Method for preparing dff based on imo6-znIn2s4 / nitiO3 oxidizing hmf

Abstract

The application discloses a method for preparing DFF by oxidizing HMF based on IMo6-ZnIn2S4 / NiTiO3, and specifically comprises the following steps: first, preparing ZnIn2S4 / NiTiO3 metal sulfide IMo6-ZnIn2S4 / NiTiO3 loaded with heteropoly acid Na5IMo6O 24 ; and second, adding the IMo6-ZnIn2S4 / NiTiO3 into a HMF solution and performing a photocatalytic oxidation experiment under the condition of visible light with a wavelength greater than 400 nm. The process can not only efficiently synthesize DFF with a selectivity of 90.97%, but also has mild reaction conditions and simple operation, and is a cheap and efficient method for preparing DFF. The application provides valuable information for solving the problems of environmental pollution and energy shortage by developing and utilizing the photocatalysis of the metal sulfide loaded with the heteropoly acid, and provides a reference for the conversion of renewable biomass resources.

Description

TECHNICAL FIELD

[0001] The application relates to the chemical technology field and relates to a method for preparing DFF by oxidizing HMF based on IMo6-ZnIn2S4 / NiTiO3. 24 The application relates to a method for preparing 2,5-furandicarboxaldehyde (DFF) by catalytically oxidizing 5-hydroxymethylfurfural (HMF) by using ZnIn2S4 / NiTiO3 (IMo6-ZIS / NiTiO3) metal sulfide loaded with different amounts of Na5IMo6O BACKGROUND

[0002] Biomass is considered to be the most abundant renewable resource in nature, and it is of great significance to use it to produce value-added chemicals. Among various biomass derivatives, HMF is considered to be an important part of producing value-added chemicals and biofuels. HMF is released in the dehydration process of biomass-derived carbohydrates such as fructose, sucrose, starch and cellulose, and is considered to be one of the most basic bio-derived chemicals, which can be converted into various high-value chemicals. 2,5-diformylfuran (DFF), one of the oxidation products of HMF, is of great concern because it can be used to synthesize medicines, functional polymers and bactericides. However, the traditional catalytic system has the disadvantages of high cost, high energy consumption, poor stability, harsh reaction conditions, serious pollution and the like, so a green and environmentally friendly, efficient and feasible catalytic system should be explored to realize the efficient utilization of HMF. Multiple metal sulfides have attracted more and more attention in the field of photocatalysis due to their excellent photoelectron properties, but the problems of low photo-generated carrier separation efficiency and poor light stability need to be solved. SUMMARY

[0003] To solve the above technical problems, the application provides a method for preparing DFF by oxidizing HMF based on IMo6-ZnIn2S4 / NiTiO3, in particular a method for preparing 2,5-furandicarboxaldehyde (DFF) by catalytically oxidizing 5-hydroxymethylfurfural (HMF) by using ZnIn2S4 / NiTiO3 (IMo6-ZIS / NiTiO3) loaded with different amounts of Na5IMo6O 24 The application provides a method for preparing 2,5-furandicarboxaldehyde (DFF) by catalytically oxidizing 5-hydroxymethylfurfural (HMF) by using ZnIn2S4 / NiTiO3 (IMo6-ZIS / NiTiO3) loaded with different amounts of Na5IMo6O

[0004] The technical scheme for solving the above technical problems is as follows:

[0005] The method for preparing DFF by oxidizing HMF based on IMo6-ZnIn2S4 / NiTiO3 comprises the following steps:

[0006] 1) preparing IMo6-ZnIn2S4 / NiTiO3:

[0007] Step 1.1) Ni(Ac)2·H2O and Ti(OC4H9)4 were dispersed into ethylene glycol at a molar ratio of 1: (1-1.5), stirred at room temperature until a precipitate was formed, then washed by water and ethanol alternately by centrifugation, dried in vacuum for 12 h, and then calcined at 700℃ with a temperature rising rate of 2℃ / min for 2 h to obtain NiTiO3 microspheres;

[0008] Step 1.2) NiTiO3 was dispersed in water and stirred, then ZnCl2, InCl3, and C2H5NS were added and stirred until uniformly dispersed, wherein the mass ratio of NiTiO3, ZnCl2, InCl3, and C2H5NS was 1: (3.5-4) : (5.5-6) : (4-4.5), and the mixture was heated to 80℃ in an oil bath until the reaction was completed, then washed by water and ethanol alternately, and dried in a vacuum oven at 60℃ for 12 h to obtain ZnIn2S4 / NiTiO3;

[0009] Step 1.3) ZnIn2S4 / NiTiO3 and Na5IMo6O 24 were added to ethanol at a mass ratio of 1:0.05-0.2, stirred, heated in an oil bath at 75℃ with condensation reflux, washed by water and ethanol alternately after 3 h, and dried in a vacuum oven at 60℃ for 12 h to obtain IMo6-ZnIn2S4 / NiTiO3 with a mass fraction of 5-20%;

[0010] 2) Dark reaction: IMo6-ZnIn2S4 / NiTiO3 was added to an aqueous HMF solution, wherein the mass ratio of IMo6-ZnIn2S4 / NiTiO3 to HMF was 1-5:1;

[0011] Then, the mixture was placed in a photocatalytic reactor and stirred for 0-40 o under dark, circulating water conditions for 0.2-1 h to reach adsorption equilibrium;

[0012] 3) Photocatalytic reaction: catalytic oxidation reaction was carried out under light irradiation with a wavelength of greater than 400 nm for 1-6 h to obtain 2,5-furandicarboxaldehyde.

[0013] Preferably, the dark reaction time is 0.5 h, and the photocatalytic reaction time is 2 h.

[0014] Preferably, the light irradiation condition is one of ultraviolet light, visible light, and ultraviolet-visible light.

[0015] The significant improvement of the selectivity of photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to prepare 2,5-furan dicarboxaldehyde (DFF) lies in that the metal sulfide of ZnIn2S4 / NiTiO3 loaded with IMo6 has a lower recombination rate of photo-carriers and a longer life, which is beneficial to charge transfer, and thus significantly improves the redox capacity of 5-hydroxymethylfurfural (HMF). Taking the embodiment 2 with the optimal selectivity as an example, the heteropoly acid Na5IMo6O 24 After that, 10% IMo6-ZIS / NiTiO3, as shown in FIG. 3(a)(b), the test of UV-vis on light absorption capacity shows that the light absorption range and absorption intensity of the metal sulfide of ZnIn2S4 / NiTiO3 loaded with IMo6 are obviously improved; and, as shown in FIG. 3(c)(d), the PL test shows that the photoluminescence intensity of IMo6-ZIS / NiTiO3 is the lowest, which proves that in the method for photocatalytic HMF to prepare DFF, the recombination rate of the surface photo-generated electrons and photo-generated holes of 10% IMo6-ZIS / NiTiO3 is the lowest, so that the electron-hole is effectively separated, and thus the selectivity of photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to prepare 2,5-furan dicarboxaldehyde (DFF) is significantly improved. Moreover, the experimental results also prove that under the optimal reaction condition, the photocatalytic method of the application can improve the selectivity of DFF to 90.97%, which is close to the goal of completely oxidizing HMF to DFF. Figure 4 The significant improvement of the selectivity of photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to prepare 2,5-furan dicarboxaldehyde (DFF) lies in that the metal sulfide of ZnIn2S4 / NiTiO3 loaded with IMo6 has a lower recombination rate of photo-carriers and a longer life, which is beneficial to charge transfer, and thus significantly improves the redox capacity of 5-hydroxymethylfurfural (HMF). Taking the embodiment 2 with the optimal selectivity as an example, the heteropoly acid Na5IMo6O Advantages

[0016] (1) The application provides a new catalytic system, i.e. the metal sulfide of ZnIn2S4 / NiTiO3 loaded with IMo6, which can be effectively applied to catalytic oxidation of 5-hydroxymethylfurfural to prepare 2,5-furan dicarboxaldehyde.

[0017] (2) The metal sulfide of 5~20% IMo6-ZnIn2S4 / NiTiO3 has a stronger light absorption range and a lower carrier recombination rate, and exhibits more excellent photocatalytic performance.

[0018] (3) The selective oxidation of HMF of the application is effective under visible light with a wavelength greater than 400 nm.

[0019] (4) The selective oxidation reaction of HMF of the application is short, and the selectivity of DFF can reach 90.97% in 2 h.

[0020] (5) The process of the application can synthesize DFF with high selectivity (the selectivity reaches 90.97%), and the process is simple in operation, mild in reaction condition, high in selectivity, low in cost, green and pollution-free, which is a cheap and efficient method for preparing DFF. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, constitute a part of the specification and are used together with the specific embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0022] Figure 1 The figure is a comparison chart of the effect of 10% IMO6-ZnIn2S4 / NiTiO3 of the embodiment 2 of the present application on selective oxidation of HMF. Reaction conditions: 10 mL (0.03 g) 5-hydroxymethylfurfural aqueous solution, m(cat) = 0.04 g, 25 ℃, 2 h.

[0023] Figure 2 The figure is an XRD test chart of M%IMo6-ZnIn2S4 / NiTiO3 of the embodiment 2 of the present application.

[0024] Figure 3(a) is a UV-vis test chart of 10%IMo6-ZnIn2S4 / NiTiO3 of the embodiment 2 of the present application, and figure 3(b) is a chart for calculating the band gap of the material.

[0025] Figure 4 The figure is a PL test chart of 10%IMo6-ZnIn2S4 / NiTiO3 of the embodiment 2 of the present application.

[0026] Figure 5 The figure is a recovery test chart of 10%IMo6-ZnIn2S4 / NiTiO3 of the embodiment 2 of the present application. DETAILED DESCRIPTION

[0027] The principles and features of the present application are described below, and the examples are only used to explain the present application, and are not used to limit the scope of the present application.

[0028] Example 1 5%IMo6-ZnIn2S4 / NiTiO3

[0029] (1) Disperse Ni(Ac)2·H2O (1 mmol) and 3.4 ml Ti(OC4H9)4 into 60 ml ethylene glycol, and continuously stir at room temperature. Stop stirring after 2 h, centrifuge the formed precipitate, wash with water and ethanol alternately, vacuum dry for 12 h, and then calcine at 700 ℃ under the condition of temperature rising at 2 ℃ / min for 2 h, to obtain NiTiO3 microspheres;

[0030] (2) Disperse 30 mg NiTiO3 in 40 mL water and stir for 30 min, add 108.8 mg ZnCl 2,176.8 mg InCl3, 120 mg C2H5NS in 100 ml round-bottom flask, after stirring for 5 min, placed in an oil bath pot to heat to 80 °C, 2 h after washing with water, ethanol alternately, dried in a vacuum oven at 60 °C for 12 h, ZnIn2S4 / NiTiO3 was prepared;

[0031] (3) 176.8 mg InCl3, 120 mg C2H5NS in 100 ml round-bottom flask, after stirring for 5 min, placed in an oil bath pot to heat to 80 °C, 2 h after washing with water, ethanol alternately, dried in a vacuum oven at 60 °C for 12 h, ZnIn2S4 / NiTiO3 was prepared;

[0032] (4) photocatalytic oxidation reaction

[0033] 1) Dark reaction: 0.04 g 5% IMo6-ZnIn2S4 / NiTiO3 was added to the HMF (0.03 g) aqueous solution, then placed in a photocatalytic reactor 0~40 o C, light, circulating water conditions, stirring reaction 0.5 h to reach adsorption equilibrium;

[0034] 2) Photocatalytic reaction: under visible light irradiation, catalytic oxidation reaction was carried out for 2 h, and 2,5-furandicarboxaldehyde (DFF) was obtained.

[0035] As Figure 1 The results show that the DFF selectivity of 5% IMo6-SZIS is 84.52%.

[0036] Example 2 10%IMo6-ZnIn2S4 / NiTiO3

[0037] (1) Ni(Ac)2·H2O (1 mmol) and 3.4 ml Ti(OC4H9)4 were dispersed into 60 ml ethylene glycol, and stirred at room temperature. After 2 h, the stirring was stopped, and the precipitate was centrifuged, washed with water and ethanol alternately, and dried in a vacuum oven for 12 h, then calcined at 700 °C with a temperature rise of 2 °C / min for 2 h to prepare NiTiO3 microspheres;

[0038] (2) 30 mg NiTiO3 was dispersed in 40 mL water and stirred for 30 min, 108.8 mg ZnCl 2,176.8 mg InCl3, 120 mg C2H5NS in 100 ml round-bottom flask, after stirring for 5 min, placed in an oil bath pot and heated to 80 °C, washed with water and ethanol alternately after 2 h, dried in a vacuum oven at 60 °C for 12 h, to prepare ZnIn2S4 / NiTiO3;

[0039] (3) ZnIn2S4 / NiTiO3 and 10% IMo6 by mass fraction and 50 ml ethanol were weighed in a 100 ml round-bottom flask, stirred for 5 min, placed in an oil bath pot and heated at 75 °C, and condensation reflux was carried out, washed with water and ethanol alternately after 3 h, dried in a vacuum oven at 60 °C for 12 h, to prepare 10% IMo6-ZnIn2S4 / NiTiO3;

[0040] As shown in Figure 2 , XRD of different composite materials was tested, after ZnIn2S4 was compounded with NiTiO3, ZnIn2S4 / NiTiO3 had more peaks appearing at 33.1 o and 36.1 o than ZnIn2S4, which could prove that NiTiO3 was successfully loaded.

[0041] (4) Photocatalytic oxidation reaction

[0042] 1) Dark reaction: 0.04 g 10% IMo6-ZnIn2S4 / NiTiO3 was taken and added to an aqueous solution of HMF (0.03 g), then placed in a photocatalytic reactor, stirred under the conditions of 25 o C, light shielding, and circulating water for 0.5 h to reach adsorption equilibrium;

[0043] 2) Photocatalytic reaction: after 2 h of catalytic oxidation reaction under visible light irradiation, 2,5-furandicarboxaldehyde (DFF) was obtained.

[0044] As shown in Figure 1 , the results show that the DFF selectivity of 10% ZnMo6-SZIS is 90.97%.

[0045] At the same time, since IMo6-ZnIn2S4 / NiTiO3 is in a solid state, it can be recovered by simple filtration and washing. The recycling experiment of 10% IMo6-ZnIn2S4 / NiTiO3 was carried out, and the test results are shown in Figure 5 , 10% IMo6-ZnIn2S4 / NiTiO3 shows good recycling performance, and still maintains a selectivity of more than 60% after being used for 5 times.

[0046] Example 3 15% IMo6-ZnIn2S4 / NiTiO3

[0047] (1) Ni(Ac)2·H2O (1 mmol) and 3.4 ml Ti(OC4H9)4 were dispersed into 60 ml ethylene glycol, and stirred at room temperature. After 2 h, the stirring was stopped, the formed precipitate was centrifuged, washed with water and ethanol alternately, dried in vacuum for 12 h, and then calcined at 700℃ with a temperature rising condition of 2 ℃ / min for 2 h to prepare NiTiO3 microspheres;

[0048] (2) 30 mg NiTiO3 was dispersed in 40 mL water and stirred for 30 min, 108.8 mg ZnCl 2, 176.8 mg InCl3, and 120 mg C2H5NS in a 100 ml round-bottom flask, and after stirring for 5 min, the mixture was heated to 80℃ in an oil bath, and after 2 h, the mixture was washed with water and ethanol alternately, and dried in a vacuum oven at 60℃ for 12 h to prepare ZnIn2S4 / NiTiO3;

[0049] (3) ZnIn2S4 / NiTiO3 and 15% IMo6 by mass fraction were weighed into a 100 ml round-bottom flask containing 50 ml ethanol, and after stirring for 5 min, the mixture was heated to 75℃ in an oil bath with condenser reflux, and after 3 h, the mixture was washed with water and ethanol alternately, and dried in a vacuum oven at 60℃ for 12 h to prepare 15% IMo6-ZnIn2S4 / NiTiO3;

[0050] (4) Photocatalytic oxidation reaction

[0051] 1) Dark reaction: 0.04 g 15% IMo6-ZnIn2S4 / NiTiO3 was added to an aqueous solution of HMF (0.03 g), and then the mixture was placed in a photocatalytic reactor and stirred for 0.5 h under the conditions of 0~40 o C, light shielding, and circulating water to reach adsorption equilibrium;

[0052] 2) Photocatalytic reaction: the catalytic oxidation reaction was carried out under the conditions of 10 o C for 2 h under visible light irradiation to obtain 2,5-furandicarboxaldehyde (DFF).

[0053] As Figure 1 shown by the results, the DFF selectivity of 15% IMo6-ZnIn2S4 / NiTiO3 was 86.66%.

[0054] Example 4 20% IMo6-ZnIn2S4 / NiTiO3

[0055] (1) Ni(Ac)2.H2O (1 mmol) and 3.4 ml Ti(OC4H9)4 were dispersed into 60 ml ethylene glycol, and stirred at room temperature. After 2 h, the stirring was stopped, the formed precipitate was centrifuged, washed with water and ethanol alternately, dried in vacuum for 12 h, and then calcined at 700℃ with a temperature rising condition of 2℃ / min for 2 h to prepare NiTiO3 microspheres;

[0056] (2) 30 mg NiTiO3 was dispersed in 40 mL water and stirred for 30 min, 108.8 mg ZnCl 2, 176.8 mg InCl3, 120 mg C2H5NS in 100 ml round bottom flask, after stirring for 5 min, placed in an oil bath pot and heated to 80℃, after 2 h, washed with water and ethanol alternately, dried in a vacuum oven at 60℃ for 12 h to prepare ZnIn2S4 / NiTiO3;

[0057] (3) ZnIn2S4 / NiTiO3 and 50 ml ethanol with 20% mass fraction of IMO6 were weighed in a 100 ml round bottom flask, stirred for 5 min, placed in an oil bath pot and heated at 75℃, and condensation reflux was carried out, after 3 h, washed with water and ethanol alternately, dried in a vacuum oven at 60℃ for 12 h to prepare 20% IMo6-ZnIn2S4 / NiTiO3;

[0058] (4) photocatalytic oxidation reaction

[0059] 1) dark reaction: 0.04 g 20% IMo6-ZnIn2S4 / NiTiO3 was taken and added to an aqueous solution of HMF (0.03 g), and then placed in a photocatalytic reactor and stirred at 0~40 o C, under the conditions of light shielding and circulating water for 0.5 h to reach adsorption equilibrium;

[0060] 2) photocatalytic reaction: under the condition of 40 o C, the catalytic oxidation reaction was carried out under visible light for 2 h to obtain 2,5-furandicarboxaldehyde (DFF).

[0061] As Figure 1 the results show that the DFF selectivity of 20% IMo6-ZnIn2S4 / NiTiO3 is 84.5%.

[0062] The above specific implementation test shows that the supported Na5IMo6O 24The ZnIn2S4 / NiTiO3 (IMo6-ZIS / NiTiO3) metal sulfide significantly improves the redox capacity of 5-hydroxymethylfurfural (HMF). This is because the coupling of the IMo6 heteropoly acid of the application with the metal sulfide ZnIn2S4 / NiTiO3 during the photocatalytic oxidation reaction makes the recombination probability of the surface photo-generated electrons and holes low, the electron-hole is effectively separated, and the photocatalytic activity is improved. As shown in FIG. 3(a), the UV-vis test of light absorption capacity shows that the light absorption range and absorption intensity of the IMo6-loaded ZnIn2S4 / NiTiO3 metal sulfide are significantly improved; the band gap energy of the catalyst is calculated by Tauc, and the results are shown in FIG. 3(b), which shows that the band gap energy of the IMo6-ZIS / NiTiO3 of the application is the lowest, indicating that the light absorption range of the catalyst is larger; Figure 4 The PL test shows that the photoluminescence intensity of the IMo6-ZIS / NiTiO3 is the lowest, which proves that the recombination probability of the surface photo-generated electrons and holes of the IMo6-ZIS / NiTiO3 in the method of the application for photocatalytic preparation of DFF is the lowest. Moreover, the experimental results also confirm that under the optimal reaction conditions, the photocatalytic method of the application can improve the selectivity of DFF to 90.97%, which is close to the goal of realizing the complete oxidation of HMF to DFF.

[0063] The above only describes the preferred embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for preparing DFF based on the oxidation of HMF using IMo6-ZnIn2S4 / NiTiO3, characterized in that... The steps are as follows: 1) Preparation of IMo6-ZnIn2S4 / NiTiO3: Step 1.1) Ni(Ac)2·H2O and Ti(OC4H9)4 in a molar ratio of 1:1~1.5 were dispersed in ethylene glycol and stirred continuously at room temperature until a precipitate was formed. Then, the precipitate was centrifuged, washed alternately with water and ethanol, dried under vacuum for 12 h, and then calcined at 700 °C with a heating rate of 2 °C / min for 2 h to obtain NiTiO3 microspheres. Step 1.2) Disperse NiTiO3 in water and stir, then add ZnCl2, InCl3, and C2H5NS and stir until uniformly dispersed. The mass ratio of NiTiO3, ZnCl2, InCl3 and C2H5NS is 1:3.5~4:5.5~6:4~4.

5. Place in an oil bath and heat to 80℃ until the reaction is complete. After 2 h, wash with water and ethanol alternately, and dry in a vacuum oven at 60 ℃ for 12 h to obtain ZnIn2S4 / NiTiO3. Step 1.3) ZnIn2S4 / NiTiO3 and Na5IMo6O 24 Add it to ethanol at a mass ratio of 1:0.05~0.2, stir, place it in an oil bath and heat at 75 ℃, and reflux it. After 3 h, wash it alternately with water and ethanol, and dry it in a vacuum oven at 60 ℃ for 12 h to obtain IMo6-ZnIn2S4 / NiTiO3 with a mass fraction of 5~20%. 2) Dark reaction: IMo6-ZnIn2S4 / NiTiO3 is added to HMF aqueous solution, wherein the mass ratio of IMo6-ZnIn2S4 / NiTiO3 to HMF is 1~5:1; Then, the mixture was placed in a photocatalytic reactor at 0-40 °C, in the dark, and under circulating water conditions, and stirred for 0.2-1 h to reach adsorption equilibrium. 3) Photocatalytic reaction: Under light conditions with a wavelength greater than 400 nm, catalytic oxidation reaction is carried out for 1~6 h to obtain 2,5-furandicarboxaldehyde.

2. The method for preparing DFF based on the oxidation of HMF using IMo6-ZnIn2S4 / NiTiO3 according to claim 1, characterized in that... The dark reaction time is 0.5 h, and the photocatalytic reaction time is 2 h.

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