Supported catalyst and preparation method thereof and synthesis method of N-alkoxyalkyl-2,6-dialkylaniline

Abstract

The invention discloses a supported catalyst and a preparation method thereof and a synthesis method of N-alkoxyalkyl-2,6-dialkylaniline. The supported catalyst is used to catalyze the synthesis of N-alkoxyalkyl-2,6-dialkylaniline. The supported catalyst includes an active component and a carrier. The active component is a mixture of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, Er metal oxide or any two or more metal oxides, and the carrier includes aluminum oxide. The supported catalyst of the present invention is used to catalyze the reaction of alkyl glycol alkyl ether and 2,6-dialkylaniline to prepare N-alkoxyalkyl-2,6-dialkylaniline. The reaction does not require any solvent, thereby achieving the green synthesis of N-alkoxyalkyl-2,6-dialkylaniline, with the advantages of high reactivity and selectivity, low production cost, and no generation of "three wastes" pollutants.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis of organic compounds, and particularly relates to a supported catalyst, a preparation method of the supported catalyst, and use of the supported catalyst in the synthesis of N-alkoxyalkyl-2,6-dialkylaniline. Background Art

[0002] N-Alkoxyalkyl-2,6-dialkylaniline is an important chemical intermediate, especially N-propoxyethyl-2,6-diethylaniline, which is an important intermediate of the rice herbicide pretilachlor.

[0003] Taking the synthesis of N-propoxyethyl-2,6-diethylaniline as an example, it currently generally consists of a three-step chemical reaction. First, the hydroxyl group of ethylene glycol monopropyl ether is converted into a sulfonate or halide. This is then reacted with 2,6-diethylaniline in the presence of an acid-binding agent (such as triethylamine) using DMF or triethylamine as the solvent to obtain the corresponding N-propoxyethyl-2,6-diethylaniline salt. Finally, an aqueous solution of an inorganic base (such as NaOH) is added for neutralization and washing, followed by extraction with toluene or xylene. The resulting organic phase is then distilled to obtain the N-propoxyethyl-2,6-diethylaniline fraction. The overall yield of the reaction is reportedly 80-92%.

[0004] Chinese patent CN101475508A uses methanesulfonyl chloride to react with ethylene glycol monopropyl ether to obtain the corresponding methanesulfonate (see the following formula 1); Chinese patent CN101525298A and Shi Changfu et al. (Shi Changfu, Liu Qiaoyun, Pretilachlor intermediate 2,6-diethylaniline and ethyl propyl ether [J] Liaoning Chemical Industry, 2016 (06): 690-695) use p-toluenesulfonyl chloride to react with ethylene glycol monopropyl ether to obtain the corresponding p-toluenesulfonate; and Chinese patent CN104478741A , Yi Jianhui et al. (Yi Jianhui, Chen Wanglong, Jiang Chengjun, Synthesis of 2,6-diethylaniline ethyl propyl ether [J] Zhejiang Chemical Industry, 2008(07): 17-18) and Wu Jinming et al. (Wu Jinming, Li Guohua, Shen Aibao, Fan Chongguang, Highly selective synthesis of N-(2-propoxyethyl)-2,6-diethylaniline [J] Chemical Reagents, 2011, 33(3): 283-285) converted ethylene glycol monopropyl ether into the corresponding chloroethyl monopropyl ether, and then reacted it with 2,6-diethylaniline.

[0005]

[0006] In addition, Chinese patent CN102229542A discloses a method for synthesizing another pretilachlor intermediate, N-propoxyethyl-2,6-diethylaniline (see Formula 2 below). 2,6-Diethylaniline is first reacted with ethylene oxide in the presence of acetic acid and zinc acetate to obtain N-(2-hydroxyethyl)-2,6-diethylaniline. The reaction solvent is ethanol. After separation and purification by methods such as water washing, extraction, and distillation, the product is then reacted with n-chloropropane in the presence of an acid-binding agent, triethylamine, to produce a crude target compound, N-propoxyethyl-2,6-diethylaniline. The crude product is then separated and purified by methods such as water washing, extraction, and distillation to obtain the final product. The yields of the two steps are 96% and 92%, respectively.

[0007]

[0008] It can be seen from this that no matter which of the above-mentioned traditional synthesis methods is used, there are problems such as many reaction steps, serious pollution of "three wastes", low reaction yield, and high synthesis cost. Faced with increasingly urgent environmental protection and cost pressures, it has become crucial to develop a green and environmentally friendly synthesis method for the intermediate N-propoxyethyl-2,6-diethylaniline of pretilachlor.

[0009] Ciba, Switzerland, US Pat. No. 4,183,868 and US Pat. No. 4,921,980, respectively, utilize a catalyst containing 0.05-10% palladium (Pd) and 0.2-10% platinum (Pt) to catalyze the reaction of ethylene glycol monopropyl ether with 2,6-diethylaniline to produce N-propoxyethyl-2,6-diethylaniline and water in a single step (see Formula 3). The catalyst is added to a reactor and activated by hydrogen reduction at 200°C. Ethylene glycol monopropyl ether and 2,6-diethylaniline are then added in a molar ratio of 1:2. The raw materials are added in an amount sufficient to provide 4 moles of 2,6-diethylaniline per liter of catalyst. The reaction temperature is 190-270°C, the pressure is 1-2 atm, and the reaction time is 4 hours. The reaction achieves a single-pass conversion of 52% and a selectivity of 89.7% for the target product, N-propoxyethyl-2,6-diethylaniline.

[0010]

[0011] Although the above reaction process is a green synthesis process that does not produce "three wastes", the catalyst has low activity and poor selectivity, and the catalyst contains a high content of precious metals, resulting in very high catalyst costs (calculated based on the precious metal content, the cost of a ton of catalyst exceeds RMB 10 million), which is unaffordable for actual industrial production.

[0012] Therefore, further research on the synthesis process and catalyst of N-alkoxyalkyl-2,6-dialkylaniline is still needed in this field. Summary of the Invention

[0013] The main purpose of the present invention is to provide a supported catalyst and a preparation method thereof and a synthesis method of N-alkoxyalkyl-2,6-dialkylaniline, so as to overcome the defects of the prior art in the synthesis of N-alkoxyalkyl-2,6-dialkylaniline, such as the complicated synthesis steps, low catalyst activity and high catalyst cost.

[0014] In order to achieve the above-mentioned object, the present invention provides a supported catalyst for catalytically synthesizing N-alkoxyalkyl-2,6-dialkylaniline, wherein the supported catalyst comprises an active component and a carrier, wherein the active component is a metal oxide of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, Er, or a mixture of any two or more metal oxides, and the carrier comprises alumina.

[0015] The supported catalyst of the present invention has an active component content of 5-30% by mass based on the total mass of the supported catalyst.

[0016] The supported catalyst of the present invention, wherein the carrier further comprises all-silicon beta molecular sieve, USY molecular sieve and / or fumed silica; based on the total mass of the carrier, the mass content of alumina in the carrier is 20-100%, the mass content of all-silicon beta molecular sieve and USY molecular sieve is 0-20%, and the mass content of fumed silica is 0-80%.

[0017] In order to achieve the above object, the present invention also provides a method for preparing a supported catalyst for catalytically synthesizing N-alkoxyalkyl-2,6-dialkylaniline, the preparation method comprising the following steps:

[0018] Step 1: mixing and kneading an alumina precursor, all-silicon beta molecular sieve, USY molecular sieve, fumed silica and an additive, adding an acid solution, extruding, drying and calcining to obtain a catalyst carrier;

[0019] Step 2, loading the active component precursor onto the catalyst support, drying, and calcining to obtain a supported catalyst;

[0020] Wherein, based on the total mass of the catalyst support, the addition amount of the alumina precursor is 20-100% in terms of alumina, the addition amount of the all-silicon beta molecular sieve and the USY molecular sieve is 0-20%, and the addition amount of the fumed silica is 0-80%;

[0021] Among them, the active component precursor is at least one of a Ni-containing compound, a Cu-containing compound, a Fe-containing compound, a Zr-containing compound, a Co-containing compound, a Cr-containing compound, a Ga-containing compound, a Ge-containing compound, an In-containing compound, a Mn-containing compound, a Zn-containing compound, an Ag-containing compound, a La-containing compound, a Ce-containing compound, and an Er-containing compound.

[0022] The method for preparing a supported catalyst of the present invention comprises the following steps: based on the total mass of the catalyst support, the amount of the additive added is 1-5%, and the additive is starch and / or sesbania powder; the acid solution is a nitric acid aqueous solution, an oxalic acid aqueous solution, or a citric acid aqueous solution; the mass concentration of the acid solution is less than 5%, and the amount of the acid solution added is 20-40wt% of the total mass of the catalyst support.

[0023] The method for preparing a supported catalyst of the present invention, wherein the active component precursor is a nitrate of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, Er, or a mixture of any two or more nitrates.

[0024] In the method for preparing a supported catalyst of the present invention, the active component precursor is loaded on the catalyst carrier by impregnation, and the impregnation is performed at least once.

[0025] The preparation method of the supported catalyst of the present invention, wherein, based on the total mass of the supported catalyst, the addition amount of the active component precursor in terms of metal oxide is 5-30%; and the alumina precursor is pseudo-boehmite alumina.

[0026] To achieve the above object, the present invention further provides a method for synthesizing N-alkoxyalkyl-2,6-dialkylaniline, which uses an alkyl glycol alkyl ether and 2,6-dialkylaniline as reactants and the above-mentioned supported catalyst as a catalyst to perform a one-step reaction to obtain N-alkoxyalkyl-2,6-dialkylaniline.

[0027] The present invention provides a method for synthesizing N-alkoxyalkyl-2,6-dialkylaniline, wherein the structural formula of the alkyl glycol alkyl ether is HO-R1-O-R2, R1 is an alkyl group having 2-8 carbon atoms, and R2 is an alkyl group having 1-8 carbon atoms; and the two alkyl groups in the 2,6-dialkylaniline are the same or different and have 1-8 carbon atoms.

[0028] The method for synthesizing N-alkoxyalkyl-2,6-dialkylaniline of the present invention comprises the following steps: the alkyl glycol alkyl ether is ethylene glycol monopropyl ether, the 2,6-dialkylaniline is 2,6-diethylaniline, and the N-alkoxyalkyl-2,6-dialkylaniline is N-propoxyethyl-2,6-diethylaniline; the catalyst is subjected to H2 reduction treatment before catalysis, and the reduction temperature is 200°C-400°C; and the reaction temperature of the one-step reaction is 150-200°C.

[0029] Beneficial effects of the present invention:

[0030] The present invention comprehensively utilizes the catalytic effects of molecular sieves and active metals. Through the reaction of alkyl glycol alkyl ether and 2,6-dialkylaniline, the main products are N-alkoxyalkyl-2,6-dialkylaniline and water, without generating other polluting inorganic products. The product water can be purified by distillation to obtain high-purity distilled water for replenishing production circulating water, thereby eliminating the pollution problems such as the generation of a large amount of waste acid and high-salt and high-COD wastewater in current domestic production processes.

[0031] The present invention realizes the green and clean production of N-alkoxyalkyl-2,6-dialkylaniline, especially N-propoxyethyl-2,6-diethylaniline, an intermediate of pretilachlor, without using a precious metal catalyst, and has the advantages of fewer reaction steps (one-step reaction), high reaction yield and low production cost. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described in detail below. The following implementation methods are implemented based on the technical solution of the present invention and provide a detailed implementation process. However, the protection scope of the present invention is not limited to the following implementation methods. In the following implementation methods, structures or experimental methods without specifying specific conditions are generally based on conventional conditions.

[0033] The invention discloses a supported catalyst for catalytically synthesizing N-alkoxyalkyl-2,6-dialkylaniline. The supported catalyst comprises an active component and a carrier, wherein the active component is a metal oxide of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, Er, or a mixture of any two or more metal oxides, and the carrier comprises aluminum oxide.

[0034] The active components of the supported catalyst of the present invention are supported on a carrier. The active components are Ni metal oxide, Cu metal oxide, Fe metal oxide, Zr metal oxide, Co metal oxide, Cr metal oxide, Ga metal oxide, Ge metal oxide, In metal oxide, Mn metal oxide, Zn metal oxide, Ag metal oxide, La metal oxide, Ce metal oxide, Er metal oxide, or a combination of any two or more of these metal oxides. The present invention uses a non-noble metal oxide as the active component, which can greatly reduce the cost of the catalyst and is more conducive to industrial production. In addition, the catalyst of the present invention, through the synergistic effect of the active component and the carrier, is used for the synthesis of N-alkoxyalkyl-2,6-dialkylaniline, has high catalytic activity and selectivity, and a high reaction yield.

[0035] In one embodiment, the carrier of the present invention comprises alumina, all-silicon beta molecular sieve, USY molecular sieve, and fumed silica. Based on the total mass of the carrier, the mass content of alumina in the carrier is 20-100%, the mass content of all-silicon beta molecular sieve and USY molecular sieve is 0-20%, and the mass content of fumed silica is 0-80%. The present invention does not specifically limit the ratio of all-silicon beta molecular sieve and USY molecular sieve, and for example, only all-silicon beta molecular sieve, only USY molecular sieve, or a mixture of all-silicon beta molecular sieve and USY molecular sieve in any proportion. In addition, the present invention does not specifically limit the alumina, all-silicon beta molecular sieve, USY molecular sieve, and fumed silica, and they may be commercially available products.

[0036] The present invention does not particularly limit the ratio of metal to oxygen in the active components Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, and Er metal oxides. For example, the metal oxides can be obtained by calcining the metals Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, and Er. More specifically, the active components of the present invention are metal oxides of the metals Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, and Er, or mixtures of the metal oxides. In one embodiment, based on the total mass of the supported catalyst, the mass content of the active component in the supported catalyst is 5-30%, or 10-30%, or 15-30%, and further, for example, 18-30%. Within a certain range, as the mass content of the active component in the catalyst increases, the activity of the catalyst increases, and the selectivity of the target product in the catalytic synthesis of N-propoxyethyl-2,6-diethylaniline increases.

[0037] In one embodiment, the catalyst of the present invention comprehensively utilizes the catalytic effects of molecular sieves and active metals. Even if non-precious metal active components are used, the resulting catalyst is used to catalyze the synthesis of N-alkoxyalkyl-2,6-dialkylaniline, especially for the catalytic synthesis of N-propoxyethyl-2,6-diethylaniline, and has high catalytic activity and good selectivity.

[0038] The present invention also provides a method for preparing the above-mentioned supported catalyst, which comprises the following steps:

[0039] Step 1: mixing and kneading an alumina precursor, all-silicon beta molecular sieve, USY molecular sieve, fumed silica and an additive, adding an acid solution, extruding, drying and calcining to obtain a catalyst carrier;

[0040] Step 2, loading the active component precursor onto the catalyst support, drying, and calcining to obtain a supported catalyst;

[0041] Wherein, based on the total mass of the catalyst support, the addition amount of the alumina precursor is 20-100% in terms of alumina, the addition amount of the all-silicon beta molecular sieve and the USY molecular sieve is 0-20%, and the addition amount of the fumed silica is 0-80%;

[0042] Among them, the active component precursor is at least one of a Ni-containing compound, a Cu-containing compound, a Fe-containing compound, a Zr-containing compound, a Co-containing compound, a Cr-containing compound, a Ga-containing compound, a Ge-containing compound, an In-containing compound, a Mn-containing compound, a Zn-containing compound, an Ag-containing compound, a La-containing compound, a Ce-containing compound, and an Er-containing compound.

[0043] In one embodiment, the alumina precursor is pseudo-boehmite, and the auxiliary agent is, for example, starch or sesbania powder. Starch or sesbania powder can serve as a binder, lubricant, and pore-forming agent. Starch and sesbania powder can bond the various components of the catalyst together during extrusion, and also act as a lubricant, helping the catalyst to be more easily extruded. In addition, starch and sesbania powder will be oxidized and burned during the catalyst roasting process, leaving pores in the catalyst, thereby playing a role in pore formation and regulating the pore structure of the catalyst. The present invention does not particularly limit the ratio of all-silicon beta molecular sieve and USY molecular sieve, for example, only all-silicon beta molecular sieve, or only USY molecular sieve, or all-silicon beta molecular sieve and USY molecular sieve are mixed in any proportion. Based on the total mass of the catalyst support, the amount of the auxiliary agent added is 1-4wt%. In one embodiment, the acid solution is an aqueous nitric acid solution, an aqueous oxalic acid solution, or an aqueous citric acid solution, the mass concentration of the acid solution is less than 5%, and the amount of the acid solution added is 20-40wt% of the total mass of the catalyst support.

[0044] In one embodiment, the present invention does not particularly limit the conditions of drying and calcining in step 1, for example, the drying temperature is 100-200° C., and the drying time is 1-48 hours; the calcining temperature is 500-600° C., and the calcining time is 1-24 hours.

[0045] In one embodiment, the active component precursor of the present invention is a soluble compound of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, or Er, such as a nitrate of the above metals or a mixture of any two or more of the above metal nitrates.

[0046] The present invention does not particularly limit the method of loading the active component precursor on the catalyst support, such as impregnation, and the number of impregnations is at least once, such as twice, three times, etc., so that the desired amount of active component is loaded on the catalyst support.

[0047] In one embodiment, the drying temperature in step 2 of the present invention is 120-150° C., and the drying time is 1-48 hours; the roasting temperature is 350-480° C., and the roasting time is 1-10 hours.

[0048] In one embodiment, the present invention provides a detailed preparation method of the above-mentioned supported catalyst, which comprises the following steps:

[0049] Step 1, preparation of catalyst support: after kneading together for 20 minutes, pseudo-boehmite alumina equivalent to 20-100% of the total weight of the catalyst support in terms of alumina, all-silicon beta molecular sieve and (or) USY molecular sieve accounting for 0-20% of the total weight of the catalyst support, fumed silica accounting for 0-80% of the total weight of the catalyst support, and starch or field sesbania powder accounting for 1-5% of the total weight of the catalyst support, nitric acid or oxalic acid or citric acid aqueous solution (dilute nitric acid or oxalic acid or citric acid aqueous solution with a mass concentration of less than 5%, added at 30wt% of the weight of the catalyst support), kneading for 30-60 minutes, and then extruding into strips. The extruded strips are placed at room temperature for 0-5 days, then dried at 150°C for 24 hours, and then calcined at 530°C to obtain a porous catalyst support.

[0050] Step 2: Prepare an aqueous solution of metal nitrates such as Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, and Er (which can be a nitrate of a single metal or a mixture of two or more of the above metal nitrates).

[0051] The catalyst is prepared by an equal volume impregnation method, which comprises immersing 100 grams of the porous catalyst support in water for 1 minute, removing the support, draining the support, and weighing the support. The total weight minus the support weight is the maximum water-absorbing capacity per 100 grams of the support. The maximum water-absorbing capacity of the support made according to this formula is 100 milliliters per 100 grams of the support. According to the maximum water-absorbing capacity of the porous catalyst support to be impregnated, different concentrations of metal nitrate aqueous solutions (so that the corresponding metal oxide content accounts for 5-30% of the total weight of the catalyst) are configured and sprayed onto the corresponding porous catalyst support. The impregnated porous catalyst support is dried at room temperature for 2 days, then dried at 120-150° C. for 24 hours, and calcined at 430° C. for 6 hours. If a single impregnation does not reach the required amount of metal oxide, multiple impregnations can be performed according to the above procedure to obtain a catalyst with a corresponding metal oxide loading content.

[0052] Before being used in the catalytic synthesis of N-alkoxyalkyl-2,6-dialkylaniline, the catalyst of the present invention is subjected to H2 reduction treatment at a reduction temperature of 200°C to 400°C. In one embodiment, 18.2 g (bulk volume 20 ml) of the catalyst is placed in a trickle bed reactor, H2 is introduced, and the reactor is reduced at 200°C for 5 hours, 300°C for 5 hours, and 380°C for 5 hours under a pressure of 5 atm to obtain the reduced catalyst.

[0053] The catalyst of the invention can be used for catalyzing the synthesis of N-alkoxyalkyl-2,6-dialkylaniline by a one-step reaction with alkyl glycol alkyl ether and 2,6-dialkylaniline as reactants.

[0054] In one embodiment, the structural formula of the alkyl glycol alkyl ether of the present invention is HO-R1-O-R2, where R1 is an alkyl group having 2-8 carbon atoms, such as ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl, and R2 is an alkyl group having 1-8 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl. The two alkyl groups in the 2,6-dialkylaniline are the same or different and have 1-8 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or octyl.

[0055] In another embodiment, the alkyl glycol alkyl ether of the present invention is ethylene glycol monopropyl ether, the 2,6-dialkylaniline is 2,6-diethylaniline, and the N-alkoxyalkyl-2,6-dialkylaniline is N-propoxyethyl-2,6-diethylaniline.

[0056] The present invention does not particularly limit the ratio of the amount of alkyl glycol alkyl ether and 2,6-dialkylaniline. In one embodiment, the weight ratio of the alkyl glycol alkyl ether and 2,6-dialkylaniline is 1:2-2:1. The one-step reaction is carried out under the action of hydrogen at a hydrogen pressure of 2-5 atm.

[0057] In one embodiment, the synthesis method of N-alkoxyalkyl-2,6-dialkylaniline of the present invention is:

[0058] A mixture of an alkyl glycol alkyl ether and 2,6-dialkylaniline in a weight ratio of 1:1 is introduced as the reaction raw material, using a continuous feed method with a raw material liquid feed rate of 0.2 ml / min, an H2 pressure of 2-5 atm, an H2 flow rate of 20-80 ml / min, and a reaction temperature of 150-200°C. The reaction product is detected by gas chromatography normalization. In a representative example of the synthesis of N-propoxyethyl-2,6-diethylaniline, the resulting crude reaction product (excluding water) contains 14.3 wt% of ethylene glycol monopropyl ether and 12.3 wt% of the remaining 2,6-diethylaniline raw material, 72.4 wt% of N-propoxyethyl-2,6-diethylaniline, 0.1 wt% of N,N-di(propoxyethyl)-2,6-diethylaniline (overreaction product), and 0.9 wt% of three other impurities, with a reaction selectivity of 98.5%. The higher the reaction temperature or the smaller the raw material feed amount, the higher the single-pass yield of the reaction will be, but the impurity content including over-reaction products will increase slightly, and the reaction selectivity will decrease slightly.

[0059] Therefore, the present invention provides a green, environmentally friendly and low-cost method for synthesizing N-alkoxyalkyl-2,6-dialkylaniline. The catalyst used is a catalyst composed of a non-precious metal combination. The catalyst catalyzes the reaction of alkyl glycol alkyl ether and 2,6-dialkylaniline in a one-step manner to produce N-alkoxyalkyl-2,6-dialkylaniline and water. The reaction has high yield and good selectivity.

[0060] The technical solution of the present invention will be further described in detail below through specific examples. In the following examples, unless otherwise specified, percentages are by mass.

[0061] Example 1

[0062] Preparation of metal nitrate aqueous solution: Weigh 11.30 grams of Ni(NO3)2·6H2O, 33.50 grams of Cu(NO3)2·6H2O, 1 ml of 50 wt% Fe(NO3)3 aqueous solution, and 1.5 grams of Zn(NO3)2·6H2O, add deionized water to dissolve to 80 ml, and prepare a solution at room temperature for use.

[0063] Weigh 139 grams of pseudo-boehmite with a solid content of 72%, 85 grams of fumed silica, 15 grams of all-silicon beta molecular sieve, and 7 grams of sesbania powder, knead them for 20 minutes, then gradually add 170 ml of 5wt% nitric acid aqueous solution while kneading, knead for 120 minutes after addition, then extrude into strips, leave at room temperature for 48 hours, dry at 150°C for 24 hours, and calcine at 530°C for 6 hours to obtain a porous catalyst carrier.

[0064] Weigh 80 grams of the above-mentioned catalyst carrier, spray 80 milliliters of the prepared metal nitrate aqueous solution onto 80 grams of the carrier, leave it at room temperature for 48 hours, then dry it at 150°C for 24 hours, and calcine it at 430°C for 6 hours to obtain a catalyst containing 13.6% by weight of catalytically active metal oxide.

[0065] The catalyst was crushed and sieved to a particle size of 20-30 mesh. 20 ml of the catalyst was placed in a 60 mm diameter tubular trickle bed reactor and reduced at 200°C for 5 hours, 300°C for 5 hours, and 380°C for 5 hours. The H2 pressure was controlled at 5 atm and the H2 flow rate was 30 ml / min. The temperature was then lowered to 190°C. A mixture of ethylene glycol monopropyl ether and 2,6-diethylaniline in a 1:1 weight ratio was added as the reaction feedstock. The feedstock was added at a rate of 0.2 ml / min, the H2 pressure was maintained at 5 atm, and the H2 flow rate was 30 ml / min.

[0066] The reaction product was detected by gas chromatography normalization method. The crude reaction product (excluding water) contained 30.9 wt % of ethylene glycol monopropyl ether and 32.1 wt % of 2,6-diethylaniline remaining, 36.5 wt % of N-propoxyethyl-2,6-diethylaniline, and 0.5 wt % of other impurities.

[0067] Example 2:

[0068] The catalyst obtained in Example 1 was further sprayed with 60 ml of the metal nitrate aqueous solution in Example 1, and dried at room temperature for 48 hours, then dried at 150°C for 24 hours, and calcined at 430°C for 6 hours to obtain a catalyst with a higher metal oxide content than that in Example 1 (a catalyst containing 23.7 wt% of metal oxide).

[0069] The catalyst was crushed, the catalyst was reduced and activated, and the chemical reaction was carried out in the same manner as in Example 1.

[0070] The reaction product was detected by gas chromatography normalization method. The crude reaction product (excluding water) contained 19.3 wt% of ethylene glycol monopropyl ether and 20.0 wt% of 2,6-diethylaniline remaining raw material, 59.7 wt% of N-propoxyethyl-2,6-diethylaniline, 0.1 wt% of N,N-bis(propoxyethyl)-2,6-diethylaniline, and 0.9 wt% of other impurities.

[0071] Example 3:

[0072] Preparation of metal nitrate aqueous solution: Weigh 32.5 grams of Cu(NO3)2·6H2O, 12.3 grams of Co(NO3)2·6H2O, 1.1 grams of Cr(NO3)3·9H2O, 3 milliliters of 50wt% Mn(NO3)2 aqueous solution, 0.1 grams of La(NO3)3·6H2O, and 0.6 ml of 50% Fe(NO3)3 aqueous solution, add deionized water to dissolve to 80 milliliters, and prepare a solution at room temperature for use.

[0073] Weigh 278 grams of pseudo-boehmite with a solid content of 72% and 6 grams of sesbania powder, knead them for 20 minutes, then gradually add 170 ml of 2.6% oxalic acid aqueous solution while kneading. After adding, knead for 60 minutes, then extrude into strips, leave at room temperature for 48 hours, dry at 150°C for 24 hours, and calcine at 530°C for 6 hours to obtain a porous catalyst carrier.

[0074] Weigh 80 grams of the above-mentioned carrier, spray 80 milliliters of the prepared metal nitrate aqueous solution on the 80 grams of the carrier, leave it at room temperature for 48 hours, dry it at 150°C for 24 hours, and calcine it at 430°C for 6 hours to obtain a catalyst containing 14.9% metal oxide.

[0075] The catalyst was crushed, the catalyst was reduced and activated, and the chemical reaction was carried out in the same manner as in Example 1.

[0076] The reaction product was detected by gas chromatography normalization method. The crude reaction product (excluding water) contained 28.6% of ethylene glycol monopropyl ether and 29.9% of 2,6-diethylaniline remaining, 41.0% of N-propoxyethyl-2,6-diethylaniline, and 0.5% of other impurities.

[0077] Example 4:

[0078] Preparation of metal nitrate aqueous solution: Weigh 50.7 g Cu(NO3)2·6H2O, 20.5 g Co(NO3)2·6H2O, 4.5 g Ni(NO3)2·6H2O, 2.5 g Zn(NO3)2·6H2O, and 0.1 g La(NO3)3·6H2O, add deionized water and dissolve to 80 ml at 50°C. Prepare the solution and keep it warm at 50°C for later use.

[0079] Weigh 138 grams of pseudo-boehmite with a solid content of 72%, 85 grams of fumed silica, 10 grams of all-silicon β molecular sieve, 5 grams of USY molecular sieve, and 6 grams of corn starch and knead them together for 120 minutes. Then gradually add 170 ml of 2.6% citric acid aqueous solution while kneading. After adding, knead for 120 minutes, then extrude into strips, dry at room temperature for 24 hours, then dry at 150°C for 24 hours, and calcine at 530°C for 6 hours to obtain a porous catalyst carrier.

[0080] Weigh 80 grams of the above-mentioned carrier, spray 80 ml of a prepared 50°C metal nitrate aqueous solution onto the 80 grams of the carrier, leave it at room temperature for 36 hours, dry it at 150°C for 24 hours, and calcine it at 430°C for 6 hours to obtain a catalyst containing 21.8% metal oxide.

[0081] The catalyst was crushed and sieved to a particle size of 20-30 mesh. 20 ml of the catalyst was placed in a 60 mm diameter tubular trickle bed reactor. H₂ was introduced and reduced at 200°C for 5 hours, 300°C for 5 hours, and 380°C for 5 hours. The H₂ pressure was controlled at 5 atm and the H₂ flow rate was 30 ml / min. The temperature was then lowered to 170°C. A mixture of ethylene glycol monopropyl ether and 2,6-diethylaniline in a 1:1 weight ratio was added as the reaction feedstock. The feedstock was added at a rate of 0.2 ml / min, the H₂ pressure was maintained at 3 atm, and the H₂ flow rate was 30 ml / min.

[0082] The reaction product was detected by gas chromatography normalization method. The crude reaction product (excluding water) contained 18.2% of ethylene glycol monopropyl ether and 18.3% of 2,6-diethylaniline remaining, 62.6% of N-propoxyethyl-2,6-diethylaniline, 0.1% of N,N-bis(propoxyethyl)-2,6-diethylaniline, and 0.8% of other impurities.

[0083] Example 5:

[0084] Preparation of metal nitrate aqueous solution: Weigh 53.8 grams of Cu(NO3)2·6H2O, 13 grams of Co(NO3)2·6H2O, 11.5 grams of Ni(NO3)2·6H2O, 2 ml of 50% Fe(NO3)3, 2 ml of 50% Mn(NO3)2 aqueous solution, 3 grams of Zr(NO3)4·5H2O, and 1.5 grams of Cr(NO3)3·9H2O, add deionized water and dissolve to 80 ml at 50°C, prepare a solution and keep it warm at 50°C for later use.

[0085] Weigh 83 grams of pseudo-boehmite with a solid content of 72%, 110 grams of fumed silica, 5 grams of USY molecular sieve, 25 grams of all-silicon beta molecular sieve, and 8 grams of corn starch and knead them together for 20 minutes. Then, gradually add 170 ml of 2.6% nitric acid aqueous solution while kneading. After the addition, knead for another 120 minutes, then extrude into strips, dry at room temperature for 48 hours, then dry at 150°C for 24 hours, and calcine at 530°C for 6 hours to obtain a porous catalyst carrier.

[0086] Weigh 80 grams of the above-mentioned carrier, spray 80 milliliters of the prepared metal nitrate aqueous solution on the 80 grams of the carrier, place it at room temperature for 48 hours, dry it at 150°C for 24 hours, and calcine it at 430°C for 6 hours to obtain a catalyst containing 22.6% of metal oxide.

[0087] The catalyst was crushed and sieved to a particle size of 20-30 mesh. 20 ml of the catalyst was placed in a 60 mm diameter tubular trickle bed reactor. H₂ was introduced and reduced at 200°C for 5 hours, 300°C for 5 hours, and 380°C for 5 hours. The H₂ pressure was controlled at 5 atm and the H₂ flow rate was 50 ml / min. The temperature was then lowered to 170°C. A mixture of ethylene glycol monopropyl ether and 2,6-diethylaniline in a 1:1 weight ratio was added as the raw material. The raw material addition rate was controlled at 0.2 ml / min. The H₂ pressure was maintained at 3 atm and the H₂ flow rate was 20 ml / min.

[0088] Gas chromatography normalization revealed that the crude reaction product (excluding water) contained 14.3% ethylene glycol monopropyl ether and 12.3% of the remaining 2,6-diethylaniline starting material, 72.4% N-propoxyethyl-2,6-diethylaniline, 0.1% N,N-bis(propoxyethyl)-2,6-diethylaniline, and 0.9% of three other impurities. The reaction selectivity was 98.5%.

[0089] Example 6

[0090] After the reaction of Example 5 was continuously run for 122 days (four months), except that the reaction temperature was gradually increased to 177° C., other reaction conditions were the same as those of Example 5. Samples were taken and analyzed after 122 days.

[0091] Gas chromatography normalization revealed that the crude reaction product (excluding water) contained 15.2% ethylene glycol monopropyl ether and 14.3% of the remaining 2,6-diethylaniline starting material, 69.7% N-propoxyethyl-2,6-diethylaniline, 0.1% N,N-bis(propoxyethyl)-2,6-diethylaniline, and 0.7% of three other impurities. The reaction selectivity was 98.8%.

[0092] As shown in the reaction results of Example 6 and Example 5, after the catalyst reacted continuously for 122 days, the catalytic activity did not show a significant decrease, and the reaction selectivity was still able to maintain a high level, indicating that the catalyst of the present invention has a long life, and the catalyst is prepared from non-precious metals and has a low catalyst cost.

[0093] By appropriately increasing the reaction temperature or reducing the raw material feed amount, the single-pass reaction yield will be further improved, but the impurity content, including the over-reaction product N,N-di(propoxyethyl)-2,6-diethylaniline, will increase slightly, and the reaction selectivity will decrease slightly.

[0094] The method for preparing N-propoxyethyl-2,6-diethylaniline, an intermediate of pretilachlor, adopts ethylene glycol monopropyl ether and 2,6-diethylaniline as raw materials, and uses a catalyst composed of active non-noble metals. The method has low cost, high catalytic activity and selectivity, and long service life, and does not require any solvent for the reaction. The crude reaction product comprises the target product N-propoxyethyl-2,6-diethylaniline, water, and a trace amount of high-boiling-point impurities. The boiling points of the components differ greatly, so that water, two remaining raw materials, high-purity N-propoxyethyl-2,6-diethylaniline target product, and high-boiling-point impurities can be easily separated through continuous distillation. The entire production process can easily realize continuous automated production, and the water separated by distillation is distilled water, which can be used to supplement production circulating water. No "three wastes" are generated in the entire reaction process, and near-zero emissions can be achieved.

[0095] The catalyst of the present invention can fundamentally solve the serious "three wastes" environmental protection problem existing in the current production process of N-propoxyethyl-2,6-diethylaniline, an intermediate of pretilachlor, from the source of the reaction. Compared with the multi-step intermittent synthesis process currently adopted in industrialization, the synthesis process of N-propoxyethyl-2,6-diethylaniline using the catalyst of the present invention also has the advantages of low production cost, small number of workers, low energy consumption (significant reduction in separation steps), etc., and is a low-energy-consumption, green, environmentally friendly and low-cost synthesis process.

[0096] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for synthesizing N-propoxyethyl-2,6-diethylaniline, characterized in that: Using ethylene glycol monopropyl ether and 2,6-diethylaniline as reactants, N-propoxyethyl-2,6-diethylaniline is obtained through a one-step reaction in the presence of a catalyst. The catalyst is a supported catalyst, comprising an active component and a carrier, wherein the active component is a metal oxide of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, Er, or a mixture of any two or more metal oxides; the carrier comprises alumina, all-silicon beta molecular sieve, USY molecular sieve, and fumed silica; based on the total mass of the carrier, the mass content of alumina in the carrier is greater than or equal to 20% and less than 100%, the mass content of all-silicon beta molecular sieve and USY molecular sieve is greater than 0 and less than or equal to 20%, and the mass content of fumed silica is greater than 0 and less than or equal to 80%; Wherein, based on the total mass of the supported catalyst, the mass content of the active component in the supported catalyst is 5-30%.

2. The method for synthesizing N-propoxyethyl-2,6-diethylaniline according to claim 1, characterized in that: The preparation method of the supported catalyst comprises the following steps: Step 1: mixing and kneading an alumina precursor, all-silicon beta molecular sieve, USY molecular sieve, fumed silica and an additive, adding an acid solution, extruding, drying and calcining to obtain a catalyst carrier; Step 2, loading the active component precursor onto the catalyst support, drying, and calcining to obtain a supported catalyst; Wherein, based on the total mass of the catalyst support, the amount of the alumina precursor added in terms of alumina is greater than or equal to 20% and less than 100%, the amount of the all-silicon beta molecular sieve and the USY molecular sieve added is greater than 0 and less than or equal to 20%, and the amount of the fumed silica added is greater than 0 and less than or equal to 80%; Among them, the active component precursor is at least one of a Ni-containing compound, a Cu-containing compound, a Fe-containing compound, a Zr-containing compound, a Co-containing compound, a Cr-containing compound, a Ga-containing compound, a Ge-containing compound, an In-containing compound, a Mn-containing compound, a Zn-containing compound, an Ag-containing compound, a La-containing compound, a Ce-containing compound, and an Er-containing compound.

3. The method for synthesizing N-propoxyethyl-2,6-diethylaniline according to claim 2, characterized in that: Based on the total mass of the catalyst support, the amount of the additive added is 1-5%, and the additive is starch and / or sesbania powder; the acid solution is a nitric acid aqueous solution, an oxalic acid aqueous solution or a citric acid aqueous solution, the mass concentration of the acid solution is less than 5%, and the amount of the acid solution added is 20-40wt% of the total mass of the catalyst support.

4. The method for synthesizing N-propoxyethyl-2,6-diethylaniline according to claim 2, characterized in that: The active component precursor is a nitrate of Ni, Cu, Fe, Zr, Co, Cr, Ga, Ge, In, Mn, Zn, Ag, La, Ce, Er, or a mixture of any two or more nitrates.

5. The method for synthesizing N-propoxyethyl-2,6-diethylaniline according to claim 2, characterized in that: The active component precursor is loaded on the catalyst carrier by impregnation, and the number of impregnations is at least one.

6. The method for synthesizing N-propoxyethyl-2,6-diethylaniline according to claim 2, characterized in that: The aluminum oxide precursor is pseudo-boehmite.

7. The method for synthesizing N-propoxyethyl-2,6-diethylaniline according to claim 1, characterized in that: The catalyst is subjected to H2 reduction treatment before catalysis, and the reduction temperature is 200-400°C; the reaction temperature of the one-step reaction is 150-200°C.

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