JP5418481B2 - New FAU type metalloaluminosilicate - Google Patents

Description

  The present invention relates to a novel FAU type metalloaluminosilicate. The present invention also relates to a novel method for introducing metal into the framework of FAU-type zeolites.

  Today, zeolites are used in a wide range of applications in the petroleum refining, petrochemical, and environmental purification fields due to their solid acid properties and unique catalytic and adsorption properties derived from molecular size pores.

  Zeolite is a crystalline condensed aluminosilicate having a crystal skeleton composed of aluminum, silicon, and oxygen in a narrow sense, and the solid acid characteristics differ depending on the crystal structure and the aluminum content. Metalloaluminosilicates that contain other metal species such as Ga, Fe, and Ti instead of aluminum or silicon in the zeolite framework for the purpose of modifying the solid acid properties since the 1980s, or metallosilicates that do not contain aluminum, and silica only Those having a zeolite crystal structure are synthesized.

  The crystalline zeolite referred to in the present invention refers to the above-mentioned metallosilicate, metalloaluminosilicate, and crystalline silicate having a zeolite structure in addition to zeolite in a narrow sense.

  As a method for producing crystalline zeolites, a method in which an aqueous mixture mainly composed of an aluminum source, a silicon source, a metal source, and an alkali is crystallized by a hydrothermal reaction, that is, a hydrothermal synthesis method is generally used in the industry. It is. For example, Patent Document 1 reports BEA type metallosilicates and metalloaluminosilicates having a metal (Al, Cr, Fe, or La) / Si molar ratio of 0.08 or less. Patent Document 2 reports a MOR type titanoaluminosilicate having a Ti / Si molar ratio of 0.2 or less and a Si / Al molar ratio of 10 to 42. Patent Document 3 reports a MOR type ferro (alumino) silicate having an Fe / Si molar ratio of 0/0014 to 0.4 and an Si / Al molar ratio of 5.4 to infinity.

  On the other hand, there is also known a method of introducing a metal into a skeleton by treating a once synthesized zeolite with a metal salt aqueous solution treatment in a liquid phase or a metal salt vapor treatment in a gas phase. Patent Document 4 discloses a BEA type gallo having a Ga / Si molar ratio of 0.0004 to 0.066 obtained by treating a BEA type aluminosilicate or boroaluminosilicate with Al or deboron and then treating with a gallium salt aqueous solution. Aluminosilicate or galloborosilicate has been reported. In Patent Document 5, a metal / Si molar ratio in which Al in a skeleton is replaced with chromium or tin by treatment with a chromium or tin fluoro salt aqueous solution is 0.01 to 0.98, and a Si / Al molar ratio is 50. FAU type, MOR type, LTL type and MAZ type metalloaluminosilicates of ~ 98 have been reported. Patent Document 6 discloses that a FAU type zeolite having a Si / Al molar ratio of 1.75 or more is subjected to steaming and then treated with an acid and iron salt aqueous solution, whereby the Fe / Si molar ratio is 0.01 to 0.30. FAU type ferroaluminosilicates having a Si / Al molar ratio of 7.5 to 50 have been reported. In Patent Document 7, Si / Al carrying a metal by performing ammonium ion exchanged zeolite Y (FAU type aluminosilicate) by steaming and dealuminating with mineral acid, followed by metal salt aqueous solution treatment and pH increase treatment. FAU type zeolite having a molar ratio of 7.0 to 13.5 is reported.

Non-Patent Document 1 discloses that a BEA / aluminosilicate having a Si / Al molar ratio of 37.5 was acid-treated and then contacted with TiCl ₄ vapor at 500 ° C., and the Ti / Si molar ratio was 0.018-0. A BEA type titanoaluminosilicate having a Si / Al molar ratio of 72 to 450 at 0.048 has been reported.

Japanese Patent Publication No. 1-58128 Japanese Patent Laid-Open No. 5-24820 JP 59-116120 A Japanese Patent Laid-Open No. 2-184517 Japanese Examined Patent Publication No. 7-108770 JP-A-2-289419 Japanese Patent Laid-Open No. 5-178611

Microporous and Mesoporous Materials 31 (1999) 163-173

  Hydrothermal synthesis is the most common method for producing zeolites in the industry, but since other metal species are less likely to enter the zeolite framework compared to aluminum, only a relatively small amount can be introduced into the framework and can be synthesized. There are also limited crystal structure types.

  In addition, the method of introducing metal species into the synthesized zeolite by a gas phase reaction is difficult to achieve uniform solid-gas contact, and the reaction apparatus requires special heat and corrosion resistant materials. It is hard to say that it is a method.

  The present invention provides a novel FAU-type metalloaluminosilicate in which a metal is introduced into the skeleton and a production method that is simple and industrially applicable.

  The present inventors have studied for the purpose of producing new zeolites having solid acid characteristics, adsorption characteristics, and catalytic performance that have not been obtained with conventional zeolites by inserting metal atoms into the crystal lattice. As a result, the present invention has been reached. That is, when the pH of an acidic slurry in which crystalline zeolites having lattice defects are mixed with an aqueous metal salt solution is increased using an alkali, the metal is easily introduced into the defect sites of the crystal lattice. As a result, the present invention has been completed. The present invention is described in detail below.

In the present invention, the metal is at least one selected from Ti, Fe, Ga, In, Sn, and Zr, the metal / Si molar ratio is 0.005 to 0.15, and the Si / Al molar ratio is 100 or more. FAU type metalloaluminosilicate. When the metal is Fe, it is preferable that the Fe / Si molar ratio is 0.005 to 0.15 and the Si / Al molar ratio is 100 or more. When the metal is Sn, it is preferable that the Sn / Si molar ratio is 0.005 to 0.15 and the Si / Al molar ratio is 100 or more.

  Further, in the present invention, FAU type crystalline zeolite having lattice defects is suspended in an aqueous metal salt solution to form an acidic slurry (step a), and the pH of the acidic slurry is increased by 1 or more by addition of alkali, Is a new FAU-type metalloalumino characterized in that it comprises a step of 6 or less (step b), a step of filtering crystals from the slurry with increased pH, washing with water and drying (step c). It is a manufacturing method of a silicate.

  Furthermore, the metal introduced into the skeleton can be further stabilized by firing the crystals obtained in the step c at a temperature of 300 ° C. to 800 ° C.

  In addition, when sodium hydroxide or potassium hydroxide is used as the alkali, the crystals obtained in the step c may be partially obtained as alkali metal ions, so that the crystals obtained in the step c are obtained if necessary. Alkali metal ions can be removed by subjecting the crystals to normal ion exchange treatment.

  The lattice defect referred to in the present invention refers to a portion called a “nest” in the industry, in which four Si—OH groups are concentrated due to lack of aluminum or silicon atoms in a crystal skeleton composed of oxygen, silicon, and aluminum. say. Such lattice defects may already exist at the stage of crystallization by a hydrothermal synthesis reaction, or may be generated by a process after synthesis. As a method for generating lattice defects, a method of calcining and dealumination of a crystal, a method of dealumination of a crystal using an acid, a method of combining the firing and acid treatment, and a method of desiliconizing a crystal using an alkaline aqueous solution. And a method of dealumination.

  The raw material for preparing FAU-type crystalline zeolites having lattice defects used in the production method of the present invention is FAU-type aluminosilicate, metalloaluminosilicate, or silicate having lattice defects. The generation of lattice defects may be performed by any of the methods described above, but the method of dealumination using an acid is industrially simple and preferable. In the case of FAU type zeolite, the Si / Al molar ratio is as low as 1 to 3 at the stage of synthesis, so that the acid treatment cannot be performed. Therefore, after removing the alkali metal ions, firing in an atmosphere containing water vapor replaces the lattice defect sites generated simultaneously with dealumination with Si atoms to increase the Si / Al molar ratio of the skeleton. Thus, it is necessary to perform at least one steaming called ultra-stabilization treatment. After steaming firing, it can be dealuminated by acid treatment, but when the framework Si / Al molar ratio after steaming firing is 7 or less, the acid resistance is insufficient and the crystal structure collapses during acid treatment. Therefore, the Si / Al molar ratio after acid treatment cannot be 25 or more. In the present invention, FAU-type zeolite having a framework Si / Al molar ratio before acid treatment of 7 to 15 and an Si / Al molar ratio after acid treatment of 25 or more can be preferably used. Those having a skeleton Si / Al molar ratio of 20 or more before the acid treatment can be used in the present invention, but the amount of lattice defects generated by the acid treatment is reduced and the amount of the target metal introduced into the lattice is reduced. It is not preferable. It is well known in the art that the framework Si / Al molar ratio of FAU-type zeolite can be obtained by solid MAS-NMR measurement of Si or Al.

  In the production method of the present invention, since the slurry in step a is acidic, it is obvious that dealumination of the zeolite skeleton occurs in the step and lattice defects are generated. Therefore, defect-free aluminum is used as a starting material. Although many FAU-type zeolites can be used, in this case, aluminum released from the skeleton is also reintroduced into the skeleton in the step b, making it difficult to control the amount of the target metal introduced. Therefore, it is not preferable. Therefore, the FAU type zeolite having lattice defects preferably has a Si / Al molar ratio of 25 or more, more preferably 50 or more, and still more preferably 100 or more.

  It is preferable that the pH of the slurry obtained by mixing the aqueous metal salt solution and the raw material zeolites in step a is not more than the aqueous metal salt solution. If the raw material zeolite is H ion type, it is not necessary to add an acid, but if it is an alkali metal ion type, the pH increases and local metal precipitation may occur. Hereinafter, it is preferable that the pH is preferably 1 or less and the metal salt in the mixed slurry is sufficiently dissolved. Further, the metal is introduced only at lattice defect points, and it is important that the amount of metal used or the amount of metal desired to be introduced into the framework is equal to or less than the lattice defect amount in the starting zeolite.

  As the alkali used in step b, sodium hydroxide, potassium hydroxide, aqueous ammonia and the like can be used. The form of the aqueous solution is suitable for handling. The concentration of the alkali to be used is not particularly limited, but if it is too high, local metal precipitation or zeolite crystal structure collapse may occur at the time of addition, so the concentration should be as low as possible, preferably 5% or less. Is desirable. Further, it is desirable that the alkali addition rate be gradually and quantitatively added. Since zeolites having many lattice defects have poor alkali resistance, it is important that the pH of slurry added with alkali is 6 or less. Since the collapse of the zeolite crystal structure progresses as the pH exceeds 6, the final pH of the slurry is preferably in the range of 2-6, more preferably in the range of 3-6.

  Even if the metal salt is added after the alkali is added to the zeolite aqueous slurry to increase the pH, or the zeolite is added after the pH of the metal salt aqueous solution is increased by the alkali addition, the metallo according to the present invention can be used. You can't get an aluminosilicate.

  The higher the final pH, the greater the amount of metal introduced. Therefore, the amount of metal introduced can be controlled by the amount ratio of the metal salt and raw material zeolite in step a and the final pH in step b.

  The reaction temperature in step a and step b is not particularly limited, but the higher the temperature, the faster the reaction proceeds. Industrially, the range of 30 ° C to 100 ° C is preferable.

  The metal salt used in the present invention is a trivalent or tetravalent metal salt which is water-soluble and whose aqueous solution exhibits acidity. In particular, chloride, sulfate, nitrate, or acetate of Ti, Fe, Ga, In, Sn, and Zr can be used preferably.

  The present invention provides a novel FAU type metalloaluminosilicate. The present invention also provides a simple and industrial method for introducing various metals into the zeolite crystal skeleton. The novel FAU-type metalloaluminosilicate obtained by the present invention can be used as a catalyst, a catalyst base, or an adsorbent having an excellent performance that has not been achieved in the fields of petroleum refining, petrochemistry, and environmental purification.

2 shows UV diffuse reflection spectra of the FAU type metalloaluminosilicate of the present invention in Example 1 and dealuminated mordenite before Ti introduction.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the examples.

Example 1
500 g of NH ₄ type Y zeolite (FAU type aluminosilicate, Si / Al molar ratio 2.75, Na / Al molar ratio 0.13) was steamed and calcined at 750 ° C. for 2 hours in an atmosphere with a water vapor concentration of 50% to obtain HY zeolite. It was. The framework Si / Al molar ratio of this HY zeolite was 11.0 from Si solid MAS-NMR measurement. The HY zeolite and 2,000 ml of pure water were mixed to prepare a 20% slurry, 885 g of 35% hydrochloric acid was added, the mixture was stirred at 60 ° C. for 1 hour to dealuminated, and the crystals were filtered and warmed with 80 ° C. hot pure water. Washed to prepare dealuminated Y zeolite (Si / Al molar ratio 112). A titanium sulfate aqueous solution was prepared by diluting 67.7 g of an aqueous solution of titanium sulfate (IV) (manufactured by Kanto Chemical Co., Ltd., content: 24%) with 1 L of pure, mixed with 50 g of the dealuminated Y zeolite absolutely dry weight, Stir at 10 ° C. for 10 minutes. The pH at this time was 1.0. While stirring the slurry at 50 ° C., a 5% aqueous sodium hydroxide solution was continuously added at a rate of 14 ml / min to adjust the pH of the slurry to 6.0, and stirring and holding at 50 ° C. for 30 minutes, followed by filtration. Then, it was washed with warm pure water at 80 ° C. and dried at 120 ° C. to obtain the FAU type titanoaluminosilicate of the present invention.

  Table 1 shows chemical analysis values of the obtained crystals. From the powder X-ray diffraction measurement, this maintained the high crystallinity of the FAU type, and no crystalline substance other than the FAU type was observed. Moreover, the result of UV diffuse reflection spectrum analysis of the obtained crystal is shown in FIG. In the UV spectrum of FIG. 1, the titanoaluminosilicate has a large absorption at 220 to 250 nm. This absorption is attributed to tetrahedrally coordinated titanium in the skeleton, as described in Microporous and Mesoporous Materials 31 (1999) pages 163-173. From this, it can be seen that most of the titanium is taken into the skeleton.

Example 2
A dealuminated Y zeolite prepared in Example 1 was prepared by dissolving 18.3 g of iron (III) chloride hexahydrate (manufactured by Kanto Chemical Co., Inc., content 97%) in 1 L of pure water to prepare an aqueous iron chloride solution. After mixing with an absolute dry weight of 50 g, 1N hydrochloric acid was added to adjust the pH to 1.0, and the mixture was stirred at 50 ° C. for 10 minutes. While stirring the slurry at 50 ° C., a 5% aqueous sodium hydroxide solution was continuously added at a rate of 14 ml / min to adjust the pH of the slurry to 6.0, and stirring and holding at 50 ° C. for 30 minutes. The FAU type ferroaluminosilicate of the present invention was obtained by filtering off, washing with warm pure water at 80 ° C., and drying at 120 ° C.

  Table 1 shows chemical analysis values of the obtained crystals. From the powder X-ray diffraction measurement, this maintained the high crystallinity of the FAU type, and no crystalline substance other than the FAU type was observed. Further, the Na / (Al + Fe) molar ratio of the obtained crystal was 0.15. 10 g of the crystals were ion-exchanged twice at 50 ° C. using 500 ml of 1N aqueous sodium nitrate solution. The Na / (Al + Fe) molar ratio of the crystal after ion exchange was 0.86. This shows that most of Fe is inserted into the skeleton.

Comparative Example 1
Titanium (IV) sulfate aqueous solution (Kanto Chemical Co., Ltd., content: 24%) 67.7 g was diluted with 1 L of pure water to prepare a titanium sulfate aqueous solution. After mixing with 50 g and holding at 50 ° C. for 30 minutes with stirring, the crystals were filtered off, washed with warm pure water at 80 ° C. and dried at 120 ° C.

  Table 1 shows chemical analysis values of the obtained crystals. It is clear that the product of the invention cannot be obtained without an increase in pH.

比較例２
硫酸チタン（ＩＶ）水溶液（関東化学（株）製、含有量２４％）６７．７ｇを純水１Ｌで希釈して硫酸チタン水溶液を調製し、実施例１で調製した脱アルミニウムＹゼオライト絶乾重量５０ｇと混合して５０℃で１０分間撹拌した。この時のスラリーｐＨは１．０であった。該スラリーを５０℃で撹拌しながら、５％水酸化ナトリウム水溶液を１４ｍｌ／ｍｉｎの速度で連続的に添加してスラリーのｐＨを１０．０とし、５０℃で３０分間撹拌保持した後、結晶をろ別及び８０℃の温純水で洗浄し、１２０℃で乾燥した。

Comparative Example 2
Titanium (IV) sulfate aqueous solution (Kanto Chemical Co., Ltd., content: 24%) 67.7 g was diluted with 1 L of pure water to prepare a titanium sulfate aqueous solution. The mixture was mixed with 50 g and stirred at 50 ° C. for 10 minutes. The slurry pH at this time was 1.0. While stirring the slurry at 50 ° C., a 5% aqueous sodium hydroxide solution was continuously added at a rate of 14 ml / min to adjust the pH of the slurry to 10.0, and the mixture was stirred and held at 50 ° C. for 30 minutes. It was filtered and washed with warm pure water at 80 ° C. and dried at 120 ° C.

  From the powder X-ray diffraction measurement, the obtained crystal did not maintain the high crystallinity of the FAU type, and the XRD peak intensity was 10% or less with respect to the dealuminated Y zeolite.

Claims (3)

A FAU type metallo metal in which the metal is at least one selected from Ti, Fe, Ga, In, Sn, and Zr, the metal / Si molar ratio is 0.005 to 0.15, and the Si / Al molar ratio is 100 or more. Aluminosilicate. The FAU type metalloaluminosilicate according to claim 1, wherein the metal is Fe, the Fe / Si molar ratio is 0.005 to 0.15, and the Si / Al molar ratio is 100 or more. The FAU type metalloaluminosilicate according to claim 1, wherein the metal is Sn, the Sn / Si molar ratio is 0.005 to 0.15 , and the Si / Al molar ratio is 100 or more.

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