Application of a metal-organic framework material JNU-2 in the separation of chemical benzene compounds and / or hexane isomers

Abstract

The present invention provides an application of a metal-organic framework material JNU-2 in separating chemical benzene compounds and / or hexane isomers. The application adopts a penetration test for separation, comprising the following steps: (1) first activating the metal-organic framework material JNU-2; (2) filling 0.7-1.2 g of the metal-organic framework material JNU-2 powder into a stainless steel column filled with silica glass wool, and performing an ionization reaction at a temperature of 353 K and a carrier gas of helium at a flow rate of 3.0-20 mL min ‑1 Penetration experiments with gaseous mixtures of two or more chemical benzene compounds or hexane isomers were conducted. The material's interconnected channels and pores, along with a window aperture of approximately #imgabs0#, are larger than the kinetic diameters of #imgabs1# and #imgabs2# but comparable to #imgabs3#. This prevents oX molecules from diffusing into the internal cavity of JNU‑2, as is the case with other BTEX molecules. Furthermore, this value is within the molecular size range of hexane isomers, effectively excluding the slightly larger 22DMB molecule.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical separation, and in particular relates to the application of a metal organic framework material JNU-2 in separating chemical benzene compounds and / or hexane isomers. Background Art

[0002] Benzene (Bz), toluene (Tol), ethylbenzene (EB), and xylene isomers, including o-xylene (oX), m-xylene (mX), and p-xylene (pX), are commonly obtained as a mixture in the petroleum industry, commonly known as BTEXs. Among them, oX is mainly used to prepare phthalic anhydride, and the global market size is expected to exceed US$4.3 billion by 2025. Currently, the main industrial method for separating oX from BTEXs is fractional distillation. However, due to their very close boiling points, the process requires a large number of trays (>150) and a high reflux ratio to obtain high-purity oX, which is not only energy intensive but also environmentally unfriendly.

[0003] Adsorption separation technologies based on porous materials are considered an energy-efficient alternative to distillation. Compared to traditional porous materials, metal-organic frameworks (MOFs) hold great potential for the adsorption separation of similar hydrocarbons due to their extensive tunability and designability in pore size and surface chemistry. Although many MOFs have been reported to separate oX from C8 isomers, most exhibit little oX / EB selectivity, likely due to their nearly identical quadrupole moments and polarizabilities. Therefore, surface chemical engineering alone does not appear to be sufficient to achieve high selectivity for one xylene over others, given their similar physical and chemical properties. It is worth noting that oX-selective materials are not ideal adsorbents for oX purification, as further desorption is required to obtain high-purity oX, a process that still incurs significant energy costs. Due to the large kinetic size of oX molecules, molecular sieving is more suitable for their separation from other BTEX molecules. If the openings of the molecular sieving material are precisely tuned, this strategy allows for the direct production of oX with unlimited selectivity.

[0004] Hexane is a key commodity in the petrochemical industry, primarily obtained from crude oil refining. Its global market value exceeded $1.3 billion in 2022. This process typically produces a mixture of linear, singly, and doubly branched isomers. Research octane number (RON) is a key indicator of gasoline fuel quality; higher alkane branching indicates a higher octane number. For example, n-hexane (nHEX), 2-methylpentane (2MP), 3-methylpentane (3MP), 2,2-dimethylbutane (22DMB), and 2,3-dimethylbutane (23DMB) have RON values of 24.8, 74.5, 75.5, 94, and 105, respectively. To improve the RON value of gasoline fuel, a mixture of doubly branched hexanes (preferably 23DMB) is preferred over a mixture of hexane isomers. However, due to the similar physical and chemical properties of hexane isomers, their separation is challenging. Current industrial separation methods rely on heat-driven distillation, which is energy-intensive and requires significant equipment investment. In the search for alternative separation methods to heat-driven distillation, porous solid adsorption separation is considered one of the most promising technologies due to its energy-efficient, non-thermal separation process. For example, zeolite 5A, an industrially used porous solid, can completely adsorb linear alkanes, effectively separating them from their branched isomers. However, zeolite 5A cannot distinguish between singly and doubly branched isomers, which limits further improvements in RON values.

[0005] Although some metal-organic frameworks have been used in the separation of hexane isomers, and significant progress has been made in designing MOFs for distinguishing between double-branched, linear, and single-branched hexane isomers, it is worth noting that no MOF materials have been reported for the separation of 23DMB and 22DMB. This may be due to their almost identical kinetic diameters (23DMB: 22DMB: ) and molecular size (22DMB: 23DMB: ).

[0006] Therefore, it is of great significance to study a method that can efficiently separate o-xylene from BTEXs by precisely controlling the pore size of a metal-organic framework material and gradually separate hexane using adsorption kinetics and thermodynamics. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention aims to provide an application of a metal organic framework material JNU-2 in the separation of chemical benzene compounds and / or hexane isomers. The present invention uses a penetration test to separate chemical benzene compounds and / or hexane isomers. Due to the structural characteristics of the metal organic framework material JNU-2 in which the channels and pores are interconnected, and the window aperture is approximately This value is greater than and kinetic diameter, but with This value is quite large, preventing oX molecules from diffusing into the internal cavity of JNU-2 like other BTEX molecules. Furthermore, this value is within the molecular size range of hexane isomers, and can also exclude the slightly larger 22DMB molecule.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an application of a metal organic framework material JNU-2 in the separation of chemical benzene compounds and / or hexane isomers.

[0009] Furthermore, the application uses a penetration experiment for separation, comprising the following steps:

[0010] (1) First, the metal organic framework material JNU-2 is activated;

[0011] (2) 0.7-1.2 g of the above metal organic framework material JNU-2 powder was filled into a stainless steel column containing silica glass wool at a temperature of 353 K and a carrier gas of helium at a flow rate of 3.0-20 mL min -1 The breakthrough experiment of gas phase mixture of two-component or multi-component chemical benzene compounds or hexane isomers was carried out under the conditions of 1:1.

[0012] Furthermore, in step (2), when the separation object is a chemical benzene compound, the two components can be pX / oX, EB / oX, mX / oX, Tol / oX or Bz / oX in an equimolar ratio.

[0013] Furthermore, in step (2), when the separation object is a chemical benzene compound, the multiple components are four components pX / mX / oX / EB, and the volume ratio of the four components is 22 / 50 / 22 / 6.

[0014] Furthermore, in step (2), when the separation object is a chemical benzene compound, the multiple components are six components, and the six components are in equal molar ratios of pX / EB / mX / Tol / Bz / oX.

[0015] Furthermore, in step (2), when the separation object is hexane isomers, the two components are in an equimolar ratio of 23DMB / 22DMB.

[0016] Furthermore, in step (2), when the separation object is hexane isomers, the multiple components are four components, and the four components are 2MP / 3MP / 23DMB / 22DMB in an equal molar ratio.

[0017] Furthermore, in step (2), when the separation object is hexane isomers, the multiple components are five components, and the five components are nHEX / 2MP / 3MP / 23DMB / 22DMB in equal molar ratios.

[0018] Furthermore, when the separation object is a chemical benzene compound, liquid phase extraction can also be used for separation.

[0019] Furthermore, the liquid phase extraction separation method is: immersing 10 g of the activated metal-organic framework material JNU-2 in 18.0 mL of pX / EB / mX / Tol / Bz / oX with a volume ratio of 2 / 2 / 2 / 2 / 2 / 2 / 90, placing it on a shaker at 298 K for 24 hours; then, collecting the liquid using a cold trap vacuum.

[0020] The present invention uses the metal organic framework material JNU-2 to separate o-xylene from BTEXs and the mechanism of gradually separating hexane by using adsorption kinetics and thermodynamics is as follows: the structural characteristics of the material's channels and pores are interconnected, and the window aperture is about This value is greater than and kinetic diameter, but with This value is quite large, which prevents oX molecules from diffusing into the internal cavity of JNU-2 like other BTEX molecules. In addition, this value is also within the molecular size range of hexane isomers, and can also exclude 22DMB, which is slightly larger in size. (See Figure 1 ) Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention uses the metal-organic framework material JNU-2 to separate o-xylene from BTEXs. Two-component competitive adsorption penetration studies show that the adsorption selectivity of other BTEX molecules for o-xylene has reached a record high; multi-component gas phase penetration experiments verify its superior separation potential for screening o-xylene from BTEXs.

[0022] 2. The present invention further purifies o-xylene by immersing the metal-organic framework material JNU-2 (10 g) in BTEXs (18 mL, 90% o-xylene) at room temperature, and an average of 15.2 mL of o-xylene (purity 99.5%+, recovery rate 94%) can be obtained in 10 cycles.

[0023] 3. The metal-organic framework material JNU-2 employed in the present invention can also completely separate dibranched hexanes (23DMB and 22DMB) from linear (nHEX) and singly branched hexane (2MP and 3MP) isomers via adsorption kinetics, and further separate 23DMB from 22DMB via thermodynamics. Furthermore, during the stepwise separation of hexanes using adsorption kinetics and thermodynamics, multicomponent hexane isomer vapor phase permeation experiments demonstrated JNU-2's potential to separate dibranched hexanes from linear and singly branched hexanes. Two-component dibranched hexane vapor phase permeation experiments demonstrated that JNU-2 achieved the first complete separation of the two dibranched hexane isomers, achieving 99.4% purity and a RON of 104.9 for the isolated 23DMB. In situ gravimetric analysis of multiple nHEX adsorption / desorption cycles confirmed JNU-2's excellent cyclic stability.

[0024] 4. Compared with the molecular sieve 5A used in traditional industry, the JNU-2 adsorbent used in the present invention has lower energy consumption for separating n-hexane. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The mechanism of using the metal-organic framework material JNU-2 to separate o-xylene from BTEXs and the stepwise separation of hexane using adsorption kinetics and thermodynamics was studied.

[0026] Figure 2 The test diagram of the metal organic framework material JNU-2 after reflux in BTEXs for 30 days, where (a) is the PXRD test diagram and (b) is the 77KN2 adsorption test diagram;

[0027] Figure 3 The PXRD patterns (Figure (a)) and 77KN2 adsorption patterns (Figure (b)) of the metal organic framework material JNU-2 before and after 64 cycles of adsorption / desorption of n-hexane;

[0028] Figure 4 This is the vapor adsorption isotherm of BTEXs on the metal-organic framework material JNU-2 at 353K;

[0029] Figure 5 This is a data collection diagram of the mass curve of single-component BTEXs vapor changing with time in JNU-2 at 353K. The data were obtained by thermogravimetric analyzer (TGA);

[0030] Figure 6 A computational model diagram of BTEXs entering the JNU-2 pore;

[0031] Figure 7 To determine the sites of BTEXs in JNU-2 by single crystal X-ray diffraction technique;

[0032] Figure 8 The pure component vapor phase adsorption isotherms of the metal organic framework material JNU-2 for nHEX, 2MP, 3MP, 23DMB and 22DMB at a temperature of 353K and a maximum pressure of 16kPa;

[0033] Figure 9 In situ gravimetric analysis (IGA) of the adsorption kinetics of nHEX, 2MP, 3MP, and 23DMB on the metal-organic framework JNU-2 at 353 K and 10 kPa.

[0034] Figure 10 This is the breakthrough experimental curve of the metal-organic framework material JNU-2 at 353K for an equimolar pX / oX gas phase mixture;

[0035] Figure 11 This is the breakthrough experimental curve of the metal organic framework material JNU-2 at 353K for an equimolar EB / oX gas phase mixture;

[0036] Figure 12 This is the breakthrough experimental curve of the metal-organic framework material JNU-2 at 353K for an equimolar mX / oX gas phase mixture;

[0037] Figure 13 This is the breakthrough experimental curve of the metal-organic framework material JNU-2 at 353K for an equimolar Tol / oX gas phase mixture;

[0038] Figure 14 This is the breakthrough experimental curve of the metal organic framework material JNU-2 in an equimolar Bz / oX gas phase mixture at 353K;

[0039] Figure 15 The breakthrough curve of the gas phase mixture of four components pX / mX / oX / EB (22 / 50 / 22 / 6) of the metal organic framework material JNU-2 at 353K (Figure (a)) and the three-cycle breakthrough curve (Figure (b));

[0040] Figure 16 The breakthrough experimental curve of the six-component pX / EB / mX / Tol / Bz / oX (1 / 1 / 1 / 1 / 1 / 1) gas phase mixture of the metal organic framework material JNU-2 at 353K (Figure (a)) and the three-cycle breakthrough experimental curve (Figure (b));

[0041] Figure 17 Schematic diagram of the metal-organic framework material JNU-2 being used to purify oX by immersing it in a mixture of pX / EB / mX / Tol / Bz / oX (2 / 2 / 2 / 2 / 2 / 90);

[0042] Figure 18Changes in oX purity of the initially prepared 18.0 ml BTEXs mixed solution and after extraction recovery;

[0043] Figure 19 Schematic diagram of oX purity (Figure (a)) and recovery (Figure (b)) after 10 adsorption / desorption cycles;

[0044] Figure 20 This is the breakthrough curve of the five-component equimolar mixture of nHEX / 2MP / 3MP / 23DMB / 22DMB of the metal-organic framework material JNU-2 at 353K;

[0045] Figure 21 Figure 2 shows the breakthrough curve of a two-component equimolar mixture of 23DMB and 22DMB on JNU-2 at 353K (Figure (a)), the flow rate curve of 22DMB and 23DMB desorption on JNU-2, and the flow rate curve of 20mL min-1 at 423K. -1 Purity of 23DMB eluted during regeneration under helium conditions (Figure (b));

[0046] Figure 22 The metal organic framework material JNU-2 was prepared at 353K and 3.0mL min -1 At the same flow rate, five consecutive breakthrough cycle experiments with equimolar 23DMB / 22DMB were performed;

[0047] Figure 23 Figure 2 is the nHEX desorption analysis of JNU-2 and 5A zeolites by in situ gravimetric analysis. DETAILED DESCRIPTION

[0048] The present method is described in detail below with reference to specific examples. The metal-organic framework (MOF) material JNU-2 used in this invention was prepared according to the method described in the Chinese patent "A MOF material with ethane preferential adsorption and its preparation method" (Granted Publication No. CN110237823B). In this invention, BTEXs is an abbreviation for a mixture of benzene (Bz), toluene (Tol), ethylbenzene (EB), and xylene isomers, including o-xylene (oX), m-xylene (mX), and p-xylene (pX). Octane number (RON) is a key indicator of gasoline fuel quality. n-HEX is abbreviated for n-hexane, 2MP for 2-methylpentane, 3MP for 3-methylpentane, 22DMB for 2,2-dimethylbutane, and 23DMB for 2,3-dimethylbutane. The MOF material JNU-2 in this invention requires activation treatment for penetration experiments. Specifically, the sample is regenerated in situ at 473K under high vacuum for 8 hours. The present invention adopts a breakthrough experiment separation method to produce a vapor mixture by a helium bubbling method, and adjusts the composition of the liquid mixture in the bubbler until the desired vapor mixture ratio is reached. The outlet effluent of the column is continuously monitored using a gas chromatograph with a hydrogen flame ionization detector (FID). After each breakthrough experiment, the sample is regenerated in situ under a high vacuum of 473K for 8 hours.

[0049] 1. Characterization and testing of the metal-organic framework material JNU-2

[0050] Example 1

[0051] This example tests the chemical stability of the metal organic framework material JNU-2.

[0052] 120 mg of desolvated metal organic framework material JNU-2 was placed in BTEXs for reflux for 30 days, and the treated samples were subjected to PXRD test ( Figure 2 (a)) and N2 adsorption test at 77K ( Figure 2 The results are shown in the figure. From the PXRD diffraction pattern and N2 adsorption isotherm, it can be seen that JNU-2 has excellent chemical stability. This result indicates that the highly stable JNU-2 has great potential for separating and purifying oX from BTEXs.

[0053] The PXRD and 77KN2 patterns of the synthesized 120 mg desolvated JNU-2 sample before and after adsorption / desorption of n-hexane 64 times (see Figure 3 As can be seen from the figure, the PXRD of JNU-2 after 64 nHEX adsorption / desorption cycles at 353K (Figure a) and the N2 adsorption test at 77K (Figure b) indicate the excellent stability of JNU-2 under high-temperature nHEX and its long-term availability in industrial applications.

[0054] Example 2

[0055] This embodiment is a BTEXs single-component gas adsorption isothermal test of the metal organic framework material JNU-2 at 353K and a mass change over time test of the material on a thermogravimetric analyzer (TGA).

[0056] 120 mg of desolvated metal organic framework material JNU-2 was placed in an adsorption sample tube, and the BTEXs single component gas adsorption isotherm at 353 K was collected by BELSORP adsorption analyzer (see Figure 4 ). pX, EB, mX, Tol, Bz, and oX vapors carried by helium were introduced into the thermogravimetric analyzer at a flow rate of 50 mL min -1 , data were collected at 353K (see Figure 5 ). The result is as follows Figure 4 and Figure 5 As shown in the figure, it can be seen that the adsorption amount and adsorption behavior of JNU-2 on BTEXs are consistent, indicating that JNU-2 can adsorb BTEXs other than oX. In addition, computational modeling and simulation show (see Figure 6 ), the energy barrier for oX to pass through the aperture is (1587.3 kJ mol -1 ), than pX(105.5kJ mol -1 ), EB(112.7kJ mol -1 )、mX(111.8kJ mol -1 )、Tol(141.4kJ mol -1 ) and Bz (127.8 kJ mol -1 ) is much higher, indicating that the larger oX molecules cannot diffuse in the pores. The initial host-guest calculation model was determined by single crystal X-ray diffraction technology. (See Figure 7 )

[0057] 120 mg of desolvated metal organic framework material JNU-2 was used to perform single component gas adsorption isothermal test and kinetic in situ gravimetric analysis (IGA) of nHEX, 2MP, 3MP, 23DMB and 22DMB at 353 K using BELSORP adsorption analyzer and BSD vapor adsorption analyzer (see Figure 9 ).from Figure 8 It can be seen that the material exhibits exclusion behavior towards 22DMB. Figure 9 It can be seen that nHEX, 2MP, 3MP and 23DMB reached adsorption equilibrium at 20, 70, 80 and 360 min, and their dynamic adsorption capacities were 245, 214, 198 and 73 mg g, respectively. -1The slow diffusion behavior of 23DMB and the size exclusion behavior of 22DMB in JNU-2 suggest its potential for separating dibranched hexanes from linear and singly branched isomers via a kinetic and thermodynamic stepwise separation process.

[0058] 2. Breakthrough Experiments on Separation of o-Xylene from BTEXs Using Metal-Organic Framework Material JNU-2

[0059] Example 3

[0060] In this example, a penetration experiment of a pX / oX gas phase mixture was conducted on the metal organic framework material JNU-2 at 353K.

[0061] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a breakthrough experiment of an equimolar pX / oX (50:50) gas phase mixture was carried out at 353 K using a multicomponent competitive adsorption breakthrough analyzer. Figure 10 This is the breakthrough curve of JNU-2 at 353K for an equimolar pX / oX gas mixture with a carrier gas flow rate of 20mLmin -1 The figure shows that oX eluted directly from the column, while pX did not reach adsorption saturation until nearly 400 minutes. The calculated pX / oX adsorption selectivity was 261, indicating that JNU-2 can efficiently separate oX from equimolar pX / oX gas phase mixtures.

[0062] Example 4

[0063] In this example, a penetration experiment of an EB / oX gas phase mixture was conducted on the metal organic framework material JNU-2 at 353K.

[0064] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a breakthrough experiment of an equimolar EB / oX (50:50) gas phase mixture was carried out at 353 K using a multicomponent competitive adsorption breakthrough analyzer. Figure 11 This is the breakthrough curve of JNU-2 at 353K for an equimolar EB / oX gas mixture with a carrier gas flow rate of 20mLmin -1 The figure shows that oX flows directly out of the column, while EB is not saturated until approximately 325 minutes. The calculated EB / oX adsorption selectivity is 272, indicating that JNU-2 can efficiently separate oX from an equimolar EB / oX gas phase mixture.

[0065] Example 5

[0066] In this example, a penetration experiment of a mX / oX gas phase mixture was conducted on the metal organic framework material JNU-2 at 353K.

[0067] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a breakthrough experiment of an equimolar mX / oX (50:50) gas phase mixture was carried out at 353 K using a multicomponent competitive adsorption breakthrough analyzer. Figure 12 This is the breakthrough curve of JNU-2 at 353K for an equimolar mX / oX gas mixture with a carrier gas flow rate of 20 mL / min. -1 The figure shows that oX flows directly out of the column, while mX reaches adsorption saturation at approximately 200 minutes. The calculated mX / oX adsorption selectivity is 100, indicating that JNU-2 can efficiently separate oX from an equimolar mX / oX gas phase mixture.

[0068] Example 6

[0069] In this example, a penetration experiment of a Tol / oX gas phase mixture was conducted on the metal organic framework material JNU-2 at 353K.

[0070] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a breakthrough experiment of an equimolar Tol / oX (50:50) gas phase mixture was carried out at 353 K using a multicomponent competitive adsorption breakthrough analyzer. Figure 13 This is the breakthrough curve of JNU-2 at 353K for an equimolar Tol / oX gas mixture with a carrier gas flow rate of 20mLmin -1 The figure shows that oX flows directly out of the column, while Tol reaches adsorption saturation at approximately 260 minutes. The calculated Tol / oX adsorption selectivity is 83, indicating that JNU-2 can efficiently separate oX from an equimolar Tol / oX gas phase mixture.

[0071] Example 7

[0072] In this example, a penetration experiment of a Bz / oX gas phase mixture was conducted on the metal organic framework material JNU-2 at 353K.

[0073] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a breakthrough experiment of an equimolar Bz / oX (50:50) gas phase mixture was carried out at 353 K using a multicomponent competitive adsorption breakthrough analyzer. Figure 14 This is the breakthrough curve of JNU-2 at 353K for an equimolar Bz / oX gas mixture with a carrier gas flow rate of 20 mL / min. -1The figure shows that oX flows directly out of the column, while Bz is not saturated until nearly 50 minutes. The calculated Bz / oX adsorption selectivity is 27, indicating that JNU-2 can efficiently separate oX from an equimolar Bz / oX gas phase mixture.

[0074] Example 8

[0075] In this example, a penetration experiment of a four-component pX / mX / oX / EB gas phase mixture and three cyclic penetration experiments were performed on the metal organic framework material JNU-2 at 353K.

[0076] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a penetration experiment of a pX / mX / oX / EB (22 / 50 / 22 / 6) gas phase mixture was carried out at 353 K using a multi-component competitive adsorption penetration analyzer. Figure 15 (a) is a breakthrough curve for a pX / mX / oX / EB (22 / 50 / 22 / 6) gas mixture on JNU-2 at 353 K. The figure shows that oX rapidly penetrates the column at approximately 4 minutes, while mX, EB, and pX do not penetrate until 135, 297, and 310 minutes, respectively. Gas chromatography analysis of the effluent vapor reveals that oX with a purity of 99.9% or higher can be collected before the other components break through. Figure 15 (b) Three consecutive adsorption / desorption breakthrough cycle experiments were conducted under similar conditions, during which JNU-2 was regenerated under high vacuum conditions at 473 K. The results showed that the breakthrough times of the four components fluctuated within a few minutes, indicating that there was no obvious loss in separation ability.

[0077] Example 9

[0078] In this example, a breakthrough test curve of a six-component pX / EB / mX / Tol / Bz / oX gas phase mixture and three cyclic breakthrough tests were performed on the metal organic framework material JNU-2 at 353K.

[0079] 0.7 g of metal-organic framework material JNU-2 sample powder was loaded into a special stainless steel column tube (45 mm ID×300 mm), and a multi-component competitive adsorption penetration analyzer was used to carry out a penetration experiment of a pX / EB / mX / Tol / Bz / oX (1 / 1 / 1 / 1 / 1 / 1) gas phase mixture at 353 K. Figure 16(a) is a breakthrough curve for a JNU-2 gas mixture of pX / EB / mX / Tol / Bz / oX (1 / 1 / 1 / 1 / 1 / 1) at 353 K. The figure shows that oX breaks through the column quickly, while the other impurities do not break through until much later. Gas chromatography analysis of the effluent vapor reveals that oX with a purity of 99.9% or higher can be collected before the other components break through. Figure 16 (b) Three consecutive adsorption / desorption breakthrough cycle experiments were conducted under similar conditions, during which JNU-2 was regenerated under high vacuum conditions at 473 K. The results showed that the breakthrough times of the four components fluctuated within a few minutes, indicating that there was no obvious loss in separation ability.

[0080] Example 10

[0081] In this example, the metal organic framework material JNU-2 sample powder was immersed in a pX / EB / mX / Tol / Bz / oX mixed solution to purify oX.

[0082] Figure 17 This is a schematic diagram of the operational flow of Example 10. First, 18.0 ml of a mixed solution of pX / EB / mX / Tol / Bz / oX (2 / 2 / 2 / 2 / 2 / 90) was prepared. Then, 10 g of the synthesized, desolvated JNU-2 was immersed in the mixed solution and maintained on a shaker at 298 K for 24 hours. Next, 15.2 ml of oX was collected using a cold trap under high vacuum at 298 K, while other BTEXs remained adsorbed within the JNU-2 pores. To facilitate further recycling, the JNU-2 was maintained under high vacuum at 473 K for 24 hours to remove the adsorbed BTEXs. Figure 18 It is the change of oX purity of the initially prepared 18.0ml BTEXs mixed solution and the oX after extraction and recovery. Figure 19 Schematic diagram of oX purity (Figure (a)) and oX recovery (Figure (b)) after 10 adsorption / desorption cycles.

[0083] 3. Penetration experiment of separating hexane isomers using the metal-organic framework material JNU-2

[0084] Example 11

[0085] 1.2 g of desolvated JNU-2 sample powder was loaded into a custom stainless steel column (45 mm ID × 300 mm) and a five-component equimolar nHEX / 2MP / 3MP / 23DMB / 22DMB mixture was subjected to a penetration test at 353 K using a multicomponent competitive adsorption penetration analyzer (see Figure 20 ), flow rate is 10 ml min -1, it can be clearly observed from the figure that the dibranched hexane is separated from the other isomers. 22DMB and 23DMB broke through the column almost simultaneously without much retention, while 3MP, 2MP and nHEX broke through the column at 52, 67 and 148 min g, respectively. -1 Calculated from the breakthrough curve, the real-time RON value was greater than 98 before 3MP eluted from the column. This result indicates that JNU-2 can effectively separate dibranched hexanes from linear and monobranched hexanes.

[0086] Example 12

[0087] 1.2 g of desolvated JNU-2 sample powder was loaded into a custom stainless steel column (45 mm ID × 300 mm) and a breakthrough experiment of a two-component equimolar 23DMB / 22DMB mixture was performed at 353 K using a multicomponent competitive adsorption breakthrough analyzer (see Figure 21 ), flow rate is 3mLmin -1 , Figure 21 (a) is the breakthrough curve of a two-component equimolar mixture of 23DMB and 22DMB on JNU-2 at 353 K with a flow rate of 3.0 ml min -1 From the figure, it can be seen that 22DMB almost immediately broke through the column, indicating that there was no adsorption in the column, while 23DMB did not absorb the chromatographic column until about 34 min g -1 Only then did it break through the chromatographic column. Figure 21 (b) The flow rate curve of JNU-2 desorption of 22DMB and 23DMB at 423K at 20mL min -1 The purity of 23DMB eluted during regeneration under helium. As shown in the figure, the purity of 23DMB after elution was 99.4%, with an RON value of 104.9. This result demonstrates that JNU-2 has achieved complete separation of the two dibranched isomers for the first time, yielding 23DMB with an ultra-high RON value. This result also demonstrates that JNU-2 is capable of effectively separating dibranched hexanes from linear and monobranched hexanes.

[0088] Example 13

[0089] 1.2 g of desolvated JNU-2 sample powder was loaded into a custom stainless steel column (45 mm ID × 300 mm) and a two-component equimolar 23DMB / 22DMB cycle breakthrough experiment was performed five times at 353 K using a multicomponent competitive adsorption breakthrough analyzer (see Figure 22 ), flow rate was 3 mL min -1 , flow rate 20 mL min at 473 K -1 The five breakthrough curves almost completely overlap, indicating that JNU-2 has good cycling stability.

[0090] Example 14

[0091] Figure 23 The desorption analysis of nHEX on JNU-2 and 5A zeolites by in situ gravimetric analysis shows that the nHEX adsorbed on JNU-2 is almost completely released within 450 min, and the desorption time constant is calculated to be -5.5E-4 min. -1 On the other hand, although the nHEX adsorption capacity of 5A molecular sieve is about half that of JNU-2, under the same conditions, the nHEX released is only about one-third of the adsorption capacity, and its desorption time constant is -2.3E-4min. -1 The results show that JNU-2 molecular sieve has certain advantages over 5A molecular sieve in terms of desorption energy consumption when separating hexane isomers.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. Application of a metal organic framework material JNU-2 in the separation of chemical benzene compounds and / or hexane isomers, characterized in that: The JNU-2 window aperture is The chemical benzene compounds include benzene, toluene, ethylbenzene and xylene isomers, the xylene isomers include o-xylene, m-xylene and p-xylene, and the hexane isomers are obtained by completely separating double-branched hexane from straight-chain and single-branched hexane isomers.

2. The use of the metal organic framework material JNU-2 according to claim 1 in separating chemical benzene compounds and / or hexane isomers, characterized in that: The application uses a penetration experiment for separation, which includes the following steps: (1) First, the metal organic framework material JNU-2 is activated; (2) 0.7-1.2 g of the above metal organic framework material JNU-2 powder was filled into a stainless steel column containing silica glass wool at a temperature of 353 K and a carrier gas of helium at a flow rate of 3.0-20 mL min -1 The breakthrough experiment of gas phase mixture of two-component or multi-component chemical benzene compounds or hexane isomers was carried out under the conditions of 1:

1.

3. Use of the metal organic framework material JNU-2 according to claim 2 in separating chemical benzene compounds and / or hexane isomers, characterized in that: In step (2), when the separation object is a chemical benzene compound, the two components can be pX / oX, EB / oX, mX / oX, Tol / oX or Bz / oX in an equimolar ratio.

4. Use of the metal organic framework material JNU-2 according to claim 2 in separating chemical benzene compounds and / or hexane isomers, characterized in that: In step (2), when the separation object is a chemical benzene compound, the multiple components are four components pX / mX / oX / EB, and the volume ratio of the four components is 22 / 50 / 22 / 6.

5. Use of the metal organic framework material JNU-2 according to claim 2 in separating chemical benzene compounds and / or hexane isomers, characterized in that: In step (2), when the separation object is a chemical benzene compound, the multiple components are six components, and the six components are in equal molar ratios of pX / EB / mX / Tol / Bz / oX.

6. Use of the metal organic framework material JNU-2 according to claim 2 in separating chemical benzene compounds and / or hexane isomers, characterized in that: In step (2), when the separation object is hexane isomers, the two components are separated in an equimolar ratio of 23DMB / 22DMB.

7. Use of the metal organic framework material JNU-2 according to claim 2 in separating chemical benzene compounds and / or hexane isomers, characterized in that: In step (2), when the separation object is hexane isomers, the multiple components are four components, and the four components are 2MP / 3MP / 23DMB / 22DMB in an equal molar ratio.

8. Use of the metal organic framework material JNU-2 according to claim 2 in separating chemical benzene compounds and / or hexane isomers, characterized in that: In step (2), when the separation object is hexane isomers, the multiple components are five components, and the five components are nHEX / 2MP / 3MP / 23DMB / 22DMB in equal molar ratios.

9. Use of the metal organic framework material JNU-2 according to claim 1 in separating chemical benzene compounds and / or hexane isomers, characterized in that: When the separation object is chemical benzene compounds, liquid phase extraction can also be used for separation.

10. Use of the metal organic framework material JNU-2 according to claim 9 in separating chemical benzene compounds and / or hexane isomers, characterized in that: The liquid phase extraction separation method comprises immersing 10 g of the activated metal organic framework material JNU-2 in 18.0 mL of pX / EB / mX / Tol / Bz / oX with a volume ratio of 2 / 2 / 2 / 2 / 2 / 2 / 90, placing the mixture on a shaker at 298 K for 24 hours, and then collecting the liquid using a cold trap vacuum.

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