A method for the catalytic amination of tetrahydrofuran to synthesize tetrahydropyrrole

Abstract

The application discloses a method for synthesizing tetrahydropyrrole by catalyzing amination of tetrahydrofuran, which comprises the following steps: reacting raw materials containing tetrahydrofuran and ammonia with a catalyst to obtain a tetrahydropyrrole product; and the catalyst is a porous alumina catalyst. The catalyst uses solid acid alumina as an active component, is formed into a porous alumina catalyst after being extruded into a strip or rolled into a ball, and has a large specific surface area, pore volume and average pore diameter. The catalyst shows excellent reaction activity and catalytic stability in the reaction of synthesizing tetrahydropyrrole by aminating tetrahydrofuran.

Description

Technical Field

[0001] This application relates to a method for the catalytic amination of tetrahydrofuran to synthesize tetrahydropyrrole, belonging to the field of tetrahydropyrrole preparation technology. Background Technology

[0002] Tetrahydropyrrole is an important intermediate in fine chemicals, widely used in organic synthesis, pharmaceuticals, pesticides, coatings, and daily chemicals. It can be used to synthesize dozens of drugs, including butorphanil, dextromethorphan tartrate, propiconazole, procyclidine, and carbamazepine; it can also be used to synthesize insecticides such as indomethacin; tetrahydropyrrole reacts with aldehydes and ketones to form enamine compounds; it is an important solvent in the fine chemical and pharmaceutical industries; it is an organic template agent for the synthesis of molecular sieves such as ZSM-5, ZSM-35, and ZSM-48; furthermore, it can be used as a desulfurizing agent, additive, and other raw materials in fine chemicals.

[0003] Tetrahydropyrrole can be synthesized from raw materials such as 1,4-butanediol, 1,4-butanedione, 1,4-butanediamine, and tetrahydrofuran. Among them, the synthesis of tetrahydropyrrole by catalytic amination of 1,4-butanediol and tetrahydrofuran has the advantages of simple reaction process, low raw material cost, and high atom utilization rate, and has high industrial application value.

[0004] However, existing catalysts are all in powder form and cannot be directly added to the reactor, which is not conducive to industrial-scale reactions. Summary of the Invention

[0005] To address the aforementioned issues, this application presents a pre-formed catalyst for industrial production, which maintains the catalyst's catalytic activity, as well as high tetrahydropyrrole selectivity and yield.

[0006] According to one aspect of this application, a method for synthesizing tetrahydropyrrole by catalytic amination of tetrahydrofuran is provided, comprising the following steps:

[0007] A raw material containing tetrahydrofuran and ammonia is reacted with a catalyst to obtain a tetrahydropyrrole product.

[0008] The catalyst is a porous alumina catalyst;

[0009] The porous alumina catalyst has a specific surface area of ​​200–315 m². 2 / g;

[0010] The total pore volume of the porous alumina catalyst is 0.6–1.0 cm³. 3 / g;

[0011] The porous alumina catalyst has a pore size of 9–20 nm.

[0012] The porous alumina catalyst in this application is a solid acid catalyst.

[0013] Optionally, the reaction pressure is 0–3 MPa; the reaction temperature is 160–450 °C.

[0014] In this application, "0MPa" indicates atmospheric pressure.

[0015] Optionally, the pressure of the reaction is selected from any value or a range between two values ​​from 0 MPa, 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa, 2.8 MPa, and 3.0 MPa.

[0016] Optionally, the reaction temperature is selected from any value or a range between two values ​​from 160℃, 200℃, 220℃, 260℃, 310℃, 320℃, 360℃, 380℃, 400℃, and 450℃.

[0017] Optionally, the space velocity of the tetrahydrofuran is 0.02–2.0 h⁻¹. -1 .

[0018] Optionally, the space velocity of the tetrahydrofuran is selected from 0.02 h⁻¹. -1 0.08h -1 0.5h -1 1.0h -1 1.5h -1 1.8h -1 2.0h -1 Any value in the range or between two values.

[0019] Optionally, the molar ratio of ammonia to tetrahydrofuran in the raw material is 2 to 20.

[0020] Optionally, the molar ratio of ammonia to tetrahydrofuran in the raw material is selected from any value of 2, 4, 6, 8, 10, 14, 18, 20 or a range between two values.

[0021] Optionally, the porous alumina catalyst is spherical or columnar.

[0022] Optionally, the porous alumina catalyst is prepared by:

[0023] The porous alumina catalyst is obtained by mixing activated alumina, guar gum powder, and acid solution, molding, drying, and calcining.

[0024] Optionally, the mass of the guar gum powder accounts for 0.1 to 15.0 wt% of the mass of the activated alumina.

[0025] Optionally, the mass of the guar gum powder accounts for 2 to 10 wt% of the mass of the activated alumina.

[0026] Optionally, the mass of the guar gum powder is any value or a range between two values ​​from 0.1wt%, 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 4.0wt%, 5.0wt%, 7.0wt%, 9.0wt%, 12wt%, 14.0wt%, and 15.0wt% of the mass of the activated alumina.

[0027] Optionally, the mass of the acid solution accounts for 40 to 180 wt% of the mass of the activated alumina;

[0028] The concentration of the acid solution is 1–8 wt%.

[0029] Optionally, the acid solution accounts for 50 to 160 wt% of the mass of the alumina;

[0030] The concentration of the acid solution is 2.5–6.5 wt%.

[0031] Optionally, the mass of the acid solution is any value or a range between two values ​​from 40wt%, 50wt%, 70wt%, 90wt%, 120wt%, 160wt%, 170wt%, and 180wt% of the mass of the activated alumina.

[0032] Optionally, the acid solution is selected from at least one of nitric acid, sulfuric acid, hydrochloric acid, and acetic acid.

[0033] Optionally, the drying temperature is 60–130°C, and the drying time is 6–12 hours.

[0034] Optionally, the roasting temperature is 400–800°C, and the roasting time is 3–5 hours.

[0035] Alternatively, the forming method may include extrusion or ball rolling.

[0036] The beneficial effects that this application can produce include:

[0037] 1) The method for synthesizing tetrahydropyrrole by catalytic amination of tetrahydrofuran provided in this application uses a shaped porous alumina catalyst in the preparation of tetrahydropyrrole, which can realize the industrial production of tetrahydropyrrole. The reaction device is simple; and the selectivity of tetrahydropyrrole product reaches 81% and the yield reaches 60%.

[0038] 2) The method for synthesizing tetrahydropyrrole by catalytic amination of tetrahydrofuran provided in this application improves the selectivity and yield of tetrahydropyrrole products by controlling the specific surface area, total pore volume and pore size of porous alumina catalyst.

[0039] 3) The method for synthesizing tetrahydropyrrole by catalytic amination of tetrahydrofuran provided in this application can achieve high selectivity and yield of tetrahydropyrrole in a reaction range of 160 to 450 °C by using a shaped porous alumina catalyst. Detailed Implementation

[0040] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0041] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0042] In the embodiments of this application, the conversion rate, selectivity, and yield are calculated as follows:

[0043] Tetrahydrofuran conversion rate = (number of carbon moles of tetrahydrofuran in reactants - number of carbon moles of tetrahydrofuran in products) / number of carbon moles of tetrahydrofuran in reactants × 100%

[0044] Tetrahydropyrrole selectivity = (Number of carbon atoms in tetrahydropyrrole in the product) / (Number of carbon atoms in tetrahydrofuran in the reactants - Number of carbon atoms in tetrahydrofuran in the product) × 100%

[0045] Tetrahydropyrrole yield = (number of moles of tetrahydropyrrole carbon in the product / number of moles of tetrahydrofuran carbon in the reactants) × 100%

[0046] In the embodiments of this application, the tetrahydrofuran conversion, tetrahydropyrrole selectivity, and tetrahydropyrrole yield are all calculated based on the number of carbon moles.

[0047] Example 1

[0048] 100g of activated alumina powder, 0.5g of guar gum powder, and 160g of 2wt% dilute nitric acid solution were thoroughly mixed, shaped by extrusion, dried at 70℃ for 10 hours, and then calcined at 700℃ for 3 hours to prepare columnar porous alumina catalyst, denoted as catalyst A.

[0049] Example 2

[0050] 100g of activated alumina powder, 12g of guar gum powder, and 50g of 7.5wt% dilute hydrochloric acid solution were thoroughly mixed, shaped by rolling, dried at 120℃ for 8 hours, and then calcined at 500℃ for 3 hours to prepare a spherical porous alumina catalyst, denoted as catalyst B.

[0051] Example 3

[0052] 100g of activated alumina powder, 5g of guar gum powder, and 120g of 4wt% oxalic acid solution were thoroughly mixed, shaped by extrusion, dried at 110℃ for 10 hours, and then calcined at 600℃ for 3 hours to prepare columnar porous alumina catalyst, denoted as catalyst C.

[0053] Comparative Example 1

[0054] Commercially purchased alumina pellets are designated as comparative catalyst D.

[0055] Table 1. Pore structure information of the catalyst of the present invention and the comparative catalyst.

[0056] catalyst <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Total pore volume (cm 3 / g)]]> Average pore size (nm) Catalyst A 206 0.63 9.7 Catalyst B 311 0.91 17.6 Catalyst C 247 0.76 12.4 Comparison of catalyst D 122 0.35 4.5

[0057] As shown in Table 1, the catalyst prepared in this application has a large specific surface area (206–311 m²). 2 / g), total pore volume (0.63~0.91cm³) 3 The average pore size (9.7–17.6 nm) is significantly greater than that of the comparative catalyst.

[0058] Example 4

[0059] The catalytic performance of the prepared catalyst in the amination of tetrahydrofuran to tetrahydropyrrole was evaluated in a fixed-bed reactor. The reactor diameter was 13 mm, the catalyst loading was 3 g, the reaction pressure was 0.0–3.0 MPa (0.0 MPa represents atmospheric pressure), the reaction temperature was 160–450 °C, and the tetrahydrofuran space velocity was 0.02–2.0 h⁻¹. -1 The ammonia / tetrahydrofuran molar ratio was 2–20. The reaction results are shown in Table 2.

[0060] Table 2 Catalytic performance of the catalyst of this invention and comparative catalysts in the reaction of tetrahydrofuranamine to tetrahydropyrrole.

[0061]

[0062] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for synthesizing tetrahydropyrrole by catalytic amination of tetrahydrofuran, characterized in that, Includes the following steps: A raw material containing tetrahydrofuran and ammonia is reacted with a catalyst to obtain a tetrahydropyrrole product. The catalyst is a porous alumina catalyst; The specific surface area of ​​the porous alumina catalyst is 200~315 m² / g; The total pore volume of the porous alumina catalyst is 0.6~1.0 cm³ / g; The porous alumina catalyst has a pore size of 9~20 nm; The porous alumina catalyst is spherical or columnar; The reaction pressure is 0~3 MPa, where 0 MPa is atmospheric pressure; The reaction temperature is 160~450℃; The space velocity of the tetrahydrofuran is 0.02~2.0 h⁻¹. -1 ; The molar ratio of ammonia to tetrahydrofuran in the raw material is 2 to 20.

2. The method according to claim 1, characterized in that, The porous alumina catalyst is prepared by: The porous alumina catalyst is obtained by mixing activated alumina, guar gum powder and acid solution, molding, drying and calcining.

3. The method according to claim 2, characterized in that, The mass of the guar gum powder accounts for 0.1 to 15.0 wt% of the mass of the activated alumina.

4. The method according to claim 2, characterized in that, The mass of the guar gum powder accounts for 2 to 10 wt% of the mass of the activated alumina.

5. The method according to claim 2, characterized in that, The acid solution comprises 40-180 wt% of the activated alumina. The concentration of the acid solution is 1~8wt%.

6. The method according to claim 2, characterized in that, The acid solution comprises 50-160 wt% of the alumina. The concentration of the acid solution is 2.5~6.5 wt%.

7. The method according to claim 2, characterized in that, The acid solution is selected from at least one of nitric acid, sulfuric acid, hydrochloric acid, and acetic acid.

8. The method according to claim 2, characterized in that, The drying temperature is 60~130℃, and the drying time is 6~12h.

9. The method according to claim 2, characterized in that, The roasting temperature is 400~800℃, and the roasting time is 3~5h.

10. The method according to claim 2, characterized in that, The forming method includes extrusion or ball rolling.

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