Preparation method and application of crystalline material

Abstract

The invention discloses a preparation method and application of a crystalline material, and relates to the technical field of chemical materials.The preparation method specifically comprises the following steps that S1, sodium chloride, oxydiacetic acid and terephthalic acid are sequentially dissolved in distilled water, and a mixed solution is obtained; s2, sequentially adding N, N-dimethylformamide and terbium perchlorate into the mixed solution to obtain a reaction solution; fully stirring the reaction liquid at room temperature; s3, transferring the fully stirred reaction liquid into a closed reactor, and reacting at a proper temperature to obtain an initial product; and carrying out filtering, acetone washing and vacuum drying on the initial product to obtain the crystalline material. The crystalline material synthesized by the method can realize high-efficiency purification of n-butane and isobutane gas under the conditions of room temperature and normal pressure, and is suitable for popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical materials and relates to a preparation method of a crystalline material and application thereof. Background Art

[0002] n-Butane (n-C4H 10 ) and isobutane (iso-C4H 10 ) are very important raw materials in the petrochemical industry and have a wide range of application value. 10 It is an important refrigerant with good refrigeration effect and can be used to produce isobutylene and then manufacture butyl rubber and other products. 10 It is mainly used for alkylation with isobutylene to produce isooctane, which is used as a gasoline octane improver. 10 It is also widely used in industry. 10 It can be used as a raw material to produce a series of chemical raw materials, such as important chemical raw materials such as ethylene, propylene and butadiene. However, in industry, butane is usually obtained from cracking gas, n-C4H 10 and iso-C4H 10 always coexist, so it is very important to separate them effectively to obtain high purity products. However, n-C4H 10 and iso-C4H 10 are isomers of each other, and they have similar physical and chemical properties, such as similar kinetic diameters ( and ) and boiling point (n-C4H 10 : 272.66K and iso-C4H 10 :261.34K), which makes it possible to achieve n-C4H 10 / iso-C4H 10 The effective separation of mixtures is very challenging. In industry, n-C4H 10 / iso-C4H 10 However, this process is not only energy-consuming, but also requires high equipment investment and complicated operation process. Therefore, it is necessary to develop energy-saving, environmentally friendly and efficient n-C4H 10 / iso-C4H 10 New separation technologies can bring huge economic and ecological benefits to enterprises, countries and society.

[0003] New materials that can efficiently enrich specific gases are the material basis for the development of modern gas separation technology. 10 or iso-C4H 10 A considerable number of metal-organic frameworks (MOFs) crystalline materials have been synthesized, but they also have n-C4H10 and iso-C4H 10 Crystalline materials with selective separation capabilities are relatively rare.

[0004] Therefore, the development of 10 and iso-C4H 10 New MOFs crystalline materials with purification capabilities can overcome the shortcomings of existing technologies, and this technology has important commercial value. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a method for preparing a crystalline material and its application. The crystalline material prepared by the method is a crystalline material having both n-C4H 10 and iso-C4H 10 A new type of MOFs crystalline material with purification capabilities can be used in the purification process of n-butane and isobutane and is suitable for promotion and application.

[0006] The specific technical solution is:

[0007] In one aspect, the present invention provides a method for preparing a crystalline material, the method comprising the following steps:

[0008] S1: dissolving sodium chloride, oxydiacetic acid, and terephthalic acid in distilled water in sequence to obtain a mixed solution;

[0009] S2: adding N,N-dimethylformamide and terbium perchlorate to the mixed solution obtained in step S1 in sequence to obtain a reaction solution; and fully stirring the reaction solution at room temperature at a speed of 800-1200 r / min;

[0010] S3: placing the stirred reaction liquid in a closed reactor and reacting it at an appropriate temperature to obtain an initial product; filtering the initial product, washing it with acetone, and vacuum drying it to obtain a white transparent block-like crystalline substance, which is the crystalline material.

[0011] Furthermore, in step S1, the mass of sodium chloride is 3-9 mg; the mass of oxydiacetic acid is 3-9 mg; the mass of terephthalic acid is 4-12 mg; and the volume of distilled water is 0.5-1.5 mL.

[0012] Furthermore, in step S2, the volume of N,N-dimethylformamide is 4.5-13.5 mL; the mass of terbium perchlorate is 15-45 mg; the stirring time is 0.25-0.75 h, and the stirring speed is 1200 r / min.

[0013] Furthermore, in step S3, the appropriate temperature is 85° C., and the reaction time is 7-12 days; the vacuum drying temperature is 40° C., and the vacuum drying time is 10-12 hours.

[0014] On the other hand, the present invention provides the use of the crystalline material prepared by the preparation method of the crystalline material in the purification process of n-butane and isobutane.

[0015] Furthermore, the application specifically includes the following steps:

[0016] (1) soaking the crystalline material prepared by the present invention in acetone and vacuum degassing to obtain an activated crystalline material;

[0017] (2) The pore structure of the activated crystalline material was analyzed using an adsorption instrument at 77K. The adsorption of the activated crystalline material to n-butane (n-C4H 10 ) and isobutane (iso-C4H 10 )'s single-component gas adsorption capacity;

[0018] (3) The Clausius-Clapeyron equation was used to calculate the activation of crystalline materials for n-C4H 10 、iso-C4H 10 The adsorption enthalpy is used to determine the regeneration temperature of the material after adsorbing the corresponding gas;

[0019] (4) Using a gas dynamic penetration experimental device, the activated crystalline material was loaded into a fixed separation column and purged with N2 at 100°C for 3 h; n-C4H 10 / iso-C4H 10 Mixed gas, test n-C4H 10 and iso-C4H 10 The penetration time and the separation column outlet n-C4H 10 and iso-C4H 10 purity.

[0020] Furthermore, in step (1), the vacuum degassing temperature is 100° C., and the vacuum degassing time is 24 h;

[0021] In step (2), the adsorption instrument is a Micromeritics ASAP 2460 from the United States;

[0022] In step (4), the gas dynamic penetration experimental device is BSD-MAB, the volume of the fixed separation column is 8 mL; the test temperature is 298-333 K, and the n-C4H 10 / iso-C4H 10 The volume ratio is 50:50, and the total flow rate of the mixed gas is 1.0-10.0 mL / min.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention uses a rational step-by-step reaction to mix terbium perchlorate, sodium chloride, oxydiacetic acid, terephthalic acid, N,N-dimethylformamide, distilled water, and other substances in groups, and then heats the mixture, filters and washes it, and then vacuum-dries it to obtain a white, transparent, blocky crystalline substance, i.e., a new crystalline material (NXU-2-Tb). This material is synthesized for the first time by the inventors. The above-mentioned synthesis method of the present invention is simple and easy to operate, and the synthesized material can efficiently achieve n-C4H 10 / iso-C4H 10 Adsorption separation of the material synthesized by the present invention and its efficient n-C4H 10 / iso-C4H 10 Adsorption separation capability has great practical value and market prospects in the field of n-butane and isobutane gas purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a crystal structure diagram of NXU-2-Tb of the present invention;

[0026] Figure 2 The nitrogen adsorption-desorption isotherm and pore width distribution diagram of NXU-2-Tb(a) of the present invention at 77K are shown;

[0027] Figure 3 The n-C4H 10 and iso-C4H 10 Single component adsorption isotherm diagram;

[0028] Figure 4 is n-C4H of NXU-2-Tb(a) of the present invention 10 and iso-C4H 10 Adsorption enthalpy curve of ;

[0029] Figure 5 The n-C4H 10 / iso-C4H 10 Penetration curve graph;

[0030] Figure 6 The n-C4H 10 / iso-C4H 10 Penetration curve graph;

[0031] Figure 7The n-C4H 10 / iso-C4H 10 Penetration curve graph;

[0032] Figure 8 This is the powder X-ray diffraction pattern of NXU-2-Tb(a) of the present invention after multiple rounds of adsorption-desorption cycles. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation plans.

[0034] Example 1

[0035] This embodiment provides a method for preparing a crystalline material, which specifically comprises the following steps:

[0036] S1: Dissolve 3 mg of sodium chloride, 3 mg of oxydiacetic acid, and 4 mg of terephthalic acid in 0.5 mL of distilled water to obtain a mixed solution;

[0037] S2: 5.0 mL of N,N-dimethylformamide and 15 mg of terbium perchlorate were added to the mixed solution in sequence to obtain a reaction solution; the reaction solution was stirred at room temperature for 0.25 h at a stirring speed of 800 r / min;

[0038] S3: The dissolved reaction solution was placed in a closed reaction chamber and reacted at 85°C for 7 days to obtain an initial product; the initial product was filtered, washed with acetone, and vacuum-dried at 40°C for 10 hours to obtain a white transparent block crystalline substance, which is the crystalline material, named NXU-2-Tb, which has a columnar-layer structure and two-dimensional through-hole channels, as shown in the attached Figure 1 .

[0039] Example 2

[0040] This embodiment provides a method for preparing a crystalline material, which specifically comprises the following steps:

[0041] S1: Dissolve 6 mg of sodium chloride, 6 mg of oxydiacetic acid, and 8 mg of terephthalic acid in 1.0 mL of distilled water to obtain a mixed solution;

[0042] S2: 10.0 mL of N,N-dimethylformamide and 30 mg of terbium perchlorate were added to the mixed solution in sequence to obtain a reaction solution; the reaction solution was stirred at room temperature for 0.5 h at a stirring speed of 1000 r / min;

[0043] S3: The dissolved reaction solution is placed in a closed reactor and reacted at 85°C for 9 days to obtain an initial product; the initial product is filtered, washed with acetone, and vacuum-dried at 40°C for 11 hours to obtain a white transparent block-like crystalline substance, which is the crystalline material.

[0044] Example 3

[0045] This embodiment provides a method for preparing a crystalline material, which specifically comprises the following steps:

[0046] S1: Dissolve 9 mg of sodium chloride, 9 mg of oxydiacetic acid, and 12 mg of terephthalic acid in 1.5 mL of distilled water to obtain a mixed solution;

[0047] S2: 13.5 mL of N,N-dimethylformamide and 45 mg of terbium perchlorate were added to the mixed solution in sequence to obtain a reaction solution; the reaction solution was stirred at room temperature for 0.75 h at a stirring speed of 1200 r / min;

[0048] S3: The dissolved reaction solution was placed in a closed reaction chamber and reacted at 85°C for 10 days to obtain an initial product; the initial product was filtered, washed with acetone, and vacuum-dried at 40°C for 12 hours to obtain a white transparent block crystalline substance, which is the crystalline material, named NXU-2-Tb.

[0049] Example 4

[0050] This embodiment provides an application of the crystalline material prepared by the above method in the purification process of n-butane and isobutane. Taking Example 1 as an example, the application method is specifically as follows:

[0051] (1) 150 mg of the crystalline material NXU-2-Tb prepared in Example 1 was soaked in 20 mL of acetone for 5 days and vacuum degassed at 100° C. for 24 hours to obtain the activated crystalline material NXU-2-Tb (a);

[0052] (2) Using the American Micromeritics ASAP 2460 adsorption instrument at 77K, NXU-2-Tb(a) was subjected to nitrogen adsorption to analyze its pore structure. Then, the adsorption of n-C4H 10 and iso-C4H 10 Single-component gas adsorption capacity;

[0053] By the attached Figure 2 It can be seen that the BET specific surface area of ​​NXU-2-Tb(a) is 563.85 m 2 / g, there are two types of pores with pore widths of 0.84nm and 1.34nm respectively.

[0054] By the attached Figure 3 It can be seen that at 298K temperature, n-C4H 10 and iso-C4H 10 The adsorption capacity was 45.7 cm 3 / g, 35.7cm 3 / g.

[0055] From the comparison results of the above adsorption amounts, it can be seen that the adsorption amount of the material for n-butane is much higher than that for isobutane, indicating that NXU-2-Tb(a) can be used for n-C4H 10 / iso-C4H 10 Adsorption separation can be used to purify n-butane and isobutane.

[0056] (3) Calculate the effect of NXU-2-Tb(a) on n-C4H by Clausius-Clapeyron equation 10 and iso-C4H 10 The adsorption enthalpy (Q st ), and accordingly determine the regeneration temperature of the material after adsorbing the corresponding gas;

[0057] By the attached Figure 4 It can be seen that n-C4H 10 and iso-C4H 10 Q st They are 48.4 kJ / mol and 51.4 kJ / mol, respectively, indicating that NXU-2-Tb(a) can be regenerated at a lower temperature (40-80°C) after adsorbing the corresponding gas.

[0058] (4) Using the BSD-MAB gas dynamic penetration experimental device, 1000 mg of NXU-2-Tb(a) was loaded into a fixed separation column with a volume of 8 mL and purged with N2 (20 mL / min) at 100 °C for 3 h. Based on the actual situation of the current industrial n-butane and isobutane production, first, n-C4H2O and n-C4H3O with a volume ratio of 50:50 were introduced at 1 atm and 298 K. 10 / iso-C4H 10 The total flow rate of the mixed gas is 1.0 mL / min. The test of n-C4H 10 and iso-C4H 10 The penetration time and the separation column outlet n-C4H 10 and iso-C4H 10 Purity, see attached Figure 5 Furthermore, n-C4H2O2 with a volume ratio of 50:50 was introduced at 1 atm and 298 K. 10 / iso-C4H 10The total flow rate of the mixed gas is 1.0-10.0 mL / min. The test of n-C4H 10 and iso-C4H 10 The penetration time and the separation column outlet n-C4H 10 and iso-C4H 10 Purity, see attached Figure 6 Furthermore, n-C4H2O2 with a volume ratio of 50:50 was introduced at 1 atm 298-333K. 10 / iso-C4H 10 The total flow rate of the mixed gas is 1.0 mL / min. The test of n-C4H 10 and iso-C4H 10 The penetration time and the separation column outlet n-C4H 10 and iso-C4H 10 Purity, see attached Figure 7 In the figure, C0 represents the total concentration of the mixed gas, C A Indicates the concentration of a specific component gas in a mixed gas, C A / C0 represents the relative concentration of a specific component gas in the mixed gas.

[0059] By the attached Figure 5 The test results show that in n-C4H 10 / iso-C4H 10 n-C4H in mixed gas 10 and iso-C4H 10 The breakthrough times for n-butane and isobutane were 37.6 min / g and 19.4 min / g, respectively. Purity testing of the gas at the column outlet revealed that both n-butane and isobutane were ≥99.999%. The long relative difference in breakthrough times and the large relative concentration differences between groups indicate good purification effectiveness. These results confirm that NXU-2-Tb(a) has excellent purification capabilities for n-butane and isobutane.

[0060] By the attached Figure 6 The test results show that when the mixed gas flow rate is 1.0mL / min, 2.0mL / min, 5.0mL / min, and 10.0mL / min, n-C4H 10 / iso-C4H 10 n-C4H in mixed gas 10 and iso-C4H 10The breakthrough times for the three groups were 37.6 min / g and 19.4 min / g, 21.93 min / g and 8.37 min / g, 7.43 min / g and 2.16 min / g, and 3.36 min / g and 0.12 min / g, respectively. Purity testing of the gas at the column outlet revealed that both n-butane and isobutane were ≥99.999%. The long relative difference in breakthrough times and the large relative concentration differences between groups indicate good purification effectiveness. These results confirm that NXU-2-Tb(a) has excellent n-butane and isobutane purification capabilities at different gas flow rates.

[0061] By the attached Figure 7 The test results show that at 298K, 313K, and 333K, n-C4H 10 / iso-C4H 10 n-C4H in mixed gas 10 and iso-C4H 10 The breakthrough times were 37.6 min / g and 19.4 min / g, 39.92 min / g and 18.92 min / g, and 33.56 min / g and 15.80 min / g, respectively. Purity testing of the gas at the column outlet revealed that both n-butane and isobutane were ≥99.999%. The large relative concentration differences between the groups indicate good purification effectiveness. These results confirm that NXU-2-Tb(a) has excellent n-butane and isobutane purification capabilities at different temperatures.

[0062] In particular, when the material is used for the first time to purify n-butane and isobutane, steps (1) to (4) of the application method of Example 4 need to be followed. From the second time onwards, only steps (1) and (4) need to be followed.

[0063] Further verification of the structural integrity after adsorption-desorption cycles:

[0064] Each round of n-C4H 10 / iso-C4H 10 After separation, NXU-2-Tb(a) was regenerated by N2 purge at 60℃ for 3h, and the above step (5) was repeated after regeneration. Figure 8 It can be seen from the results that the crystallinity and structural integrity of NXU-2-Tb(a) have no obvious changes compared with the original NXU-2-Tb(a).

[0065] According to the above step (2), NXU-2-Tb (a) was subjected to 20 rounds of n-C4H 10 and iso-C4H 10Single-component gas adsorption-desorption cycle, PXRD pattern of NXU-2-Tb(a) after testing the cycle and nitrogen adsorption-desorption isotherm at 77K. Figure 8 and attached Figure 2 The results in the small and medium figures show that the crystallinity and structural integrity of NXU-2-Tb(a) have not changed significantly compared with the original NXU-2-Tb.

[0066] The above description is only a preferred specific embodiment of the present invention, and the protection scope of the present invention is not limited thereto. Any simple change or equivalent replacement of the technical solution that can be obviously obtained by any technician familiar with this technical field within the technical scope disclosed in the present invention falls within the protection scope of the present invention.

Claims

1. A method for preparing a crystalline material, characterized in that: The following steps are involved: S1: dissolving sodium chloride, oxydiacetic acid, and terephthalic acid in distilled water in sequence to obtain a mixed solution; S2: adding N,N-dimethylformamide and terbium perchlorate to the mixed solution obtained in step S1 in sequence to obtain a reaction solution; and fully stirring the reaction solution at room temperature at a speed of 800-1200 r / min; S3: placing the stirred reaction liquid in a closed reactor and reacting it at an appropriate temperature to obtain an initial product; filtering the initial product, washing it with acetone, and vacuum drying it to obtain a white transparent block-like crystalline substance, which is the crystalline material.

2. The method for preparing a crystalline material according to claim 1, wherein: In step S1, the mass of sodium chloride is 3-9 mg; the mass of oxydiacetic acid is 3-9 mg; the mass of terephthalic acid is 4-12 mg; and the volume of distilled water is 0.5-1.5 mL.

3. The method for preparing a crystalline material according to claim 1, wherein: In step S2, the volume of N,N-dimethylformamide is 4.5-13.5 mL; the mass of terbium perchlorate is 15-45 mg; the stirring time is 0.25-0.75 h, and the stirring speed is 1200 r / min.

4. The method for preparing a crystalline material according to claim 1, wherein: In step S3, the appropriate temperature is 85° C., and the reaction time is 7-12 days; the vacuum drying temperature is 40° C., and the vacuum drying time is 10-12 hours.

5. Use of the crystalline material prepared by the method for preparing the crystalline material according to any one of claims 1 to 4 in the purification process of n-butane and isobutane.

6. The use according to claim 5, characterized in that The application specifically includes the following steps: (1) soaking the crystalline material prepared in claim 1 in acetone and vacuum degassing to obtain an activated crystalline material; (2) The pore structure of the activated crystalline material was analyzed using an adsorption instrument at 77K. The adsorption capacity of the activated crystalline material for single-component gases, n-butane and isobutane, was then tested at 1atm / 273K and 1atm / 298K, respectively. (3) Calculate the adsorption enthalpy of the activated crystalline material for n-butane and isobutane using the Clausius-Clapeyron equation, and determine the regeneration temperature of the material after adsorbing the corresponding gas; (4) Using a gas dynamic penetration experimental device, the activated crystalline material was loaded into a fixed separation column and purged with N2 at 100°C for 3 h. A mixed gas of n-butane / isobutane was introduced at 1 atm 298K to test the penetration time of n-butane and isobutane and the purity of n-butane and isobutane at the outlet of the separation column.

7. The use according to claim 6, characterized in that In step (1), the vacuum degassing temperature is 100° C. and the vacuum degassing time is 24 h; In step (2), the adsorption instrument is a Micromeritics ASAP 2460 from the United States; In step (4), the gas dynamic penetration experimental apparatus is BSD-MAB, the volume of the fixed separation column is 8 mL; the test temperature is 298-333 K, the volume ratio of n-butane / isobutane in the mixed gas is 50:50, and the total flow rate of the mixed gas is 1.0-10.0 mL / min.

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