JP7113697B2 - MFI type zeolite - Google Patents

Description

The present invention relates to an MFI-type zeolite having a novel pore structure.

Zeolite is a crystalline aluminosilicate having SiO ₂ , Al ₂ O ₃ or the like as a framework and having regular channels (pores). In particular, MFI-type zeolites are silica-rich and are widely known to contain pores with a 10-membered ring structure (5.1×5.5 Å and/or 5.3×5.6 Å).

It is known that Al ₂ O ₃ in the crystal framework of zeolite affects hydrophilicity, and that the higher the Al content, the higher the hydrophilicity, and the lower the Al content, the lower the hydrophilicity. Silica-rich MFI-type zeolite has low hydrophilicity due to its low Al content, and therefore exhibits high adsorption to hydrophobic organic components, and has a pore diameter close to the size of low-molecular-weight hydrocarbons. Therefore, its use as an adsorbent for organic compounds has been proposed (see Patent Documents 1 to 3).
In addition, Al in the crystal skeleton of zeolite is known to act as a solid acid site, and since it has pores close to the molecular diameter of aromatics as described above, MFI type zeolite is used for hydrocarbon aromatization. It is also widely known to be used as a catalyst or catalyst carrier, and when MFI-type zeolite is used as a solid acid catalyst or catalyst carrier, zeolites with relatively high Al content and many active sites are often used ( See Patent Document 4).

The various MFI-type zeolites described above are those obtained by reacting a silica source and an alumina source by adding a template and, if necessary, seed crystals in a mixed gel containing a silica source and an alumina source, and heating the mixture. However, according to the studies of the present inventors, crystallographically speaking, the MFI type zeolite obtained by such a method has the property that the interplanar spacing of the (053) plane is larger than 2.99 Å. I know that. The present inventors believe that this large interplanar spacing is due to the strain or distortion formed in the crystal structure or pore structure of the zeolite.

The present inventors have studied the strain and distortion that occur in the MFI type zeolite as described above, and in particular, the reaction (crystallization) between the silica source and the alumina source is performed at a low temperature lower than 100 ° C. and under normal pressure. By suppressing such strain and distortion, an MFI zeolite having a (053) plane spacing (d value) of 2.99 Å or less can be obtained. A patent application has been filed as an adsorbent (PCT/JP2017/005755).

JP H01-171554 JP H09-253483 JP 2003-126689 A JP-A-2001-62305

The present inventors have further promoted research on MFI-type zeolite in which the interplanar spacing of the (053) plane is 2.99 Å or less as described above, and the mixing step or aging step of the silica source and alumina source used in this production process They also found that by controlling the conditions of the reaction process, it is possible to obtain an MFI-type zeolite with a very unique pore structure in which many macropores are present, which is effective when used as a catalyst or adsorbent.

Accordingly, an object of the present invention is to provide an MFI-type zeolite having a novel pore structure in which many macropores are formed.

According to the present invention, an MFI-type zeolite having a SiO ₂ /Al ₂ O ₃ (molar ratio) of 30 or more,
In the pore distribution by mercury porosimetry, the pore volume of macropores with a pore diameter of 30 to 200 nm is in the range of 0.34 to 1.0 ml / g ,
In the pore distribution by the mercury intrusion method, the pore volume of mesopores with a pore diameter of 3.6 to 30 nm is in the range of 0.01 to 0.5 ml / g,
Provided is an MFI-type zeolite characterized in that the volume ratio of the macropores to the mesopores is macropores/mesopores=2-6 .

In the MFI zeolite of the present invention,
( 1 ) having a BET specific surface area of 300 m ² /g or more;
( 2 ) It is preferable that the interplanar spacing (d value) of the (053) plane is 2.99 Å or less in the X-ray diffraction spectrum.

According to the present invention, a raw material liquid (A) in which a silica source and a template are dissolved or dispersed in water or an alkaline aqueous solution, and a raw material liquid (B) in which an alumina source is dissolved or dispersed in water or an alkaline aqueous solution are prepared. preparing process;
A raw material mixing step of adding the raw material liquid (B) into the raw material liquid (A) so that the SiO ₂ /Al ₂ O ₃ (molar ratio) is 30 or more;
Aging step of aging the raw material mixed liquid obtained in the raw material mixing step while maintaining the aging temperature of 60 to 95° C. to produce a mixed gel containing a silica source and an alumina source;
a crystallization reaction step in which the mixed gel is maintained at a crystallization temperature higher than the aging temperature of 80 to 99° C. under normal pressure to produce MFI-type zeolite;
A pore definition step in which the generated crystal is fired to eliminate the template;
There is provided a method for producing MFI-type zeolite, comprising:

In the production method of the present invention, the following means can be preferably employed.
(1) In the raw material mixing step, the raw material liquid (B) is added over 20 minutes or longer.
(2) In the aging step, the raw material mixture is maintained at the aging temperature for 1 to 96 hours.
(3) The raw material liquid (B) contains an alkali silicate as part of the silica source.
(4) A seed crystal mixing step of adding and mixing seed crystals (C) is provided before the crystallization reaction step.
(5) MFI type zeolite is used as the seed crystal (C), and the amount of the seed crystal is 0.05 to 10 parts by mass per 100 parts by mass of SiO ₂ in the mixed gel.
(6) The seed crystals (C) are fine particles having a single particle diameter of 10 µm or less, and the fine particles are added to the mixed gel in a state of being dispersed in an alkaline aqueous solution.

The MFI zeolite of the present invention has a very large pore volume of 0.34 to 1.0 ml/g for macropores with a pore diameter of 30 to 200 nm. Furthermore, the MFI-type zeolite of the present invention has, for example, a lattice spacing (d value) of (053) plane of 2.99 Å or less in the X-ray diffraction spectrum. That is, the d value represents the distance between specific planes of the pores of the zeolite. It means that the pore volume is large as well as being large. That is, such a pore structure in which many large macropores are present is constructed as a result of the zeolite having no strain and having pores uniformly distributed. This is a pore structure unique to the MFI-type zeolite of the present invention, which is not found in zeolites at all.

The MFI-type zeolite of the present invention, which contains many macropores with a large pore diameter, is not only used as an adsorbent for various volatile compounds, but also causes offensive odor even when dispersed in a resin. It is expected that the adsorption performance for various gas components is improved. It is also expected to improve performance as a catalyst or catalyst carrier, especially as a catalyst in liquid phase reactions. This is because, with such adsorption performance and catalytic function, gases and reactants easily penetrate into this MFI zeolite through large macropores even in the resin or liquid phase.

In addition, the method for producing MFI-type zeolite of the present invention does not require special raw materials such as expensive raw materials or pore-forming agents to produce MFI-type zeolite having a unique macropore structure. can be carried out without using, and is superior to conventionally known production methods in terms of cost and complexity of the production process.

1 is an X-ray diffraction image of MFI-type zeolite synthesized in Example 1. FIG. Pore distribution curves of MFI-type zeolite synthesized in Example 4, Comparative Example 1 and Comparative Example 3. SEM photographs of MFI-type zeolite synthesized in Example 4 and Comparative Example 2. FIG.

<MFI type zeolite>
The MFI-type zeolite of the present invention exhibits X-ray diffraction peaks as shown in FIG. 1 due to the formation of 10-membered ring pores unique to the zeolite. For example, sharp diffraction peaks of the (011) plane near 2θ=7.9°, the (200) plane near 2θ=8.9°, and the (051) plane near 2θ=23.1° are shown.
Such zeolite is silica-rich with a SiO ₂ /Al ₂ O ₃ (molar ratio) of 30 or more, preferably 50 or more, and the upper limit is preferably 5000 or less, particularly preferably 500 or less, and most preferably 150 or less. It is in.

The MFI-type zeolite of the present invention has no distortion, and for example, the interplanar spacing (d value) of the (053) plane is 2.99 Å or less in the X-ray diffraction spectrum. As mentioned above, the d value represents the distance between specific planes of pores in the zeolite. It means that the pores are free from strain and distortion, that the pores are uniformly distributed, and that more pores are included. As a result, a large nitrogen adsorption amount is exhibited even in an atmosphere with a low nitrogen partial pressure P _N2 (P/P ₀ ). For example, when the nitrogen partial pressure P _N2 (P/P ₀ ) is 0.005, the nitrogen adsorption amount is 80 cm ³ /g or more, preferably 90 cm ³ /g or more, and particularly preferably 103 cm ³ /g or more, which is extremely large.

In the MFI zeolite of the present invention, the pore volume of macropores with pore diameters of 30 to 200 nm is in the range of 0.34 to 1.0 ml/g in the pore size distribution determined by mercury porosimetry. That is, the existence of many macropores of such large size has a great influence on the adsorption performance and catalyst performance. For example, even if there is no significant difference when the MFI-type zeolite exists in the gas phase, it can effectively adsorb gas components even when it exists in a resin-dispersed state, Furthermore, even when present in the liquid phase, they can readily come into contact with the reactants, thus exhibiting high catalytic performance.
In the present invention, many such macropores are formed. The ratio of the pore volume occupied by macropores to the pore volume is 45% or more, preferably 50% or more, and particularly preferably 60% or more.

Furthermore, in relation to the fact that the MFI-type zeolite of the present invention contains many large macropores as described above, in the pore distribution by the mercury intrusion method, the pore diameter is in the range of 3.6 to 30 nm. The pore volume of mesopores is 0.01 to 0.5 ml/g, preferably the lower limit is 0.05 or more, particularly preferably 0.10 or more, and the upper limit is preferably 0.5 or less, particularly preferably 0.5 ml/g. 4 or less. In addition, in the mesopores having a pore diameter in the range of 3.6 to 30 nm, the ratio of the pore volume occupied by the mesopores to the total pore volume in the range of 3.6 to 1100 nm is 55% or less, preferably 35% or less. , particularly preferably 25% or less. That is, along with the formation of macropores, mesopores with a size close to macropores are formed in an appropriate amount, although not as large as macropores. When the MFI-type zeolite of the present invention is used as a carrier, diffusion of the substrate can be facilitated. For example, the volume ratio of macropores to mesopores is about 2 to 6 (macropores/mesopores).

In the present invention, this MFI-type zeolite has a hierarchical structure (also called a mulberry shape, etc.) in which small particles of 50 nm or less aggregate, as shown in the SEM photograph of FIG. Along with this, it has an extremely large specific surface area. For example, the BET specific surface area is 300 m ² /g or more, preferably 400 m ² /g or more, particularly preferably 430 m ² /g or more, and most preferably 450 m ² /g or more. extremely large. That is, the inter-particle gaps between such small primary particles contribute to the formation of the macropores.
Such a large specific surface area also brings about improvement in adsorption performance and catalyst performance.

<Production of MFI type zeolite>
The MFI-type zeolite described above uses a raw material liquid (A) containing a silica source and a template, a raw material liquid (B) containing an alumina source, and more preferably a seed crystal (C) as raw materials, and a raw material mixing step, It is produced through an aging step, a crystallization reaction step, and a pore definition step, preferably through a seed crystal mixing step after the aging step.

Raw material liquid (A);
The raw material liquid (A) used for the production of such MFI-type zeolite is obtained by dissolving or dispersing a silica source and a template in water or an alkaline aqueous solution.

As the silica source used here, conventionally known SiO ₂ content-containing materials used in the production of various zeolites, such as tetraethyl orthosilicate, colloidal silica, silica gel dry powder, silica hydrogel and the like are used. It is also preferred to use alkali silicates such as sodium silicate and potassium silicate as part of the silica source. However, although tetraethylorthosilicate and colloidal silica are highly reactive, they are expensive. In particular, tetraethylorthosilicate is not suitable for large-scale synthesis because it is necessary to volatilize EtOH from the reaction solution.
The production method of the present invention enables production without being limited to the use of these expensive raw materials, and is more advantageous in terms of cost than conventional methods.

These silica sources are dissolved once in an aqueous solution in the crystallization reaction step to be described later, and are constructed into MFI-type zeolite. does not significantly affect the crystallization of MFI-type zeolite.

The template is a structure-directing agent for forming pores with a 10-membered ring peculiar to MFI-type zeolite, and is an amine compound containing an n-alkyl group having 2 to 4 carbon atoms and a nitrogen cation in the molecule, such as , a salt of a tetraalkyl (ethyl, n-propyl or n-butyl) ammonium cation and an anion (eg Br ⁻ ), or a hydroxide of the ammonium.

The amount of the template to be used varies greatly depending on the type of template, particularly the number of carbon atoms in the alkyl group, and cannot be generally defined. It is used in an amount of TPA/SiO ₂ =0.03 to 0.20 (molar ratio) with respect to the Si component.

Although it is not necessary when using the quaternary ammonium hydroxide as a template, when using a salt of a quaternary ammonium and an anion such as Br or Cl as a template, a silica source and a template can be used. For dissolution or dispersion, it is preferable that an alkali metal hydroxide (for example, caustic soda) is added and mixed into the raw material liquid (A) to form an alkaline aqueous solution. Such an alkali metal hydroxide has a ratio of A ₂ O/SiO ₂ (molar ratio) of 0.01 to 0.20 (A is an alkali metal element), preferably 0.15 or less, or more, relative to the Si component. It is preferably used in an amount of 0.10 or less. In this case, the greater the amount of alkali metal hydroxide added, the _more the effect of shortening the crystallization reaction _time (time required for crystallization), which will be described later, can be obtained. However, a large amount of hydrophilic alkali metal remains in the resulting MFI zeolite, which may impair its physical properties.
Also, the use of an alkali silicate as part of the silica source described above is advantageous in avoiding the use of such alkali metal hydroxides.

Raw material liquid (B);
The raw material liquid (B) is used as an alumina source that reacts with a silica source to produce MFI zeolite.
As such an alumina source, conventionally known ones used for producing various zeolites can be used, and representative examples thereof include aluminum chloride and sodium aluminate. Among these alumina sources, sodium aluminate is particularly preferred for producing the MFI zeolite of the present invention, and an aqueous solution of sodium aluminate is preferably used as the raw material liquid (B).

Seed crystal (C)
Although the addition of seed crystals is not essential in the present invention, the addition shortens the crystallization reaction time and prevents decomposition and modification of the template during the reaction. As a result of the addition of such seed crystals (C), an MFI zeolite framework structure with less strain and distortion is formed, and an MFI zeolite having a larger specific surface area and pore volume can be produced.

For such seed crystals (C), conventionally known MFI-type zeolite or MFI-type zeolite of the present invention is used. Such an MFI-type zeolite is preferably used after the template has been removed by calcination or the like and pores have been defined. By using MFI zeolites with defined pores, it is possible to produce MFI zeolites of the present invention that are less strained and have uniformly distributed pores. In addition, it is more preferable from the standpoint of dispersibility after addition of seed crystals that the crystals are appropriately pulverized by, for example, dry pulverization using a rotary jet mill or the like or wet pulverization using a bead mill.

Raw material mixing process;
In the present invention, first, the raw material liquid (A) containing the silica source and (B) containing the alumina source are mixed so that the SiO ₂ /Al ₂ O ₃ (molar ratio) is 30 or more. Such mixing must be performed by adding the raw material liquid (B) to the raw material liquid (A). That is, in the present invention, in order to synthesize MFI zeolite containing a large excess of Si relative to Al, it is necessary to uniformly disperse a small amount of alumina source in a large amount of silica source. The template in liquid (A) must also be uniformly dispersed in the mixed liquid.

Further, in the present invention, in order to more reliably disperse the alumina source homogeneously, it is preferable to gradually add the raw material liquid (B) into the raw material liquid (A) while stirring. It is desirable to add the raw material liquid (B) over a period of 60 minutes or more, preferably 60 minutes or more. As a result, it is possible to reliably form the 10-membered ring pores unique to MFI-type zeolite, and to stably form macropores and mesopores.

In addition, the addition of the raw material liquid (B) to the raw material liquid (A) is preferably performed at a temperature of 80° C. or lower, particularly preferably 40° C. or lower, generally at room temperature, in order to prevent unnecessary gelation. .

In addition, the raw material liquid (A) and the raw material liquid (B) must be selected from a combination of raw materials that does not cause a neutralization reaction in the mixing step. For example, when No. ₃ sodium silicate is used as a silica source, a large amount of Na ₂ O is present in excess of the amount necessary for the crystallization reaction. However, the mirabilite (Na ₂ SO ₄ ) generated at this time significantly lowers the solubility of silica in the reaction solution in the crystallization process due to the effect of salting out. It delays the construction of zeolite. As a result, the crystallization reaction time becomes extremely long, which is industrially unsuitable. In addition, the extremely long reaction time as described above hinders uniform crystal growth, also because the amount of accumulated thermal energy increases, and the MFI type zeolite with characteristic macropores like the present invention cannot be generated.

In addition, when only silica hydrogel containing alkaline components such as Na ₂ O and the like as unavoidable contaminants is selected as the silica source for the raw material solution (A), in the mixing step with the raw material solution (B) Al is likely to be insufficiently dispersed, the process required for the aging process becomes long, and as a result, the overall reaction rate becomes slow, which is not desirable. Furthermore, when silica hydrogel alone is used as a silica source, it is necessary to add a large amount of alkali source such as caustic soda, which is industrially undesirable. Therefore, the raw material liquid (A) preferably contains an alkali silicate as part of the silica source.

For the above reasons, a combination of two or more silica sources such as sodium silicate and silica hydrogel is preferably employed as the silica source of the present invention. By using these silica raw materials together, the even arrangement of Si and Al bonds through oxygen, which will be described later, becomes more precise, and MFI-type zeolite with a characteristic macropore distribution like the present invention is produced. can do.

aging process;
After the raw material liquid (A) and the raw material liquid (B) are mixed as described above, the mixed liquid is heated to a temperature of 60 to 95° C. (aging temperature) for aging, whereby homogeneous silica-alumina is produced. A mixed gel is produced.
That is, by such an aging step, a SiOSi chain is formed so as to surround the cation of the template as shown in the following schematic formula, and a skeleton of a 10-membered ring structure unique to MFI-type zeolite is formed. In addition, OAlO is evenly formed in a part of the SiOSi chain.
OH-Si-O ^- +Si-OH → [OH-Si-O...SiOH] ^-
→ OH-Si-O-Si ^-- OH
→ OH-Si-O-Si(-OH) ^-O- + _H2O

Such heating to the maturing temperature is preferably carried out by gradually raising the temperature of the mixed liquid. For example, by carrying out the heating over 30 minutes or longer, it is possible to reliably prevent gelation due to rapid heating.
Such gelation is carried out by holding the mixture at the aging temperature for 1 hour or more, preferably 1 to 96 hours, particularly preferably 8 to 24 hours. In this case, when the aging temperature is set to a temperature higher than the above range, gelation proceeds rapidly. Undesirable. Macropores and mesopores characteristic of the present invention can be formed through the process of mixing the raw material liquid (A) and the raw material liquid (B).

That is, if the presence of Al is biased against the presence of Si present in a large excess without going through the process of the present invention, fine crystal grains cannot be produced, and the above-described macroscopic MFI type zeolite with many pores cannot be produced. For example, the pore volume of the macropores (pores with a pore diameter of 30 to 200 nm) is less than 0.34 ml/g, and the macropores with respect to the total pore volume in the region of the pore diameter of 3.6 to 1100 nm The ratio of the pore volume occupied by is also lower than 45%. Furthermore, the BET specific surface area is also reduced, and the selectivity when used as a catalyst or catalyst carrier is lowered.

Seed crystal mixing step;
When the seed crystal (C) is added, it is preferably added before the crystallization reaction step. The mixing method is not particularly limited, and it can be used by pre-mixing with part or all of the mixed gel and/or part or all of the raw materials of the mixed gel prior to crystallization. For example, it is preferable to have a mixing step in which the seed crystals are added to the mixed gel or raw materials of the mixed gel so that the seed crystals are not unevenly distributed. Particularly preferably, after the silica-alumina mixed gel in which Al is homogeneously distributed is produced as described above, seed crystals serving as nuclei of MFI-type zeolite crystals are mixed into this mixed gel as necessary. be.

In the present invention, MFI-type zeolite is used as the seed crystal, and the amount of the seed crystal is 0.05 to 10 parts by mass, particularly 1 to 5 parts by mass, per 100 parts by mass of SiO ₂ in the mixed gel. It is desirable to add and mix in the inside, and by accelerating the crystallization reaction, the pore volume of the macropores can be reliably adjusted within the range described above.

In addition, the MFI type zeolite used as such seed crystals is preferably used after the template has been removed by calcination or the like. A pulverized one is used.

In addition, in the present invention, a dilute alkaline aqueous solution such that the seed crystals (C) are not completely dissolved, for example, a NaOH aqueous solution having a NaOH concentration of 10% by mass or less, preferably 0.1 to 5% by mass, is prepared. , and the seed crystal (C) can be added to the mixed gel. That is, in such an alkaline aqueous solution, seed crystals are finely dispersed in a colloidal form, and exist in the form of extremely fine particles with a single particle diameter of 10 µm or less, preferably 5 µm or less, and particularly preferably 1 µm or less. and can make the crystallization reaction faster. At this time, the amount of the seed crystal (C) added is preferably 0.01 to 15 parts by mass with respect to 100 parts by mass of the alkaline aqueous solution. Further, the dispersion may be carried out to the extent that the seed crystals (C) are disaggregated. For example, the dispersion is carried out with a generally used stirrer for 0.1 to 12 hours.

Crystallization reaction step;
In the present invention, the mixed gel obtained as described above is heated and held at a crystallization temperature higher than the aging temperature under normal pressure, thereby constructing crystal nuclei and forming seed crystals (C). When it is added, crystals grow from a large number of fine seed crystals distributed as nuclei, and the MFI-type zeolite of the present invention having a large pore volume of the desired macropores can be obtained in an extremely short period of time. Surprisingly, as shown in Examples 1 and 2 which will be described later, when seed crystals are used, crystals are formed in about one-third of the time when the crystallization reaction is performed without using seed crystals. Transformation can be completed. As a result, an MFI zeolite framework structure with less strain and distortion is formed, and an MFI zeolite having a greater specific surface area and pore volume can be produced.

It is important to carry out such a crystallization reaction step under normal pressure, that is, in an open system. That is, if the crystallization reaction step is carried out in a closed system using an autoclave or the like, the internal pressure will reduce the inter-particle spacing of the crystals, resulting in a reduction in the pore volume of the macropores.

It is also important to set the crystallization reaction temperature to 85 to 99°C. That is, if this temperature is too low, crystallization will not be sufficiently carried out, and the desired MFI zeolite will not be obtained. In addition, if this temperature is high, for example, exceeds 100° C., the template and fine seed crystals will flow significantly, resulting in non-uniform pore distribution and distortion of the pores that are formed. As a result, the d value, which is the interplanar spacing of the (053) plane, becomes larger than 2.99 Å.

The crystallization reaction step as described above usually varies depending on the composition of the mixed gel to be crystallized, and cannot be defined unconditionally. When seed crystals are used, it takes about 8 to 120 hours. Further, when the seed crystals are dispersed in an alkaline aqueous solution and added to the mixed gel, it takes about 8 to 96 hours.

pore definition step;
After the crystallization reaction is completed as described above, the crystal is filtered and washed with water to remove impurities such as alkali metals, and then fired to eliminate the template contained in the crystal. 10-membered ring-shaped pores are defined, and the desired MFI-type zeolite of the present invention can be obtained.
The calcination temperature is such that the template is decomposed but the zeolite crystals are not damaged.

The MFI-type zeolite thus obtained has a median diameter of 0.1 to 100 μm, preferably 0.5 to 10 μm. Considering ease of use, the particle size is adjusted to a size of 0.5 to 4.0 μm for use in adsorption applications.
The MFI-type zeolite of the present invention is used, for example, by kneading it with a resin composition, mixing it with a liquid containing a hydrophobic solvent such as a paint or a coating agent, or filling equipment such as an adsorption column or an adsorption tower. In particular, since the MFI-type zeolite of the present invention has a large pore volume of macropores, it is suitable for applications such as adsorption and removal of odors by blending with resins, and applications such as catalysts in liquid phase reactions.

Furthermore, the MFI-type zeolite of the present invention exhibits excellent properties as a catalyst and/or a catalyst carrier. For example, it has been confirmed by experiments described later that the catalyst of the present invention in which platinum is supported on MFI-type zeolite exhibits excellent properties as a catalyst for hydroisomerization dewaxing of n-paraffin.
That is, when long-chain n-paraffins such as nC ₁₄ are reacted with hydrogen in the presence of a catalyst, C ₃ is eliminated in the form of, for example, propylene (olefin) from the terminal of the molecule, and the eliminated C ₃ again reacts with n _- paraffinic residues (addition reaction) or with further elimination of C3 and addition reaction again, resulting in iso-paraffins, e.g. mono-branched with one branch Isomers or multi-branched isomers with multiple branches are produced. As a catalyst for such n-paraffin hydroisomerization reaction, when platinum is supported on the MFI type zeolite with specifically developed mesopores of the present invention, a high n-paraffin conversion rate at low temperature or a high isomer Yields can be obtained.
Branched isomers (iso forms) of n-paraffins have a lower melting point and higher volatility than n-paraffins, and are suitable for applications such as lubricating oils and jet fuels.

The invention is illustrated by the following experimental examples.
Various measurements in the experiment were performed by the following methods, and the measurement results are shown in Tables 2-4.

(1) X-ray diffraction (measurement and analysis conditions for surface spacing d value analysis)
A dry sample was placed in a desiccator already adjusted to a relative humidity of 75% and allowed to stand at room temperature for 48 hours or longer to absorb a saturated amount of water. X-ray diffraction measurement was performed on the sample taken out from 2Θ=29.6 to 30.2°. The X-ray diffraction measurement was performed using Ultima4 manufactured by Rigaku Co., Ltd. under the following conditions with Cu-Kα.
Target: Cu
Filter: curved crystal graphite monochromator Detector: SC
Voltage: 40kV
Current: 50mA
Step size: 0.005°
Counting time: 10 sec/step
Slit: DS2/3° RS0.3mm SS2/3°
The d value (Å) was obtained based on the following formula for the angle with the maximum peak in the X-ray diffraction within the intended range.
(Bragg condition)
d=nλ/2 sin Θ
d: surface spacing n: integer λ: wavelength sinΘ: angle between crystal plane and X-ray (confirmation of crystal type)
Confirmation of the crystal was performed by changing the following conditions among the conditions used for the measurement of the d value.
Measurement range: 3 to 40°
Current: 40mA
Step size: 0.02°
Counting time: 0.6 sec/step

(2) Measurement of pore distribution Pore volume and pore distribution were measured by a mercury intrusion method using Autopore IV 9500 manufactured by Micromeritics. The pore diameter is measured from 3.6 to 1100 nm, and the cumulative pore volume is defined as the total pore volume. The pore volume of each section was defined as each pore volume.
The cumulative pore volume was used for the notation of the vertical axis of the pore size distribution.

(3) Composition analysis For the elemental analysis necessary for calculating the alkali metal content in terms of oxide and SiO ₂ /Al ₂ O ₃ (molar ratio), Rigaku ZSX primus II manufactured by Rigaku Co., Ltd. was used, and the target was Rh, analytical line was Kα, and other measurements were made under the following conditions.
The standard sample was dried at 110° C. for 2 hours.

(4) Measurement of Particle Size Agglomerated particle sizes of MFI zeolite were measured from SEM images measured by JSM-6510LA manufactured by JEOL Ltd. Ten particles were selected at random, and the average of the major and minor axes was taken as the particle size of each agglomerated particle, and the average particle size of the MFI zeolite was taken.

(5) Measurement of Particle Size of Seed Crystal The particle size of the seed crystal (C) was measured as a single particle size by similarly observing the primary particles of the MFI-type zeolite from the SEM image.

(6) BET Specific Surface Area The specific surface area was calculated by the BET method from the measured values of the nitrogen adsorption isotherm P/P ₀ =0.005 to 0.015.

(7) Evaluation of catalyst performance <hydroisomerization dewaxing of n-paraffin>
Using 5 g of the Pt-supported catalyst prepared in the following example, n-C14 (Normal Tetradecane, manufactured by Nacalai Tesque Co., Ltd.) was hydroisomerized and dewaxed in a flowing fixed-bed catalytic reactor. After the catalyst was reduced at 400° C. for 2 hours under a stream of H ₂ , the reactor temperature was lowered to the reaction temperature. Next, after increasing the pressure to 0.8 MPa with H ₂ , n-C14 was added at WHSV=1 h ^-1 . The raw material ratio (n _H2 /n _n-C14 ) was set to 10. Two hours after the reaction, the liquid reaction product in the gas-liquid separator was recovered and analyzed for its composition by gas chromatography.
<Component composition analysis by gas chromatography>
The reaction product was measured using GC-2014 manufactured by Shimadzu Science, and DB-1 (manufactured by Agilent Technologies, inner diameter 0.25 mm, 30 m, film thickness 0.25 μm) was used as a capillary column. A measurement sample was prepared by diluting the liquid component obtained by the hydroisomerization dewaxing reaction of n-paraffin with four times the amount of acetone. The detector is FID, the carrier gas is He, the vaporization chamber temperature is set to 320°C, 1 μl is injected (split ratio is 1:20), then the measurement chamber temperature is maintained at 40°C for 10 minutes, and the temperature is increased to 320°C at 5°C/min. A chromatogram was obtained by raising the temperature and finally holding at 320° C. for 10 minutes. The n-C14 conversion rate X [%], yields M [%] and B [%] of mono-branched and multi-branched isomers, and yield C [%] of decomposition products were defined as follows. The decomposition product yield C does not include the decomposition product obtained as a gas component. Conversion rate (X) of n-paraffin and isomerization yield (M+B) were evaluated as catalytic performance.
n-C14 conversion rate X [%] = 100 - residual n-C14 in sample [%]
Mono-branched isomer yield M [%] = total mono-branched C14 isomers in sample [%]
Yield of multi-branched isomer B [%] = total of multi-branched C14 isomers in sample [%]
Yield of decomposed product C [%] = 100 - residual n-C14-M-B

<Comparative Example 1>
MFI type zeolite MT-100 manufactured by Mizusawa Chemical Industry Co., Ltd. was used.

<Comparative Example 2>
An MFI-type zeolite was obtained by preparing in the same manner as in Example 6 shown in PCT/JP2017/005755.

<Comparative Example 3>
An MFI-type zeolite was obtained by crystallization at 80° C. in the same manner as in Example 1 shown in Japanese National Publication of International Patent Application No. 7-502964.

<Example 1>
<Preparation of raw material liquid (A)>
67.8 g of 98% TPABr, 953 g of water, 457 g of No. 3 sodium silicate (SiO ₂ =22.8% by mass, Na ₂ O=7.6% by mass, H ₂ O=69.6% by mass) and A raw material solution A was prepared by mixing 511 g of silica hydrogel (SiO ₂ =38.5% by mass, Na ₂ O=0.02% by mass, H ₂ O=61.4% by mass). The composition of each component of the raw material liquid (A) was SiO ₂ :Na ₂ O:TPA-Br:H ₂ O=120:13:6:2114 in molar ratio.
<Preparation of raw material liquid (B)>
18.4 g of sodium aluminate (Al ₂ O ₃ =23.0% by mass, Na ₂ O=19.2% by mass, H ₂ O=57.8% by mass) and 200 g of water were used to prepare the raw material solution (B). prepared. The composition of each component of the raw material liquid (B) was Al ₂ O ₃ :Na ₂ O:H ₂ O=1:1.4:281 in molar ratio.
<Mixing and Aging of Raw Material Liquid (A) and Raw Material Liquid (B)>
The raw material liquid (B) was added to the raw material liquid (A) over 30 minutes under stirring at room temperature. The resulting mixed gel was heated to 85° C. over 30 minutes in a hot water bath, and aged at 85° C. for 20 hours.
<Crystallization reaction and pore definition>
The mixed gel at 85° C. was heated to 95° C., sampled appropriately and reacted for 144 hours while confirming X-ray diffraction. It was judged that crystallization was completed in 120 hours because the crystal type and peak intensity in X-ray diffraction at 120 hours and 144 hours were the same. The resulting crystal slurry was washed by repeating centrifugation and redispersion with ion-exchanged water until the pH of the dispersion became 9.0 or less, and then dried at 110° C. for 10 hours. The dried product was calcined at 550° C. for 2 hours in an electric muffle furnace to obtain MFI zeolite.

<Example 2>
The composition of each component of the raw material liquid (A) is SiO ₂ : Na ₂ O: TPA-Br: H ₂ O = 120: 9.4: 6: 1374 in molar ratio, and the composition of each component of the raw material liquid (B) is Al ₂ O ₃ : Na ₂ O: H ₂ O = 1: 1.4: 281 in molar ratio, and the raw material solution (A) Seed crystal (C) pulverized with a rotary jet mill equivalent to 3% by mass (9 g) of SiO ₂ (particle diameter 0.7 μm, SiO ₂ /Al ₂ O ₃ molar ratio = 100, template-free MFI-type zeolite ) and 25.1 g of 49% NaOH and 534 g of water were mixed and added, and the MFI type zeolite of Example 2 was obtained in the same manner as in Example 1 except that the crystallization reaction time was changed to 48 hours. As for the crystallization reaction, there was no change in the crystal type and peak intensity in X-ray diffraction at 33 hours and 48 hours, so it was determined that the crystallization reaction was completed at 33 hours.

<Example 3>
An MFI-type zeolite was obtained in the same manner as in Example 2 except that the raw material solutions (A) and (B) shown below were used and the crystallization time was changed to 72 hours.
Raw material liquid (A): SiO ₂ :Na ₂ O:TPA-Br:H ₂ O=100:3.6:5:1144
Raw material liquid (B): _Al2O3 : _Na2O : _H2O = ₁ :1.4:237

<Example 4>
An MFI-type zeolite was obtained in the same manner as in Example 2 except that the raw material solutions (A) and (B) shown below were used and the crystallization time was changed to 72 hours.
Raw material liquid (A): SiO ₂ :Na ₂ O:TPA-Br:H ₂ O=80:2.6:4:912
Raw material liquid (B): _Al2O3 : _Na2O : _H2O = ₁ :1.4:192

<Example 5>
An MFI-type zeolite was obtained in the same manner as in Example 2, except that the following raw material solutions (A) and (B) were used and the crystallization time was changed to 96 hours.
Raw material liquid (A): SiO ₂ :Na ₂ O:TPA-Br:H ₂ O=60:1.6:3:681
Raw material liquid (B): _Al2O3 : _Na2O : _H2O = ₁ :1.4:148

The physical properties of the obtained MFI-type zeolite are shown in Table 2 below. Since the MFI-type zeolite obtained by the method of the present invention has extremely developed macropores and associated mesopores, it has a high external surface area. It is possible to impart high diffusion rates. In addition, when used as a catalyst or catalyst carrier, it is expected to show good contact with the reaction substrate and exhibit high activity. High selectivity in the reaction is expected.

<Comparative Example 4>
98% TPABr, water, silica hydrogel (SiO ₂ =38.5% by mass, Na ₂ O=0.02% by mass, H ₂ O=61.4% by mass), and 1.8 g of MFI-type zeolite of Comparative Example 1 were mixed to prepare a raw material liquid (A). The composition of each component of the raw material liquid (A) was SiO ₂ :Na ₂ O:TPA-Br:H ₂ O=:1:0.0005:0.05:14.5 in molar ratio. Sodium aluminate, water, and 49% NaOH were mixed to prepare a raw material solution (B). The composition of each component of the raw material liquid (B) was Al ₂ O ₃ :Na ₂ O:H ₂ O=1:5:123 in molar ratio. The raw material liquid (A) and the raw material liquid (B) were mixed under the same conditions as in Example 1 to obtain a mixed gel. The SiO ₂ /Al ₂ O ₃ molar ratio of the mixed gel was 85. The mixed gel was placed in a 1.5 L volume autoclave equipped with a stirrer, heated to 170° C. over 2 hours under stirring conditions, and then maintained at 170° C. for 24 hours for crystallization reaction. The resulting crystal slurry was washed, dried and calcined in the same manner as in Example 1 to obtain MFI-type zeolite of Comparative Example 4.
<Preparation of Pt-supported catalyst using Comparative Example 4>
Using the MFI-type zeolite of Comparative Example 4, a catalyst was prepared by the following operation.
After adding 90 g of water to 10 g of MFI-type zeolite and re-dispersing by stirring, 10 g of ammonium chloride was added, and after stirring for 3 hours, the mixture was filtered, washed with water, and exchanged. Water was added again to obtain a zeolite-dispersed slurry of 100 g in total, and then the same exchange treatment of adding 10 g of ammonium chloride was repeated twice to obtain an ammonium-MFI zeolite. After drying the obtained ammonium-MFI zeolite in a constant temperature drying rack at 110° C. for 10 hours, ammonium is removed using a muffle furnace under conditions of holding at 550° C. for 3 hours to obtain dealkalized MFI zeolite. got This zeolite was pulverized to obtain H-MFI type zeolite. It was confirmed that the resulting zeolite had a Na ₂ O content of 0.05% by mass or less. Next, Pt(NH ₃ ) ₄ Cl ₂ ·xH ₂ O (manufactured by Aldrich, Pt content 55.8%) was dissolved in ion-exchanged water so that the Pt content was 1% by mass, and H-MFI type zeolite 150 was obtained. C. The supporting treatment was carried out by a wet method (incipient wetness method) so that the amount of Pt supported was 0.4% by mass relative to the dry weight. Next, air was fed at 500 ml/min into a muffle furnace whose temperature was adjusted to 300° C., and calcination was performed for 3 hours to remove Cl. The obtained powder was pressure-molded at 50 MPa, crushed, and sieved to a size of 0.5 to 1.0 mm to obtain a Pt-supported catalyst A (hereinafter referred to as catalyst A).

<Example 6>
The composition of each component of the raw material liquid (A) is SiO ₂ : Na ₂ O: TPA-Br: H ₂ O=82:3.5:7:974 in molar ratio, and the composition of each component of the raw material liquid (B) is The molar ratio of Al ₂ O ₃ : Na ₂ O: H ₂ O = 1: 1.4: 260, and the mixed gel is 2% by mass (9 g) of SiO ₂ in the raw material solution (A). Seed crystals (C) pulverized by a jet mill (particle size 0.7 μm, SiO ₂ /Al ₂ O ₃ molar ratio = 100, template-free MFI zeolite) and 299.1 g of NaOH aqueous solution (NaOH concentration: 1.9 %) was mixed and stirred for 1 hour, and the MFI-type zeolite of Example 6 was obtained in the same manner as in Example 2, except that the crystallization reaction time was changed to 48 hours.
<Preparation of Pt-supported catalyst using Example 6>
A Pt-supported catalyst B supporting 0.4% by mass of Pt (hereinafter referred to as catalyst B) was prepared in the same manner as in Comparative Example 4, except that the MFI-type zeolite of Example 6 was used.

<Example 7>
The composition of each component of the raw material liquid (A) is SiO ₂ : Na ₂ O: TPA-Br: H ₂ O=120:9.4:6:1144 in molar ratio, and the composition of each component of the raw material liquid (B) is The molar ratio of Al ₂ O ₃ : Na ₂ O: H ₂ O = 1: 1.4: 211, 414.4 g of NaOH aqueous solution (NaOH concentration: 2.2% by mass) was added to the mixed gel, and then Seed crystal (C) pulverized with a rotary jet mill equivalent to 3% by mass (7 g) of SiO ₂ in raw material liquid (A) (particle diameter 4.2 μm, SiO ₂ /Al ₂ O ₃ molar ratio = 100, template The MFI zeolite of Example 7 was obtained in the same manner as in Example 2, except that an MFI zeolite containing no MFI was added and the crystallization time was changed to 80 hours.

<Example 8>
Using the raw material liquid (A) and the raw material liquid (B) prepared by the same operation as in Example 7, the mixed gel was subjected to a swirling jet equivalent to ₃ % by mass (7 g) with respect to the SiO of the raw material liquid (A) Mill-pulverized seed crystals (C) (particle size 4.2 μm, SiO ₂ /Al ₂ O ₃ molar ratio = 100, template-free MFI zeolite) and 414.4 g of NaOH aqueous solution (NaOH concentration: 2.2 mass %) was mixed and stirred for 1 hour, and the MFI-type zeolite of Example 8 was obtained in the same manner as in Example 6, except that the crystallization time was changed to 53 hours.

For the MFI-type zeolite of the present invention, the time required for the crystallization reaction can be shortened by using seed crystals, for example, as shown in Examples 2-8. It is believed that the seed crystals act as zeolite crystal nuclei, thereby shortening the induction period for the formation of zeolite from the mixed gel. The present inventors have found that the shortening effect can be further increased by changing the unit particle size of the seed crystal and the method of addition, and have completed the present invention. For example, by comparing Examples 1, 6, 7 and 8 of the present invention, the effect of seed crystals can be verified in more detail. That is, from a comparison of Examples 1 and 7, it was found that the crystallization time was shortened by 40 hours by adding seed crystals having a unit particle size of 4.2 μm, and the addition of seed crystals shortened the crystallization reaction time. did it. From the comparison of Examples 7 and 8, the crystallization time was shortened by 27 hours by dispersing the seed crystals (C) in the alkaline aqueous solution in advance and then adding them to the mixed gel for crystallization. Furthermore, from a comparison of Examples 6 and 8, the use of seed crystals having a smaller unit particle size of 0.7 µm shortened the crystallization time by 5 hours. Further, Examples 3, 4, and 6 are production examples of the MFI-type zeolite of the present invention having a SiO ₂ /Al ₂ O ₃ molar ratio of around 70; Crystallization by adding to the mixed gel after dispersing in the aqueous solution shortened the crystallization time for 24 hours, although the amount of the seed crystal (C) added was reduced. From the above, it can be said that the smaller the unit particle diameter of the seed crystals used, and the addition of the seed crystals dispersed in the alkaline aqueous solution in advance to the mixed gel, the effect of shortening the crystallization reaction time is exhibited.

Furthermore, in order to demonstrate the excellent effects of the present invention, prepared catalysts A and B were used to perform hydroisomerization dewaxing reaction of n-paraffin. As a result, when the MFI-type zeolite (catalyst B) of the present invention was used as an acid catalyst, the presence of well-developed meso-macropores increased the contact surface with n-C14, increasing the cracking activity. In addition, it was possible to obtain an extremely high conversion rate at a low temperature compared to the ordinary MFI-type zeolite acid catalyst (catalyst A). Furthermore, in order to improve the re-addition reaction with Pt, in the hydroisomerization dewaxing reaction of n-paraffin, it was possible to obtain a higher isomer yield than the conventional MFI type zeolite. As described above, since the MFI-type zeolite of the present invention can be synthesized by normal pressure synthesis, it does not require special equipment such as a pressure vessel, and the reaction is completed in a short time, so it is not only economical. Alternatively, they exhibit excellent performance as adsorption applications, catalysts and/or catalyst supports.

Claims (10)

MFI-type zeolite having a SiO ₂ /Al ₂ O ₃ (molar ratio) of 30 or more, wherein the pore volume of macropores having a pore diameter of 30 to 200 nm is 0.34 to 0.34 in the pore distribution by mercury porosimetry. In the range of 1.0 ml / g , the pore volume of mesopores with a pore diameter of 3.6 to 30 nm in the pore distribution by the mercury intrusion method is in the range of 0.01 to 0.5 ml / g and wherein the volume ratio of the macropores to the mesopores is macropores/mesopores=2-6 . The MFI zeolite according to claim 1 , having a BET specific surface area of 300 m ² /g or more. 3. The MFI type zeolite according to claim 1, wherein the interplanar spacing (d value) of the (053) plane is 2.99 Å or less in the X-ray diffraction spectrum. A step of preparing a raw material liquid (A) in which a silica source and a template are dissolved or dispersed in water or an alkaline aqueous solution, and a raw material liquid (B) in which an alumina source is dissolved or dispersed in water or an alkaline aqueous solution;
A raw material mixing step of adding the raw material liquid (B) into the raw material liquid (A) so that the SiO ₂ /Al ₂ O ₃ (molar ratio) is 30 or more;
Aging step of maintaining the raw material mixture obtained in the raw material mixing step at an aging temperature of 60 to 95° C. and aging it to produce an aged mixed gel containing a silica source and an alumina source;
a crystallization reaction step in which the mixed gel is maintained at a crystallization temperature higher than the aging temperature of 80 to 99° C. under normal pressure to produce MFI-type zeolite;
A pore definition step in which the generated crystal is fired to eliminate the template;
A method for producing MFI-type zeolite, comprising: 5. The production method according to claim 4 , wherein in the raw material mixing step, the raw material liquid (B) is added over 20 minutes or more. 6. The production method according to claim 4 , wherein in the aging step, the raw material mixture is maintained at the aging temperature for 1 to 96 hours. The production method according to any one of claims 4 to 6 , wherein the raw material liquid (A) contains alkali silicate as part of the silica source. The production method according to any one of claims 4 to 7 , further comprising a seed crystal mixing step of adding and mixing seed crystals (C) before the crystallization reaction step. The production method according to claim 8 , wherein MFI-type zeolite is used as the seed crystal (C), and the amount of the seed crystal is 0.05 to 10 parts by mass per 100 parts by mass of SiO ₂ in the mixed gel. 10. The production method according to claim 8 or 9 , wherein the seed crystals (C) are fine particles having a single particle diameter of 10 μm or less, and the fine particles are added to the mixed gel in a state of being dispersed in an alkaline aqueous solution. .

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