CN110609053A - In-Situ Chemical Reactor and Its Combined System with Nuclear Magnetic Resonance - Google Patents

Abstract

The invention relates to a device for researching a chemical reaction process in situ, which is suitable for operation under high-temperature and low-temperature conditions, can provide nuclear magnetic resonance information of the chemical reaction process and a material structure by being combined with a nuclear magnetic resonance technology, can also provide reaction product information such as quadrupole mass spectrometry and the like, and can also realize millisecond time-resolved reaction dynamic research. The device is suitable for nuclear magnetic resonance research in the fields of chemistry and materials, and can also be used in the fields of hyperpolarized atomic magnetic resonance imaging, magnetic resonance spectroscopy test and the like in the medical field.

Description

In-Situ Chemical Reactor and Its Combined System with Nuclear Magnetic Resonance

technical field

The invention relates to an in-situ chemical reactor and its combined system with nuclear magnetic resonance, which is suitable for nuclear magnetic resonance research in the fields of chemistry and materials, and can also be used for hyperpolarized atom magnetic resonance imaging and magnetic resonance spectroscopy in the medical field testing and other fields.

Background technique

The in-situ study of chemical reaction process and material structure under chemical reaction conditions is the analytical method that most chemists strive for. Scientists try to study the chemical reaction process in situ on a variety of chemical analysis instruments in order to reveal the secrets of the chemical reaction process. The chemical reaction process has little information detail. NMR technology can give its structural information through the bulk phase test of the measured substance, and has aroused great interest because it is very suitable for studying, for example, the structural changes of catalysts during catalytic reactions and the detection of reaction intermediate species. However, the inherent low sensitivity of NMR technology limits the practice of in situ research on material structure and chemical reaction process.

The low sensitivity of nuclear magnetic resonance technology is based on its physical principle, that is, the intensity of nuclear magnetic resonance signal depends on the difference in population number between different energy levels after the energy level splitting of atomic nuclei in an external magnetic field. The number of different energy level layouts conforms to the Boltzmann distribution. Under the condition of thermal equilibrium, the difference in the population number between different energy levels of the nucleus is very small. In a Zeeman split two-level system, the polarizability is defined as the difference between the two-level populations divided by the sum of the populations. Usually the polarization degree of ¹ H nuclei can only reach the order of 10 ^-5 at room temperature. To increase the sensitivity of NMR detection, there are usually two methods. One method is to increase the nuclear spin polarization under thermal equilibrium conditions. Therefore, at present, major instrument manufacturers are constantly increasing the strength of the external magnetic field to increase the polarization and thus improve the detection sensitivity. However, the increase in the strength of the external magnetic field means a rapid increase in the cost of instrument production, and theoretically does not support magnetic resonance technology with higher resonance frequencies. Another idea is to increase the nuclear spin polarization beyond the thermal equilibrium condition through polarization transfer, thereby greatly improving the detection sensitivity. At present, there are many effective methods to increase the degree of polarization by several orders of magnitude, such as spin-exchange optical pumping, dynamic nuclear polarization (DNP), and so on. The method of obtaining hyperpolarized ¹²⁹ Xe by spin-exchange optical pumping has been partially applied in the field of biomedicine and material structure research.

Hyperpolarized noble noble gases are usually obtained by optically pumped spin-exchange methods. For example, the mixture of alkali metal and rare inert gas is placed under a magnetic field of a certain strength, and the mixture in the magnetic field is irradiated with circularly polarized light of a specific wavelength to obtain a hyperpolarized rare inert gas. The principle is that the energy level of the alkali metal atom is split under the action of a magnetic field, and its spin is highly polarized under the action of circularly polarized light. Because the alkali metal atom is fully mixed with the rare inert gas, the alkali metal will change its spin angle through collisions and other ways. The momentum is transferred to the rare inert gas, so hyperpolarized rare inert gas is obtained. Bouchiat et al. studied the spin exchange transfer mechanism [1], and believed that the van der Waals molecules formed by alkali metal atoms-rare inert gases played an important role in the electron polarization relaxation of alkali metal atoms. The lower spin exchange process mainly occurs between the alkali metal atoms and the van der Waals molecules of the rare inert gas. The spin exchange mechanism between noble gas molecules can be explained by the two-body collision theory. Grover found that [2], in a low magnetic field, the spin exchange between alkali metal atoms and Xe atoms has a very high efficiency. Applying spin exchange technology can increase the polarizability of rare inert gases by about 10 ³ -10 ⁵ orders of magnitude.

The acquisition of hyperpolarized gas provides great convenience for people to use it to detect chemical reaction process and material structure knowledge. In the 1980s, Fraissard[3] and Ripmeester[4] first introduced ¹²⁹ Xe as a probe atom into the NMR research field of catalytic materials such as molecular sieves. Xenon (Xe) is an inert monatomic gas that hardly reacts chemically with other substances. The ¹²⁹ Xe isotope has a nuclear spin quantum number of 1/2 and a natural abundance of 26.4%. The spherical electron cloud of the xenon atom is large and easily affected by the surrounding environment. Since it does not chemically react with other substances, it is very easy to act on the inner and outer surfaces of the substance when it contacts the substance, thereby affecting the electron cloud density of ¹²⁹ Xe, and then affecting the magnetic shielding of the Xe nucleus and affecting its chemical shift. One-dimensional and two-dimensional ¹²⁹ Xe NMR techniques are widely used to study the pore structure of inorganic and organic materials, the distribution of guest particles, the location of carbon formation on catalysts, and the diffusion process of adsorbed molecules on the surface. The sensitivity of Xe atom to its surrounding environment has made ¹²⁹ Xe NMR become one of the important means to study the structure of catalysts. Laser-induced hyperpolarized ¹²⁹ Xe isotope probe technology, by using the interaction between inert Xe atoms and substances, as well as the interaction with products and intermediate species during chemical reactions, can analyze the structural changes and The state of reaction intermediate species can be effectively studied.

In situ NMR studies of chemical reaction processes have a history of two decades. In 1995, Hunger carried out the NMR detection of the in situ heterogeneous catalytic reaction (J.Chem.Soc., Chem.Commun., 1995, 1423-1424), and the catalytic conversion process of methanol was carried out under close to real reaction conditions conducted a systematic study and found evidence for the formation of a reaction intermediate transition state on the catalyst surface during the catalytic conversion. Liu et al [5-8] used hyperpolarized NMR technology in the study of material pore structure and achieved many meaningful results.

[1] Bouchiat C C, Bouchiat M A, Porrier L C. Phys. Rev., 1969, 181:144

[2]Grover B C.Phys.Rev.Let t.,1978,40:391

[3] Ito T, Fraissard J.J Chem Phys, 1982, 76(11): 5225

[4] Ripmeester J A. J A m Chem Soc, 1982, 104(1): 289

[5] Liu S B, Lin T S, Yang T C, Chen T H, Hong E C, Ryoo R.J Phys Chem, 1995,99(20):8277

[6] Sakthivel A, Huang S J, Chen W H, Lan Z H, Chen K, H, Kim T W, Ryoo R, Chiang A S T, Liu S B. ChemMater, 2004, 16(16): 3168

[7] Huang S J, Huang C H, Chen W H, Sun X P, Zeng X Z, Lee H K, Ripmeester JA, Mou C Y, Liu S B.J PhysChem B, 2005, 109(2): 681

[8] Huang S J, Huh S, Lo P S, Liu S H, Lin V S Y, Liu SB. Phys Chem ChemPhys, 2005, 7(16): 3080

Contents of the invention

The present invention aims to develop in-situ on-line nuclear magnetic resonance detection with wide adaptability and a chemical reaction device combined with other analytical means. Other analytical means can be analytical instruments such as mass spectrometers, chromatographs, and spectrometers. The interaction of the reaction system to study the chemical reaction process, and then establish a device that can controllably and effectively introduce the hyperpolarized rare inert gas probe into the above reactor, so that the two can work together, so as to study the chemical reaction process the goal of.

In order to achieve the goal of applying hyperpolarized rare inert gas probes to study chemical reaction processes, an online chemical reactor and its control system suitable for in-situ detection of nuclear magnetic resonance are established. One aspect of the present invention provides an in-situ A chemical reaction device working under nuclear magnetic resonance conditions, an in-situ chemical reactor, the in-situ chemical reactor is a sealed straight tube reactor, including an inlet pipeline, an outlet pipeline, and nested inner and outer pipes ;The bottom of the outer tube is closed and the top is open; the bottom of the inner tube is open and the top is open; the top of the inner tube and the outer tube are equipped with a removable seal; There is a gap between the pipe wall and the outer pipe wall; the inlet pipeline is connected with the inner pipe; the outlet pipeline is connected with the outer pipe; the material of the in-situ chemical reactor is a non-magnetic material; the non-magnetic material is preferably glass, ceramic or organic polymer.

Further, when the reactant is in solid phase, the solid phase reactant is filled in the inner tube; when the reactant is in liquid phase, the liquid phase reactant is filled in the outer tube.

Further, when the reactant is in the solid phase, the solid phase reactant is filled at the bottom of the inner tube; when the reactant is in the liquid phase, the bottom of the inner tube is close to the liquid level of the liquid phase reactant or the inner tube extends into the liquid phase reaction bottom of the object.

Further, the in-situ chemical reactor also includes a gas control system, the gas control system is provided with two or more reaction gas input pipelines, and the reaction gas input pipelines are sequentially set along the gas flow direction for pressure regulation. valve, water oxygen filter, mass flow controller, check valve.

Another aspect of the present invention provides an in-situ chemical reactor and nuclear magnetic resonance combined system, the combined system includes the above-mentioned in-situ chemical reactor; the in-situ chemical reactor extends into the detection coil of the nuclear magnetic resonance probe Position; the reaction gas required for the in-situ chemical reaction is communicated with the inner tube through the inlet pipeline.

The method for detecting a chemical reaction using the in-situ chemical reaction coupled with nuclear magnetic resonance system includes the following steps: (1) filling a solid-phase reactant into an inner tube or filling a liquid-phase reactant into an outer tube; (2) filling the inner tube with a liquid-phase reactant; The in-situ chemical reactor extends into the detection coil position of the nuclear magnetic resonance probe; (3) the chemical reaction gas is fed into the inner tube through the intake pipeline.

In yet another aspect of the present invention, the hyperpolarized gas is used as a probe, combined with the above-mentioned in-situ chemical reactor, and nuclear magnetic resonance technology is used to study the chemical reaction process and material structure characteristics. Provide a rare inert gas probe generator, an in-situ chemical reactor, and a combined nuclear magnetic resonance system, the combined system includes the above-mentioned in-situ chemical reactor; the in-situ chemical reactor extends into the detection of the nuclear magnetic resonance probe The position of the coil; the reaction gas required for the in-situ chemical reaction is communicated with the inner tube through the intake line; the rare inert gas generated by the rare inert gas probe generator is used as the detection gas to pass into the inner tube through the intake line.

Using the above rare inert gas probe generator, in-situ chemical reactor and nuclear magnetic resonance combined system to detect chemical reactions, using hyperpolarized rare inert gases as probes and applying nuclear magnetic resonance technology to detect material structure information and chemical reaction processes The device comprises the following steps: (1) filling the inner tube with the solid-phase reactant or filling the outer tube with the liquid-phase reactant; (2) extending the in-situ chemical reactor into the position of the detection coil of the nuclear magnetic resonance probe; ( 3) Passing hyperpolarized rare inert gas and/or chemical reaction gas into the inner tube through the intake pipeline.

Another aspect of the present invention also provides a rare inert gas probe generator, in-situ chemical reactor, nuclear magnetic resonance, gas analysis instrument combination system, the combination system includes the above-mentioned in-situ chemical reactor; in-situ The chemical reactor extends into the detection coil position of the nuclear magnetic resonance probe; the gas outlet pipeline is connected to the gas analysis instrument; the gas analysis instrument is preferably a quadrupole mass spectrometer or a gas chromatograph.

Another aspect of the present invention also provides the application of any combination system mentioned above in the test of the pore structure of the microporous catalyst material.

The in-situ chemical reactor of the present invention is made of special materials. Since the reactor is placed in the center of a strong magnetic field, its magnetic field strength can reach more than 14 Tesla. This special material is required not to contain ferromagnetic substances, because ferromagnetic substances can strongly affect the magnetic field of the NMR spectrometer under the action of a strong magnetic field. The uniformity, thus affecting the detection of NMR. The material must also not contain metallic materials, or materials that strongly absorb electromagnetic radiation. The principle of nuclear magnetic resonance shows that when nuclear magnetic resonance is detected, it emits electromagnetic radiation with a power of several hundred watts or even thousands of watts. The above materials will absorb a large amount of electromagnetic radiation, greatly reducing the efficiency of nuclear magnetic resonance, and can also emit secondary radiation, which is displayed in the nuclear magnetic resonance spectrum. In addition, false signals may be brought about; in addition, it may cause undesired heating of the sample, thereby affecting the stability of the detection and chemical reaction system. The materials described in the present invention may be materials that do not conflict with the above requirements, including materials such as glass, ceramics, and organic polymers.

The in-situ chemical reactor of the present invention is not limited by the magnetic field strength of the nuclear magnetic resonance spectrometer. The style of the reactor is only related to the probe form of the nuclear magnetic resonance spectrometer used, and a reactor suitable for various probe forms of the nuclear magnetic resonance spectrometer is realized.

The invention relates to a device for studying chemical reaction process in situ. The chemical reaction device is suitable for operation under high temperature and low temperature conditions. It can provide nuclear magnetic resonance information of chemical reaction process and material structure when used in conjunction with nuclear magnetic resonance technology, and can also provide quadrupole Reaction product information such as mass spectrometry analysis can also realize reaction dynamics research with 50 millisecond time resolution. The device is suitable for nuclear magnetic resonance research in the field of chemistry and materials, and can also be used in fields such as hyperpolarized atom magnetic resonance imaging and magnetic resonance spectroscopy testing in the medical field.

Description of drawings

Fig. 1 gas control system, in-situ chemical reactor and flow chart of connection with nuclear magnetic resonance spectrometer and mass spectrometer;

Figure 2 is a block diagram of the combined instrument system;

Figure 3A Schematic diagram of liquid probe reactor (gas-solid phase) structure

Figure 3B Schematic diagram of liquid probe reactor (gas-solid phase) decomposition

Fig. 4A is the placement diagram of the in-situ chemical reactor and the nuclear magnetic resonance instrument;

Figure 4B is a partially enlarged view of Figure 4A

Fig. 5A, 5B are the structural schematic diagrams of the liquid probe reactor (gas-liquid phase)

Fig.6 Hyperpolarized ¹²⁹ Xe NMR spectra of MFI structure under different treatment conditions

Fig.7 NMR spectrum of MFI sample 2# hyperpolarized ¹²⁹ Xe

In Figure 1, 501,502 air source, 511,512 pressure regulator, 521,522 water oxygen filter, 531,532 mass flow meter, 541,542 one-way valve, 551,552 ball valve, 594,596 globe valve, 561 pressure gauge, 597 hyperpolarized gas inlet, 592 nuclear magnetic resonance spectrometer, 593 reactor, 591 quadrupole mass spectrometer, 595 needle valve;

In Fig. 2, 811 reaction gas control system, 812 NMR spectrometer, 813 hyperpolarized generator, 814 NMR control system, 815 quadrupole mass spectrometer;

In Fig. 3B, 601 reactor outer tube, 602 reactor inner tube, 611 sealing rod fixing bolt, 612 sealing rod, 613 rubber sealing O-ring, 621 air inlet sealing cap, 622 air outlet sealing cap, 623 air inlet pipe, 624 air outlet pipe ;

In FIG. 4B , 702 reactor, 711 nuclear magnetic resonance spectrometer superconducting coil 711 , nuclear magnetic resonance probe 712 , and nuclear magnetic resonance spectrometer transmitting coil 713 .

Detailed ways

A specific implementation principle and operation method of the present invention will be described below in conjunction with illustrations.

Figure 1 is a flow chart of the gas control system, in-situ chemical reactor, and simultaneous detection with nuclear magnetic resonance spectrometers and other analytical instruments (such as mass spectrometers). Using nuclear magnetic resonance method to study chemical reaction process and material structure characteristics through hyperpolarized probe molecules requires an in-situ chemical reaction system used by nuclear magnetic resonance instruments, including in-situ reactors and chemical reaction control systems. The chemical reaction control system includes gas source type control facilities, gas flow control facilities, gas pressure control facilities, and reactor temperature control facilities (not shown in the figure).

The gas control system of the invention can realize arbitrary adjustment and control of the concentration and flow rate of the rare inert gas. The hyperpolarized rare inert gas is used as a chemical reaction probe, which can be adjusted to meet the requirements of the chemical reaction system in the reactor when responding to different chemical reaction requirements.

Preferably, the gas control system is designed with two or more reaction gas inlet pipelines, and the reaction gas inlet pipelines are sequentially provided with a pressure regulating valve, a water-oxygen filter, a mass flow controller, and a one-way valve along the gas flow direction. . After the gas is decompressed to the set pressure, the oxygen molecules and water molecules in the gas are further filtered through the water-oxygen filter, and then enter the reactor 593 after being controlled by the mass flow controller to the required gas flow rate. During the chemical reaction, The hyperpolarized gas probe enters the reactor through the inlet 597 and the shut-off valve 596. The detection of the NMR spectrometer 592 gives information on the reaction process and material structure changes. At the same time, the reaction products can be analyzed by the quadrupole mass spectrometer 591. Information on the progress of the reaction. The needle valve 595 can adjust the reaction pressure of the reactor. The reactor can be operated in a wider range of reaction conditions.

Two or more inlet pipes are merged before entering the reactor, and one-way valves are respectively set before the merge. When several channels of gas are mixed, it can prevent other channels of gas from reversely pressing the flow meter of this channel and flowing back.

The invention dynamically controls the output volume of each gas channel by controlling the mass flow controller connected to each gas channel, and achieves the purpose of arbitrarily controlling the concentration of reaction gas and detection gas.

The present invention involves that the channel through which the hyperpolarized gas probe flows is made of specific materials. These materials can be brass, glass, polyethylene, polytetrafluoroethylene, etc. The inner walls of the equipment formed by the above-mentioned materials need to pass through Functional processing. The functionalization treatment here refers to covering the surface with a non-polar solvent to remove polar groups on the surface. Because the polar groups on the surface have a strong depolarization effect on hyperpolarized rare inert gases, covering the polar groups on the inner surface to the greatest extent is essential for maintaining the polarizability of hyperpolarized rare inert gases. Critical. The non-polar solvent mentioned here generally refers to a silylating agent, such as chlorosiloxane, etc., which can firmly combine with the inner surface of the material to be covered and effectively cover the polar groups on the inner surface.

Fig. 2 is a schematic flow chart of the entire chemical reaction analysis combined instrument system. The nuclear magnetic resonance spectrometer 812 is the key instrument of the system, and it is the key equipment for the in-situ chemical reaction described in the present invention and the hyperpolarized rare inert gas probe nuclear magnetic resonance detection, and the in-situ reactor is placed in the nuclear magnetic resonance spectrometer 812 In the detection coil, it is usually a commercial nuclear magnetic resonance spectrometer, and the NMR control system 814 provides radio frequency pulse emission, nuclear magnetic resonance signal detection, in-situ reactor temperature control, etc. for the nuclear magnetic resonance spectrometer. The gas required by the in-situ chemical reactor is provided by the reaction gas control system 811, the hyperpolarized rare inert gas probe is provided by the hyperpolarized generator 813, and the reaction product in the in-situ reactor flows out of the reactor and passes through the quadrupole mass spectrometer 815 Detection can give information on the extent to which the reaction has progressed. Next, the key parts are described, and the control part irrelevant to the invention is not described in detail.

The in-situ chemical reactor of the present invention is a closed straight tube reactor, one end of the reactor is closed, the other end is open, and the open end is equipped with a sealing connection facility, which can be disassembled and can load and unload test samples. The sealing connection facility is equipped with Gas inlet and outlet pipelines. The reactor is a nested structure of an inner tube and an outer tube, the inner tube is nested inside the outer tube, and the inner tube can be taken out.

The invention relates to a device for studying chemical reaction process in situ. The chemical reaction device is suitable for operation under high temperature and low temperature conditions. It can provide nuclear magnetic resonance information of chemical reaction process and material structure when used in conjunction with nuclear magnetic resonance technology, and can also provide quadrupole Reaction product information such as mass spectrometry analysis can also realize reaction dynamics research with millisecond time resolution. The device is suitable for nuclear magnetic resonance research in the field of chemistry and materials, and can also be used in fields such as hyperpolarized atom magnetic resonance imaging and magnetic resonance spectroscopy testing in the medical field.

Example 1

An implementation form of the in-situ chemical reactor of the present invention is shown in Figure 3A and Figure 3B, Figure 3A is a structural diagram of a gas-solid phase reactor (reactor A), and Figure 3B is a gas-solid phase reactor (reactor A) Composition exploded diagram.

The reactor is a closed straight tube type. The bottom end of the outer tube 601 of the reactor is closed, the top end is open, and the top end has threads. The top end seals the outer tube 601 through a sealing rod 612. The sealing rod 612 is equipped with a rubber sealing O-ring 613, and the sealing rod 612 is sealed together with the outer tube 601 through the fixing bolt 611 of the sealing rod. The sealing rod 612 is equipped with gas inlet and outlet pipelines. The reactor is a nested structure of an inner tube and an outer tube. The gas enters the upper part of the sample through the inner tube, flows out from the bottom after flowing through the sample, and exits through the gap between the outer tube and the inner tube wall. Reactor inner tube 602 can be removed. The solid reactants are placed at the bottom of the inner tube, which is close to the bottom of the outer tube of the reactor. When performing in-situ NMR research, the bottom of reactor A extends into the position of the detection coil of the NMR probe. This position is at the center of the superconducting coil of the nuclear magnetic resonance spectrometer, and the sample to be measured is completely placed within the range of the detection coil. See attached drawing 4. The reactor is connected to the gas control device through pipelines, and the reaction gas is provided by the gas control device, and its pressure, flow rate, and the type of reaction gas are all regulated by it.

The manufacturing materials of the chemical reactor are all non-magnetic materials. The reaction tube is made of heat-resistant glass, and the sealing rod is made of PEEK material. The pressure that the reactor can withstand can reach 1MPa, and the temperature it can withstand is -100°C to 400°C. Reactors can replace sample tubes for NMR.

The working principle of reactor A is described as follows:

The bottom of the reactor A extends into the position of the detection coil of the nuclear magnetic resonance probe. This position is at the center of the superconducting coil of the nuclear magnetic resonance spectrometer, and the sample to be measured is completely placed within the range of the detection coil. The reactor is connected to the gas control device through pipelines, and the reaction gas is provided by the gas control device, and its pressure, flow rate, and the type of reaction gas are all regulated by it. The pressure that the reactor can withstand can reach 1MPa, and the temperature it can withstand is -100°C to 400°C. The multiphase chemical reaction is carried out under proper working conditions; the hyperpolarized rare inert gas is fed into the reactor through parallel pipes, so that the nuclear magnetic resonance detection of the hyperpolarized rare inert gas probe can be carried out while the reactor is working. The tail gas after the completion of the reaction flows out through the outlet channel of the reactor and is vented through a controllable valve. A gas analysis instrument is connected to the outflow channel. The analysis instrument can be a quadrupole mass spectrometer or a gas chromatograph. Perform detection analysis. In this way, the real-time analysis and research of the reaction system can be realized by combining the NMR detection with other analytical instruments.

There are two working states of reactor A, the difference is that the heating method of the reactor is different and the working position of the reactor is different. The first is the working state of the on-line in-situ nuclear magnetic resonance spectrometer. The reactor is placed inside the nuclear magnetic resonance spectrometer when it is working. The temperature control method of the reactor is provided by the probe of the nuclear magnetic resonance spectrometer itself. Usually, its temperature control range is small. However, in-situ detection can be truly realized. The NMR detection of the hyperpolarized rare inert gas probe can be performed while the chemical reaction is in progress; Outside, the temperature control of the reactor is implemented by an additional temperature control unit, which has the advantage that the reaction temperature is not limited by the temperature of the nuclear magnetic resonance spectrometer, and can reach any temperature required. Fast online transfer to the inside of the nuclear magnetic spectrometer for nuclear magnetic resonance detection. The reactor has the following characteristics, which integrates chemical reaction and rare inert gas probe NMR detection. The reactor is suitable for studying the reaction system in which the mobile phase is gas and the stationary phase is solid powder. This reactor is suitable for common liquid probes of nuclear magnetic resonance spectrometers.

When the multiphase chemical reaction is carried out under proper working conditions, the hyperpolarized rare inert gas is passed into the reactor, so that the nuclear magnetic resonance detection of the hyperpolarized rare inert gas probe can be carried out while the reactor is working. The tail gas after the reaction flows out through the outlet channel of the reactor and is emptied through a controllable valve. A gas analysis instrument is connected to the outflow channel. The analysis instrument can detect and analyze the reaction product and the degree of reaction. In this way, the real-time analysis and research of the reaction system can be realized by combining the NMR detection with other analytical instruments.

Example 2

Another realization of the above-mentioned chemical reactor is a gas-liquid chemical reactor (reactor B), in which liquid reactants are filled into the outer tube, and its basic structure is similar to that of reactor A, the difference is that the length or shape of the inner tube of the sample tube is different , the reactor is suitable for studying the multiphase chemical reaction system of liquid and gas.

Accompanying drawing 5A and 5B are the structural representations of two kinds of different gas-liquid reactors respectively: the reactor shown in accompanying drawing 5A, inner tube is 30～40mm shorter than the inner tube of reactor A, when filling liquid reactant, inner tube bottom The end (that is, the gas outlet) is close to the liquid surface of the liquid reactant in the outer tube but does not touch the liquid surface. This design makes the flowing gas have little influence on the liquid, and the liquid will not be blown and bubbling by the gas. The detection of resonance has little effect. In the reactor shown in accompanying drawing 5B, the length of the inner tube is the same as that of the reactor A inner tube, and the inner tube (preferably its bottom diameter is smaller) stretches to the liquid bottom of the liquid reactant in the outer tube, and enters the liquid by the inner tube The gas can fully contact with the liquid, and the contact area between the gas and the liquid is increased, thereby increasing the solubility of the gas in the liquid. Hyperpolarized rare inert gases can be dissolved into liquids, and NMR detection can be used to study the progress of chemical reactions.

The reactor can not only conduct nuclear magnetic resonance research of hyperpolarized rare inert gases, but also further study the process of chemical reactions by collecting other nuclear magnetic resonance signals of the reaction system, such as ¹ H spectrum and ¹³ C spectrum. The reactor is used to study gas and liquid heterogeneous reaction system, and the range of applicable nuclear magnetic instruments is the same as that of the previous reactor.

Example 3

In this embodiment, a hyperpolarized ¹²⁹ Xe probe is used to study the change of the pore structure in a porous material with an MFI structure. Using the reactor described in Example 1, the ¹²⁹ Xe NMR spectrum of each MFI structure material with different structures was recorded at different temperatures for the tested substance.

1. Experimental method

Using the reactor of Example 1, using hyperpolarized ¹²⁹ Xe probe atoms, the research system is a molecular sieve with MFI structure obtained by different preparation and processing methods. The molecular sieve system is 3 H-ZSM-5 (MFI structure) comparison samples, Sample 1 is the original powder H-ZSM-5 sample, that is, the synthesized H-ZSM-5 sample, without special treatment, the sample particles are about 40-60 mesh (40-10 microns); sample 2 is the addition of sample 1 40% binder, the binder is non-porous powder material γ-alumina powder, which is extruded into granules with a diameter of 2 to 3 mm after mechanical mixing; sample 3 is directly extruded from sample 1 to Granules with a diameter of 2 to 3 mm. The three tested samples were vacuum dehydrated at 420°C for 20 hours, and the vacuum degree was maintained at 10 ^-4 Pa. The hyperpolarized ¹²⁹ Xe nuclear magnetic resonance test is carried out, and the test temperature is from -80°C to 35°C. The resonance frequency of ¹²⁹ Xe is 110MHz, and the pulse program is a single pulse program.

2. Experimental results

H-ZSM-5 is a microporous catalyst material commonly used in the petrochemical industry, and its pore properties are one of the most important factors affecting the industrial process. Commonly used pore analysis instruments such as physical adsorption instruments can give information on the specific surface area and pore distribution of materials, but they are helpless for small differences in pore channels. However, xenon atoms are particularly sensitive to changes in the size of the pores because of their extranuclear electron clouds that are easily affected by the surrounding environment. Figure 6 shows the hyperpolarized ¹²⁹ Xe NMR spectra of the above three samples. It can be seen from the figure that the chemical shift of H-ZSM-5 sample 1# without molding treatment at 273K is ~109ppm; The H-ZSM-5 sample 3# has a chemical shift of ~104ppm, and the peak is slightly broadened; while the H-ZSM-5 sample 2# physically mixed with a binder has a shoulder in the range of 104~109ppm. The bimodal structure of the peaks showed obvious differences under different treatment conditions. In the range of -80°C to 35°C, three samples were studied, and it was found that sample 1# and sample 3# showed a single peak in all temperature ranges, which meant that their pore structures were all single, but their The channels between them show the difference. Figure 7 shows the spectrum peaks of sample 2# in the range of -30°C to 35°C, and it is obvious that it has a double peak structure. From the chemical shift analysis of the spectral peaks, these two peaks are microporous structures, and aluminum oxide usually does not appear microporous structures, which means that the two kinds of channels are all from the micropores of H-ZSM-5, and we know that the Molecular sieves have only a single micropore, and the appearance of two peaks means that there are two different channels, and the two channels are separated. This experimental result has very important significance for the preparation of the catalyst.

Claims (10)

1. In situ chemical reactor, The in-situ chemical reactor is a sealed straight tube reactor, including an inlet pipeline, an outlet pipeline, and nested inner and outer pipes; The outer tube is closed at the bottom and open at the top; The inner tube is open at the bottom and open at the top; The tops of the inner tube and the outer tube are equipped with detachable seals; There is a gap between the bottom end of the inner tube and the bottom end of the outer tube; There is a gap between the inner tube wall and the outer tube wall; The intake pipe is connected with the inner pipe; The outlet pipe is connected with the outer pipe; The material of the in-situ chemical reactor is a non-magnetic material; The non-magnetic material is preferably glass, ceramic or organic polymer. 2. The in-situ chemical reactor according to claim 1, characterized in that, When the reactant is a solid phase, the solid phase reactant is filled in the inner tube; When the reactant is in liquid phase, the liquid phase reactant is filled in the outer tube. 3. The in-situ chemical reactor according to claim 2, characterized in that, When the reactant is a solid phase, the solid phase reactant is filled at the bottom of the inner tube; When the reactant is in liquid phase, the bottom end of the inner tube is close to the liquid level of the liquid phase reactant or the inner tube extends into the bottom of the liquid phase reactant. 4. in-situ chemical reactor according to claim 1, is characterized in that, described in-situ chemical reactor also comprises gas control system, and described gas control system is provided with two or more reaction gas input pipes The reaction gas input pipeline is provided with a pressure regulating valve, a water-oxygen filter, a mass flow controller, and a one-way valve in sequence along the gas flow direction. 5. In situ chemical reactor and nuclear magnetic resonance coupled system, characterized in that, The combined system comprises the in-situ chemical reactor described in any one of claims 1-4; The in-situ chemical reactor extends into the detection coil position of the nuclear magnetic resonance probe; The reaction gas required for the in-situ chemical reaction is communicated with the inner tube through the inlet pipeline. 6. adopt the method for the in-situ chemical reaction described in claim 5 and nuclear magnetic resonance coupling system detection chemical reaction, comprise the following steps, (1) Fill the inner tube with the solid-phase reactant or fill the outer tube with the liquid-phase reactant; (2) extending the in-situ chemical reactor into the detection coil position of the nuclear magnetic resonance probe; (3) Pass the chemical reaction gas into the inner pipe through the air intake pipeline. 7. Rare inert gas probe generator, in-situ chemical reactor, nuclear magnetic resonance combined system, characterized in that, The combined system comprises the in-situ chemical reactor described in any one of claims 1-4; The in-situ chemical reactor extends into the detection coil position of the nuclear magnetic resonance probe; The reaction gas required for the in-situ chemical reaction is communicated with the inner pipe through the intake pipe; The rare inert gas produced by the rare inert gas probe generator is passed into the inner tube through the inlet pipeline as the detection gas. 8. adopt the method for detecting chemical reaction of rare inert gas probe generator described in claim 6, in-situ chemical reactor and nuclear magnetic resonance system, comprising the following steps, (1) Fill the inner tube with the solid-phase reactant or fill the outer tube with the liquid-phase reactant; (2) extending the in-situ chemical reactor into the detection coil position of the nuclear magnetic resonance probe; (3) Pass hyperpolarized rare inert gas and/or chemical reaction gas into the inner tube through the intake pipeline. 9. A rare inert gas probe generator, in-situ chemical reactor, nuclear magnetic resonance, and gas analysis instrument combined system, characterized in that, the combined system includes the described in-situ chemical reactor; the in-situ chemical reactor Extending into the detection coil position of the nuclear magnetic resonance probe; the gas outlet pipeline is connected to the gas analysis instrument; the gas analysis instrument is preferably a quadrupole mass spectrometer or a gas chromatograph. 10. The combined system of claim 5 or 7 or 9, used in the testing of the pore structure of microporous catalyst materials.