Catalyst for preparing furfuryl alcohol through furfural hydrogenation as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for preparing furfuryl alcohol through furfural hydrogenation as well as a preparation method and application of the catalyst. The preparation method of the catalyst comprises the following steps: (1) adding precursor salt of copper, aluminum oxide and urea into deionized water, and stirring at normal temperature to obtain a nitrogen-containing metal salt solution; (2) adding a sodium hydroxide solution into the nitrogen-containing metal salt solution, and carrying out heating reaction treatment to obtain a reaction solution; and (3) centrifuging, drying and roasting the reaction liquid to obtain the catalyst for preparing furfuryl alcohol through furfural hydrogenation. The catalyst does not involve precious metal and high-cost components, so that the production cost is low, the catalyst preparation process is simple, the process cost is low, the catalyst has the advantages of high hydrogenation activity, mild reaction conditions, no need of high-temperature and high-pressure reaction conditions and the like in the reaction for preparing furfuryl alcohol through furfural hydrogenation, the furfural conversion rate is high, furfuryl alcohol selectivity is high, and the catalyst is suitable for industrial production. And the method has extremely high application value.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a catalyst for preparing furfuryl alcohol by hydrogenating furfural, and a preparation method and application thereof. Background Art

[0002] With the increasing depletion of fossil resources and increasingly stringent environmental protection requirements, the use of renewable non-food biomass resources for "biorefining" has received widespread attention. Among them, the preparation of furfuryl alcohol using bio-based furfural as raw material through selective hydrogenation is a promising green route. Furfuryl alcohol is a key intermediate in the synthesis of many fine chemicals, such as tetrahydrofurfuryl alcohol, phenolic resin binder, synthetic fiber, plasticizer, polyurethane foam, etc. Furfural hydrogenation to furfuryl alcohol generally requires harsh conditions of high pressure, which increases the cost of the production process. Therefore, it is urgent to develop high-performance catalysts to promote the high-value-added conversion of furfural.

[0003] At present, the industrial hydrogenation of furfural is mainly based on liquid phase catalytic hydrogenation, and the catalyst is mostly Cu-Cr catalyst. Due to the high toxicity and environmental damage of Cr metal, its process is gradually being eliminated. The precious metal Pt catalyst shows excellent catalytic performance in the preparation of furfural alcohol by hydrogenation of furfural, but the precious metal catalyst is expensive and difficult to achieve industrial application. In addition to the precious metal Pt catalyst, Cu-based catalysts are also widely used in furfural hydrogenation. For example, patent document CN106694011A discloses Cu / SiO 2 Catalyst, although the catalyst has high catalytic activity for furfural hydrogenation, the required reaction temperature is 220°C and the hydrogen pressure is 3.5MPa. The reaction conditions are relatively harsh, the requirements for reaction equipment are high, and the production cost investment is large.

[0004] Therefore, designing and preparing high-performance Cu-based catalysts and realizing low-pressure hydrogenation are crucial to reducing production costs and improving the market competitiveness of furfuryl alcohol products. Summary of the invention

[0005] The main purpose of the present invention is to provide a catalyst for preparing furfuryl alcohol by hydrogenating furfural with mild catalytic reaction conditions, high furfural conversion rate and high furfuryl alcohol selectivity, as well as a preparation method and application thereof.

[0006] To achieve the above object, the present invention provides a method for preparing a catalyst for preparing furfuryl alcohol by hydrogenating furfural, comprising the following steps:

[0007] (1) adding a copper precursor salt, aluminum oxide and urea to deionized water, stirring at room temperature to obtain a nitrogen-containing metal salt solution;

[0008] (2) adding a sodium hydroxide solution to a nitrogen-containing metal salt solution, heating the solution for reaction, and obtaining a reaction solution;

[0009] (3) The reaction solution is centrifuged, dried, and calcined to obtain the catalyst for preparing furfuryl alcohol by hydrogenating furfural.

[0010] Furthermore, in step (1), the copper precursor salt is copper sulfate pentahydrate, the mass ratio of copper sulfate pentahydrate to alumina and urea is 2.5-5:3:3, and the stirring treatment time at room temperature is 1 hour.

[0011] Furthermore, the mass ratio of the sodium hydroxide added in step (2) to the aluminum oxide added in step (1) is 8:3, and the temperature of the heating reaction treatment is 80° C. and the time is 1 hour.

[0012] Furthermore, in step (3), the drying temperature is 110° C. and the drying time is 10 to 15 hours.

[0013] Furthermore, in step (3), the calcination temperature is 500° C. and the calcination time is 2 h.

[0014] The invention also provides a catalyst for preparing furfuryl alcohol by hydrogenating furfural, which is prepared according to the above preparation method.

[0015] The present invention also provides a method for preparing furfuryl alcohol by hydrogenating furfural, comprising the following steps: adding furfural, the catalyst and a reaction solvent into a reactor, then introducing hydrogen to replace the air in the reactor, and finally performing a heating reaction.

[0016] Furthermore, the usage ratio of furfural to catalyst is 12 mmol:0.5 g.

[0017] Furthermore, the initial hydrogen pressure in the reactor is 0.5 MPa, and the temperature of the heating reaction is 120-160°C.

[0018] The beneficial effects of the present invention are embodied in:

[0019] The catalyst for preparing furfuryl alcohol by hydrogenating furfural prepared by the invention has copper oxide as the main active component and basic nitrogen (provided by urea) as the active auxiliary agent. The catalyst activity is improved by screening the precipitant and optimizing the Cu loading amount, thereby improving the furfural conversion rate and the target product yield.

[0020] The catalyst of the present invention does not involve precious metals and high-cost components, so its production cost is low. At the same time, the catalyst preparation process is simple and the process cost is low. In the reaction of furfural hydrogenation to prepare furfuryl alcohol, the catalyst of the present invention has the advantages of high hydrogenation activity, mild reaction conditions, and no need for high temperature and high pressure reaction conditions. The furfural conversion rate is high and the furfuryl alcohol selectivity is high, and the application value is extremely high. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Catalyst 20Cu / Al for hydrogenation of furfural to furfuryl alcohol 2 O3 SEM images and element distribution maps.

[0022] Figure 2 Furfural on 20Cu / Al catalyst 2 O 3 Infrared spectra of the surface at different hydrogenation times. DETAILED DESCRIPTION

[0023] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0024] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or can be obtained by existing known methods; unless otherwise specified, the methods used in the examples of the present invention are methods known to those skilled in the art.

[0025] Example 1

[0026] Catalyst 20Cu / Al for hydrogenation of furfural to furfuryl alcohol 2 O 3 Preparation

[0027] (1) Add 5 g of copper sulfate pentahydrate, 3 g of aluminum oxide and 3 g of urea to 100 mL of deionized water and stir at room temperature for 1 h to obtain a nitrogen-containing metal salt solution;

[0028] (2) adding 100 mL of 2 mol / L sodium hydroxide aqueous solution as a precipitant to the nitrogen-containing metal salt solution, stirring and reacting in a water bath at 80° C. for 1 h to obtain a reaction solution;

[0029] (3) The reaction solution was centrifuged, and the obtained precipitate was washed with deionized water until neutral, and then placed in a drying oven at 110° C. for 12 h, and finally calcined at 500° C. for 2 h in an air atmosphere to obtain a catalyst for hydrogenating furfural to furfuryl alcohol, which was recorded as 20Cu / Al 2 O 3 .

[0030] Example 2

[0031] Catalyst 10Cu / Al for hydrogenation of furfural to furfuryl alcohol 2 O 3 Preparation

[0032] This example is prepared in the same manner as in Example 1, except that the amount of copper sulfate pentahydrate is adjusted to 2.5 g, and a catalyst for preparing furfuryl alcohol by hydrogenation of furfural is obtained, which is recorded as 10Cu / Al 2 O 3 .

[0033] Comparative Example 1

[0034] Comparative catalyst 30Cu / Al 2 O 3 Preparation

[0035] This comparative example was prepared in the same manner as in Example 1, except that the amount of copper sulfate pentahydrate was adjusted to 7.5 g to obtain a comparative catalyst, which was recorded as 30Cu / Al 2 O 3 .

[0036] Comparative Example 2

[0037] Comparative catalyst 20Ni / Al 2 O 3 Preparation

[0038] This comparative example was prepared in the same manner as in Example 1, except that 5 g of copper sulfate pentahydrate was replaced with 5.3 g of nickel sulfate to obtain a comparative catalyst, which was recorded as 20Ni / Al 2 O 3 .

[0039] Comparative Example 3

[0040] Comparative catalyst 20Fe / Al 2 O 3 Preparation

[0041] This comparative example was prepared in the same manner as in Example 1, except that 5 g of copper sulfate pentahydrate was replaced with 5.4 g of ferric chloride to obtain a comparative catalyst, recorded as 20Fe / Al 2 O 3 .

[0042] Comparative Example 4

[0043] Comparative catalyst 20Zn / Al 2 O 3 Preparation

[0044] This comparative example was prepared in the same manner as in Example 1, except that 5 g of copper sulfate pentahydrate was replaced with 4.4 g of zinc acetate to obtain a comparative catalyst, recorded as 20Zn / Al 2 O 3 .

[0045] Comparative Example 5

[0046] Comparative catalyst 20Cu / SiO 2 Preparation

[0047] This comparative example was prepared in the same manner as in Example 1, except that 3 g of alumina was replaced with 5 g of silicon dioxide to obtain a comparative catalyst, which was recorded as 20Cu / SiO2 .

[0048] Comparative Example 6

[0049] Preparation of comparative catalyst 20Cu / SBA-15

[0050] This comparative example was prepared in the same manner as in Example 1, except that 3 g of alumina was replaced with 5 g of SBA-15 to obtain a comparative catalyst, which was recorded as 20Cu / SBA-15.

[0051] Comparative Example 7

[0052] Comparative catalyst 20Cu@Al 2 O 3 Preparation

[0053] This comparative example was prepared in the same manner as in Example 1, except that the addition of urea was omitted to obtain a comparative catalyst, which was recorded as 20Cu@Al 2 O 3 .

[0054] Experimental Example 1

[0055] Catalyst 20Cu / Al for hydrogenation of furfural to furfuryl alcohol 2 O 3 Characterization

[0056] Figure 1 Catalyst 20Cu / Al 2 O 3 The SEM photo shows that the catalyst 20Cu / Al 2 O 3 The SEM-EDS elemental analysis results show that the catalyst 20Cu / Al 2 O 3 The Cu nanoparticles are evenly dispersed on the surface, and the N elements are evenly distributed around the Cu nanoparticles, which indicates that the 20Cu / Al 2 O 3 During the preparation process, nitrogen doping was successfully achieved to form a stable structure.

[0057] C=O hydrogenation is the rate-determining step of the furfural reaction. The hydrogenation activity of C=O is the key to evaluate the hydrogenation activity of the catalyst. 2 Under the reaction conditions, the catalyst 20Cu / Al 2 O 3 In situ infrared testing was performed. Figure 2 As shown, the catalyst surface is located at 1670 cm -1The peak at 1505cm is attributed to the stretching vibration of the C=O bond of the adsorbed furfural on the catalyst surface. Its appearance indicates that the reaction substrate is successfully adsorbed on the catalyst surface. As the reaction time increases, the stretching vibration of the furfural C=O on the catalyst surface gradually disappears. -1 、1228cm -1 A weak peak appears at 910cm -1 A new peak belonging to the CO bond appears at , indicating that with the completion of the C=O hydrogenation process, the produced furfuryl alcohol is also successfully adsorbed on the catalyst surface, and the adsorption intensity is relatively weak, indicating that furfuryl alcohol has excellent desorption ability on the catalyst. Therefore, based on the in situ infrared experiment, the catalyst 20Cu / Al 2 O 3 The above furfural hydrogenation reaction mechanism, the nitrogen doping on the catalyst surface provides sufficient active sites for the adsorption of C=O double bonds, and the nitrogen at the basic position increases the possibility of C=O bond activation, which is beneficial to the hydrogenation of the aldehyde group; then, the activated hydrogen on the surface of the Cu nanoparticles combines with C=O to realize the hydrogenation of furfural to prepare furfuryl alcohol, the active site has a weak ability to bind to the product, and the furfuryl alcohol is quickly desorbed, preventing the excessive hydrogenation of furfuryl alcohol, and improving the 20Cu / Al 2 O 3 Catalyst hydrogenation rate and selectivity of target products.

[0058] Experimental Example 2

[0059] Experimental study on the effect of catalyst on the hydrogenation of furfural to produce furfuryl alcohol

[0060] The catalysts prepared in the above examples and comparative examples were used to catalyze the hydrogenation of furfural to prepare furfuryl alcohol. The experimental method was as follows: 12 mmol of furfural, 0.5 g of catalyst and 15 mL of isopropanol were placed in an autoclave, and H 2 After replacing the air in the reactor, hydrogen was continuously introduced to reach a pressure of 0.5 MPa, and the reactor was heated to 160°C. The reaction was stopped after 4 hours under this condition, and the reaction liquid was collected.

[0061] The reaction liquid was analyzed by gas chromatography. The activity of the catalyst was expressed by the conversion rate of furfural and the yield of furfuryl alcohol. The amount of furfural and furfuryl alcohol in the reaction liquid was calculated based on the gas chromatography results. The furfural conversion rate and the yield of furfuryl alcohol were calculated by the following formulas. The experimental results are shown in Table 1.

[0062]

[0063] Table 1

[0064]

[0065]

[0066] It can be seen that the catalyst 20Cu / Al prepared by the present invention for preparing furfuryl alcohol by hydrogenation of furfural 2 O 3 、10Cu / Al 2 O 3 has the best catalytic performance.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for preparing furfuryl alcohol by hydrogenating furfural, characterized in that: The following steps are involved: (1) adding a copper precursor salt, aluminum oxide and urea to deionized water, stirring at room temperature to obtain a nitrogen-containing metal salt solution; (2) adding a sodium hydroxide solution to a nitrogen-containing metal salt solution, heating the solution for reaction, and obtaining a reaction solution; (3) The reaction solution is centrifuged, dried, and calcined to obtain the catalyst for preparing furfuryl alcohol by hydrogenating furfural.

2. The method for preparing a catalyst for preparing furfuryl alcohol by hydrogenating furfural as claimed in claim 1, wherein: In step (1), the copper precursor salt is copper sulfate pentahydrate, the mass ratio of copper sulfate pentahydrate to alumina and urea is 2.5-5:3:3, and the stirring treatment time at room temperature is 1 hour.

3. The method for preparing a catalyst for furfuryl alcohol by hydrogenating furfural as claimed in claim 1, wherein: The mass ratio of the sodium hydroxide added in step (2) to the aluminum oxide added in step (1) is 8:3, and the temperature of the heating reaction treatment is 80° C. and the time is 1 hour.

4. The method for preparing a catalyst for furfuryl alcohol by hydrogenating furfural as claimed in claim 1, wherein: In step (3), the drying temperature is 110° C. and the drying time is 10 to 15 hours.

5. The method for preparing a catalyst for preparing furfuryl alcohol by hydrogenating furfural as claimed in claim 1, wherein: In step (3), the calcination temperature is 500° C. and the calcination time is 2 h.

6. A catalyst for preparing furfuryl alcohol by hydrogenating furfural, characterized in that: Prepared according to the preparation method as described in any one of claims 1 to 5.

7. A method for preparing furfuryl alcohol by hydrogenating furfural, characterized in that: The method comprises the following steps: adding furfural, the catalyst as claimed in claim 6 and a reaction solvent into a reactor, then introducing hydrogen to replace the air in the reactor, and finally performing heating reaction.

8. The method for preparing furfuryl alcohol by hydrogenating furfural as claimed in claim 7, characterized in that: The usage ratio of furfural to catalyst is 12mmol:0.5g.

9. The method for preparing furfuryl alcohol by hydrogenating furfural as claimed in claim 7, characterized in that: The initial hydrogen pressure in the reactor is 0.5 MPa, and the temperature of the heating reaction is 120-160°C.

Images