CN115850042A - A method for preparing 2-pentanone by hydrogenation of 2-methylfuran using a platinum-based catalyst - Google Patents

Abstract

The invention uses a platinum-based catalyst for the hydrogenation of 2-methylfuran to prepare 2-pentanone. The method has the advantages of orderly and controllable multiphase flow, high mixing efficiency, precise and controllable reaction parameters, good reaction repeatability, and integrated With the characteristics of high degree of automation, it effectively solves the problems of long time for catalyst preparation by traditional impregnation method, low selectivity, depending on the operator's technique and easy mixing and unevenness. Secondly, the method screens different amounts of solvents and reaction temperatures, determines the amount of solvent and the optimum reaction temperature, and prepares a platinum-carbon catalyst, which can make 2-methylfuran hydrogenated to prepare 2-pentanone. The conversion rate can reach 88%. The selectivity of 2-pentanone is 79%, while the platinum-based catalyst prepared by the impregnation method has a selectivity of 25% for the hydrogenation of 2-methylfuran to prepare 2-pentanone, and the catalytic efficiency can be improved compared with the impregnation method. Nearly 50%. Mechanized operation can avoid human errors, make the results easier to repeat, and improve production efficiency.

Description

A method for preparing 2-pentanone by hydrogenating 2-methylfuran using a platinum-based catalyst

Technical Field

The invention belongs to the technical field of biomass energy catalysis and continuous flow preparation, and specifically relates to a preparation method of a platinum-based catalyst for hydrogenating a biomass derivative 2-methylfuran to prepare 2-pentanone. The catalyst uses activated carbon as a carrier and platinum as a main active component. Through the adjustment of different amounts of solvents and temperatures, a continuous flow preparation method is used to improve the production efficiency of the catalyst and ensure the performance. The catalyst can effectively catalyze 2-methylfuran to prepare 2-pentanone, and the continuous flow preparation method is efficient and simple, can be continuously mass-produced, reduces manual errors, and has great application value.

Background Art

Continuous flow reactor (CFR) is a novel technology in which the reaction takes place in a channel with an inner diameter ranging from a few microns to a few millimeters. In chemical engineering, micro-continuous flow equipment can provide unique control over key reaction parameters due to the small size of the reactor. Continuous flow reactors have many advantages, including high mass and heat transfer efficiency, precise control of reaction temperature, pressure and time, easier integration and automation, and improved reaction efficiency, and therefore have attracted the attention of many researchers.

Lignocellulosic biomass is an abundant and renewable carbon resource that has the potential to replace traditional non-renewable fossil resources in the production of chemicals and fuels to alleviate the heavy dependence on fossil resources and reduce the associated environmental impacts. Lignin, cellulose, and hemicellulose are all derived from lignocellulosic biomass, which can be depolymerized into various platform compounds that can be further upgraded into high-value chemicals and fuels.

2-Methylfuran is one of the most promising biomass-based platform compounds. It is an important chemical intermediate that can be used as a solvent and raw material. It is widely used in the production of antimalarial drugs (chloroquine), pyrethroid pesticides, flavors and fragrances, nitrogen and sulfur functionalized heterocyclics, and functional group substituted aliphatic compounds. In addition, 2-methylfuran can be converted into many derivatives and downstream products. For example, 2-methylfuran can also be obtained by C=C hydrogenation to 2-methyltetrahydrofuran, or by hydrogenolysis of C-O bonds to obtain C5 alcohols.

2-Pentanone is an excellent dewaxing agent for lubricating oils, and is also used as a solvent for nitro lacquer, synthetic resin coatings, and an intermediate and extractant for organic synthesis. In addition, 2-pentanone can be used as an intermediate and solvent for organic and pharmaceutical synthesis, and can be used to synthesize the vasodilator drug Virga. 2-Pentanone can be prepared by dehydrogenation of 2-pentanol or by heating ethyl butyryl acetate with water. However, this process uses a large amount of organic solvents and inorganic substances, produces three wastes, and not only causes high costs, but also causes environmental problems. Chinese patent CN106478386A discloses a method for preparing 2-pentanone from ethanol, which has a wide source of raw materials and a simple process, but the catalytic effect is poor, and the selectivity of 2-pentanone is only 36.8%. In view of the above problems, it is imperative to develop a new method for preparing 2-pentanone to improve the conversion efficiency and the selectivity of the target product.

Summary of the invention

To solve the above technical problems, the present invention provides a method for preparing a platinum-based catalyst for preparing 2-pentanone by hydrogenating 2-methylfuran, which is simple, efficient, and can be produced in one step and continuously. A high-activity catalyst is prepared simply and efficiently by screening the amount of solvent and the reaction temperature using a continuous flow method. Under the reaction conditions of a reaction temperature of 200° C. and a hydrogen pressure of 1 MPa, the conversion rate of 2-methylfuran can reach 88%, and the selectivity of pentanol is 79%. At the same time, the method can be used to prepare a high-activity catalyst in one step, simplify the reaction steps, save reaction time, and continuous production also greatly improves production efficiency.

In order to solve the technical problem of the present invention, a technical solution is proposed: a method for preparing 2-pentanone by hydrogenating 2-methylfuran using a platinum-based catalyst, wherein the reaction of hydrogenating 2-methylfuran to prepare 2-pentanone is carried out in an autoclave equipped with a thermal conductivity detector, and the prepared platinum-based catalyst, 2-methylfuran and isopropanol are added to the autoclave to react and obtain 2-pentanone;

The preparation method of the platinum-based catalyst comprises: using a continuous flow device to prepare the platinum-based catalyst; the continuous flow device is composed of a peristaltic pump, a magnetic stirrer, a Teflon pipeline, a reaction device and a collection device; the inlet end pipeline of the peristaltic pump is introduced into a container, the outlet end pipe of the peristaltic pump is connected to a length of Teflon pipeline, the Teflon pipeline is fixed in the reaction device, and finally the outlet end of the Teflon pipeline is fixed above the collection device; the specific steps are as follows:

(1) using ethylene glycol, adding an appropriate amount of chloroplatinic acid (H ₂ PtCl ₆ ·6H ₂ O) solid thereto, and ultrasonicating to prepare a H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution;

(2) Add activated carbon to a container, add appropriate amount of ethylene glycol, appropriate amount of sodium hydroxide solution, appropriate amount of ultrapure water, and add appropriate amount of H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution prepared in step (1) to the container and perform ultrasonic dispersion;

(3) The temperature of the reaction device is 160°C;

(4) Dry the collected catalyst in a vacuum drying oven.

Preferably, in step (1), the Pt mass content in chloroplatinic acid is Pt≥37.5%, and the ultrasonic frequency is 40 KHz.

Preferably, the reaction of hydrogenating 2-methylfuran to prepare 2-pentanone is carried out in an autoclave equipped with a thermal conductivity detector, a certain amount of 2-methylfuran, a solvent and a platinum-based catalyst are added to the autoclave, and the autoclave is sealed; the autoclave is purged with 2MPa hydrogen for 3 times to remove the air in the autoclave, and then filled with 1MPa hydrogen, the reaction temperature is 120-220°C, the reaction time is 3h, and after the reaction is completed, the temperature is lowered, the pressure is released, the autoclave is opened, filtered, and detected by gas chromatography.

Preferably, the collecting device is a beaker, the container is a beaker, the outlet section of the peristaltic pump is connected to a length of Teflon pipe, the Teflon pipe is circularly wound, and the fixed disk is suspended in the reaction device.

Preferably, 990 mg of activated carbon is weighed into a beaker, 80 ml of ethylene glycol and 20 ml of NaOH solution are added, 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (20 mg H ₂ PtCl ₆ ·6H ₂ O per 1 ml of solution) is added thereto, and ultrasonic treatment is performed for 20 minutes; the beaker is placed in a continuous flow device, the reaction device switch is turned on, the peristaltic pump is adjusted to set the flow rate (50 ml/min), and after the temperature of the reaction device reaches 160° C., the pump switch is started, and after waiting for 15 minutes, the solution is collected in a beaker, stirred overnight, and filtered. Finally, the solid obtained after the filtration is placed in a culture dish, placed in a vacuum drying oven at 80° C. and dried for 12 hours, and then sealed and stored.

Preferably, the method comprises the following steps:

(1) Use ethylene glycol, add an appropriate amount of chloroplatinic acid (H ₂ PtCl ₆ ·6H ₂ O) solid into it, and ultrasonicate for 30 minutes to prepare H ₂ PtCl ₆ ·6H ₂ O ethylene glycol (each 1 ml of ethylene glycol contains 20 mg H ₂ PtCl ₆ ·6H ₂ O; store in a sealed container at low temperature;

(2) using ultrapure water, adding an appropriate amount of sodium hydroxide (NaOH) solid thereto, stirring, and preparing a NaOH aqueous solution;

(3) Weigh 100 mg of carbon carrier activated carbon and add it to a beaker, add an appropriate amount of ethylene glycol, take an appropriate amount of H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution prepared in step (1) and an appropriate amount of NaOH aqueous solution prepared in step (2) and add them to the beaker for ultrasonic dispersion, place it under a peristaltic pump, lead the pipeline, open the reaction device, and after the temperature reaches the reaction temperature, inject the sample, wait for a while, and collect it in a beaker;

(4) After the collected reaction liquid is filtered, it is placed in a vacuum drying oven for 12 hours and then sealed and stored.

Preferably, 990 mg of activated carbon is weighed into a beaker, 80 ml of ethylene glycol and 20 ml of NaOH solution are added, 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) is measured and added thereto, and ultrasonicated for 20 minutes; the beaker is placed in a continuous flow device, the reaction device switch is turned on, the peristaltic pump is adjusted, the flow rate (20 ml/min) is set, and after the oil bath temperature reaches 160° C., the pump switch is started, and after waiting for 15 minutes, all the solution flows out, and finally collected in a beaker, acid is added and stirred, the reaction solution is filtered and washed, and finally the solid obtained after filtration is placed in a culture dish, placed in a vacuum drying oven at 80° C. and dried for 12 hours, and then sealed and stored after completion.

Preferably, (1) the continuous flow device is composed of a peristaltic pump, a magnetic stirrer, a multi-section Teflon pipe, a reaction device, and a beaker. The inlet pipe of the peristaltic pump is introduced into the beaker, and the outlet pipe of the peristaltic pump is connected to a Teflon pipe of a suitable length, the Teflon pipe is a circular winding coil suspended in the device, and finally the outlet end of the pipe is fixed above the beaker.

(2) Use ethylene glycol, add an appropriate amount of chloroplatinic acid (H ₂ PtCl ₆ ·6H ₂ O) solid, ultrasonicate for 30 minutes to prepare H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution, and seal and store at low temperature;

(3) using ultrapure water, adding an appropriate amount of sodium hydroxide (NaOH) solid thereto, stirring, and preparing a NaOH aqueous solution;

(3) Weigh 100 mg of carbon carrier activated carbon into a beaker, add an appropriate amount of ethylene glycol, take an appropriate amount of H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution prepared in step (1) and an appropriate amount of NaOH aqueous solution prepared in step (2) and add them to the beaker for ultrasonic dispersion.

(4) Place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait until the oil bath temperature reaches 160°C, start the pump switch, wait for 15 minutes, and let all the solution flow out. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 hours. After completion, seal it for storage.

(5) 3.4 mmol of 2-methylfuran, 8 ml of isopropanol and 50 mg of a platinum-based catalyst were added to a reaction kettle and sealed; after replacing with 2 MPa of hydrogen three times, the pressure of hydrogen in the reaction kettle was 1 MPa; the reaction temperature was 200° C.; the reaction time was 3 h. After the reaction was completed, the temperature was lowered, the pressure was released, the kettle was opened, filtered, and detected by gas chromatography;

The beneficial effects of the present invention are as follows:

The present invention provides a continuous flow preparation method for platinum-based catalysts. Compared with the impregnation method, which takes a long time, depends on the operator's technique and is prone to uneven mixing, this method is simpler, more efficient and can be produced in one step and continuously. First, the method uses a pipe diameter of several millimeters, which greatly increases the specific surface area of the reaction liquid, and can quickly transfer mass and heat, so that the reaction liquid can be better mixed and evenly mixed. Secondly, the method screened different amounts of solvent and reaction temperature. When the amount of solvent was 100 ml, the reaction temperature was 160 ° C, 100 ml of solution was used for every 990 mg of activated carbon, including 80 ml of ethylene glycol and 20 ml of NaOH solution, and the ratio of H ₂ PtCl ₆ ·6H ₂ O solution to catalyst was: 1.4 ml of H ₂ PtCl ₆ ·6H ₂ O solution for every 990 mg of activated carbon, the best conversion rate of 2-methylfuran hydrogenation to 2-pentanone could reach 88%, and the selectivity of 2-pentanone was 79%. The conversion rate of 2-methylfuran hydrogenation to 2-pentanone prepared by the platinum-based catalyst prepared by the impregnation method was 98%, but the selectivity of 2-pentanone was 25%, which was only a by-product. (For the specific method of the impregnation method, refer to patent CN113999088B). The catalytic efficiency was improved by nearly 50%. According to TEM and particle size distribution diagram, the particle size of the platinum-based catalyst prepared by the method was stable at about 3.7 nm. The platinum-based catalyst prepared by the impregnation method has agglomeration phenomenon and the particle sizes are different. Mechanized operation can avoid human errors, make the results easier to repeat, greatly improve the production efficiency, and provide a new way for the catalytic hydrogenation of furan derivatives to prepare 2-pentanone. In addition, the raw materials used in the invention are renewable biomass derivatives, which are abundant and cheap and easy to obtain. They are expected to replace traditional non-renewable fossil resources in the production of chemicals and fuels, are environmentally friendly, and have broader application potential in industrial production. The overall reaction formula of the present invention is:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of a continuous flow device

Figure 2 is a reaction mechanism diagram of the hydrogenolysis of 2-methylfuran to 2-pentanone

Figure 3 TEM image and particle size distribution of platinum-based catalyst prepared by continuous flow

Figure 4 TEM image and particle size distribution of platinum-based catalyst prepared by impregnation method

Fig.5 Effect of different temperatures on the distribution of 2-methylfuran hydrogenation products

Figure 1: Peristaltic pump-1; Peristaltic pump controller-2; Reaction liquid-3; Teflon tube-4; Reaction liquid-5; Reaction device controller-6

DETAILED DESCRIPTION

The present invention is further described in detail below in conjunction with specific examples. These embodiments are only for illustrating the present invention, but the present invention is not limited to the following embodiments.

Example 1

(1) The continuous flow device consists of a peristaltic pump, a magnetic stirrer, a multi-section Teflon pipe, a reaction device, and a beaker. The inlet pipe of the peristaltic pump is introduced into the beaker, and the outlet pipe of the peristaltic pump is connected to a Teflon pipe of appropriate length. The Teflon pipe is a circular winding coil suspended in the reaction device, and finally the outlet end of the pipe is fixed above the beaker; a 3 mm diameter Teflon pipe is used;

(2) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(3) Weigh 990 mg of activated carbon into a beaker, add 80 ml of ethylene glycol and 20 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 160°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage.

The catalyst was named 1% Pt/C (V(EG:NaOH solution)=4). The particle size was 3.7±0.28 nm.

Comparative Example 1-1 Catalyst Preparation

(1) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(2) Weigh 990 mg of activated carbon into a beaker, add 50 ml of ethylene glycol and 50 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 160°C, start the pump switch, wait for 15 minutes, and the solution will all flow out. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage;

The catalyst was named 1% Pt/C (V(EG:NaOH solution)=1).

Comparative Example 1-2 Catalyst Preparation

(1) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(2) Weigh 990 mg of activated carbon into a beaker, add 60 ml of ethylene glycol and 40 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ OO ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 160°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage;

The catalyst was named 1% Pt/C (V(EG:NaOH solution)=1.5).

Comparative Examples 1-3 Catalyst Preparation

(1) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(2) Weigh 990 mg of activated carbon into a beaker, add 70 ml of ethylene glycol and 30 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 160°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage;

The catalyst was named 1% Pt/C (V(EG:NaOH solution)=2.3).

Comparative Examples 1-4 Catalyst Preparation

(1) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(2) Weigh 990 mg of activated carbon into a beaker, add 90 ml of ethylene glycol and 10 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 160°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage;

The catalyst was named 1% Pt/C (V(EG:NaOH solution)=9).

Comparative Examples 1-5 Catalyst Preparation

(1) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(2) Weigh 990 mg of activated carbon into a beaker, add 50 ml of ethylene glycol and 50 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 150°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage;

The catalyst was named 1% Pt/C (150°C).

Comparative Examples 1-6 Catalyst Preparation

(1) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(2) Weigh 990 mg of activated carbon into a beaker, add 50 ml of ethylene glycol and 50 ml of NaOH solution, and add 1.4 ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg of H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 170°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage;

The catalyst was named 1% Pt/C (170°C).

Example 2

(1) The continuous flow device consists of a peristaltic pump, a magnetic stirrer, a multi-section Teflon pipe, a reaction device, and a beaker. The inlet pipe of the peristaltic pump is introduced into the beaker, and the outlet pipe of the peristaltic pump is connected to a Teflon pipe of an appropriate length. The Teflon pipe is a circular winding coil suspended in the reaction device, and finally the outlet end of the pipe is fixed above the beaker;

(2) Dissolve 1 g of chloroplatinic acid in 50 mL of ethylene glycol to prepare a platinum precursor solution (Pt: 7.5 mg/mL) for later use;

(3) Weigh 1.98 g of activated carbon into a beaker, add 160 ml of ethylene glycol and 40 ml of NaOH solution, and add 2.8 ml of the prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (each 1 ml of solution contains 20 mg H ₂ PtCl ₆ ·6H ₂ O) and ultrasonicate for 20 min; place the above beaker in a continuous flow device, turn on the reaction device switch, adjust the peristaltic pump, set the flow rate (20 ml/min), wait for the oil bath temperature to reach 160°C, start the pump switch, wait for 15 minutes, and let the solution flow out completely. Finally, collect it in a beaker, add acid and stir, filter and wash the reaction solution, and finally place the solid obtained after filtration in a culture dish, put it in a vacuum drying oven at 80°C and dry it for 12 h, and then seal it for storage.

Example 3 Catalyst ICP Test

The platinum-based catalysts prepared in Example 1 and Comparative Examples 1-1, 1-2, 1-3, 1-4, 1-5, and 1-6 were weighed, dissolved in aqua regia, diluted to a fixed volume, and tested by an inductively coupled plasma optical emission spectrometer (ICP-OES). The results are shown in Table 1.

Table 1 Catalyst ICP test results

According to the above results, the loading rates of the catalysts prepared in Examples 1 and 2 are both greater than 95%, while the loading rates of Comparative Examples 1-1, 1-2, 1-3, 1-4, 1-5, and 1-6 are all between 50% and 90%, and the loading effect is not good. In order to better follow the impregnation method (the specific method of the impregnation method is referenced to patent CN113999088B), Examples 1 and 2 can be used for hydrogenation of 2-methylfuran to prepare 2-pentanone.

Example 4 Reaction Activity Test of 2-Methylfuran Hydrogenation to 2-Pentanone

The reaction of hydrogenating 2-methylfuran to prepare 2-pentanone was carried out in an autoclave equipped with a thermal conductivity detector. 50 mg of the prepared platinum-based catalyst, 3.4 mmol of 2-methylfuran, and 8 ml of isopropanol were added to the reactor. Before the reaction, the reactor was purged with 2 MPa of hydrogen for 3 times to remove the air in the reactor, and then filled with 1 MPa of hydrogen. The reaction temperature was 200°C and the reaction time was 3 hours. After the reaction was completed, the reactor was placed in ice water and quickly cooled to room temperature, the catalyst and the reaction liquid were separated, and the composition of the reaction liquid was detected by gas chromatography to obtain the reaction results.

The test results are shown in Table 2.

Table 2 Reaction activity test of 2-methylfuran hydrogenation to 2-pentanone

In order to better reflect the superiority of the platinum-based catalyst prepared by the continuous flow method, the above catalyst was tested for the activity of hydrogenating dimethylfuran to prepare 2-pentanone. According to the experimental results in Table 2, the conversion rate of 2-methylfuran on the catalyst of Example 1 has reached 88%, of which the yield of 2-pentanone is 79%, which is nearly 30% higher than the yield of 2-pentanone (50%) obtained by 1% Pt/C prepared by the impregnation method. In addition, in other comparative results, although the loading rate is not reached, the activity of hydrogenating dimethylfuran to prepare 2-pentanone is mostly better than that of the catalyst prepared by the impregnation method.

Example 5 Reaction Activity Test of 2-Methylfuran Hydrogenation to 2-Pentanone

Investigate the effect of temperature on the hydrogenation of 2-methylfuran to prepare 2-pentanone: The difference between this example and Example 4 is that the reaction temperature in the operation steps is 120°C, and the other processes are the same as Example 4.

Example 6 Test on the Reaction Activity of 2-Methylfuran Hydrogenation to 2-Pentanone

Investigate the effect of temperature on the hydrogenation of 2-methylfuran to prepare 2-pentanone: The difference between this example and Example 4 is that the reaction temperature in the operation steps is 140°C, and the other processes are the same as Example 4.

Example 7 Test of the Reaction Activity of 2-Methylfuran Hydrogenation to 2-Pentanone

Investigate the effect of temperature on the hydrogenation of 2-methylfuran to prepare 2-pentanone: The difference between this example and Example 4 is that the reaction temperature in the operation steps is 160°C, and the other processes are the same as Example 4.

Example 8 Test on the Reaction Activity of 2-Methylfuran Hydrogenation to 2-Pentanone

Investigate the effect of temperature on the hydrogenation of 2-methylfuran to prepare 2-pentanone: The difference between this example and Example 4 is that the reaction temperature in the operation steps is 180°C, and the other processes are the same as Example 4.

Example 9 Test on the Reaction Activity of 2-Methylfuran Hydrogenation to 2-Pentanone

Investigate the effect of temperature on the hydrogenation of 2-methylfuran to prepare 2-pentanone: The difference between this example and Example 4 is that the reaction temperature in the operation steps is 220°C, and the other processes are the same as Example 4.

According to Figure 5, the effect of reaction temperature on product distribution is shown. The reaction product is mainly 2-pentanone. As the temperature increases, the conversion rate of 2-methylfuran increases, and the yield of 2-pentanone reaches the highest at 200°C.

According to the reaction results, the present invention uses a continuous flow method to prepare a platinum-based catalyst. By optimizing the amount of solvent used, a catalyst with the highest loading rate is obtained, which is applied to the reaction of preparing 2-pentanone by hydrogenation of 2-methylfuran, and the yield is significantly improved. The prepared particles are evenly distributed and have a small particle size. Compared with the previous process production route, the process route preparation process of the invention is simple, and the mechanized operation can effectively avoid human errors. The required catalyst can be obtained in one step, which greatly reduces the production time. The raw materials are renewable, the catalyst has high activity, the reaction conditions are mild, the energy consumption is reduced to a certain extent, it is environmentally friendly, and can effectively alleviate the energy problems facing the world today. Therefore, the present invention has broad application potential in industrial production.

The present invention is not limited to the specific technical solutions described in the above embodiments, and all technical solutions formed by equivalent replacement are within the protection scope required by the present invention.

Claims (6)

1. A method for preparing 2-pentanone by hydrogenation of 2-methylfuran by using a platinum-based catalyst is characterized by comprising the following steps: the reaction for preparing 2-pentanone by hydrogenating 2-methylfuran is carried out in an autoclave provided with a thermal conductivity detector, and the prepared platinum-based catalyst, 2-methylfuran and isopropanol are added into the autoclave for reaction to obtain 2-pentanone; the method comprises the following specific steps: the reaction for preparing 2-pentanone by hydrogenating 2-methylfuran is carried out in an autoclave provided with a thermal conductivity detector, isopropanol is used as a solvent, 1wt.% of Pt/C platinum-based catalyst is in a reaction solution with the mass concentration of 2-methylfuran of 5wt.%, the reaction kettle is purged for 3 times by using 2MPa hydrogen to remove air in the reaction kettle, 1MPa hydrogen is charged, the reaction temperature is 200 ℃, and the reaction time is 3 hours; 2-pentanone is prepared;

the preparation method of the platinum-based catalyst comprises the following steps: preparing a platinum-based catalyst using a continuous flow apparatus; the continuous flow device consists of a peristaltic pump, a magnetic stirrer, a Teflon pipeline, a reaction device and a collection device; the inlet end pipeline of the peristaltic pump is introduced into the container, the outlet end pipe of the peristaltic pump is connected with a section of Teflon pipeline with a length, the section of Teflon pipeline is fixed in the reaction device, and finally the outlet end of the Teflon pipeline is fixed above the collecting device; the method comprises the following specific steps:

(1) Using ethylene glycol, adding appropriate amount of chloroplatinic acid (H) ₂ PtCl ₆ ·6H ₂ O) a solid, and (C) a solid,

preparation of H by ultrasound ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution; wherein, pt:7.5mg/mL;

(2) Adding activated carbon into a container, adding a proper amount of glycol, a proper amount of sodium hydroxide solution and a proper amount of ultrapure water, and taking a proper amount of H prepared in the step (1) ₂ PtCl ₆ ·6H ₂ Adding O glycol solution into the mixture to perform ultrasonic dispersion; wherein each 990mg of activated carbon corresponds to 100ml of solution, wherein 80ml of ethylene glycol and 20ml of NaOH solution, and each 990mg of activated carbon corresponds to 1.4ml of H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution;

(3) The temperature of the reaction device is 160 ℃;

the collected catalyst 1% by weight Pt/C (V (EG: naOH solution) = 4) was dried in a vacuum drying oven.

2. The process for the hydrogenation of 2-methylfuran to 2-pentanone using a platinum-based catalyst according to claim 1, characterized in that: step 1 of the preparation method of the platinum-based catalyst is H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (20 mg H in 1ml ethylene glycol) ₂ PtCl ₆ ·6H ₂ O); and (5) sealing and storing at low temperature.

3. The process for the hydrogenation of 2-methylfuran to 2-pentanone using a platinum-based catalyst according to claim 1, characterized in that: in the preparation method of the platinum-based catalyst, a sodium hydroxide solution is prepared in the step 2, ultrapure water is used, a proper amount of sodium hydroxide NaOH solid is added into the ultrapure water, and stirring is carried out to prepare a NaOH aqueous solution.

4. The process for the hydrogenation of 2-methylfuran to 2-pentanone using a platinum-based catalyst according to claim 1, characterized in that: in the preparation method of the platinum-based catalyst, the Pt mass content Pt in chloroplatinic acid in the step (1) is more than or equal to 37.5 percent, and the ultrasonic frequency is 40KHz.

5. The process for the hydrogenation of 2-methylfuran to 2-pentanone using a platinum-based catalyst according to claim 1, characterized in that: in the preparation method of the platinum-based catalyst, the collecting device is a beaker, the container is a beaker, a section of Teflon pipeline with the length is connected to the outlet of the peristaltic pump, and a Teflon pipeline with the diameter of 3 mm is adopted; the Teflon pipeline is circularly wound and is suspended in the reactor through a thin iron wire fixing disc.

6. The process for the hydrogenation of 2-methylfuran to 2-pentanone using a platinum-based catalyst according to claim 1, characterized in that:

the reaction for preparing 2-pentanone by hydrogenating 2-methylfuran is carried out in an autoclave provided with a thermal conductivity detector, 50mg of the prepared platinum-based catalyst, 3.4mmol of 2-methylfuran and 8ml of isopropanol are added into the autoclave, the autoclave is purged for 3 times by using 2MPa hydrogen before the reaction, so as to remove the air in the autoclave, and then 1MPa hydrogen is charged into the autoclave, the reaction temperature is 200 ℃, and the reaction time is 3 hours; 2-pentanone is prepared;

the preparation method of the platinum-based catalyst comprises the steps of weighing 990mg of active carbon in a beaker, adding 80ml of ethylene glycol and 20ml of NaOH solution, and weighing 1.4ml of prepared H ₂ PtCl ₆ ·6H ₂ O ethylene glycol solution (20 mg H per 1ml solution) ₂ PtCl ₆ ·6H ₂ O) adding the mixture into the mixture, and performing ultrasonic treatment for 20min; placing the beaker in a continuous flow device, turning on a switch of a reaction device, regulating and controlling a peristaltic pump to set a flow rate of 50ml/min, starting the switch of the pump after the temperature of the reaction device reaches 160 ℃, waiting for 15 minutes, collecting the solution in the beaker, stirring overnight, carrying out suction filtration, finally placing the solid obtained after the suction filtration in a culture dish, placing the culture dish in a vacuum drying oven at 80 ℃ for drying for 12 hours, and sealing and storing after the completion.

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