JP6360808B2 - Clay mineral analysis method, quality control method, and clay mineral production method using the same - Google Patents

Description

  The present invention relates to a solid acid analysis method, a solid acid quality control method using the analysis method, and a solid acid production method using the quality control method. More specifically, the present invention uses a temperature-programmed desorption-mass spectrometry (TPD-MS) using a specific nitrogen-containing compound and infrared spectroscopy (IR), and a Bronsted acid point ( The present invention relates to a solid acid analysis method for calculating the amount and acid strength distribution of B acid point) and Lewis acid point (L acid point).

  Solid acids are widely applied in petroleum refining and organic synthesis as catalysts. For example, it is used as a catalyst for various reactions such as isomerization, nuclear alkylation, disproportionation, polymerization, depolymerization, condensation, hydration, dehydration, esterification, acetalization, amination, cracking, etc. It is known that it is actually superior in terms of not only activity and selectivity but also operability and mechanism of reaction. However, the nature and structure of active sites on solid acids and the reaction mechanism are often unclear, and the search and application of solid acid catalysts has not been rationally carried out. Therefore, in order to clarify the principle of the solid acid catalyst and to grasp the relationship between the solid acid catalyst and the developed catalyst performance, it is essential to characterize the solid acid.

  As an example of examining the acid amount and acid strength distribution of zeolite as a property of solid acid, there is a temperature programmed desorption-mass spectrometry (TPD-MS) using ammonia or pyridine as a probe molecule (non-patent) Reference 1). In addition, a Bronsted acid point (B acid point) and a Lewis acid point (L acid point) are distinguished by infrared spectroscopy (IR) using ammonia or pyridine as a probe molecule (Non-Patent Documents 2 to 4). ). In addition, studies have been conducted on the amount of acid and the distribution of acid strength while distinguishing between L acid points and B acid points by combining IR with TPD-MS as a probe molecule and IR (Patent Document 1 and non-patent document 1). Patent Documents 5 and 6).

JP 2008-292366 A

L. Froni et al. , J .; Catal. 130, 392 (1991) K. Domen et al. Phys. Chem. Chem. Phys. , 12, 11576 (2010) A. Satsuma et al. , Applied Catalysis A: General, 433-434, 135 (2012). A. Satsuma et al. , Journal of Molecular Catalysis A: Chem. , 284, 89 (2008) M.M. Niwa, K .; Suzuki, K .; Isamoto, N .; Katada, J .; Phys. Chem. B110 264 (2006) M.M. Niwa, N .; Katada, K .; Okumura, Characterization and Design of Zeolite Catalysts: Solid Acidity, Shape Selectivity and Loading Properties, Springer, Berlin (2010)

  However, when ammonia is used as a probe molecule, treatment with water vapor is required to remove physically adsorbed ammonia. Therefore, it is difficult to apply a conventional analysis method to a solid acid whose acid behavior is changed by water, and improvement has been desired.

The object of the present invention is to provide a Bronsted acid point (B acid point) and a Lewis acid point (L acid acid) in a solid acid that can be used for a solid acid whose acid behavior changes with water. It is to provide a novel analysis method for calculating the amount and the acid strength distribution.

  In order to solve the above problems, the present inventors have conducted extensive research, and as a result, conducted temperature-programmed desorption-mass spectrometry (TPD-MS) and infrared spectroscopy (IR) using specific nitrogen-containing compounds. The combined analysis has found that the amount and acid strength distribution of the Bronsted acid point (B acid point) and Lewis acid point (L acid point) in the solid acid can be calculated, and the present invention has been completed.

That is, the present invention relates to the following <1> to <8>.
<1> Analysis of Bronsted acid point and Lewis acid point in solid acid by analysis combining temperature-programmed desorption-mass spectrometry and infrared spectroscopy using a nitrogen-containing compound having an acid dissociation constant of 9.0 or less The solid acid analysis method calculates the amount and acid strength distribution.
<2> The solid acid analysis method according to <1>, wherein the solid acid is a clay mineral, zeolite, or composite oxide.
<3> In the measurement by the temperature programmed desorption-mass spectrometry and the infrared spectroscopy, a vacuum treatment is performed to remove the nitrogen-containing compound physically adsorbed on the solid acid. 2> The solid acid analysis method according to 2>.
<4> In the infrared spectroscopy, the ratio between the Bronsted acid point and the Lewis acid point is determined from the position and intensity ratio of the absorption band due to stretching vibration of the nitrogen-containing compound adsorbed on the acid point of the solid acid. The method for analyzing a solid acid according to any one of <1> to <3>.
<5> The method for analyzing a solid acid according to any one of <1> to <4>, wherein the nitrogen-containing compound is a nitrogen-containing heterocyclic compound.
<6> The method for analyzing a solid acid according to any one of <1> to <5>, wherein the nitrogen-containing compound is a pyridine compound.
<7> The amount and acid strength distribution of Bronsted acid point and Lewis acid point in the solid acid calculated by the solid acid analysis method according to any one of <1> to <6> are used. , Quality control method of solid acid.
<8> Production of solid acid having a desired Bronsted acid point and Lewis acid point amount and acid strength distribution, comprising the solid acid quality control method according to <7> above in a production process Method.

According to the solid acid analysis method of the present invention, the amount and acid strength distribution of Bronsted acid point (B acid point) and Lewis acid point (L acid point) in the solid acid can be calculated, and the catalyst of the solid acid catalyst Characterization of the solid acid to unravel the action is possible.
Also, the quality control of the solid acid using the amount and acid strength distribution of Bronsted acid point (B acid point) and Lewis acid point (L acid point) in the solid acid calculated by the solid acid analysis method Is possible. Therefore, by adding the quality control method to the solid acid production process, it is possible to produce a solid acid in which the quality with respect to the amount and acid strength distribution of Bronsted acid points and Lewis acid points is guaranteed.

It is a TPD-MS spectrum which made pyridine adsorb | suck to the chemically-processed montmorillonite concerning Example 1. FIG. It is a figure showing the total acid amount and acid intensity distribution of the chemical processing montmorillonite concerning Example 1. FIG. It is a figure showing the L acid ratio in each temperature of the chemically-processed montmorillonite concerning Example 1. FIG. It is a figure showing the amount of Bronsted acids, the amount of Lewis acids, and acid intensity distribution of the chemically treated montmorillonite according to Example 1. 2 is a TPD-MS spectrum in which pyridine is adsorbed on an organoaluminum-treated montmorillonite according to Example 2. It is a figure showing the amount of Bronsted acids, the amount of Lewis acids, and acid strength distribution of the organoaluminum processing montmorillonite concerning Example 2. FIG. 4 is a TPD-MS spectrum in which ammonia is adsorbed on the organoaluminum-treated montmorillonite according to Comparative Example 1.

  Hereinafter, the method for calculating the amount and acid strength distribution of the Bronsted acid point (B acid point) and the Lewis acid point (L acid point) in the solid acid of the present invention will be described in detail for each item.

1. Solid acid The solid acid used in the present invention exhibits the characteristics of Brested acid and / or Lewis acid while being solid, and exhibits a catalytic action due to its acidity.
Specific solid acids include zeolites, metal oxides, inorganic oxides (composite oxides) such as metal oxides having multiple metal elements, metal sulfates, metal phosphates, solid phosphoric acid, cation exchange Resins, heteropoly acids, clay minerals and the like can be mentioned. These elements have different acid strength, acid amount, and acid type depending on the surface state.

More specifically, as the solid acid, Al ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , SiO ₂ —TiO ₂ , SiO ₂ —MgO, SiO ₂ —Al ₂ O ₃ , SiO ₂ —ZrO ₂ , SiO ₂ — _{BeO, SiO 2 -Y 2 O 3} , SiO 2 -La 2 O 3, SiO-WO 3, SiO 2 -V 2 O 5, SiO 2 -Ga 2 O 3, SiO 2 -MoO 3, Al 2 O 3 - _{ZrO 2, Al 2 O 3 -Bi} 2 O 3, Al 2 O 3 -MoO 3, Al 2 O 3 -V 2 O 5, Al 2 O 3 -WO 3, Cr 2 O 3 -Al 2 O 3, TiO _2- Al ₂ O ₃ , TiO ₂ —SiO ₂ , TiO ₂ —ZrO ₂ , ZnO—Al ₂ O ₃ , H—Y, La—Y, Ca—Y, heteropolyacid, clay mineral, NiSO ₄ .H ₂ O , _Al 2 (SO _{4 3 · nH 2 O, Fe 2} (SO 4) 3 · nH 2 O, BPO 4, FePO 4, TiO 2 -B 2 O 3, TiO 2 -SnO 2, ZnOSiO 2, ZnO-ZrO 2, WO 3 -TiO ₂ , solidified boric acid, solidified sulfuric acid, solidified phosphoric acid and the like.
Among solid acids, clay minerals, zeolites, SiO ₂ -Al ₂ O ₃ , composite oxides combining SiO ₂ and other metals, Al ₂ O ₃ , composite oxides combining Al ₂ O ₃ and other metals , And composite oxides in which ZnO ₂ and other metals are combined are preferable. Among them, clay minerals are more preferable because they can exhibit the effects of the present invention because the acid behavior may be changed by water.

These solid acids may be solid acids obtained by treatment with an organoaluminum compound.
Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctylaluminum, trinormaldecylaluminum, diethylaluminum chloride, diethylaluminum. Examples thereof include sesquichloride, diethylaluminum hydride, diethylaluminum ethoxide, diethylaluminum dimethylamide, diisobutylaluminum hydride, and diisobutylaluminum chloride.
Of these, triethylaluminum, triisobutylaluminum, and trinormaloctylaluminum are preferable.
In particular, a solid acid obtained by treatment with an organoaluminum compound often exhibits a large change in acid behavior due to water, and thus the effects of the present invention can be further exhibited.

1-1. Clay Mineral As a clay mineral that can be used as a solid acid, a synthetic product or a naturally occurring mineral may be used.
Specific examples of clay minerals include allophanes such as allophane, kaolins such as dickite, nacrite, kaolinite, and anokisite, halloysites such as metahalloysite and halloysite, and serpentine groups such as chrysotile, lizardite, and antigolite. , Montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite and other smectites, vermiculite and other vermiculite minerals, illite, sericite and sea chlorite and other mica minerals, attapulgite, sepiolite, pigolite, bentonite and xylem clay , Gyrome clay, hysingelite, pyrophyllite, ryokdeite group. These may form a mixed layer.
Examples of the artificial compound include synthetic mica, synthetic hectorite, synthetic saponite, and synthetic teniolite.

  Of these specific examples, preferably, montmorillonite, sauconite, beidellite, nontronite, saponite, mucite minerals such as hectorite, illite, sericite, sea chlorite, synthetic mica, synthetic hectorite, synthetic saponite. Synthetic teniolites, and more preferably smectite groups such as montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite and the like.

These clay minerals may be used as they are, but acid treatment with hydrochloric acid, nitric acid, sulfuric acid, etc. and / or LiCl, NaCl, KCl, CaCl ₂ , MgCl ₂ , Li ₂ SO ₄ , MgSO ₄ , ZnSO ₄ , Ti _{(SO 4) 2, Zr (} SO 4) 2, Al 2 (SO 4) may be subjected to salt treatment such as _3. In the treatment, the corresponding acid and base may be mixed to produce a salt in the reaction system, and the treatment may be performed, or shape control such as pulverization and granulation and drying treatment may be performed.

  The acid treatment has an effect of eluting a part of the components from the clay mineral. Further, the salt treatment has an effect of ion exchange and an effect of changing the swellability of the ion exchange layered silicate. As a result, by selecting the conditions for acid treatment and / or salt treatment, the acid properties of the clay mineral, the surface area of the particles, and the pore volume can be controlled.

2. Nitrogen-containing compound The nitrogen-containing compound used in the present invention has an acid dissociation constant (pKa) of 9.0 or less. If the pKa is higher than this, the adsorption force to the surface of the solid acid becomes stronger, and the excessively physically adsorbed nitrogen-containing compound cannot be removed by vacuum treatment, and accurate measurement cannot be performed. . That is, ammonia having a high pKa (pKa = 9.4) can remove nitrogen-containing compounds physically adsorbed by steam treatment, but cannot be used for solid acids that are reactive with water. .
The nitrogen-containing compound used in the present invention has a pKa of 9.0 or less, preferably 8.0 or less, more preferably 7.5 or less. Further, the lower limit of pKa is preferably 0 or more.

Nitrogen-containing compounds having an acid dissociation constant (pKa) of 9.0 or less include nitrogen-containing heterocyclic compounds such as pyrrole compounds, pyridine compounds and quinoline compounds; primary amines such as aniline compounds and naphthylamine compounds A compound can be mentioned.
Specifically, pyrrole compounds such as pyrrole, 2-methylpyrrole, 2-ethylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole; pyridine, 2-methyl Pyridine, 2-ethylpyridine, 3-methylpyridine, 3-ethylpyridine, 4-methylpyridine, 4-ethylpyridine, 4-propylpyridine, 4-t-butylpyridine, 2,3-dimethylpyridine, 2,4- Dimethylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, 3,4-dimethylpyridine, 3,5-dimethylpyridine, 2,5-di-t-butylpyridine, 2,6-di-t- Pyridine compounds such as butylpyridine and 2,4,6-trimethylpyridine; quinoline, 2-methylquinoline, 3-methylxyl Quinoline compounds such as phosphorus, 4-methylquinoline, 6-methylquinoline, 7-methylquinoline, 8-methylquinoline, 2,4-dimethylquinoline, 2,6-dimethylquinoline, 4,6,8-trimethylquinoline; Aniline, 2-methylaniline, 2-ethylaniline, 3-methylaniline, 3-ethylaniline, 4-methylaniline, 4-ethylaniline, 4-propylaniline, 4-t-butylaniline, 2,3-dimethylaniline Aniline compounds such as 2,4-dimethylaniline, 2,5-dimethylaniline, 3,4-dimethylaniline, 2,5-di-t-butylaniline, 2,4,6-trimethylaniline; 1-naphthylamine And naphthylamine compounds such as 2-methyl-1-naphthylamine.

  Among these, nitrogen-containing heterocyclic compounds are preferable from the viewpoint of adsorbing only at acid sites as described above, and quinoline compounds and pyridine compounds are particularly preferable. More preferred are quinoline, 4-methylquinoline, pyridine, 3,5-dimethylpyridine, 2,6-dimethylpyridine, and 2,6-di-t-butylpyridine. These nitrogen-containing compounds can be used not only alone but also in combination with a plurality of compounds.

The pKa of typical compounds among the nitrogen-containing compounds exemplified above is shown in parentheses below.
Pyrrole (0.4), pyridine (5.3), 2-methylpyridine (5.9), 3-methylpyridine (5.7), 3-ethylpyridine, 4-methylpyridine (6.0), 2 , 3-dimethylpyridine (6.6), 2,4-dimethylpyridine (6.7), 2,5-dimethylpyridine (6.5), 2,6-dimethylpyridine (6.8), 3,4 -Dimethylpyridine (6.5), 3,5-dimethylpyridine (6.1), 2,6-di-t-butylpyridine (3.6), 2,4,6-trimethylpyridine (7.5) Quinoline (4.9), 2-methylquinoline (5.4), 3-methylquinoline (5.1), 4-methylquinoline (5.2), 6-methylquinoline (4.9), 7- Methylquinoline (5.1), 8-methylquinoline (4.6), aniline (4.6) , 2-methylaniline (4.4), 3-methylaniline (4.7), 4-methyl aniline (5.1), 1-naphthylamine (3.9).

3. Thermal desorption-mass spectrometry (TPD-MS)
Thermal desorption-mass spectrometry (TPD-MS) used in the present invention is desorption caused by adsorbing a nitrogen-containing compound on the acid point of a solid acid and continuously raising the temperature of the sample layer. This is a method for measuring a nitrogen-containing compound gas. The amount of acid can be determined by measuring the amount of nitrogen-containing compound gas that is desorbed. Further, since the nitrogen-containing compound adsorbed at the weak acid point is desorbed at a low temperature and the nitrogen-containing compound adsorbed at a strong acid point is desorbed at a high temperature, the acid strength distribution can be obtained. In order to remove excess water in the solid acid before the measurement, a drying process may be performed. As drying conditions, the degree of vacuum is preferably 1.0 torr abs or less, and particularly preferably 0.5 torr abs or less. The drying temperature is preferably 0 to 1000 ° C, particularly preferably 0 to 600 ° C. The drying time is preferably 30 to 360 minutes, particularly preferably 30 to 240 minutes.

The adsorption of the nitrogen-containing compound to the acid sites of the solid acid can be performed by contacting the nitrogen-containing compound with a gas. Further, the nitrogen-containing compound gas may contain an inert gas that does not adsorb to the acid sites, and the concentration of the nitrogen-containing compound gas is preferably 5 mol% or more, particularly preferably 50 mol% or more. Further, when adsorbing a liquid nitrogen-containing compound to the acid point of the solid acid, a measuring device including a liquid reservoir is used. By putting a nitrogen-containing compound into the liquid reservoir and reducing the pressure in the system, a nitrogen-containing compound vapor can be generated and brought into contact with the acid point of the solid acid.
The longer the adsorption time is, the longer the nitrogen-containing compound is adsorbed at all acid sites. Specifically, it is preferably 10 minutes or more, particularly preferably 30 minutes or more. The adsorption temperature is preferably -100 to 500 ° C, particularly preferably 0 to 300 ° C.

In order to remove the nitrogen-containing compound physically adsorbed at a position other than the acid point of the solid acid, it is preferable to remove by a vacuum treatment. The degree of vacuum in the vacuum treatment is preferably 1.0 torr abs or less, and particularly preferably 0.5 torr abs or less. Moreover, as removal temperature, 0-300 degreeC is preferable and 0-200 degreeC is especially preferable. The removal time is preferably from 30 to 360 minutes, particularly preferably from 30 to 240 minutes.
Even if not all the physical adsorption can be removed by vacuum treatment, the nitrogen-containing compound used in the present invention has a small acid dissociation constant (pKa), and the physical adsorption force is much higher than the adsorption force to the acid sites. Since each peak of TPD-MS is observed at a completely different position, it is easy to separate the peaks. However, when a nitrogen-containing compound higher than the acid dissociation constant (pKa) described in the present invention is used, the physical adsorption and the adsorption power to the acid point are close, and the respective peaks of TPD-MS overlap. Therefore, peak separation is difficult.

  The measurement temperature is preferably −100 to 1000 ° C., particularly preferably 0 to 1000 ° C. The temperature rising rate is preferably 1 to 30 ° C./min, and particularly preferably 5 to 20 ° C./min. The measurement atmosphere is preferably an inert gas such as helium, argon or nitrogen, and helium is particularly preferred.

4). Infrared spectroscopy (IR)
There are two types of acid sites with different properties in solid acids. One is a Bronsted acid point (B acid point) that gives protons to the partner molecule, and the other is a Lewis acid point (L acid point) that accepts an electron pair from the partner molecule. Infrared spectroscopy (IR) used in the present invention is a method in which a nitrogen-containing compound is adsorbed at each of the L acid point and the B acid point, and these acid points are distinguished by the difference in the position of the absorption band due to stretching vibration. is there.
For example, a case where pyridine is used as the nitrogen-containing compound will be described. Pyridine when adsorbed to B acid sites becomes pyridinium ion, absorption bands of C-N stretching vibration by IR is observed near 1500 cm ^-1 and 1540 cm ^-1. The pyridine is a coordination bond with pyridine to adsorb the L acid sites, the absorption band of the C-N stretching vibration by IR is observed near 1450 cm ^-1 and 1500 cm ^-1. Molar extinction coefficient of each of the absorption band (epsilon), the non-patent document 3 than ^{1.73 (1450cm -1), 1.46 (} 1490cm -1), are known and 1.23 (1545 cm ^-1), The ratio of B acid point to L acid point can be determined from the intensity ratio of the absorption band. Moreover, the temperature dependence of the ratio of B acid point and L acid point can be calculated | required by changing measurement temperature.

  As the measurement of IR, a drying treatment may be performed in order to remove excess moisture in the solid acid before the measurement. As drying conditions, the degree of vacuum is preferably 1.0 torr abs or less, and particularly preferably 0.5 torr abs or less. Moreover, as drying temperature, 10-1000 degreeC is preferable, and 10-600 degreeC is especially preferable. The drying time is preferably 30 to 360 minutes, particularly preferably 30 to 240 minutes.

The adsorption of the nitrogen-containing compound to the acid sites of the solid acid can be performed by contacting the nitrogen-containing compound with a gas. Further, the nitrogen-containing compound gas may contain an inert gas that does not adsorb to the acid sites, and the concentration of the nitrogen-containing compound gas is preferably 5 mol% or more, particularly preferably 50 mol% or more. Further, when adsorbing the liquid nitrogen-containing compound to the acid point of the solid acid, a method of bubbling the nitrogen-containing compound with a flow gas and bringing the nitrogen-containing compound gas into contact with the flow gas can be employed. As the flow gas, an inert gas such as helium, argon or nitrogen is preferable, and helium is particularly preferable. The speed of the flow gas is preferably 10 to 200 mL / min, and particularly preferably 20 to 150 mL / min.
The longer the contact time, the better, because the nitrogen-containing compound is adsorbed at all acid sites. Specifically, it is preferably 1 minute or longer, particularly preferably 5 minutes or longer. The contact temperature is preferably 10 to 500 ° C, particularly preferably 10 to 300 ° C.

  In order to remove the nitrogen-containing compound physically adsorbed at a position other than the acid point of the solid acid, it is preferable to remove by a vacuum treatment. The degree of vacuum in the vacuum treatment is preferably 1.0 torr abs or less, and particularly preferably 0.5 torr abs or less. The removal temperature is preferably 10 to 300 ° C, particularly preferably 10 to 200 ° C. The removal time is preferably from 30 to 360 minutes, particularly preferably from 30 to 240 minutes.

  As measurement temperature, 10-1000 degreeC is preferable, and 10-800 degreeC is especially preferable. The temperature rising rate is preferably 1 to 30 ° C./min, and particularly preferably 5 to 20 ° C./min. The holding time after the temperature rise is preferably 1 to 30 minutes, particularly preferably 5 to 20 minutes.

5). Combination of thermal desorption-mass spectrometry (TPD-MS) and infrared spectroscopy (IR) Bronsted acid point (B acid point) and Lewis acid point (L acid point) in the solid acid calculated in the present invention The amount and acid strength distribution can be achieved by combining thermal desorption-mass spectrometry (TPD-MS) and infrared spectroscopy (IR). As described above, temperature desorption-mass spectrometry (TPD-MS) can determine acid amount and acid strength distribution, and infrared spectroscopy (IR) can determine Bronsted acid point (B acid point) and Lewis acid point. The ratio of (L acid point) can be determined. By dividing the acid amount of TPD-MS into the ratio of B acid point and L acid point of IR for each temperature, Bronsted acid point (B acid point) and Lewis acid point (L acid point) at each temperature The amount and acid strength distribution can be calculated.
In addition, when there is a difference in measurement temperature between measuring instruments, it is possible to correct the temperature by regarding the same desorption rate of the nitrogen-containing compound as the same temperature.
The TPD-MS and IR measurements may be performed continuously with the same apparatus or separately.

  Further, as described in detail in “2. Nitrogen-containing compound”, when TPD-MS measurement or IR measurement is performed without completely removing the nitrogen-containing compound physically adsorbed on the solid acid, Since the peak derived from is detected, the acid amount and acid strength distribution of a solid acid cannot be calculated | required correctly. For this reason, steam treatment has been conventionally performed. However, in the case of a solid acid whose acid behavior is changed by water, the steam treatment cannot be performed to remove the physically adsorbed nitrogen-containing compound. For solid acids whose acid behavior changes with water, it is possible to remove the nitrogen-containing compounds physically adsorbed by vacuum treatment instead of steam treatment, but vacuum treatment is more effective than nitrogen treatment. Since the removing ability is low, the nitrogen-containing compound may not be completely removed. Therefore, in the analysis method according to the present invention, by determining the upper limit of the pKa of the nitrogen-containing compound to be adsorbed on the solid acid, it is possible to sufficiently remove the nitrogen-containing compound that has been physically adsorbed even in vacuum treatment. Thus, the amount and acid strength distribution of B acid point and L acid point in the solid acid can be accurately calculated by TPD-MS and IR.

6). Quality control method of solid acid In the solid acid, the Bronsted acid point and the Lewis acid point exist where the crystal structure of the solid acid is disturbed. When a solid acid is used as a catalyst, it can be said that the acid point is an important factor for determining the catalyst activity because the acid point becomes an active point and exhibits catalytic activity. Therefore, knowing the amount of each acid point and the acid strength distribution is very important for knowing the activity of the solid acid catalyst.
Therefore, by using the analysis method according to the present invention for the solid acid, the solid acid using the amount and acid strength distribution of the Bronsted acid point and the Lewis acid point in the solid acid calculated by the analysis method is used. Quality control is possible. By controlling the quality of the solid acid, the quality of the solid acid as a catalyst can be guaranteed, or the catalytic activity can be quantitatively evaluated.

7). Production method of solid acid By including the “6. Quality control method of solid acid” according to the present invention in the production process of solid acid, the amount and acid strength distribution of desired Bronsted acid points and Lewis acid points are obtained. Solid acids can be produced. That is, when a solid acid is used as a catalyst, it is possible to produce a solid acid having a desired catalytic activity through the quality control step of the solid acid.

The present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.
[Example 1]
<Method for preparing solid acid>
Chemical treatment of ion-exchange layered silicate:
In a separable flask, 96% sulfuric acid (668 g) was added to 2264 g of distilled water, and then 400 g of montmorillonite (Mizusawa Chemical Benclay SL: average particle size 19 μm) was added as a layered silicate. The slurry was heated at 90 ° C. for 210 minutes. The reaction slurry was added to 4000 g of distilled water and then filtered to obtain 810 g of a cake-like solid.
The obtained solid was preliminarily dried overnight at 100 ° C. under a nitrogen stream, and then coarse particles of 53 μm or more were removed and further dried under reduced pressure at 200 ° C. for 2 hours to obtain 220 g of chemically treated montmorillonite.
The composition of this chemically treated montmorillonite is Al: 6.45 wt%, Si: 38.30 wt%, Mg: 0.98 wt%, Fe: 1.88 wt%, and Al / Si = 0.175 [ mol / mol].

<Temperature desorption-mass spectrometry (TPD-MS)>
100 mg of the chemically treated montmorillonite, which was a solid acid obtained above, was weighed in a high-purity nitrogen glove box and filled into a cell. Subsequently, the cell was taken out from the high purity nitrogen glove box and installed in the TPD-MS measuring apparatus. After reducing the pressure in the cell to 5 × 10 ⁻² torr abs, the temperature was raised to 200 ° C. and maintained for 1 hour to remove adsorbed water. The temperature was lowered to 150 ° C. under reduced pressure, pyridine vapor was introduced and held for 1 hour, and adsorbed on the solid acid. The pressure was further reduced to 5 × 10 ⁻² torr abs at 150 ° C., and vacuum treatment was performed for 1 hour to remove physically adsorbed pyridine. Thereafter, the temperature was raised, the desorption behavior of pyridine was measured, and the acid amount and acid strength distribution were determined.

The measurement conditions are as follows.
Device: Nippon Bell Co., Ltd. Fully automatic temperature programmed desorption spectrometer TPD-1-ATw
Measurement mode:
Temperature rising rate 10 ° C / min Measuring temperature 150-810 ° C
Atmosphere: Helium flow (50 mL / min)
Uptake MASS No. : 79
Adsorption species: pyridine, pKa = 5.3

  The measurement result of the TPD-MS spectrum in which pyridine was adsorbed on chemically treated montmorillonite is shown in FIG. Further, FIG. 2 shows the total acid amount and the acid strength distribution of the chemically treated montmorillonite converted into an acid amount by converting the TPD-MS spectrum into an integrated form from the high temperature side.

<Infrared spectroscopy (IR)>
The chemically treated montmorillonite, which is a solid acid obtained as described above, was filled in a sample cup for diffuse reflection IR in a high-purity nitrogen glove box, and the surface was ground. The sample chamber was sealed with a lid with a window material (CaF ₂ ). The sample cup was then removed from the high purity nitrogen glove box and placed in an IR measuring device. After reducing the pressure in the sample chamber to 5 × 10 ⁻² torr abs, the temperature was raised to 200 ° C. and held for 2 hours to remove adsorbed water. The temperature was lowered to 150 ° C. under reduced pressure, and pyridine vapor was circulated for 10 minutes under a helium flow (50 mL / min) to be adsorbed on the solid acid. The pressure was further reduced to 5 × 10 ⁻² torr abs at 150 ° C., and vacuum treatment was performed for 1 hour to remove physically adsorbed pyridine. Thereafter, the temperature was raised to desorb pyridine, and the ratio of B acid point to L acid point at each temperature was determined.

The measurement conditions are as follows.
Apparatus: JASCO Corporation FT / IR-6200FV
Detector: MCT-M
Photometric method: Diffuse reflection method Wavelength range: 1000 to 4000 cm ⁻¹
Resolution: 4 times Measurement count: 512 times Window material: CaF ₂
Atmosphere: Vacuum background: Diamond powder adsorbed species measured at each temperature: pyridine, pKa = 5.3
Temperature: every 50 ° C., molar extinction coefficient (ε): 1.73 (1450 cm ⁻¹ ) until no peak is detected
1.46 (1490 cm ⁻¹ )
1.23 (1545 cm ⁻¹ )

Pyridine From the measurement results of IR spectrum was adsorbed to the chemically treated montmorillonite ^shows 1450 cm -1, the peak intensity of each temperature in 1545 cm ^-1 and 1490cm ^-1 in Table 1. Further, using the absorption band of 1490cm ^-1 (B acid sites + L acid sites) and 1545 cm ^-1 (B acid sites) to the analysis of the ratio of B acid sites and L acid sites, chemical treatment obtained from the integral value of the absorption band The L acid ratio at each temperature of montmorillonite is shown in FIG.

<Combination of TPD-MS and IR>
Considering the difference between the TPD-MS and IR measurement temperatures, the analysis was performed assuming that the same temperature was taken when the pyridine desorption rates were the same. The analysis temperature was unified with the temperature of TPD-MS. The amount and acid strength distribution of Bronsted acid and Lewis acid at each temperature of chemically treated montmorillonite were determined by allocating the total acid amount of TPD-MS to the L acid amount and B acid amount from the ratio obtained by IR. . The results are shown in FIG.

[Example 2]
<Method for preparing solid acid>
In a separable flask, 280 g of distilled water was added to 100 g of montmorillonite subjected to the chemical treatment obtained in <Preparation Method of Solid Acid> in Example 1 to form a slurry, and 138 g of lithium sulfate and 200 g of distilled water were added thereto. An aqueous solution was added. The slurry was reacted at room temperature for 120 minutes. 1 L of distilled water was added to the slurry, followed by filtration, further washing with distilled water to pH 5-6, and filtration. As a result, 300 g of a cake-like solid was obtained.
The obtained solid was preliminarily dried overnight at 100 ° C. under a nitrogen stream, and then coarse particles having a size of 53 μm or more were removed and further dried under reduced pressure at 200 ° C. for 2 hours to obtain 70 g of chemically treated montmorillonite. The Li content contained in this chemically treated montmorillonite was 0.16% by weight.
Into a three-necked flask (volume: 1 L), 10 g of the montmorillonite subjected to the chemical treatment obtained above was put, and heptane (66 mL) was added to form a slurry. The solution was added with 34.0 mL), stirred for 1 hour, washed with heptane until the residual liquid ratio became 1/100, and further dried under reduced pressure at 200 ° C. for 2 hours to obtain an organoaluminum-treated montmorillonite.

<Temperature desorption-mass spectrometry (TPD-MS)>
100 mg of the organoaluminum-treated montmorillonite, which was a solid acid obtained above, was weighed in a high-purity nitrogen glove box and filled into a cell. Subsequently, the cell was taken out from the high purity nitrogen glove box and installed in the TPD-MS measuring apparatus. The pressure inside the cell was reduced to 5 × 10 ⁻² torr abs, and then kept at room temperature for 2 hours to remove adsorbed water. While maintaining the vacuum at room temperature, pyridine vapor was introduced and held for 1 hour, and adsorbed on the solid acid. The pressure was further reduced to 5 × 10 ⁻² torr abs at room temperature, and vacuum treatment was performed for 1 hour to remove physically adsorbed pyridine. Thereafter, the temperature was raised, the desorption behavior of pyridine was measured, and the acid amount and acid strength distribution were determined.

The measurement conditions are as follows.
Device: Nippon Bell Co., Ltd. Fully automatic temperature programmed desorption spectrometer TPD-1-ATw
Measurement mode:
Temperature rising rate 10 ° C / min Measuring temperature Room temperature to 810 ° C
Atmosphere: Helium flow (50 mL / min)
Uptake MASS No. : 79
Adsorption species: pyridine, pKa = 5.3

  FIG. 5 shows the results of TPD-MS spectrum measurement in which pyridine was adsorbed on organoaluminum-treated montmorillonite.

<Infrared spectroscopy (IR)>
The organoaluminum-treated montmorillonite, which is a solid acid obtained above, was filled in a sample cup for diffuse reflection IR in a high-purity nitrogen glove box, and the surface was ground. The sample chamber was sealed with a lid with a window material (CaF ₂ ). The sample cup was then removed from the high purity nitrogen glove box and placed in an IR measuring device. The sample chamber was depressurized to 5 × 10 ⁻² torr abs and then kept at room temperature for 2 hours to remove adsorbed water. With reduced pressure, pyridine vapor was allowed to flow for 10 minutes under a helium flow (50 mL / min) and adsorbed to the solid acid. Further, the pressure was reduced to 5 × 10 ⁻² torr abs at room temperature, and vacuum treatment was performed for 1 hour to remove physically adsorbed pyridine. Thereafter, the temperature was raised to desorb pyridine, and the ratio of B acid point to L acid point at each temperature was determined.

The measurement conditions are as follows.
Apparatus: JASCO Corporation FT / IR-6200FV
Detector: MCT-M
Photometric method: Diffuse reflection method Wavelength range: 1000 to 4000 cm ⁻¹
Resolution: 4 times Measurement count: 512 times Window material: CaF ₂
Atmosphere: Vacuum background: Diamond powder adsorbed species measured at each temperature: pyridine, pKa = 5.3
Temperature: every 50 ° C., molar extinction coefficient (ε): 1.73 (1450 cm ⁻¹ ) until no peak is detected
1.46 (1490 cm ⁻¹ )
1.23 (1545 cm ⁻¹ )

  Based on the result of TPD-MS and IR, it analyzed similarly to Example 1, and calculated | required the quantity and acid strength distribution of Bronsted acid and Lewis acid in each temperature of organoaluminum processing montmorillonite. The results are shown in FIG.

[Specific application example 1]
Using organoaluminum-treated montmorillonite obtained in <Preparation Method of Solid Acid> in Example 2 and using ammonia (pKa = 9.4) instead of pyridine (pKa = 5.3), temperature programmed desorption- The acid amount and the acid strength distribution were calculated by mass spectrometry (TPD-MS).

<Temperature desorption-mass spectrometry (TPD-MS)>
60 mg of the organoaluminum-treated montmorillonite, which was a solid acid obtained above, was weighed in a high-purity nitrogen glove box and filled into a cell. Subsequently, the cell was taken out from the high purity nitrogen glove box and installed in the TPD-MS measuring apparatus. The pressure inside the cell was reduced to 5 × 10 ⁻² torr abs, and then kept at room temperature for 2 hours to remove adsorbed water. While maintaining the reduced pressure at room temperature, ammonia / helium vapor (ammonia 5%) was introduced and held for 1 hour, and adsorbed on the solid acid. The pressure was further reduced to 5 × 10 ⁻² torr abs at room temperature, and vacuum treatment was performed for 1 hour. Thereafter, the temperature was raised, the desorption behavior of ammonia was measured, and the acid amount and the acid strength distribution were obtained.

The measurement conditions are as follows.
Device: Nippon Bell Co., Ltd. Fully automatic temperature programmed desorption spectrometer TPD-1-ATw
Measurement mode:
Temperature rising rate 10 ° C / min Measuring temperature Room temperature to 610 ° C
Atmosphere: Helium flow (50 mL / min)
Uptake MASS No. : 16
Adsorption species: ammonia, pKa = 9.4

  FIG. 7 shows the results of TPD-MS spectrum measurement in which ammonia was adsorbed on organoaluminum-treated montmorillonite.

  FIG. 4 of Example 1 and FIG. 6 of Example 2 are the results of determining the amount and acid strength distribution of Bronsted acid and Lewis acid at each temperature from the results of TPD-MS and IR. The amounts of B acid and L acid exceeding the strength (desorption temperature) are extracted and summarized in Table 2. Thus, according to the analysis method of the present invention, the amount and acid strength distribution of B acid and L acid in the solid acid at each temperature can be obtained.

Further, by comparing Example 2 with Comparative Example 1, also in montmorillonite treated with organoaluminum, which is a solid acid whose acid behavior is changed by water, Bronsted acid point (B acid point) and Lewis acid point in the solid acid It can be seen that the amount and acid strength distribution of (L acid point) can be calculated.
That is, Example 2 is an example in which an organic aluminum-treated montmorillonite was subjected to acid point analysis using pyridine having a pKa = 5.3, but the amount and acid of Bronsted acid and Lewis acid were determined by the method of the present invention. The intensity distribution could be obtained.
On the other hand, as shown in Comparative Example 1, the same organoaluminum-treated montmorillonite as in Example 2 was subjected to TPD-MS measurement using pKa = 9.4 ammonia as the nitrogen-containing compound. As is apparent from the spectrum, a peak exists around 180 ° C. In the vacuum treatment, the weakly physically adsorbed ammonia on the low temperature side has not been removed, so the peak around 180 ° C. exists, and the peak is diverged. Even if analysis is performed with physical adsorption remaining, it is impossible to accurately determine the amount of Bronsted acid and Lewis acid and the acid strength distribution. When ammonia is used as the nitrogen-containing compound, it is generally possible to remove physical adsorption by steam treatment, but for solid acids that react with water, such as montmorillonite treated with organoaluminum, the method is Cannot be used. Therefore, this example is an excellent evaluation method compared to the comparative example, and can be said to be an especially excellent evaluation method in the case of a solid acid that reacts with water and changes its acid behavior.

Claims (7)

The amount of Bronsted acid point and Lewis acid point in the clay mineral was determined by analysis combining thermal desorption-mass spectrometry using a nitrogen-containing compound having an acid dissociation constant of 9.0 or less and infrared spectroscopy. An analytical method for clay minerals that calculates the acid strength distribution. The Atsushi Nobori - in the measurement of mass spectrometry and the infrared spectroscopy, in order to remove the nitrogen-containing compound physically adsorbed on the clay mineral, the clay minerals according to claim 1, implementing a vacuum treatment Analysis method. In the infrared spectroscopy, the position and the intensity ratio of the absorption band due to stretching vibration of the nitrogen-containing compound adsorbed to the acid sites of the clay mineral, claim determining the ratio of the Bronsted acid sites and the Lewis acid point 1 or 2. The method for analyzing clay minerals according to 2 . The method for analyzing a clay mineral according to any one of claims 1 to 3 , wherein the nitrogen-containing compound is a nitrogen-containing heterocyclic compound. The method for analyzing a clay mineral according to any one of claims 1 to 4 , wherein the nitrogen-containing compound is a pyridine compound. The quality of clay minerals using the amount and acid strength distribution of Bronsted acid points and Lewis acid points in the clay minerals calculated by the method for analyzing clay minerals according to any one of claims 1 to 5. Management method. A method for producing a clay mineral having a desired Bronsted acid point and Lewis acid point amount and strength distribution, wherein the production process includes the clay mineral quality control method according to claim 6 .

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