Preparation method of 2-ethyl-6-methylaniline compound

Abstract

The invention discloses a preparation method of a 2-ethyl-6-methylaniline compound, which comprises the following steps: adding a supported catalyst into a reaction device, adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline as initial raw materials, and reacting at the temperature of 60-80 DEG C for 1-2 hours to obtain the 2-ethyl-6-methylaniline compound. According to the method, 1-methoxy-2-propanol and 2-methyl-6-ethylaniline are subjected to a reaction in the absence of a solvent under the action of a supported catalyst so as to generate the 2-ethyl-6-methylaniline compound. The 2-ethyl-6-methylaniline compound is one or two of 2-ethyl-N-(2-methoxyl-1-methylethylene)-6-methylaniline and 2-ethyl-N-(2-methoxyl-1-methylethyl)-6-methylaniline, and the 2-ethyl-6-methylaniline compound is one or two of 2-ethyl-N-(2-methoxyl-1-methylethyl)-6-methylaniline and 2-ethyl-N-(2-methoxyl-1-methylethyl)-6-methylaniline. The preparation method disclosed by the invention is simple in reaction process, high in product yield and adjustable in product proportion.

Description

Technical Field

[0001] The invention relates to a method for preparing 2-ethyl-6-methylaniline compounds. Background Art

[0002] S-metolachlor is a chloroacetamide selective herbicide. It is an active S-form obtained by removing the inactive R-form from metolachlor. This product mainly inhibits cell growth by inhibiting the synthesis of very long-chain fatty acids to achieve herbicidal effects. As a highly active isomer of metolachlor, S-metolachlor is more excellent in safety and control effects, and has a wide crop spectrum. It has become an indispensable weed killer for major food crops such as soybeans and corn.

[0003]

[0004] 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline (NAI for short), chemical formula is C 13 H 19 NO, with the structural formula of Formula 1, is an important intermediate in the synthesis of the chiral pesticide S-isopropylamine and can also be used to synthesize β-lactam compounds with biological activity.

[0005]

[0006] 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline (NAA for short), chemical formula is C 13 H 21 NO, with the structural formula of Formula 2, is an important intermediate in the synthesis of isopropylamine.

[0007]

[0008] In the existing process, the most common production methods of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline are both synthesized in a reactor using 2-methyl-6-ethylaniline and methoxyacetone as starting materials, but only a single product can be obtained. At present, the industrial production process of methoxyacetone is obtained by dehydrogenation and oxidation of 1-methoxy-2-propanol, and the target product has low selectivity (only 20-25%) and high energy consumption. The subsequent preparation of amine ethers also requires the addition of H2. This route needs to go through dehydrogenation and hydrogenation processes, with cumbersome steps and complex equipment. In addition, the first step of generating hydrogen cannot be directly applied to the second step, and the process is complex.

[0009] CN108774152A discloses a method for preparing (refined) isopropyl metolachlor-imine by continuous reaction and distillation, wherein 2-methyl-6-ethylaniline and methoxyacetone are used as raw materials, and 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is prepared by reaction in a tower kettle, which improves the reaction yield and shortens the reaction cycle compared to the intermittent method. CN108504701A discloses a method for synthesizing an isopropyl metolachlor intermediate, wherein 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is used as a raw material, and 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is finally prepared by asymmetric reduction of imine reductase.

[0010] CN116851035A discloses a method for preparing a sulfonic acid resin-supported platinum catalyst and catalytically synthesizing an isopropylamine intermediate, wherein 2-methyl-6-ethylaniline and 1-methoxy-2-acetone are used as raw materials, and sulfonic acid resin-supported platinum is used as a catalyst. Hydrogen is introduced into a high-pressure reactor to react and synthesize 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline.

[0011] CN109280012A discloses a method for solvent-free synthesis of an isopropylamine intermediate 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline, wherein 2-methyl-6-ethylaniline and methoxyacetone are used as raw materials, and 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is generated by reaction under solvent-free conditions with appropriately increased reaction pressure and increased molar ratio of methoxyacetone.

[0012] At present, the synthesis methods of two 2-ethyl-6-methylaniline compounds, 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline, have low yields, high comprehensive energy consumption, long cycles, and can only synthesize one product at a time. Therefore, it is of great significance to study a continuous and efficient production process. Summary of the invention

[0013] The invention aims to provide a method for preparing 2-ethyl-6-methylaniline compounds. The method has simple reaction process, high product yield and controllable product ratio.

[0014] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0015] A method for preparing 2-ethyl-6-methylaniline compounds comprises the following steps: adding a supported catalyst into a reaction device, and adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline as starting materials, allowing 1-methoxy-2-propanol and 2-methyl-6-ethylaniline to react under the action of the supported catalyst in the absence of solvent to generate 2-ethyl-6-methylaniline compounds, wherein the 2-ethyl-6-methylaniline compounds are one or two of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline;

[0016] The supported catalyst is prepared by the following method: weighing an active metal precursor and dissolving it in a solvent to form a solution, adding a 20-40 mesh carrier to the solution, impregnating at normal pressure for 24-48 hours, then drying the water in a rotary evaporator under vacuum at 45-60° C., and finally calcining in a muffle furnace at 350-550° C. for 4-6 hours to obtain a supported catalyst; the carrier is one or more of Al2O3, ZrO2, SiO2, CeO2, and TiO2, and the active metal is one or more of Pt, Pd, Mn, Mg, Co, Cu, Sn, and Fe;

[0017]

[0018] Preferably, the active metal precursor is selected from one or more of chloroplatinic acid hexahydrate, palladium chloride, manganese nitrate tetrahydrate, magnesium nitrate hexahydrate, cobalt nitrate hexahydrate, copper nitrate trihydrate, tin tetrachloride, and iron nitrate nonahydrate; and the solvent is deionized water or hydrochloric acid solution (palladium chloride and tin tetrachloride are dissolved in hydrochloric acid solution).

[0019] Preferably, in the supported catalyst, the loading amount of active metal = mass of active metal element contained in solution a ÷ (mass of active metal element contained in solution a + mass of carrier) × 100% = 0.2-10%.

[0020] Preferably, a mixed gas of nitrogen and hydrogen is introduced while adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline, wherein the molar ratio of H2 to N2 is 0.2:1 to 5:1. The introduction of hydrogen in the present invention is conducive to the generation of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline. Furthermore, in the preparation of the supported catalyst, the active metal is Pt and / or Pd, and the carrier is Al2O3 or SiO2; a mixed gas of nitrogen and hydrogen is introduced while adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline, wherein the molar ratio of H2 to N2 is 0.2:1 to 5:1, and the product obtained under this condition is mainly 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline.

[0021] Preferably, in the preparation of the supported catalyst, the active metal is one or more of Mn, Mg, Co, Cu, Sn, and Fe, and the product obtained is mainly 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline.

[0022] Preferably, the reaction temperature of the reaction is set to 150-250°C.

[0023] Preferably, the molar ratio of the 1-methoxy-2-propanol to the 2-methyl-6-ethylaniline is 1:3 to 3:1.

[0024] Preferably, the reaction device adopts a continuous fixed bed device, and the raw material mixture consisting of 1-methoxy-2-propanol and 2-methyl-6-ethylaniline is continuously added to a reaction tube filled with a supported catalyst in the continuous fixed bed device, and the reaction is carried out at a preset reaction temperature to generate 2-ethyl-6-methylaniline compounds.

[0025] As a further preference, the mass space velocity of the raw material mixture is set to 0.2-10.0h -1 .

[0026] As a further preference, the gas-liquid mixing preheater and the reaction heating device of the continuous fixed bed device are turned on, the temperature of the gas-liquid mixing preheater is set to 150-250°C, the raw material mixture is continuously passed into the gas-liquid mixing preheater for preheating, and the preheated raw material mixture is continuously added to the reaction tube.

[0027] As a further preferred method, while continuously adding the raw material mixed liquid into the reaction tube, a mixed gas of nitrogen and hydrogen is also continuously introduced, and the space velocity of the mixed gas is set to 0 to 400 h -1 (More preferably 10 to 400 hours -1 , and further preferably 10-200h -1), and the pressure in the reaction tube is maintained at 0.1-1 MPa. The introduction of hydrogen in the present invention is beneficial to the generation of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline.

[0028] After the product is collected from the reaction device, the target product can be obtained through a simple post-treatment operation. For example, when the product contains two target compounds of 2-ethyl-6-methylaniline compounds, namely 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline, the 2-ethyl-6-methylaniline compounds can be separated through a distillation operation to obtain 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Compared with the existing technology, each product needs to undergo multiple steps of reaction, be produced separately, and need to add hydrogen for reaction. The present invention uses 1-methoxy-2-propanol and 2-methyl-6-ethylaniline as starting materials for one-pot reaction, shortens the reaction steps, simplifies the operation, has a high product yield, and can adjust the product ratio. It can realize the co-production of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline in the same production process.

[0031] (2) The fixed bed device used in the present invention can realize continuous production. Compared with the intermittent reactor equipment, it is simple to operate, has a small liquid holdup, and a short reaction cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a gas phase detection diagram of the product of Example 1 of the present invention;

[0033] Figure 2 is a gas phase detection diagram of the product of Example 3 of the present invention;

[0034] Figure 3 is a gas phase detection diagram of the product of Example 4 of the present invention;

[0035] Figure 4 is a gas phase detection diagram of the product of Example 6 of the present invention;

[0036] Figure 5 is a gas phase detection diagram of the product of Example 11 of the present invention;

[0037] Figure 6This is a diagram of a continuous fixed bed device used in the present invention, wherein 1-H2 gas cylinder, 2-gas filter, 3-gas regulating valve, 4-one-way valve, 5-mass flow controller, 6-N2 gas cylinder, 7-gas filter, 8-gas regulating valve, 9-one-way valve, 10-mass flow controller, 11-raw material pump, 12-one-way valve, 13-reaction tube, 14-one-way valve, 15-liquid storage tank, 16-one-way valve, 17-back pressure regulating valve. DETAILED DESCRIPTION

[0038] In order to better understand the technical solution of the present invention, the technical solution provided by the present invention is described in detail below in conjunction with specific embodiments, but the scope of protection claimed in the present invention is not limited to the scope described in the embodiments.

[0039] If no specific conditions are specified in the examples of the present invention, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be obtained by conventional technical means or purchased commercially.

[0040] The supported catalyst used in the embodiment of the present invention is prepared by the following method: a certain amount of active metal precursor (chloroplatinic acid hexahydrate, palladium chloride, manganese nitrate tetrahydrate, magnesium nitrate hexahydrate, cobalt nitrate hexahydrate, copper nitrate trihydrate, tin tetrachloride, and ferric nitrate nonahydrate) is weighed and dissolved in deionized water (palladium chloride and tin tetrachloride are dissolved in 4M hydrochloric acid solution) to form a solution a with a metal element concentration of 0.05 g / mL, and a certain amount of 20-40 mesh carrier (Al2O3, ZrO2, S iO2, CeO2, TiO2), impregnated at normal pressure for 24h, then dried in a rotary evaporator at 50°C in a vacuum state, and finally calcined at 500°C in a muffle furnace for 4h to obtain supported catalysts Pt / Al2O3 (Pt loading of 5wt%), Pd / Al2O3 (Pd loading of 5wt%), Pt / SiO2 (Pt loading of 5wt%), Pt / ZrO2 (Pt loading of 0.5wt%), Pd / SiO2 (Pt loading of 0.5wt%), Pt ... d loading is 2wt%), Cu / Al2O3 (Cu loading is 5wt%), Cu / Al2O3 (Cu loading is 10wt%), Mn / CeO2 (Mn loading is 5wt%), Mn / ZrO2 (Mn loading is 5wt%), Co / SiO2 (Co loading is 5wt%), Co / Al2O3 (Co loading is 5wt%), Fe / SiO2 (Fe loading is 5wt%), Sn / ZrO2 (Sn loading is 5wt%). The present invention controls the loading amount of the metal in the supported catalyst by controlling the feed amount.

[0041] The sources of the carrier used in the embodiments of the present invention are: Al2O3 (γ type) - purchased from Zibo Yinghe Chemical Co., Ltd., ZrO2 purchased from Jinan Zhiheng Zhiyuan Chemical Technology Co., Ltd., SiO2 purchased from Qingdao Borite Silicon Energy Technology Co., Ltd., CeO purchased from Fuzhou Yingfei Xunguang Technology Co., Ltd., and TiO2 purchased from Hubei Kewode Chemical Co., Ltd.

[0042] The continuous fixed bed device used in the embodiment of the present invention is shown in FIG. Figure 6 shown.

[0043] Embodiment 1:

[0044] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed at a molar ratio of MOP:MEA = 1:3 to obtain a raw material mixture, and 8 g of Pt / Al2O3 (Pt loading amount: 5 wt%) catalyst was loaded into the reaction tube 13.

[0045] (2) Turn on the heating furnace and raise the temperature to 200°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0046] (3) Start the raw material pump 11 and heat it for 1.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 50 h -1 Introduce H2:N2=1:1 and maintain the pressure in the tube at 0.5MPa.

[0047] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 81.32%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 95.62%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 3.90%.

[0048] Embodiment 2:

[0049] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed at a molar ratio of MOP:MEA = 1:2 to obtain a raw material mixture, and 8 g of Pd / Al2O3 (Pd loading amount: 5 wt%) catalyst was loaded into the reaction tube 13.

[0050] (2) Turn on the heating furnace and raise the temperature to 200°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0051] (3) Start the raw material pump 11 and heat it for 1.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 100 h -1 Introduce H2:N2=1:1 and maintain the pressure in the tube at 0.6MPa.

[0052] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 76.27%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 89.87%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 6.53%.

[0053] Embodiment 3:

[0054] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed at a molar ratio of MOP:MEA = 1:1.5 to obtain a raw material mixture, and 10 g of Pt / SiO2 (Pt loading amount is 5 wt%) catalyst was loaded into the reaction tube 13.

[0055] (2) Turn on the heating furnace and raise the temperature to 180°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0056] (3) Start the raw material pump 11 and heat it for 1.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 10 h. -1 Introduce H2:N2=1:1 and maintain the pressure in the tube at 0.6MPa.

[0057] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 88.54%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 96.66%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 2.97.

[0058] Embodiment 4:

[0059] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:2 to obtain a raw material mixture, and 8 g of Pt / ZrO2 (Pt loading amount: 0.5 wt%) catalyst was loaded into the reaction tube 13.

[0060] (2) Turn on the heating furnace and raise the temperature to 180°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0061] (3) Start the raw material pump 11 and heat it for 1.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 50 h -1 Introduce H2:N2=3:1 and maintain the pressure in the tube at 0.5MPa.

[0062] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 81.24%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 49.43%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 47.84%.

[0063] Embodiment 5:

[0064] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:2 to obtain a raw material mixture, and 7 g of Pd / SiO2 (Pd loading amount is 2 wt%) catalyst was loaded into the reaction tube 13.

[0065] (2) Turn on the heating furnace and raise the temperature to 180°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0066] (3) Start the raw material pump 11 and heat it for 1.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 100 h -1 Introduce H2:N2=1.5:1 and maintain the pressure in the tube at 0.5MPa.

[0067] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 74.27%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 77.27%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 16.23%.

[0068] Embodiment 6:

[0069] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:2 to obtain a raw material mixture, and 8 g of Cu / Al2O3 (Cu loading of 5 wt%) catalyst was loaded into the reaction tube 13.

[0070] (2) Turn on the heating furnace and raise the temperature to 250°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0071] (3) Start the raw material pump 11 and heat it for 0.4h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 50 h -1 Introduce H2:N2=2:1 and maintain the pressure in the tube at 0.4MPa.

[0072] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 51.77%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 9.96%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 85.41%.

[0073] Embodiment 7:

[0074] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed at a molar ratio of MOA:MEA = 1:1.5 to obtain a raw material mixture, and 8 g of Cu / Al2O3 (Cu loading was 10 wt%) was loaded into the reaction tube 13.

[0075] (2) Turn on the heating furnace and raise the temperature to 230°C, then turn on the vaporization chamber and raise the temperature to 220°C.

[0076] (3) Start the raw material pump 11 and heat it for 0.8h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 200 h -1 Introduce H2:N2=2:1 and maintain the pressure in the tube at 0.5MPa.

[0077] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 56.79%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 8.32%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 84.27%.

[0078] Embodiment 8:

[0079] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:3 to obtain a raw material mixture, and 10 g of Mn / CeO2 (Mn loading is 5 wt%) catalyst was loaded into the reaction tube 13.

[0080] (2) Turn on the heating furnace and raise the temperature to 180°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0081] (3) Start the raw material pump 11, and heat it at 2.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 150 h -1 Introduce H2:N2=4:1 and maintain the pressure in the tube at 0.2MPa.

[0082] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 57.17%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 3.76%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 89.23%.

[0083] Embodiment 9:

[0084] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:2 to obtain a raw material mixture, and 6 g of Mn / ZrO2 (Mn loading is 5 wt%) catalyst was loaded into the reaction tube 13.

[0085] (2) Turn on the heating furnace and raise the temperature to 180°C, then turn on the vaporization chamber and raise the temperature to 160°C.

[0086] (3) Start the raw material pump 11, and heat it at 2.0h -1 The raw materials are transported into the reaction tube 13 at a mass space velocity of , without introducing mixed gas, and the pressure inside the tube is maintained at normal pressure.

[0087] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 46.28%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 0, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 95.76%.

[0088] Embodiment 10:

[0089] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed at a molar ratio of MOA:MEA = 0.5:1 to obtain a raw material mixture, and 8 g of Co / SiO2 (Co loading of 5 wt%) catalyst was loaded into the reaction tube 13.

[0090] (2) Turn on the heating furnace and raise the temperature to 190°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0091] (3) Start the raw material pump 11, and heat it at 2.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 50 h -1 Introduce H2:N2=1:1 and maintain the pressure in the tube at 0.8MPa.

[0092] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 42.31%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 4.23%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 89.72%.

[0093] Embodiment 11:

[0094] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed at a molar ratio of MOA:MEA = 0.33:1 to obtain a raw material mixture, and 8 g of Co / Al2O3 (Co loading of 5 wt%) catalyst was loaded into the reaction tube 13.

[0095] (2) Turn on the heating furnace and raise the temperature to 200°C, then turn on the vaporization chamber and raise the temperature to 180°C.

[0096] (3) Start the raw material pump 11 and heat it for 1.0h -1 The raw materials are transported into the reaction tube 13 at a mass space velocity of , without introducing any gas, and the pressure inside the tube is maintained at normal pressure.

[0097] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 43.33%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 0.18%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 95.40%.

[0098] Embodiment 12:

[0099] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:2 to obtain a raw material mixture, and 8 g of Fe / SiO2 (Fe loading of 5 wt%) catalyst was loaded into the reaction tube 13.

[0100] (2) Turn on the heating furnace and raise the temperature to 250°C, then turn on the vaporization chamber and raise the temperature to 220°C.

[0101] (3) Start the raw material pump 11 and heat it for 0.8h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 100 h -1 Introduce H2:N2=4:1 and maintain the pressure in the tube at 0.5MPa.

[0102] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 35.23%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 4.56%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 64.96%.

[0103] Embodiment 13:

[0104] (1) 1-methoxy-2-propanol (MOP) and 2-methyl-6-ethylaniline (MEA) were mixed in a molar ratio of MOA:MEA = 1:2 to obtain a raw material mixture, and 10 g of Sn / ZrO2 (Sn loading amount is 5 wt%) catalyst was loaded into the reaction tube 13.

[0105] (2) Turn on the heating furnace and raise the temperature to 250°C, then turn on the vaporization chamber and raise the temperature to 200°C.

[0106] (3) Start the raw material pump 11, and heat it at 2.0h -1 The raw materials are transported to the reaction tube 13 at a mass space velocity of 150 h -1 Introduce H2:N2=3:1 and maintain the pressure in the tube at 0.1MPa.

[0107] (4) After the reaction reaches equilibrium, the product liquid is taken out from the liquid storage tank 15 and detected by GC. The conversion rate is 30.72%, the selectivity of 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline is 20.23%, and the selectivity of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline is 55.76%.

Claims

1. A method for preparing 2-ethyl-6-methylaniline compounds, characterized in that: The preparation method comprises the following steps: adding a supported catalyst into a reaction device, and adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline as starting materials, allowing the 1-methoxy-2-propanol and 2-methyl-6-ethylaniline to react under the action of the supported catalyst in the absence of a solvent to generate a 2-ethyl-6-methylaniline compound, wherein the 2-ethyl-6-methylaniline compound is one or both of 2-ethyl-N-(2-methoxy-1-methylethylidene)-6-methylaniline and 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline; The supported catalyst is prepared by the following method: weighing an active metal precursor and dissolving it in a solvent to form a solution, adding a 20-40 mesh carrier to the solution, impregnating at normal pressure for 24-48 hours, then drying the water in a rotary evaporator under vacuum at 45-60° C., and finally calcining in a muffle furnace at 350-550° C. for 4-6 hours to obtain a supported catalyst; the carrier is one or more of Al2O3, ZrO2, SiO2, CeO2, and TiO2, and the active metal is one or more of Pt, Pd, Mn, Mg, Co, Cu, Sn, and Fe; 2. The preparation method according to claim 1, characterized in that: In the supported catalyst, the loading amount of active metal = mass of active metal element contained in solution a ÷ (mass of active metal element contained in solution a + mass of carrier) × 100% = 0.2-10%.

3. The preparation method according to claim 1, characterized in that: While adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline, a mixed gas of nitrogen and hydrogen is introduced, wherein the molar ratio of H2 to N2 is 0.2:1 to 5:

1.

4. The preparation method according to claim 3, characterized in that: In the preparation of the supported catalyst, the active metal is Pt and / or Pd, and the carrier is Al2O3 or SiO2; while adding 1-methoxy-2-propanol and 2-methyl-6-ethylaniline, a mixed gas of nitrogen and hydrogen is introduced, wherein the molar ratio of H2 to N2 is 0.2:1 to 5:

1.

5. The preparation method according to claim 1, characterized in that: In the preparation of the supported catalyst, the active metal is one or more of Mn, Mg, Co, Cu, Sn, and Fe.

6. The preparation method according to claim 1, characterized in that: The reaction temperature of the reaction is set at 150-250°C.

7. The preparation method according to claim 1, characterized in that: The molar ratio of the 1-methoxy-2-propanol and the 2-methyl-6-ethylaniline is 1:3 to 3:

1.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The reaction device adopts a continuous fixed bed device, and a raw material mixed liquid consisting of 1-methoxy-2-propanol and 2-methyl-6-ethylaniline is continuously added into a reaction tube filled with a supported catalyst in the continuous fixed bed device, and reacts at a preset reaction temperature to generate 2-ethyl-6-methylaniline compounds.

9. The preparation method according to claim 8, characterized in that: The mass space velocity of the raw material mixture is set to 0.2~10.0h -1 .

10. The preparation method according to claim 8, characterized in that: While continuously adding the raw material mixture into the reaction tube, a mixed gas of nitrogen and hydrogen is continuously introduced, and the space velocity of the mixed gas is set to 0-400h -1 , and maintain the pressure in the reaction tube at 0.1~1MPa.

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