4 days and at 170°C for 3 days.
Alternatively, a similar silicate was obtained by reacting at 180°C for 4 days. Crystalline silicate 2 was prepared by repeating the preparation procedure for crystalline silicate 1, except that instead of diglycolamine in crystalline silicate 1, the following organic compound was added in the same molar amount as the diglycolamine.
~18 were prepared.

[Table] The composition of the above crystalline silicates (No. 2 to 18) excluding organic compounds is (0.6 to 0.8) Na ₂ O, Bi ₂ O ₃ , (70 to 85) SiO ₂ , (10
~20) It was H ₂ O. Crystalline silicates 19 to 27 were prepared by repeating the procedure for preparing crystalline silicate 1, except that the following transition metal chloride, sulfate, or aluminum sulfate was further added to liquid B in the preparation of crystalline silicate 1. Prepared.

[Table] The composition of the above crystalline silicates (No. 19 to 27) excluding organic compounds is (0.6 to 0.8) Na ₂ O (0.92 to 0.96) Bi ₂ O ₃ (0.04 to 0.8)
0.08) _{M2O3 .} (70-85) _SiO2 .(10-20) _H2O . (M: V, Ti, La, Nd, Fe, Co, Cr, Sb,
Al) Example 2 The operation of Example 1 was repeated except that the amounts of bismuth chloride and aluminum sulfate added to crystalline silicate No. 27 of Example 1 were changed.

[Table] Similar crystalline silicates were obtained even when the Bi ratio was changed as shown above. Comparative Example The operation of Example 1 was repeated except that 8 g of aluminum sulfate was added without adding bismuth chloride, and 47 g of tetrapropylammonium bromide was added instead of diglycolamine. . The composition of this product excluding organic compounds is 0.6Na ₂ O・Al ₂ O ₃・75SiO ₂・16H ₂ O, and the X-ray diffraction pattern of this powder is
It was the same as ZSM-5 described in Publication No.-10064. Experimental Example 1 The crystalline silicates synthesized in Examples 1 and 2 and the zeolite ZSM-5 synthesized in Comparative Example were immersed in 1N hydrochloric acid and treated at 80°C for 7 days. After washing and filtering, this was compression molded and reacted with methanol using a catalyst that had been calcined at 550°C for 3 hours. The reaction conditions were normal pressure and 360°C LHSV1h ^-1 .
The results shown in the table below were obtained.

【table】

[Table] Experimental Example 2 Using a catalyst in which the crystalline silicate 1 synthesized in Example 1 was activated in the same manner as in Example 3, an experiment was conducted for the following reaction, and the following results were obtained.

【table】

Claims (1)

[Claims] 1 In the dehydrated form, expressed as the molar ratio of oxides, (1.0±0.4)R _2/o O.[a.Bi ₂ O.b.M ₂ O ₃ ].
ySiO ₂ {In the above formula, R; one or more monovalent or divalent
Valence cation, n; Valency of R, M; One or more trivalent transition metal ions and/or aluminum ions, a+b=1, a>0, b0, y
5} Crystalline bismuth silicate having the chemical composition. 2. Creating a reaction mixture containing a silica source, a bismuth source, a transition metal and/or alumina source, an alkali metal source, water, and a special organic compound, and heating this mixture for a time and at a temperature that results in the formation of crystalline bismuth silicate. (1.0±0.4)R _2/o O・[a・Bi ₂ O・b・M ₂ O ₃ ]・
ySiO ₂ {In the above formula, R; one or more monovalent or divalent
Valence cation, n; Valency of R, M; One or more trivalent transition metal ions and/or aluminum ions, a+b=1, a>0, b0, y
5} A method for producing crystalline bismuth silicate having a chemical composition.