Quinoline hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention provides a quinoline hydrogenation catalyst as well as a preparation method and application thereof. The general formula of the quinoline hydrogenation catalyst is CuzZn (10-z) / SiO2, wherein z is more than 1 and less than 10; the quinoline hydrogenation catalyst comprises a gas-phase SiO2 carrier, an active component Cu loaded on the carrier and an auxiliary agent Zn loaded on the carrier, the active component accounts for 10-20% by mass of the quinoline hydrogenation catalyst, and the auxiliary agent accounts for 2-10% by mass of the quinoline hydrogenation catalyst. The catalyst has good stability.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a quinoline hydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] Coal chemical wastewater contains many complex and highly toxic organic substances, among which nitrogen-containing heterocyclic substances are one of the most critical and difficult-to-degrade components. Common nitrogen-containing heterocyclic compounds in coal chemical wastewater treatment include indole, pyridine, quinoline and their corresponding derivatives, and the hydrogenation products of nitrogen heterocyclic compounds are widely used as intermediates for dyes and drugs. However, the stability of existing catalysts in the hydrogenation process of nitrogen heterocyclic compounds is not high. Therefore, improving the stability of the catalyst is crucial for the hydrogenation treatment of nitrogen heterocyclic compounds and the optimal utilization of resources.

[0003] Most of the current catalysts are based on precious metals, which are limited in resources and expensive, limiting their further application. Obviously, non-precious metal catalysts have obvious cost advantages, so the development of more cost-effective and highly selective and stable non-precious metal catalysts is of great significance for the selective hydrogenation of nitrogen heterocyclic compounds and other applications. Summary of the invention

[0004] In order to solve the above problems in the prior art, the present invention aims to provide a quinoline hydrogenation catalyst and its preparation method and application. The catalyst has good stability.

[0005] In order to achieve the above object, according to a first aspect of the present invention, a quinoline hydrogenation catalyst is provided, the general formula of which is Cu z Zn (10-z) / SiO 2 , wherein 1<z<10; the quinoline hydrogenation catalyst comprises gas phase SiO 2 A carrier, an active component Cu loaded on the carrier, and an auxiliary agent Zn loaded on the carrier;

[0006] The mass percentage of the active component in the quinoline hydrogenation catalyst is 10-20%, and the mass percentage of the auxiliary agent in the quinoline hydrogenation catalyst is 2-10%.

[0007] The introduction of the zinc adjuvant in the catalyst of the present invention can promote the formation of silicate and copper-zinc active centers, strengthen the interaction between the active component and the carrier, and enhance the structural stability of the catalyst. The stable structure of the catalyst is also conducive to its industrial application.

[0008] In addition, in the catalyst of the present invention, fumed silica is used as a carrier, which can provide a larger specific surface area and allow the active components to be fully dispersed on its surface, which is beneficial to improving the activity of the catalyst.

[0009] In some preferred embodiments of the present invention, the molar ratio of Cu to Zn is 6-9:1-4. The molar ratio of copper to zinc will affect the + / (Cu + +Cu 0 ) ratio, limiting the molar ratio of copper to zinc within the above range is beneficial to improving the activity and stability of the catalyst. + Refers to monovalent copper ion, Cu 0 Refers to zero-valent copper.

[0010] In some preferred embodiments of the present invention, in the Cu, Cu + / (Cu + +Cu 0 ) is 0.5 to 0.7: 1. The catalyst selected according to the above conditions has better catalytic activity and selectivity.

[0011] According to another aspect of the present invention, there is also provided a method for preparing the above-mentioned quinoline hydrogenation catalyst, comprising:

[0012] The copper salt, zinc salt and water are prepared into a copper-zinc salt aqueous solution;

[0013] 70-90% volume of the copper-zinc salt aqueous solution is mixed with a silica carrier, and heated to form a suspension A;

[0014] The remaining copper-zinc salt aqueous solution is mixed with urea and nitric acid to form a mixed solution B;

[0015] The suspension A and the mixed solution B are mixed and reacted at 80-95° C. for 1-8 hours;

[0016] After the reaction is completed, the mixture is filtered and washed until the pH of the filtrate is neutral, and the solid phase is separated and dried to obtain a catalyst precursor;

[0017] The catalyst precursor is subjected to calcination treatment, reduction treatment, and then passivation to obtain the quinoline hydrogenation catalyst.

[0018] The preparation method of the invention has simple process, cheap and readily available raw materials, mild reaction conditions and is conducive to large-scale production.

[0019] In some preferred embodiments of the present invention, the molar ratio of Cu in the copper salt, the nitric acid, and the urea is 1-2:1-5:10-15.

[0020] In some preferred embodiments of the present invention, the calcination temperature is 400-600° C. and the calcination time is 2-6 hours.

[0021] In some preferred embodiments of the present invention, the passivation comprises: treating the reduced material at 0.3% to 0.5% O 2 / Ar 2 The passivation is performed in an atmosphere (i.e., an atmosphere in which the volume content of oxygen is 0.3% to 0.5%).

[0022] In some preferred embodiments of the present invention, the reduction treatment is carried out at a temperature of 300 to 500° C. and for a time of 1 to 4 hours.

[0023] In some preferred embodiments of the present invention, the reducing atmosphere used in the reduction treatment is hydrogen, and the flow rate of the reducing atmosphere is 35-50 ml / min.

[0024] In some preferred embodiments of the present invention, 80% volume of the copper-zinc salt aqueous solution is mixed with a silica carrier and heated to form the suspension A.

[0025] The parameters of the preparation method such as the method for preparing the suspension, the selection of copper salt and zinc salt, etc., can be selected by those skilled in the art according to common knowledge. For example, copper salt and zinc salt can preferably be nitrate. The present invention does not make further limitations on this.

[0026] According to another aspect of the present invention, there is also provided an application of the above-mentioned quinoline hydrogenation catalyst in the catalytic hydrogenation of quinoline to prepare 1,2,3,4-tetrahydroquinoline (py-THQ), wherein the selectivity of the quinoline hydrogenation catalyst for 1,2,3,4-tetrahydroquinoline is higher than 90% after catalysis for 2 days.

[0027] In some preferred embodiments of the present invention, the conditions for catalyzing the quinoline hydrogenation reaction using the quinoline hydrogenation catalyst are: a hydrogen pressure of 3 MPa, a reaction temperature of 100° C., and a reaction time of 2 h.

[0028] According to another aspect of the present invention, there is also provided the use of the above-mentioned quinoline hydrogenation catalyst in catalyzing the hydrogenation reaction of quinoline derivatives. The catalyst of the present invention has excellent conversion rate and selectivity in catalyzing the hydrogenation reaction of quinoline derivatives. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The Cu prepared in Example 3 of the present invention is shown. 6 Zn 4 / SiO 2 TEM image of the catalyst. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a quinoline hydrogenation catalyst, and the preparation method thereof comprises:

[0033] 0.09 mol Cu(NO 3 ) 2 ·3H 2 O and 0.01 mol Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water to prepare a copper-zinc salt aqueous solution, and 3.2 g of SiO 2 The carrier is heated to 70°C under constant stirring to form a suspension A;

[0034] 7.56 g of urea was weighed and added to the remaining copper-zinc salt aqueous solution, and then 0.56 g of concentrated nitric acid (molar concentration is 8 mol / L, and the concentration of concentrated nitric acid is the same as this unless otherwise specified below) was added to form a mixed solution B;

[0035] Add the mixed solution B dropwise into the suspension A at 70°C, and slowly heat to 90°C for 4 hours. After the reaction is complete, filter and wash until the filtrate is neutral, and dry for 12 hours to obtain a catalyst precursor.

[0036] The catalyst precursor was calcined at 450 °C for 4 h and then heated in H 2 After reduction at 350 °C for 2 h at a flow rate of 40 mL / min, the 2 / Ar 2 Cu was obtained by passivation in atmosphere 9 Zn 1 / SiO 2 catalyst.

[0037] Example 2

[0038] The only difference from Example 1 is that 0.08 mol of Cu(NO 3 ) 2 ·3H 2 O and 0.02 mol Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water to prepare a copper-zinc salt aqueous solution. The subsequent treatment method was the same as in Example 1 to obtain Cu 8 Zn 2 / SiO 2catalyst.

[0039] Example 3

[0040] The only difference from Example 1 is that 0.07 mol of Cu(NO 3 ) 2 ·3H 2 O and 0.03 mol Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water to prepare a copper-zinc salt aqueous solution. The subsequent treatment method was the same as in Example 1 to obtain Cu 7 Zn 3 / SiO 2 Catalyst. The TEM image of the catalyst is shown in Figure 1 As shown. Figure 1 It can be seen that the active components in the catalyst are well dispersed.

[0041] Example 4

[0042] The only difference from Example 1 is that 0.06 mol of Cu(NO 3 ) 2 ·3H 2 O and 0.04 mol Zn(NO 3 ) 2 6H 2 O was dissolved in deionized water to prepare a copper-zinc salt aqueous solution. The subsequent treatment method was the same as in Example 1 to obtain Cu 6 Zn 4 / SiO 2 catalyst.

[0043] Comparative Example

[0044] The only difference from Example 1 is that 0.1 mol of Cu(NO 3 ) 2 ·3H 2 O was dissolved in deionized water to prepare a copper salt aqueous solution. The subsequent treatment method was the same as in Example 1 to obtain Cu / SiO 2 catalyst.

[0045] Application Example 1

[0046] The catalysts prepared in the above examples and comparative examples are used to catalyze the hydrogenation of quinoline to prepare 1,2,3,4-tetrahydroquinoline (py-THQ). The hydrogenation reaction includes:

[0047] The catalyst, quinoline and ethanol were added into a 100 mL high temperature and high pressure stainless steel intermittent reactor. After the reactor was sealed, the air in the reactor was replaced 3-5 times, hydrogen was filled in and the reactor was sealed to start the reaction. After the reaction, the reactor was quickly cooled, the residual hydrogen in the reactor was carefully discharged, and the reaction liquid was taken out. The reaction liquid after centrifugation was analyzed in an Aglient 6890N gas chromatograph, the chromatographic column was a commercially available HP-Innowax capillary column, and the hydrogen flame detector was used.

[0048] Reaction conditions: 0.1 g of supported Cu z Zn (10-z) / SiO 2 Catalyst, 5mmol quinoline, 15mL ethanol, 3MPa H 2 , reacted at 100℃ for 2h. The results are shown in Table 1.

[0049] Table 1

[0050] catalyst <![CDATA[Cu + / (With + +With 0 )]]> Quinoline conversion rate (%) Conversion rate after 2-day cycle (%) py-THQ selectivity (%) <![CDATA[Cu / SiO 2 ]]> 60.2 94.7 89.1 ＞99.9 <![CDATA[Cu 9 Zn / SiO 2 ]]> 61.7 95.6 92.3 ＞99.9 <![CDATA[Cu 8 Zn 2 / SiO 2 ]]> 69.3 97.4 95.4 ＞99.9 <![CDATA[Cu 7 Zn 3 / SiO 2 ]]> 78.9 99.8 98.2 ＞99.9 <![CDATA[Cu 6 Zn 4 / SiO 2 ]]> 54.1 93.2 91.3 ＞99.9

[0051] It can be seen from Table 1 that the molar ratio of copper and zinc has a significant effect on the performance of the catalyst for catalytic quinoline hydrogenation to prepare py-THQ. + / (Cu + +Cu 0 ) further affects the selective hydrogenation performance of the catalyst. Under the research conditions, the selectivity of the catalyst of the present invention for py-THQ is greater than 99.9%. When the catalyst is free of zinc additive, Cu + / (Cu + +Cu 0 ) ratio is small, Cu / SiO 2 As the molar ratio of copper to zinc gradually changes from 9:1 to 7:3, Cu + / (Cu + +Cu 0 ) increased from 61.7% to 78.9%. When the amount of zinc additive continued to increase, Cu + / (Cu + +Cu 0 As the content of zinc additive increases, the interaction between copper and zinc becomes stronger, the active components are evenly dispersed, and are easily reduced to Cu + As the amount of zinc additive continues to increase, the excess zinc wraps the active components and can only reduce part of the material on the catalyst surface, resulting in less active components and reducing them to Cu + As can be seen from Table 1, when the molar ratio of copper to zinc is 7:3, Cu + / (Cu + +Cu 0 ) has a maximum ratio of 78.9%, Cu 7 Zn3 / SiO 2 The catalyst has the best selective hydrogenation performance, with a conversion rate of 99.8% and a selectivity of more than 99.9%.

[0052] The stability of each catalyst was tested. After 2 days of circulation, Cu / SiO 2 , C u9 Zn 1 / SiO 2 , Cu 8 Zn 2 / SiO 2 , Cu 7 Zn 3 / SiO 2 and Cu 6 Zn 4 / SiO 2 The catalytic activity of quinoline selective hydrogenation decreased to 89.1%, 92.3%, 95.4%, 98.2% and 91.3%, respectively. 7 Zn 3 / SiO 2 After the catalyst was cycled for 2 days, the activity still reached 98.2%, showing good stability. z Zn (10-z) / SiO 2 The catalyst has high selectivity, and the selectivity is still greater than 99.9% after recycling.

[0053] Application Example 2

[0054] Cu7Zn of Test Example 3 3 / SiO 2 Experimental results of catalyst reactions at different temperatures.

[0055] Reaction conditions: 0.1 g of supported Cu 7 Zn 3 / SiO 2 Catalyst, 5mmol quinoline, 15mL ethanol, 3MPa H 2 The reaction was continued for 2 h. The results are shown in Table 2.

[0056] Table 2

[0057] Reaction temperature (℃) Quinoline conversion rate (%) py-THQ selectivity (%) 80 76.4 ＞99.9 90 89.3 ＞99.9 100 99.8 ＞99.9 110 99.8 ＞99.9

[0058] It can be seen from Table 2 that the reaction temperature has a significant effect on the performance of quinoline hydrogenation to py-THQ. As the reaction temperature increases from 80°C to 90°C, the conversion rate increases from 76.4% to 89.3%. When the reaction temperature continues to rise to 100°C, the quinoline conversion rate reaches 99.8%. When the reaction temperature continues to rise, the quinoline conversion rate does not change. It can be concluded that the optimal reaction temperature for the catalytic hydrogenation reaction is 100°C.

[0059] Application Example 3

[0060] Test the Cu of Example 3 above 7 Zn 3 / SiO 2 Experimental results of catalyst reactions at different pressures.

[0061] Reaction conditions: 0.1 g of supported Cu 7 Zn 3 / SiO 2 Catalyst, 5 mmol quinoline, 15 mL ethanol, reaction at 100°C for 2 h. The results are shown in Table 3.

[0062] Table 3

[0063] Reaction pressure (MPa) Quinoline conversion rate (%) py-THQ selectivity (%) 1 88.4 ＞99.9 2 99.0 ＞99.9 3 99.8 ＞99.9

[0064] It can be seen from Table 3 that at a reaction temperature of 100 °C, as H 2 When the pressure increases from 1MPa to 2MPa, the conversion rate of quinoline increases from 88.4% to 99.0%. When the hydrogen pressure increases to 3MPa, the conversion rate of quinoline increases to 99.8%. Therefore, the suitable reaction pressure of the hydrogenation reaction is 3MPa.

[0065] Application Example 4

[0066] Test the Cu of Example 3 above v Zn 3 / SiO 2 Experimental results of the catalyst reacting at different times.

[0067] Reaction conditions: 0.1 g of supported Cu 7 Zn 3 / SiO 2 Catalyst, 5mmol quinoline, 15mL ethanol, 3MPa H 2 , 100°C. The results are shown in Table 4.

[0068] Table 4

[0069] Reaction time (h) Quinoline conversion rate (%) py-THQ selectivity (%) 1 93.4 ＞99.9 2 99.8 ＞99.9 3 99.8 ＞99.9

[0070] It can be seen from Table 4 that under the conditions of reaction temperature of 100°C and hydrogen pressure of 3MPa, when the reaction time is 1h, the conversion rate of quinoline is only 93.4%, and the py-THQ selectivity is still 99.9%. When the reaction time is extended to more than 2h, the conversion rate of quinoline increases rapidly to 99.8%, and the product selectivity remains unchanged. The conversion rate does not change when the reaction time is further extended, so the optimal reaction time is 2h.

[0071] Application Example 5

[0072] The Cu of Example 3 above 7 Zn 3 / SiO 2 The catalyst was used to catalyze the hydrogenation reaction of quinoline derivatives. The experimental results are shown in the following table.

[0073] Reaction conditions: 0.1 g of supported Cu 7 Zn 3 / SiO 2 Catalyst, 5mmol quinoline, 15mL ethanol, 3MPa H 2 , reacted at 100℃ for 2h. The results are shown in Table 5.

[0074] Table 5

[0075] raw material Conversion rate of quinoline derivatives (%) Selectivity of tetrahydroquinoline derivatives (%) 3-Methylquinoline 100 98.6 5-Aminoquinoline 98.9 97.8 2-Chloroquinoline 98.6 97.3 8-Hydroxyquinoline 96.5 98.4 Isoquinoline 94.3 99.6

[0076] A series of quinoline derivatives were reacted in ethanol as solvent, and the test results are shown in Table 5.

[0077] It can be seen that the catalyst of the present invention has excellent selectivity for the tetrahydroquinoline derivatives corresponding to quinoline derivatives, which may be because the electron-donating group is conducive to the selective hydrogenation of the pyridine ring. It can be seen that the catalyst of the present invention can be widely used in the hydrogenation of nitrogen heterocycles.

[0078] In general, when the catalyst of the present invention is used in the selective hydrogenation reaction of quinoline and its derivatives, the conversion rate of quinoline and its derivatives and the selectivity of py-THQ and its derivatives are significantly improved. 2 , 100°C, after 2h of reaction, the quinoline conversion rate and py-THQ selectivity can reach 99.8% and 99.9% respectively; after 2 days of cyclic reaction, the conversion rate can still reach 98.2% and the selectivity is still 99.9%.

Claims

1. A quinoline hydrogenation catalyst, characterized in that The general formula is Cu z Zn (10-z) / SiO2, wherein 1<z<10; the quinoline hydrogenation catalyst comprises a gas phase SiO2 carrier, an active component Cu supported on the carrier and an auxiliary agent Zn supported on the carrier; The mass percentage of the active component in the quinoline hydrogenation catalyst is 10-20%, and the mass percentage of the auxiliary agent in the quinoline hydrogenation catalyst is 2-10%.

2. The quinoline hydrogenation catalyst according to claim 1, characterized in that The molar ratio of Cu to Zn is 6-9:1-4.

3. The quinoline hydrogenation catalyst according to claim 1, characterized in that The Cu, Cu + / (Cu + +Cu 0 ) has a molar ratio of 0.5 to 0.7:

1.

4. A method for preparing the quinoline hydrogenation catalyst according to any one of claims 1 to 3, characterized in that: include: The copper salt, zinc salt and water are prepared into a copper-zinc salt aqueous solution; 70-90% volume of the copper-zinc salt aqueous solution is mixed with a silica carrier, and heated to form a suspension A; The remaining copper-zinc salt aqueous solution is mixed with urea and nitric acid to form a mixed solution B; The suspension A and the mixed solution B are mixed and reacted at 80-95° C. for 1-8 hours; After the reaction is completed, the mixture is filtered and washed until the pH of the filtrate is neutral, and the solid phase is separated and dried to obtain a catalyst precursor; The catalyst precursor is subjected to calcination treatment, reduction treatment, and then passivation to obtain the quinoline hydrogenation catalyst.

5. The preparation method according to claim 4, characterized in that: The molar ratio of Cu in the copper salt, the nitric acid and the urea is 1-2:1-5:10-15.

6. The preparation method according to claim 4, characterized in that: The calcination temperature is 400-600° C. and the calcination time is 2-6 hours.

7. The preparation method according to claim 4, characterized in that: The passivation comprises: passivating the material obtained after reduction in an Ar2 atmosphere containing 0.3-0.5 vol% O2.

8. The preparation method according to claim 4, characterized in that: The temperature of the reduction treatment is 300-500° C., and the time is 1-4 hours.

9. The preparation method according to claim 4, characterized in that: 80% volume of the copper-zinc salt aqueous solution is mixed with the silica carrier and heated to form the suspension A.

10. Use of the quinoline hydrogenation catalyst according to any one of claims 1 to 3 in catalyzing the hydrogenation reaction of quinoline derivatives.

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