Application of lithium magnesium nitrogen hydrogen material

Abstract

The invention discloses application of a lithium-magnesium-nitrogen-hydrogen material, and belongs to the technical field of organic liquid hydrogen storage, the application is that the lithium-magnesium-nitrogen-hydrogen material is used as a cocatalyst when a liquid organic hydrogen storage material is subjected to hydrogenation reaction, and a main catalyst when the liquid organic hydrogen storage material is subjected to hydrogenation reaction is a noble metal catalyst. In the hydrogenation reaction process of the liquid organic hydrogen storage material, the dehydrogenated lithium magnesium nitrogen hydrogen material can be used as a cocatalyst of a noble metal catalyst to activate hydrogen molecules and provide reactive hydrogen for the hydrogenation reaction, and the hydrogenation reaction rate of the noble metal catalyst for catalyzing the organic liquid hydrogen storage material is effectively improved through the synergistic reaction of the catalyst and the cocatalyst; the hydrogenation saturation time is shortened, the energy consumption is reduced, the consumption of noble metals is reduced, and the cost is saved.

Description

Technical Field

[0001] The invention relates to application of a lithium magnesium nitrogen hydrogen material, belonging to the technical field of organic liquid hydrogen storage. Background Art

[0002] The principle of organic liquid hydrogen storage technology is to achieve hydrogen storage and release by means of reversible addition and dehydrogenation reactions of some liquid organic hydrogen storage carriers (LOHC) with unsaturated bonds and hydrogen. Its advantages are that it is in liquid form at room temperature and pressure, has a high hydrogen storage mass density, and can only undergo hydrogenation and dehydrogenation reactions under certain catalytic conditions, so it can safely transport hydrogen energy at room temperature and pressure with the help of existing infrastructure.

[0003] At present, the hydrogenation catalysts commonly used in the hydrogen storage process of organic hydrogen storage liquids are mainly expensive precious metal catalysts, such as palladium-based catalysts, platinum-based catalysts, ruthenium-based catalysts and rhodium-based catalysts. Precious metals as active centers have the advantages of high activity and low temperature and pressure requirements, but their high cost limits their widespread application. In the commercialization process of organic hydrogen carrier hydrogen storage and decomposition technology, reducing costs is the only way. How to reduce the amount of precious metal catalysts used in the work of organic hydrogen storage liquids has become a difficult problem that needs to be solved urgently in the field of organic liquid hydrogen storage technology. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a new use of lithium magnesium nitrogen hydrogen material, which can reduce the amount of precious metal catalyst used in the work of organic hydrogen storage liquid.

[0005] The purpose of the lithium magnesium nitrogen hydrogen material is to serve as a co-catalyst in the hydrogenation reaction of liquid organic hydrogen storage materials, wherein the main catalyst in the hydrogenation reaction is a precious metal catalyst.

[0006] The use of the lithium magnesium nitrogen hydrogen material provided in the present application helps to improve the kinetics of hydrogenation and dehydrogenation of the organic liquid hydrogen storage medium and the conversion efficiency of the reactants by using a co-catalyst, thereby enhancing the catalytic reaction activity of the catalyst, thereby reducing the amount of precious metal catalyst used and thus reducing the catalyst cost.

[0007] Furthermore, the liquid organic hydrogen storage material is selected from at least one of aromatic compounds and nitrogen-containing heterocyclic compounds.

[0008] Furthermore, the aromatic compound is selected from at least one of benzene, toluene, dibenzyltoluene, naphthalene, and naphthalene derivatives.

[0009] Preferably, the nitrogen-containing heterocyclic compound is selected from at least one of carbazole, N-ethylcarbazole, N-propylcarbazole, indole, 1-methylindole, and 2-methylindole. The hydrogenation temperature of the above preferred nitrogen-containing heterocyclic compound matches the hydrogenation temperature of lithium magnesium nitrogen hydrogen and the temperature at which the hydrogenation reaction produces a catalytic effect, which can simultaneously achieve the effect of catalytic promotion and maintain the high hydrogen storage density of the entire system.

[0010] Furthermore, the precious metal catalyst includes at least one of a platinum-based catalyst, a palladium-based catalyst, a ruthenium-based catalyst, and a rhodium-based catalyst.

[0011] Furthermore, the noble metal catalyst comprises a carrier material and a noble metal material supported on the carrier material, and the carrier material is selected from C, CeO 2 、Al 2 O 3 At least one of .

[0012] Furthermore, the noble metal material is Pt, Pd, Ru, or Rh.

[0013] Furthermore, the step of the hydrogenation reaction comprises: Mixing the liquid organic hydrogen storage material and the powdered lithium magnesium nitrogen hydrogen material into a slurry; adding the noble metal catalyst to the slurry; The slurry was heated and hydrogen was passed through.

[0014] Furthermore, the particle size of the lithium magnesium nitrogen hydrogen material is 10 nm to 10 μm.

[0015] Furthermore, the amount of the lithium magnesium nitrogen hydrogen material is 0.1wt% to 10wt% of the liquid organic hydrogen storage material.

[0016] Furthermore, the steps of preparing the lithium magnesium nitrogen hydrogen material include: Mix LiNH in a protective atmosphere 2 Powder and MgH 2 powder, or mixed with Mg(NH 2 ) 2 powder and LiH powder to obtain a mixed powder; Ball milling the mixed powder for 12 h to 48 h under a protective atmosphere, with a ball-to-powder ratio of 20:1 to 100:1 and a rotation speed of 150 rpm to 400 rpm, to obtain preliminary dehydrogenated particles; The preliminary dehydrogenated particles are subjected to a dehydrogenation treatment to obtain the lithium magnesium nitrogen hydrogen material.

[0017] The beneficial effects of the present invention are as follows: in the hydrogenation reaction process of liquid organic hydrogen storage materials, the dehydrogenated lithium magnesium nitrogen hydrogen material can be used as a co-catalyst of the precious metal catalyst to activate hydrogen molecules and provide active hydrogen for the hydrogenation reaction. Through the synergistic reaction of the catalyst and the co-catalyst, the hydrogenation reaction rate of the organic liquid hydrogen storage material catalyzed by the precious metal catalyst is effectively improved, the hydrogenation saturation time is shortened, the energy consumption is reduced, and it is helpful to reduce the amount of precious metals used and save costs.

[0018] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained through the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the XRD spectrum of the raw material of Preparation Example 1 and the nano-lithium magnesium nitrogen hydrogen particles and dehydrogenated lithium magnesium nitrogen hydrogen powder prepared in Preparation Example 1.

[0020] Figure 2 It is a comparison diagram of the hydrogenation amount curves of Example 1 and Comparative Example 1.

[0021] Figure 3 It is a comparison chart of the hydrogenation amount curves of Example 2 and Comparative Example 2.

[0022] Figure 4 It is a comparison diagram of the hydrogenation amount curves of Example 3 and Comparative Example 3.

[0023] Figure 5 It is a comparison diagram of the fitting curves of Comparative Example 4 and Comparative Example 2 and the curve of Example 2, the curve of Comparative Example 4, and the curve of Comparative Example 2.

[0024] Figure 6 It is a comparison chart of the hydrogenation amount curves of Example 2, Example 4, Comparative Example 2, Comparative Example 5 and Comparative Example 6. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be understood that, under the premise of no conflict, any and all embodiments of the present invention can be combined with the technical features in any other embodiment or multiple other embodiments to obtain another embodiment. The present invention includes such a combination to obtain another embodiment.

[0027] In this specification, groups and substituents thereof can be selected by those skilled in the art to provide stable structural moieties and compounds. When substituents are described by conventional chemical formulas written from left to right, the substituents also include chemically equivalent substituents obtained when the structural formula is written from right to left.

[0028] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.

[0029] At present, the hydrogenation kinetics of liquid organic hydrogen storage materials still have room for improvement, and it is difficult to reduce the amount of precious metal catalysts used. Liquid organic hydrogen storage materials still mainly use precious metal-based catalysts for catalytic hydrogenation to meet application requirements. The catalysts are expensive, which seriously limits the application and promotion of LOHC technology.

[0030] The project team has experimentally confirmed that the dehydrogenated lithium magnesium nitrogen hydrogen material can be used as a catalyst for hydrogenation reaction of liquid organic hydrogen storage materials, where the main catalyst in the hydrogenation reaction is a precious metal catalyst. The lithium magnesium nitrogen hydrogen material can be used as a catalyst for hydrogenation reaction of organic liquid hydrogen storage materials, and also has good hydrogen storage capacity, which can maintain a high overall hydrogen storage density of the composite slurry.

[0031] Specifically, the liquid organic hydrogen storage material is selected from at least one of an aromatic compound and a nitrogen-containing heterocyclic compound. The aromatic compound is selected from at least one of benzene, toluene, dibenzyltoluene, naphthalene, and naphthalene derivatives. The nitrogen-containing heterocyclic compound is selected from at least one of carbazole, N-ethylcarbazole, N-propylcarbazole, indole, 1-methylindole, and 2-methylindole.

[0032] The noble metal catalyst comprises a carrier material and a noble metal material loaded on the carrier material, and the carrier material is selected from at least one of carbon material, ceria and alumina.

[0033] The steps of the hydrogenation reaction include: S1: Mixing liquid organic hydrogen storage material and powdered lithium magnesium nitrogen hydrogen material into slurry.

[0034] S2: Adding a precious metal catalyst to the slurry.

[0035] S3: heating the slurry and introducing hydrogen.

[0036] Before introducing hydrogen in step S3, the gas in the reaction container may be replaced with nitrogen multiple times. The heating temperature in step S3 is the hydrogenation temperature of the liquid organic hydrogen storage material when catalyzed by a common noble metal catalyst.

[0037] The preparation steps of lithium magnesium nitrogen hydrogen material include: R1: Mixing LiNH in a protective atmosphere2 Powder and MgH 2 powder, or mixed with Mg(NH 2 ) 2 powder and LiH powder to obtain a mixed powder.

[0038] R2: Ball mill the mixed powder under protective atmosphere for 12h~48h, with a ball-to-material ratio of 20:1~100:1 and a rotation speed of 150rpm~400rpm to obtain preliminary dehydrogenated particles.

[0039] R3: Dehydrogenate the preliminary dehydrogenated particles to obtain lithium magnesium nitrogen hydrogen material.

[0040] In step R3, a hydrogen storage material performance tester or other dehydrogenation equipment may be used to more fully dehydrogenate the nano-lithium magnesium nitrogen hydrogen powder.

[0041] Preparation Example 1 Commercially available LiNH 2 Powder and commercial MgH 2 The powder is ground using a planetary ball mill for 48 hours, with a ball-to-material ratio of 80:1 and a rotation speed of 300 rpm to obtain nano-lithium magnesium nitrogen hydrogen particles (the preliminary dehydrogenated particles mentioned in step R2). During this process, partial dehydrogenation occurs due to the external mechanical energy. The nano-lithium magnesium nitrogen hydrogen particles are further dehydrogenated using a hydrogen storage material performance tester (PCT) at 200°C to obtain dehydrogenated lithium magnesium nitrogen hydrogen (LMNH) powder (the lithium magnesium nitrogen hydrogen material mentioned in step R3).

[0042] Initial dehydrogenation particles (corresponding to Figure 1 The curve named "ball-milled Li-Mg-NH" in the Figure 1 The curve named “200℃ dehydrogenation of Li-Mg-NH” in the paper), commercial LiNH 2 MgH used in powder and raw materials 2 The XRD results of the powder are as follows: Figure 1 As shown, it is confirmed that the main phase of the initial dehydrogenated particles and lithium magnesium nitrogen hydrogen materials is still LiNH 2 With MgH 2 .

[0043] Example 1: Dehydrogenation of LMNH and 1-methylindole to form a composite slurry as Ru / Al 2 O 3 Catalytic hydrogenation promoter.

[0044] 10 g of 1-methylindole was pre-mixed with the dehydrogenated lithium magnesium nitrogen hydrogen powder obtained in Preparation Example 1 to obtain a composite slurry with a mass fraction of dehydrogenated lithium magnesium nitrogen hydrogen powder of 3 wt %, and added to the reactor. 2 g of Ru / Al 2 O 3 Catalyst (metal ruthenium supported on alumina), then the reactor was evacuated and hydrogen was passed through, repeated 3 times, and finally maintained in a vacuum state.

[0045] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0046] The results are as follows Figure 2 As shown ( Figure 2 The curve named "combined with LMNH and then hydrogenated" in Figure 2 shows that when 3wt% dehydrogenated LMNH is used as a co-catalyst, Ru / Al at 145°C 2 O 3 The kinetic curve of the catalytic hydrogenation reaction of 1-methylindole shows that the complex of LMNH and 1-methylindole can reach a maximum addition value of 5.46wt% in 270 min, of which the hydrogenation amount reaches 5.08wt% in 210 min, which is 87.7% of the theoretical saturated hydrogenation amount (when LMNH and LOHC are complexed here, the hydrogenation amount is calculated based on the entire complex, and the same calculation is used in subsequent embodiments).

[0047] Comparative Example 1: Direct use of Ru / Al 2 O 3 Catalyzes the hydrogenation of 1-methylindole.

[0048] 10 g of 1-methylindole was added to the reactor, and 2 g of Ru / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0049] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0050] The results are as follows Figure 2 As shown ( Figure 2 The curve named "1-methylindole hydrogenation" in Figure 2 shows that when dehydrogenated LMNH is not used as a co-catalyst, the Ru / Al 2 O 3The kinetic curve of catalytic 1-methylindole hydrogenation reaction shows that the maximum addition amount of 1-methylindole can reach 5.72wt% in 390min, of which the hydrogenation amount reaches 2.89wt% in 210min, which is 49.9% of the theoretical saturated hydrogenation amount.

[0051] exist Figure 2 It can be seen from the comparison that after adding LMNH as a co-catalyst, the hydrogenation rate is significantly accelerated, and the maximum hydrogenation amount is reached faster. When hydrogenation is performed to the same hydrogenation amount, Example 1 takes less time than Comparative Example 1.

[0052] Example 2: Dehydrogenation of LMNH and 1-methylindole to form a composite slurry as Pd / Al 2 O 3 Catalytic hydrogenation promoter.

[0053] 10 g of 1-methylindole was pre-mixed with the dehydrogenated lithium magnesium nitrogen hydrogen powder obtained in Preparation Example 1 to obtain a composite slurry with a mass fraction of dehydrogenated lithium magnesium nitrogen hydrogen powder of 3 wt %, and added to the reactor. 4 g of Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0054] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0055] Comparative Example 2: Direct use of Pd / Al 2 O 3 Catalyzes the hydrogenation of 1-methylindole.

[0056] 10 g of 1-methylindole was added to the reactor, and 4 g of Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0057] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0058] like Figure 3 As shown, Comparative Example 2 ( Figure 3 The curve named "compounded with LMNH and then hydrogenated" in the figure) and the ... Figure 3The results of the curve named "1-methylindole hydrogenation" in Figure 1 show that when 3 wt% dehydrogenated LMNH is used as a cocatalyst, the Pd / Al 2 O 3 The kinetic curve of the catalytic hydrogenation reaction of 1-methylindole shows that the maximum addition amount of 1-methylindole can reach 5.39wt% in 240 min, of which the hydrogenation amount reaches 5.23wt% in 180 min, which is 90.3% of the theoretical saturated hydrogenation amount. 2 O 3 The kinetic curve of the catalytic hydrogenation reaction of 1-methylindole shows that the maximum addition amount of 1-methylindole can reach 5.79wt% in 660 min, and the hydrogenation amount reaches 2.51wt% in 180 min, which is 43.4% of the theoretical saturated hydrogenation amount.

[0059] Figure 3 The comparison also confirms that the addition of LMNH as a co-catalyst significantly accelerates the hydrogenation rate and reaches the maximum hydrogenation amount more quickly. When hydrogenating to the same hydrogenation amount, Example 2 takes less time than Comparative Example 2.

[0060] Example 3: Dehydrogenated LMNH and N-ethylcarbazole form a composite slurry as Pd / Al 2 O 3 Catalytic hydrogenation promoter.

[0061] 10 g of N-ethylcarbazole was pre-mixed with the dehydrogenated lithium magnesium nitrogen hydrogen powder prepared in Preparation Example 1 to obtain a composite slurry with a mass fraction of dehydrogenated lithium magnesium nitrogen hydrogen powder of 3 wt %, and added to the reactor. 4 g of Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0062] The vacuumed reactor was heated to 180°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of N-ethylcarbazole. The progress of the reaction was detected by the pressure change of the reactor, and the results were corrected by GC-MS.

[0063] Comparative Example 3: Direct use of Pd / Al 2 O 3 Catalyzes the hydrogenation of N-ethylcarbazole.

[0064] 10 g of N-ethylcarbazole was added to the reactor, and 4 g of Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0065] The vacuumed reactor was heated to 180°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of N-ethylcarbazole. The progress of the reaction was detected by the pressure change of the reactor, and the results were corrected by GC-MS.

[0066] like Figure 4 As shown, Comparative Example 3 ( Figure 4 The curve named "compounded with LMNH and then hydrogenated" in the figure) and the ... Figure 4 The results of the curve named "N-ethylcarbazole" in Figure 2 show that when 3 wt% dehydrogenated LMNH is used as a co-catalyst, the Pd / Al 2 O 3 The kinetic curve of the catalytic hydrogenation reaction of N-ethylcarbazole shows that the maximum addition value of N-ethylcarbazole can reach 5.57wt% in 420 min, of which the hydrogenation amount reaches 5.01wt% in 300 min, which is 86.5% of the theoretical saturated hydrogenation amount. 2 O 3 The kinetic curve of the catalytic N-ethylcarbazole hydrogenation reaction shows that the maximum amount of N-ethylcarbazole added can reach 5.54wt%, and the hydrogenation amount in 300min reaches 4.42wt%, which is 76.3% of the theoretical saturated hydrogenation amount.

[0067] Comparative Example 4: Dehydrogenated LMNH and n-hexane form a composite slurry (n-hexane is an inert solvent, and the prior art proves that it has no hydrogen absorption ability), using Pd / Al 2 O 3 Catalyst test dehydrogenation LMNH self hydrogenation curve.

[0068] 10 g of n-hexane and 3 wt% of the dehydrogenated lithium magnesium nitrogen hydrogen powder prepared in Preparation Example 1 were pre-mixed and added to the reactor. 4 g of Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0069] The vacuum reactor was heated to 145°C, and 8 MPa of hydrogen was introduced. Stirring was maintained to hydrogenate the dehydrogenated LMNH. The progress of the reaction was detected by the pressure change in the reactor.

[0070] The results are as follows Figure 5 As shown, in a dispersion state similar to that of the composite slurry in Example 2, Pd / Al 2 O 3The kinetic curve of 3wt% dehydrogenated LMNH hydrogenation reaction shows that ( Figure 5 The addition amount of LMNH reached 2.41 wt% at 480 min and tended to be stable.

[0071] The ordinate of the hydrogenation amount curve of Comparative Example 4*3wt% is added to the ordinate of the hydrogenation amount curve of Comparative Example 2*97wt% to obtain the ordinate of the fitted hydrogenation curve. Figure 5 The curve named "Fitted hydrogenation after compounding with dehydrogenated LMNH" in the figure is used to theoretically simulate the amount of hydrogenation after 97 parts of 1-methylindole is mixed with 3 parts of the dehydrogenated lithium magnesium nitrogen hydrogen material prepared in Preparation Example 1.

[0072] contrast Figure 5 It can be seen that whether it is the single dehydrogenated LMNH hydrogenation curve (Comparative Example 2, Figure 5 The curve named "1-methylindole hydrogenation" in the figure) or the single 1-methylindole hydrogenation curve (Comparative Example 4, Figure 5 The actual hydrogenation curve (Example 2, Figure 5 The curve named “actual hydrogenation after composite with dehydrogenated LMNH” in the figure all showed obvious acceleration, indicating that the faster hydrogenation kinetics of the composite slurry is not formed by the simple superposition of the hydrogenation performance of the two, but there is a catalytic effect.

[0073] Example 4: Preliminary dehydrogenation particles and 1-methylindole form a composite slurry as Pd / Al 2 O 3 Catalytic hydrogenation promoter.

[0074] 10 g of 1-methylindole was pre-mixed with the nano-lithium magnesium nitrogen hydrogen particles prepared in Preparation Example 1 to obtain a composite slurry with a mass fraction of 3 wt% of nano-lithium magnesium nitrogen hydrogen particles, which was added to the reactor. 4 g of Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0075] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0076] Comparative Example 5: Commercial LiNH 2 Form a composite slurry with 1-methylindole, and then add Pd / Al 2 O 3 As the main catalyst.

[0077] 10 g of 1-methylindole was mixed with the commercial LiNH 2 Pre-mixed to obtain commercial LiNH 2 The composite slurry with a mass fraction of 3wt% was added to the reactor, and 4g Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0078] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0079] Comparative Example 6: Commercial MgH 2 Form a composite slurry with 1-methylindole, and then add Pd / Al 2 O 3 As the main catalyst.

[0080] 10 g of 1-methylindole was mixed with the commercial MgH 2 Pre-mixed to obtain commercial LiNH 2 The composite slurry with a mass fraction of 3wt% was added to the reactor, and 4g Pd / Al 2 O 3 The catalyst was then evacuated and hydrogen was passed through the reactor, which was repeated three times and finally maintained in a vacuum state.

[0081] The vacuumed reactor was heated to 145°C, and 8 MPa of hydrogen was introduced while stirring to carry out hydrogenation reaction of 1-methylindole. The progress of the reaction was detected by the pressure change in the reactor, and the results were corrected by GC-MS.

[0082] The results of Example 4, Comparative Example 5 and Comparative Example 6 are as follows Figure 6 shown.

[0083] In Example 2, 3 wt% dehydrogenated LMNH was used as a co-catalyst, and Pd / Al 2 O 3 The kinetic curve of the catalytic hydrogenation reaction of 1-methylindole shows that the maximum addition amount of 1-methylindole can reach 5.39wt% in 240 min, of which the hydrogenation amount reaches 5.23wt% in 180 min, which is 90.3% of the theoretical saturated hydrogenation amount.

[0084] In Example 4, 3 wt% ball-milled nano-LMNH powder was used as a co-catalyst.2 O 3 The kinetic curve of catalytic 1-methylindole hydrogenation reaction shows that the maximum addition amount of 1-methylindole can reach 5.18wt% in 600 min, and the hydrogenation amount reaches 4.38wt% in 180 min, which is 75.6% of the theoretical saturated hydrogenation amount.

[0085] In Comparative Example 5, 3 wt% commercial LiNH 2 As a composite additive, Pd / Al at 145°C 2 O 3 The kinetic curve of catalytic 1-methylindole hydrogenation reaction shows that the maximum addition amount of 1-methylindole can reach 4.80 wt% in 500 min, and the hydrogenation amount reaches 2.55 wt% in 180 min, which is 44.0% of the theoretical saturated hydrogenation amount.

[0086] In Comparative Example 6, 3 wt% commercial MgH 2 As a composite additive, Pd / Al at 145°C 2 O 3 The kinetic curve of catalytic 1-methylindole hydrogenation reaction shows that the maximum addition amount of 1-methylindole can reach 5.33 wt% in 720 min, and the hydrogenation amount reaches 2.05 wt% in 180 min, which is 35.4% of the theoretical saturated hydrogenation amount.

[0087] In Comparative Example 2, LMNH was not used as a co-catalyst, and Pd / Al 2 O 3 The kinetic curve of the catalytic hydrogenation reaction of 1-methylindole shows that the maximum addition amount of 1-methylindole can reach 5.79wt% in 660 min, and the hydrogenation amount reaches 2.51wt% in 180 min, which is 43.4% of the theoretical saturated hydrogenation amount.

[0088] This comparison result shows that ball-milled LMNH has a catalytic effect, and after dehydrogenation treatment, the catalytic rate and final hydrogenation capacity can be further improved. However, using commercial LiNH alone 2 or commercial MgH 2 The above comparison proves that nano-lithium magnesium nitrogen hydrogen powder has unique catalytic properties, and this catalytic effect may be positively correlated with the ability of each additive to provide active hydrogen (that is, inversely proportional to the degree of dehydrogenation of each additive). Similar rules can also be observed from the comparison of the maximum hydrogenation amount of composite slurries containing various additives.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0090] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. Use of lithium magnesium nitrogen hydrogen material, characterized in that: As a co-catalyst during the hydrogenation reaction of the liquid organic hydrogen storage material, the main catalyst in the hydrogenation reaction is a precious metal catalyst.

2. The use of the lithium magnesium nitrogen hydrogen material according to claim 1, characterized in that: The liquid organic hydrogen storage material is selected from at least one of aromatic compounds and nitrogen-containing heterocyclic compounds.

3. The use of the lithium magnesium nitrogen hydrogen material according to claim 2, characterized in that: The aromatic compound is selected from at least one of benzene, toluene, dibenzyltoluene, naphthalene and naphthalene derivatives.

4. The use of the lithium magnesium nitrogen hydrogen material according to claim 2, characterized in that: The nitrogen-containing heterocyclic compound is at least one selected from carbazole, N-ethylcarbazole, N-propylcarbazole, indole, 1-methylindole, and 2-methylindole.

5. The use of the lithium magnesium nitrogen hydrogen material according to claim 1, characterized in that: The noble metal catalyst includes at least one of a platinum-based catalyst, a palladium-based catalyst, a ruthenium-based catalyst, and a rhodium-based catalyst.

6. The use of the lithium magnesium nitrogen hydrogen material according to claim 1, characterized in that: The noble metal catalyst comprises a carrier material and a noble metal material loaded on the carrier material, and the carrier material is selected from at least one of C, CeO2, and Al2O3.

7. The use of the lithium magnesium nitrogen hydrogen material according to claim 1, characterized in that: The steps of the hydrogenation reaction include: Mixing the liquid organic hydrogen storage material and the powdered lithium magnesium nitrogen hydrogen material into a slurry; adding the noble metal catalyst to the slurry; The slurry was heated and hydrogen was passed through.

8. The use of the lithium magnesium nitrogen hydrogen material according to claim 7, characterized in that: The particle size of the lithium magnesium nitrogen hydrogen material is 10nm~10μm.

9. The use of the lithium magnesium nitrogen hydrogen material according to claim 1, characterized in that: The amount of the lithium magnesium nitrogen hydrogen material is 0.1 wt% to 10 wt% of the liquid organic hydrogen storage material.

10. The use of the lithium magnesium nitrogen hydrogen material according to claim 1, characterized in that: The steps of preparing the lithium magnesium nitrogen hydrogen material include: Mixing LiNH2 powder and MgH2 powder, or mixing Mg(NH2)2 powder and LiH powder in a protective atmosphere to obtain a mixed powder; Ball milling the mixed powder for 12 h to 48 h under a protective atmosphere, with a ball-to-powder ratio of 20:1 to 100:1 and a rotation speed of 150 rpm to 400 rpm, to obtain preliminary dehydrogenated particles; The preliminary dehydrogenated particles are subjected to dehydrogenation treatment to obtain the lithium magnesium nitrogen hydrogen material.

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