JP5600923B2 - Method for producing aluminosilicate - Google Patents

Description

  The present invention relates to a method for producing an aluminosilicate and a method for producing a lower olefin using the aluminosilicate produced by the method as a catalyst.

Aluminosilicate is used in various applications such as a catalyst, an adsorbent, and a separator. In particular, aluminosilicate (Patent Document 1) having a CHA structure of high silica (SiO ₂ / Al ₂ O ₃ molar ratio of 5 or more) has a small pore diameter, a large acid strength, and high performance for olefin production, for example. Expected to be a catalyst.

However, in general, an aluminosilicate having a large SiO ₂ / Al ₂ O ₃ molar ratio is very difficult to synthesize. In the method described in Patent Document 1, N, N, N-trimethyl-1 is used as a structure-directing agent. -Expensive compounds such as an adamantane ammonium cation (hereinafter sometimes referred to as "TMADA") must be used in a large amount of 0.13 to 0.39 in TMADA / Si molar ratio. Therefore, the product has to be expensive, which has hindered the expansion of applications.

  Various proposals (Patent Documents 2 to 4) have been made as a method for producing an aluminosilicate having a high silica CHA structure, including the improved method of Patent Document 1. For example, Patent Document 2 discloses a hydrothermal synthesis method in which TMADA / Si molar ratio is about 0.5 and hydrogen fluoride is added, and Patent Document 3 discloses N, N, N-trimethyl as a structure directing agent. Hydrothermal synthesis with an alkylcyclohexylammonium cation (hereinafter sometimes referred to as “TACHA”) / Si molar ratio of 0.18 to 0.22 and an alkali metal / Si molar ratio of 0.04 to 0.13. A method has been proposed.

As a method not using hydrogen fluoride, Patent Document 4 discloses a mixture of TMADA and an N, N, N-trialkylbenzylammonium cation (hereinafter sometimes referred to as “TABA”) as a structure-directing agent. (Method of hydrothermal synthesis using TMADA: TABA = 1: 1 to 1: 7, TMADA / Si molar ratio = 0.003 to 0.1), Patent Document 5 describes a TABA / Si molar ratio of 0. 18, a hydrothermal synthesis method is disclosed with an alkali metal Si molar ratio of 0.21 to 0.33 and an H ₂ O / Si molar ratio of 4.8 to 5.0.

U.S. Pat. No. 4,544,538 US Patent Application Publication No. 2003/0176751 US Patent Application Publication No. 2007/0100185 US Patent Application Publication No. 2008/0075656 US Patent Application Publication No. 2008/0159950

  However, the methods described in Patent Documents 1 to 5 have various problems, and satisfactory results are not always obtained. That is, in the methods described in Patent Documents 1 and 2, as described above, it is necessary to use a large amount of an expensive structure-directing agent, and in the method of adding hydrogen fluoride as in Patent Document 2, a special method is required. A material reactor is required. The method described in Patent Document 3 has a low yield (yield: about 11% without hydrogen fluoride and about 30% with hydrogen fluoride addition). The method described in Patent Document 4 requires TABA in addition to TMADA. In the method described in Patent Document 5, the amount of water is small, and the stirring of the reaction mixture cannot be performed sufficiently, so that the synthesis is extremely difficult. As described above, various problems relating to the method for producing an aluminosilicate having a high silica CHA structure have not yet been solved, and it has been desired to establish an inexpensive and efficient production method.

  An object of the present invention is to provide a method for efficiently and inexpensively producing an aluminosilicate having a high silica CHA structure in which the above-mentioned problems of the prior art are overcome. Moreover, this invention makes it a subject to provide the manufacturing method of the lower olefin which uses the aluminosilicate obtained by the said method as a catalyst.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a high-silica CHA structure using N, N, N-trialkylbenzylammonium cation (TABA) as a structure-directing agent in hydrothermal synthesis. When the aluminosilicate having the above is synthesized, it is extremely important to increase the alkali metal / Si molar ratio in the reaction mixture, and the structure directing agent, the Si element source, the alkali metal, and water are used at a specific ratio. The present inventors have found that the aluminosilicate can be synthesized industrially. The present invention has been accomplished based on these findings.
That is, the gist of the present invention is as follows (1) to (4).

(1) N, N, N- trialkyl benzyl ammonium cations, Si element source, alkali metal source, the hydrothermal synthesis of a mixture containing Al element source and water, having a CHA crystal structure, SiO against _Al 2 _{O 3} A method for producing an aluminosilicate having a molar ratio of ₂ or more, wherein the molar ratio of N, N, N-trialkylbenzylammonium cation to Si element in the mixture is 0.005 or more, wherein the molar ratio of 0.35 to 1.0, and Ri der molar ratio of water of 10 or more with respect to Si element, and the amount of the seed crystals contained in the mixture is 0.5 wt% or more A manufacturing method of aluminosilicate.
(2) The mixture contains an ammonium cation other than the N, N, N-trialkylbenzylammonium cation, and the molar ratio of the ammonium cation other than the N, N, N-trialkylbenzylammonium cation to the Si element in the mixture is 0. The method according to (1), which is less than 0.005.
(3) The method for producing an aluminosilicate according to the above (1) or (2), wherein the amount of seed crystals contained in the mixture is 30% by weight or less.
( 4 ) A method for producing a lower olefin, wherein an organic compound raw material is brought into contact with an aluminosilicate produced by the method according to any one of (1) to (3) to produce a lower olefin.
( 5 ) The method according to ( 4 ), wherein the organic compound raw material is ethylene and the lower olefin is propylene.

  According to the present invention, an aluminosilicate having a high silica CHA structure can be produced inexpensively and efficiently without adding hydrogen fluoride. Since it can be produced without using hydrogen fluoride, the container material used for the synthesis need not take into account corrosion caused by hydrogen fluoride. Further, since high-silica CHA can be synthesized at low cost, for example, it can be applied as a catalyst to a use that was not suitable when a large amount of aluminum was used, that is, a reaction suitable for an aluminosilicate having a small amount of acid. Thus, according to the present invention, it is possible to expand the use of aluminosilicate having a high silica CHA structure.

2 is an X-ray diffraction (XRD) pattern of the substance obtained in Example 1. FIG. 2 is an X-ray diffraction (XRD) pattern of the substance obtained in Example 2. FIG. 2 is an X-ray diffraction (XRD) pattern of the substance obtained in Comparative Example 1. 3 is an X-ray diffraction (XRD) pattern of the substance obtained in Comparative Example 2.

  Hereinafter, typical embodiments for carrying out the present invention will be specifically described. However, the present invention is not limited to the following embodiments as long as the gist of the present invention is not exceeded, and various modifications may be made. Can do.

1. Production method of aluminosilicate The production method of the aluminosilicate of the present invention is as described above. Hydrothermal heat of a mixture containing N, N, N-trialkylbenzylammonium cation, Si element source, alkali metal source, Al element source and water A method for producing an aluminosilicate having a CHA crystal structure and having a molar ratio of SiO ₂ to Al ₂ O ₃ of 5 or more by synthesis, comprising N, N, N-trialkylbenzylammonium for Si element in the mixture The molar ratio of the cation is 0.005 or more, the molar ratio of the alkali metal to the Si element is 0.35 or more and 1.0 or less, and the molar ratio of the water to the Si element is 10 or more.

First, the physicochemical properties of an aluminosilicate having a CHA structure produced by the method of the present invention (hereinafter sometimes referred to as “CHA type aluminosilicate”) will be described.
In the present invention, the CHA structure is a code that defines the structure of the zeolite defined by the International Zeolite Association (hereinafter may be abbreviated as “IZA”) and indicates the CHA structure. This is an aluminosilicate having a crystal structure equivalent to that of naturally occurring chabazite.

The CHA structure aluminosilicate has a structure characterized by having three-dimensional pores composed of oxygen 8-membered rings having a diameter of 3.8 × 3.8 mm, and the structure is characterized by X-ray diffraction data. . The framework density is 14.5T / 1000cm. Here, the framework density means the number of elements constituting the skeleton other than oxygen per 1000 ³ of the aluminosilicate, and this value is determined by the structure of the aluminosilicate. The relationship between framework density and aluminosilicate structure is shown in ATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised Edition 2001 ELSEVIER.

The molar ratio of SiO ₂ to aluminosilicate Al ₂ O ₃ (SiO ₂ / Al ₂ O ₃ molar ratio) is usually 5 or more, preferably 8 or more, more preferably 10 or more, and still more preferably 15 or more. Moreover, an upper limit is 10,000 or less normally, Preferably it is 1000 or less, More preferably, it is 300 or less, More preferably, it is 100 or less.

As described later, this molar ratio is determined by the ratio of the Si element source and the Al element source in the reaction mixture in the hydrothermal synthesis. Those having such a SiO ₂ / Al ₂ O ₃ molar ratio are referred to herein as high silica aluminosilicates. High silica aluminosilicate has high acid resistance and high hydrothermal stability.

  Usually, when aluminosilicate is exposed to an acidic condition or hydrothermal condition, aluminum is detached from the aluminosilicate skeleton, but a high silica aluminosilicate is difficult to remove aluminum. Furthermore, since it becomes hydrophobic by setting it as high silica, when it uses as adsorption agent, adsorption | suction of hydrophobic molecules, such as a hydrocarbon, will occur easily. In addition, when used as a catalyst, the hydrophobic molecules easily enter the pores, so that the reaction of the hydrophobic molecules easily proceeds.

The aluminosilicate having the above physical properties is a reaction mixture containing an Si element source, an Al element source, an N, N, N-trialkylbenzylammonium cation (TABA), an alkali metal source and water adjusted to a specific composition. It can be produced by hydrothermal synthesis in the presence of seed crystals. Here, the “reaction mixture” means a raw material mixture for use in hydrothermal synthesis.
TABA is an organic compound used as a structure-directing agent in the hydrothermal synthesis of aluminosilicates.

  The reaction vessel used for hydrothermal synthesis is not particularly limited as long as it can be used for hydrothermal synthesis known per se, and may be a heat and pressure resistant vessel such as an autoclave. The reaction mixture is charged together with seed crystals, sealed and heated to crystallize the aluminosilicate.

  As described above, the reaction mixture contains a Si element source, an Al element source, an alkali metal source, TABA, and water in a specific composition ratio.

  Examples of the Si element source include amorphous silica, colloidal silica, silica gel, sodium silicate, amorphous aluminum silicate gel, tetraethoxysilane (TEOS), and trimethylethoxysilane. Moreover, only 1 type may be used for Si element source, and 2 or more types may be mixed and used for it.

  Examples of the Al element source include sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum oxide, and amorphous aluminosilicate gel. Moreover, only 1 type may be used for Al element source, and 2 or more types may be mixed and used for it.

  In addition, the aluminosilicate manufactured by this invention may contain other elements, for example, elements, such as Ga, Fe, B, Ti, Zr, Sn, Zn, other than Al element. These elements may be added or impregnated after adding the element source compound to the reaction mixture or after hydrothermal synthesis.

  In the present invention, N, N, N-trialkylbenzylammonium cation (TABA) is used as the structure directing agent. The three independent alkyl groups of this cation are usually lower alkyl groups, preferably methyl groups. Most preferred as TABA is N, N, N-benzyltrimethylammonium cation (BTMA).

Such cations are accompanied by anions that do not harm the formation of CHA-type aluminosilicates. Representative examples of the anion include halogen ions such as Cl ⁻ , Br ⁻ and I ⁻ , hydroxide ions, acetates, sulfates and carboxylates. Among these, hydroxide ions are particularly preferably used.

In the present invention, other structure-directing agents (ammonium cations other than TABA) can be used as long as the effects of the present invention are not impaired.
Examples of other structure-directing agents include N, N, N-trialkyl-1-adamantanammonium cation (hereinafter sometimes referred to as “TAADA”), a cation derived from 3-quinacridinal, 2-exo. -Cations derived from alicyclic amines such as cations derived from aminonorbornene, N, N, N-trialkylcyclohexylammonium cations (TACHA) and the like.

Here, more preferable as TAADA is N, N, N-trimethyl-1-adamantanammonium cation (TMADA), and more preferable as TACHA is N, N, N-methyldiethylcyclohexylammonium cation. .
These cations are also accompanied by anions that do not harm the formation of CHA-type aluminosilicate, as described above.

  Other structure directing agents may be used alone or in combination of two or more.

Examples of the alkali metal source include alkali metal hydroxides such as LiOH, NaOH, KOH and CsOH, and alkaline earth such as Mg (OH) ₂ , Ca (OH) ₂ , Sr (OH) ₂ and Ba (OH) _2. Metal hydroxides and the like. Of these, NaOH and KOH are preferably used.
Moreover, only 1 type may be used for an alkali metal source, and 2 or more types may be mixed and used for it.

The ratio of the Si element source and the Al element source in the reaction mixture is usually expressed as the molar ratio of the oxides of the respective elements (SiO ₂ / Al ₂ O ₃ molar ratio). The SiO ₂ / Al ₂ O ₃ molar ratio is usually 5 or more, preferably 8 or more, more preferably 10 or more, and still more preferably 15 or more. Moreover, an upper limit is 10,000 or less normally, Preferably it is 1000 or less, More preferably, it is 300 or less, More preferably, it is 100 or less.

When the SiO ₂ / Al ₂ O ₃ molar ratio is within this range, dense CHA type aluminosilicate is crystallized. Further, a CHA-type aluminosilicate excellent in sufficient hydrothermal stability and acid resistance can be obtained. If the SiO ₂ / Al ₂ O ₃ molar ratio is too low, hydrothermal stability and acid resistance will decrease. If the SiO ₂ / Al ₂ O ₃ molar ratio is too high, use of Al, for example, as a catalyst or use as an ion exchanger is limited.

  The ratio of N, N, N-trialkylbenzylammonium cation (TABA) and Si element source in the reaction mixture is usually 0.005 or more, preferably as a molar ratio of TABA to Si element (TABA / Si molar ratio), preferably It is 0.01 or more, more preferably 0.02 or more, and the upper limit is usually 0.6 or less, preferably 0.5 or less, more preferably 0.4 or less.

  If this value is too low, crystallization of the CHA-type zeolite does not occur. If TABA is increased, crystallization is facilitated, but if it is too much, the cost of zeolite is increased.

The ratio of the other structure-directing agent (ammonium cation other than TABA) and the Si element source in the reaction mixture is the molar ratio of the other structure-directing agent (total amount) to the Si element (other structure-directing agent / Si The molar ratio is usually less than 0.005, preferably 0.004 or less, more preferably 0.003 or less.
Other structure-directing agents serve as spacers in the zeolite-structured CHA cage. However, if the amount is too large, the possibility of a zeolite structure other than CHA directed by the structure-directing agent increases.

  The ratio of the alkali metal source to the Si element source in the reaction mixture is preferably 0.35 or more, more preferably 0.4 or more, as the molar ratio of alkali metal to Si element (alkali metal / Si molar ratio). The upper limit is usually 1.0 or less, preferably 0.8 or less, more preferably 0.7 or less.

  If the amount of alkali metal is too small, crystallization of the CHA-type zeolite will not occur. Synthesis with a reduced amount of organic structure-directing agent requires an alkali metal cation compared to synthesis using a normal amount of organic structure-directing agent. This is because the alkali metal cation functions as an inorganic structure-directing agent.

  If the amount of alkali metal is too large, hydroxide ions in the reaction mixture will increase and the alkalinity will become too high, so that crystallization of CHA-type zeolite will not occur. Under high alkali conditions, even if the reaction mixture is hydrothermally treated, the silica source is stable in a dissolved state and crystallization does not occur.

The ratio of Si element source to water in the reaction mixture is usually 10 or more, preferably 20 or more, more preferably 30 or more, and still more preferably as the molar ratio of H ₂ O to Si element (H ₂ O / Si molar ratio). The upper limit is usually 5001000 or less, preferably 300 or less, more preferably 150 or less, and still more preferably 100 or less.

  When the proportion of water is too small, the viscosity of the reaction mixture becomes high, and stirring during the production of the reaction mixture or crystallization by hydrothermal synthesis becomes difficult. On the other hand, if the ratio of water is too high, the amount of aluminosilicate obtained per reaction mixture is reduced, resulting in lower productivity.

  The seed crystal to be used is not limited as long as it promotes crystallization, but CHA type aluminosilicate is preferable for efficient crystallization. It is desirable that the seed crystal has a small particle size, and it may be used after pulverization if necessary. The particle diameter is usually 0.5 nm or more, preferably 1 nm or more, more preferably 2 nm or more, and the upper limit is usually 5 μm or less, preferably 3 μm or less, more preferably 1 μm or less.

The seed crystal may be added to the reaction mixture after being dispersed in an appropriate solvent such as water, or may be added without being dispersed.
The amount of seed crystals added to the reaction mixture is not particularly limited, and is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more, and the upper limit is usually 30% by weight. % Or less, preferably 20% by weight or less, more preferably 5% by weight or less.

  If the amount of the seed crystal is too small, the number of precursors directed to the CHA structure is reduced, so that it is difficult to obtain the CHA structure. When there are too many seed crystals, the ratio of the seed crystals contained in the product increases, so that CHA newly produced from the reaction mixture is reduced, resulting in low productivity.

By heating the reaction mixture containing a seed crystal in a reaction vessel, a high-silica CHA-type aluminum silicate crystal can be obtained.
The heating temperature (reaction temperature) is not particularly limited, and is usually 100 ° C or higher, preferably 120 ° C or higher, more preferably 150 ° C or higher, and the upper limit is usually 200 ° C or lower, preferably 190 ° C or lower, more preferably 180 ° C. or lower.
When the reaction temperature is too low, the CHA type aluminosilicate may not crystallize. Moreover, when reaction temperature is too high, the type of aluminosilicate different from CHA type may be produced | generated.

The heating time (reaction time) is usually 1 hour or more, preferably 5 hours or more, more preferably 10 hours or more, and the upper limit is usually 10 days or less, preferably 5 days or less, more preferably 2 days or less. It is.
If the reaction time is too short, the CHA type aluminosilicate may not crystallize. Moreover, when reaction time is too long, the type of aluminosilicate different from a CHA type may produce | generate.

  The pressure at the time of crystallization is not particularly limited, and the self-generated pressure generated when the reaction mixture placed in a closed vessel is heated to the above temperature range is sufficient, but if necessary, an inert gas such as nitrogen is added. May be.

The CHA-type aluminosilicate obtained by hydrothermal synthesis is preferably washed with water and then the structure-directing agent in the aluminosilicate is removed.
The method for removing the structure-directing agent is not particularly limited, and may be carried out by a commonly used method known per se such as firing and extraction, but firing is desirable.

  The firing temperature is usually 350 ° C. or higher, preferably 400 ° C. or higher, more preferably 430 ° C. or higher, more preferably 480 ° C. or higher, and the upper limit is usually 900 ° C. or lower, preferably 850 ° C. or lower, more preferably 800 ° C or lower, more preferably 750 ° C or lower.

  If the firing temperature is too low, the remaining proportion of the structure-directing agent tends to increase, and the pore volume of the aluminosilicate decreases. On the other hand, if the firing temperature is too high, the skeleton of the aluminosilicate may be collapsed and the crystallinity may be lowered, or the crystal structure may not be maintained.

The firing time is not particularly limited as long as the structure-directing agent is sufficiently removed, but is preferably 1 hour or longer, more preferably 5 hours or longer, and the upper limit is usually 24 hours or shorter.
Firing is preferably performed in an atmosphere containing oxygen, and is usually performed in an air atmosphere.

  The temperature rising rate during firing is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, and further preferably 0.5 ° C./min or less. Moreover, it is usually 0.1 ° C./min or more in consideration of workability.

The temperature lowering rate after firing is usually 6 ° C./min or less, preferably 3 ° C./min or less, more preferably 2 ° C./min or less, and further preferably 1 ° C./min or less. Moreover, it is usually 0.1 ° C./min or more in consideration of workability.
If the rate of temperature rise is too fast, the structure directing agent will burn at once in a short period of time, and the heat of combustion will cause the aluminosilicate skeleton to collapse, reducing crystallinity or maintaining the crystal structure. It may disappear.

  The high-silica CHA type aluminosilicate thus prepared may be further subjected to a treatment such as reducing the acid amount or modifying the composition by modifying metal elements such as impregnation or loading. The acid amount reduction treatment may be performed, for example, by silylation, steam treatment, dicarboxylic acid treatment, or the like. These acid amount reduction treatment and composition change can be carried out by a commonly used method known per se.

2. Method for Producing Lower Olefin The method for producing a lower olefin of the present invention is characterized in that a lower olefin is produced by bringing an organic compound raw material into contact with a high silica CHA type aluminosilicate produced by the above method. is there.
Here, the high silica CHA type aluminosilicate serves as a catalytically active component in the conversion reaction from the organic compound raw material to the lower olefin. In this reaction, preferred physical properties of the aluminosilicate used as the catalytically active component are as described above.

  The pore diameter of the aluminosilicate used in this reaction is preferably less than 0.5 nm. Here, the pore diameter indicates a crystallographic free diameter of the channels determined by IZA. A pore diameter of less than 0.5 nm means that the diameter of the pore (channel) is less than 0.5 nm when the shape of the pore (channel) is a perfect circle, and a short diameter when the shape of the pore is an ellipse. It means that the diameter is less than 0.5 nm.

  When the pore diameter of the aluminosilicate is 0.5 nm or more, for example, when producing propylene from ethylene, by-products other than propylene (butene, pentene, etc.) increase. By using an aluminosilicate having a pore diameter of less than 0.5 nm, propylene can be produced in high yield from ethanol and / or ethylene.

  Although details of this mechanism of action are not clear, it is considered that ethanol and ethylene can be activated by the expression of a strong acid point, and that propylene can be selectively produced with a small pore diameter. That is, if the pores are as small as less than 0.5 nm in diameter, the target propylene can come out of the pores, but the by-products such as butene and pentene are too large in size. Therefore, it is estimated that it remains in the pores. It is considered that the propylene selectivity is improved by such a mechanism.

  In addition, there is no restriction | limiting in particular about the minimum of the pore diameter of the aluminosilicate used as a catalyst active component.

  The aluminosilicate used as the catalyst active component may be used after hydrothermal synthesis and after treatments such as silylation, acid treatment, and steaming. It is also possible to change the composition by modification such as ion exchange, impregnation and loading.

  The catalytically active component may be used as it is in the reaction as a catalyst, or may be used in the reaction by granulating / molding using a substance or binder that is inert to the reaction, or by mixing them. Examples of the substance or binder inert to the reaction include alumina or alumina sol, silica, silica gel, quartz, and a mixture thereof.

  In addition, the composition of the above-described catalytically active component is a composition of only the catalytically active component that does not contain a substance or a binder inactive to these reactions. Therefore, in the present invention, when a substance or binder that is inert to these reactions is included, the above-mentioned catalytically active component and the substance or binder that is inert to these reactions are collectively referred to as a catalyst. In the case where no inactive substance or binder is contained, only the catalytically active component is referred to as a catalyst.

  The particle size of the catalyst varies depending on the synthesis conditions of aluminosilicate, but is usually 0.01 μm to 500 μm as an average particle size. When the particle size of the catalyst is too large, the surface area showing the catalytic activity becomes small, and when it is too small, the handleability becomes inferior. This average particle diameter can be determined by SEM observation or the like.

  The organic compound raw material (reaction raw material) used in the reaction is not particularly limited as long as it can produce a lower olefin by the above reaction, but ethanol, ethylene, and the like are particularly preferable.

  Examples of ethanol used as a reaction raw material include various known methods such as those produced by ethylene hydration, those produced from synthesis gas, and those produced by fermentation using plant-derived polysaccharides as raw materials. What is obtained by this can be used arbitrarily. At this time, a compound in which a compound (particularly water) resulting from each production method is arbitrarily mixed may be used as it is, or purified ethanol may be used.

  Examples of ethylene used as a reaction raw material include FT (Fischer-Tropsch) synthesis using, as a raw material, one produced from a petroleum feedstock by catalytic cracking or steam cracking, or a hydrogen / CO mixed gas obtained by coal gasification. Obtained by ethane dehydrogenation or oxidative dehydrogenation, obtained by propylene metathesis and homologation, obtained by MTO (methanol to olefin) reaction, ethanol dehydration What is obtained by various well-known methods, such as what is obtained by reaction, can be used arbitrarily. At this time, a compound in which a compound other than ethylene resulting from each production method is arbitrarily mixed may be used as it is, or purified ethylene may be used. Further, when propylene is produced by the method of the present invention, ethylene contained in the reactor outlet gas may be recycled and used.

  In the organic compound raw material, an olefin having 4 or more carbon atoms may be present in addition to the ethanol and ethylene. As the olefin having 4 or more carbon atoms, for example, when producing propylene by the method of the present invention, the olefin contained in the reactor outlet gas may be recycled and used. Since some of the olefins having 4 or more carbon atoms are converted to propylene, the consistent yield of propylene can be improved by recycling the olefin in the reactor outlet gas in this way.

  In addition, oxygen-containing compounds other than ethanol may be present in the organic compound raw material. Examples of oxygen-containing compounds other than ethanol include methanol and dimethyl ether.

  The operation and conditions of the production reaction of the lower olefin of the present invention using the catalyst and the organic compound raw material (reaction raw material) will be described below.

  First, as a reactor, a continuous type fixed bed reactor or a fluidized bed reactor, preferably a fluidized bed reactor is usually used.

  When packing the above catalyst into the fluidized bed reactor, in order to keep the temperature distribution of the catalyst layer small, particulates inert to the reaction such as quartz sand, alumina, silica, silica-alumina, etc. are mixed with the catalyst. It may be filled. In this case, there is no particular limitation on the amount of granular material inactive to the reaction such as quartz sand. In addition, it is preferable that this granular material is a particle size comparable as a catalyst from the surface of uniform mixing property with a catalyst.

  The reaction substrate (reaction raw material) may be divided and supplied to the reactor in order to disperse the heat generated by the reaction.

When a fluidized bed reactor is selected, a catalyst regenerator is attached to the reactor, the catalyst extracted from the reactor is continuously sent to the regenerator, and the catalyst regenerated in the regenerator is continuously reacted to the reactor. It is preferable to carry out the reaction while returning to pH.
Here, examples of the catalyst regenerator include those that regenerate the catalyst introduced from the reactor by treating it with nitrogen gas containing oxygen or water vapor.

  There is no particular limitation on the concentration of organic compound raw materials, such as ethanol and / or ethylene (ie, substrate concentration) in all feed components fed to the reactor, but the sum of ethanol and ethylene is preferably 90 moles in all feed components. % Or less, more preferably 70 mol% or less, and the lower limit is preferably 5 mol% or more.

  If the substrate concentration is too high, aromatic compounds and paraffins are prominently produced, and the lower olefin yield, for example, the yield of propylene tends to decrease. On the other hand, if the substrate concentration is too low, the reaction rate becomes slow, so a large amount of catalyst is required, and the reactor tends to be too large. Therefore, it is preferable to dilute ethanol and / or ethylene with a diluent described below as necessary to obtain such a substrate concentration.

  In the reactor, in addition to ethanol and / or ethylene, hydrocarbons such as helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water, paraffins, methane, aromatic compounds, and those A gas inert to the reaction can be present, such as a mixture of water, but it is preferable that water (water vapor) coexist among them.

As such a diluent, impurities contained in the reaction raw material may be used as they are, or a separately prepared diluent may be mixed with the reaction raw material and used.
The diluent may be mixed with the reaction raw material before entering the reactor, or may be supplied to the reactor separately from the reaction raw material.

Space velocity during the reaction is preferably between 0.01Hr ^-1 ~500Hr ^-1, more preferably between 0.1Hr ^-1 ~100Hr ^-1. When the space velocity is too high, the amount of ethylene in the reactor outlet gas increases, and the propylene yield tends to decrease. On the other hand, when the space velocity is too low, undesirable by-products such as paraffins are produced, and the propylene yield tends to decrease.

  The space velocity is a flow rate of ethanol and / or ethylene, which is a reaction raw material per weight of the catalyst (catalytic active component), and the weight of the catalyst is an inert component used for granulating and molding the catalyst. And the weight of the catalytically active component not containing a binder. The flow rate is the flow rate (weight / hour) of the total of ethanol and / or ethylene (that is, the total when ethanol and ethylene are used).

  The reaction temperature is usually 200 ° C. or higher, preferably 300 ° C. or higher, and the upper limit is usually 700 ° C. or lower, preferably 600 ° C. or lower. If the reaction temperature is too low, the reaction rate tends to be low, a large amount of unreacted raw material tends to remain, and the yield of propylene also decreases. If the reaction temperature is too high, the yield of propylene is significantly reduced.

  The reaction pressure is an absolute pressure and is usually 2 MPa or less, preferably 1 MPa or less, more preferably 0.7 MPa or less. The lower limit of the reaction pressure is not particularly limited, but is usually 1 kPa or more, preferably 50 kPa or more. When the reaction pressure is too high, the amount of undesired by-products such as paraffins increases, and the yield of propylene tends to decrease. If the reaction pressure is too low, the reaction rate tends to be slow.

  In the present invention, the conversion rate of organic compound raw materials such as ethanol and / or ethylene (conversion rate from ethanol and / or ethylene to a compound other than ethanol and ethylene) is preferably 20% to 95%, more preferably It is appropriate to carry out the reaction under the condition of 20% to 85%.

  If this conversion rate is less than 20%, for example, a large amount of unreacted ethanol or ethylene tends to decrease the propylene yield. On the other hand, if it exceeds 95%, undesirable by-products such as paraffins increase, and the propylene yield tends to decrease.

  When the reaction is carried out in a fluidized bed reactor, the catalyst can be operated at a preferable conversion rate by adjusting the residence time of the catalyst in the reactor and the residence time in the regenerator.

  As the reactor outlet gas (reactor effluent), a mixed gas containing a lower olefin as a reaction product, for example, propylene, an unreacted organic compound raw material, for example, ethylene, a by-product, and a diluent is obtained. The lower olefin concentration in the mixed gas, for example, the propylene concentration is usually 1 to 95% by weight, preferably 2 to 90% by weight.

Depending on the reaction conditions, this mixed gas contains ethanol, but it is preferable to carry out the reaction under such reaction conditions that the reactor outlet gas does not contain any ethanol. Thereby, separation of the reaction product and the unreacted raw material becomes easy. It is preferable to recycle at least a part of ethylene in the mixed gas as a reaction raw material by recycling it to the reactor.
Examples of by-products include olefins having 4 or more carbon atoms, paraffins, aromatic compounds, and water.

  The reactor outlet gas may be introduced into a known separation / purification facility, and may be collected, purified, recycled, and discharged according to each component. Some or all of the components (olefin, paraffin, etc.) other than the recovered target product, especially ethylene, can be recycled by mixing with the reaction raw materials after being separated and purified as described above, or by directly supplying them to the reactor. Is preferred. In addition, among the by-products, components inactive to the reaction can be reused as a diluent.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.
In each of the following examples, an X-ray diffraction (XRD) pattern was obtained using PW1700 manufactured by PANalytical. The X-ray source is CuKα (X-ray output: 40 kV, 30 mA), the reading width is 0.05 °, and the scanning speed is 3.0 ° / min.

<Example 1>
3.3 g of 40 wt% benzyltrimethylammonium hydroxide (BTMA OH) aqueous solution, 0.64 g of sodium hydroxide and 5.2 g of water were mixed, and aluminum hydroxide (containing 50 to 57% in terms of aluminum oxide) was added to this. After adding 76 g and stirring, 6.0 g of colloidal silica (Snowtex 40, manufactured by Nissan Chemical Industries, Ltd.) having a silica concentration of 40% by weight as a silica source was added and sufficiently stirred. Further, 0.10 g of CHA-type aluminosilicate corresponding to 4% by weight with respect to the weight of silica was added as a seed crystal, and stirred to prepare a raw material gel (reaction mixture).

  The obtained gel was charged into an autoclave and heated at 180 ° C. for 24 hours in a tumbled state. The product was filtered, washed with water, and dried at 100 ° C. overnight. After drying, it was fired at 580 ° C. in an air atmosphere to obtain 2.5 g of white powder.

The yield calculated from the theoretical yield of 3.2 g when the raw silica source and aluminum source were all Na-type aluminosilicate was 79%.
The XRD pattern of the obtained white powder is shown in FIG. Although the trace based on the MOR structure was observed from FIG. 1, it was confirmed that the main product was an aluminosilicate having a CHA structure.
Table 1 shows the composition of the raw material gel of Example 1, the yield and physical properties of the product.

<Example 2>
In Example 1, except that 3.3 g of the BTMA OH aqueous solution was changed to 1.7 g, 5.2 g of water was changed to 6.2 g, and 0.10 g of CHA type aluminosilicate (seed crystal) was changed to 0.24 g. A raw material gel was prepared and heated under the same method and conditions as in Example 1, and the product was filtered, washed with water, dried and then fired to obtain 2.5 g of a white powder.

The yield calculated from the theoretical yield of 3.3 g when the raw silica source and aluminum source were all Na-type aluminosilicate was 76%.
The XRD pattern of the obtained white powder is shown in FIG. From FIG. 2, it was confirmed that the product was an aluminosilicate having a CHA structure.
Table 1 shows the composition of the raw material gel of Example 2, the yield and physical properties of the product.

<Comparative Example 1>
In Example 1, except that 0.64 g of sodium hydroxide was changed to 0.48 g, a raw material gel was prepared and heated in the same manner and conditions as in Example 1, and the product was filtered, washed with water, dried and then fired. 2.5 g of white powder was obtained.

The yield calculated from the theoretical yield of 3.2 g when the raw silica source and aluminum source were all Na-type aluminosilicate was 79%.
The XRD pattern of the obtained white powder is shown in FIG. FIG. 3 confirms that the main product is amorphous although a very small peak based on the CHA structure is observed.
Table 1 shows the composition of the raw material gel of Comparative Example 1 and the yield and physical properties of the product.

<Comparative example 2>
In Example 1, except that BTMA OH aqueous solution was not used, water 5.2g was changed to 7.2g, and CHA type aluminosilicate (seed crystal) 0.10g was changed to 0.24g. In the same manner and conditions as in Example 1, a raw material gel was prepared and heated, and the product was filtered, washed with water, dried and then fired to obtain 2.1 g of a white powder.

The yield calculated from the theoretical yield of 3.3 g when the raw silica source and aluminum source were all Na-type aluminosilicate was 63%.
The XRD pattern of the obtained white powder is shown in FIG. FIG. 4 confirms that the main product is amorphous although a very small peak based on the CHA structure is observed.
Table 1 shows the composition of the raw material gel of Comparative Example 2, the yield of the product and the physical properties.

From the results of Example 1 and Comparative Example 1, when the synthesis is performed at a high H ₂ O / Si molar ratio that can be synthesized industrially, the alkali metal / Si molar ratio is extremely important. It can be seen that an aluminosilicate having a CHA structure can be synthesized by increasing the molar ratio.

  Further, from the results of Example 2 and Comparative Example 2, it is understood that the presence of BTMA OH is necessary even when the alkali metal / Si molar ratio is increased in order to obtain an aluminosilicate having a CHA structure.

  The present invention can be particularly suitably used in the fields related to the production and use of aluminosilicates. In particular, since the aluminosilicate produced by the method of the present invention has a small pore size, the crystals are dense, and has high acid resistance, a petrochemical raw material production catalyst, exhaust gas treatment catalyst, gas separation and It is suitable for zeolite separation membranes such as dehydration of water from organic substances such as acetic acid.

Claims (5)

Hydrothermal synthesis of a mixture containing N, N, N-trialkylbenzylammonium cation, Si element source, alkali metal source, Al element source and water has a CHA crystal structure and has a mole of SiO ₂ with respect to Al ₂ O _3. A method for producing an aluminosilicate having a ratio of 5 or more, wherein the molar ratio of N, N, N-trialkylbenzylammonium cation to Si element in the mixture is 0.005 or more, and the molar ratio of alkali metal to Si element is 0.35 to 1.0, and Ri der molar ratio of water of 10 or more with respect to Si element, and the amount of the seed crystals contained in the mixture is characterized in that 0.5 wt% or more alumino Manufacturing method of silicate.   The mixture contains an ammonium cation other than N, N, N-trialkylbenzylammonium cation, and the molar ratio of ammonium cation other than N, N, N-trialkylbenzylammonium cation to Si element in the mixture is less than 0.005 The manufacturing method according to claim 1, wherein The method for producing an aluminosilicate according to claim 1 or 2, wherein the amount of seed crystals contained in the mixture is 30% by weight or less. A method for producing a lower olefin, wherein an organic compound raw material is brought into contact with an aluminosilicate produced by the method according to any one of claims 1 to 3 to produce a lower olefin. The production method according to claim 4 , wherein the organic compound raw material is ethylene and the lower olefin is propylene.

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