CN108435171B - A kind of preparation method of bimetallic Pt-Bi catalyst and a kind of method of selective catalytic oxidation of glycerol to prepare DHA - Google Patents

Abstract

The invention discloses a preparation method of a bimetallic Pt-Bi catalyst, comprising the following steps: S1. adding a Pt catalyst to a glycerol reaction solution containing auxiliary Bi, catalyzing oxidation of glycerol to produce 1,3-dihydroxyacetone, and obtaining a glycerol containing The reaction liquid mixture of the bimetallic Pt-Bi catalyst; S2. Separating the bimetallic Pt-Bi catalyst in the reaction liquid mixture, and then calcining the bimetallic Pt-Bi catalyst in an inert atmosphere at 200-300° C. to prepare the bimetallic Pt-Bi catalyst. The preparation method provided by the invention can use the deactivated bimetallic Pt-Bi catalyst to prepare the highly active bimetallic Pt-Bi catalyst, the prepared bimetallic Pt-Bi catalyst has high catalytic activity, and can efficiently and selectively catalyze the oxidation of glycerol to produce DHA; the bimetallic Pt-Bi catalyst is recycled in the selective catalytic oxidation of glycerol to produce 1,3-dihydroxyacetone by calcination, the concentration of glycerol and the content of Bi in the glycerol reaction solution are kept constant, and after 2~6 cycles , the bimetallic Pt-Bi catalyst was able to maintain the DHA selectivity with the initial high glycerol conversion.

Description

A kind of preparation method of bimetallic Pt-Bi catalyst and a kind of selective catalytic oxidation Method for preparing DHA from glycerol

technical field

The present invention relates to the technical field of liquid-phase oxidative conversion of glycerol, and more particularly, to a preparation method of a bimetallic Pt-Bi catalyst and a method for the selective catalytic oxidation of glycerol to prepare DHA.

Background technique

As the main by-product in the production of biodiesel, glycerol has abundant sources and very low prices. Glycerol itself is a highly functionalized molecule, and its effective utilization can be converted into fine chemical products with high added value, mainly including: glyceraldehyde, 1,3-dihydroxyacetone (DHA), glyceric acid, tartaric acid, etc. Among them, DHA has a very wide range of applications in the fields of cosmetics, food and pharmaceuticals.

Glycerol has primary and secondary hydroxyl functional groups, and its oxidation reaction is also a structure-sensitive reaction, which can be selectively catalytically oxidized under certain reaction conditions and catalysts, resulting in very complex oxidation products.

Pt catalysts are widely used in this reaction, and single-component Pt is more likely to selectively catalyze the oxidation of primary hydroxyl groups of glycerol, and the generated products are mainly glyceric acid and glyceraldehyde. The introduction of promoters Bi, Sb, etc. in the Pt catalyst can effectively promote the catalytic oxidation of the secondary hydroxyl group of glycerol, and improve the conversion rate of glycerol and the selectivity of DHA.

Pt catalysts can effectively catalyze the oxidation of glycerol into high value-added chemical products, but in the reaction process, there will be poisoning, leaching, sintering and other phenomena, resulting in the deactivation of Pt catalysts and greatly reducing the conversion rate of glycerol and product selectivity.

Therefore, it is necessary to develop a method for preparing a highly active bimetallic Pt-Bi catalyst by using the deactivated bimetallic Pt-Bi catalyst, which can restore the catalytic activity of the bimetallic Pt-Bi catalyst, so that the bimetallic Pt-Bi catalyst can be recovered. The Bi catalyst maintains the initial high glycerol conversion and DHA selectivity during the production of 1,3-dihydroxyacetone.

SUMMARY OF THE INVENTION

In order to overcome the defect of catalyst deactivation described in the prior art, the present invention provides a preparation method of a bimetallic Pt-Bi catalyst, and the provided preparation method can utilize the deactivated bimetallic Pt-Bi catalyst to prepare a highly active catalyst. Bimetallic Pt-Bi catalyst.

Another object of the present invention is to provide a method for producing DHA by selective catalytic oxidation of glycerol. After deactivation of the bimetallic Pt-Bi catalyst, the activity is recovered by calcination to be recycled, and the concentration of glycerin and the content of auxiliary Bi in the glycerol reaction solution are maintained Constant, the initial high glycerol conversion and DHA selectivity can be maintained during the recycling process of the bimetallic Pt-Bi catalyst, enabling continuous production.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

A preparation method of a bimetallic Pt-Bi catalyst, comprising the following steps:

S1. adding a Pt catalyst to the glycerol reaction solution containing auxiliary Bi, and catalyzing oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing a bimetallic Pt-Bi catalyst;

S2. Separating the bimetallic Pt-Bi catalyst in the reaction solution mixture, and then calcining it in an inert atmosphere at 200-300° C. to prepare a bimetallic Pt-Bi catalyst.

In step S1., an in-situ bimetallic Pt-Bi catalyst is generated, and the in-situ bimetallic Pt-Bi catalyst is deactivated after the reaction, and the catalytic activity is significantly reduced. The deactivated bimetallic Pt-Bi catalyst is calcined under the above conditions to obtain a highly active bimetallic Pt-Bi catalyst. The prepared bimetallic Pt-Bi catalyst has high catalytic activity and can efficiently and selectively catalyze the oxidation of glycerol to produce DHA.

When the temperature is lower than 200 °C, the catalytic activity of the deactivated bimetallic Pt-Bi catalyst after calcination is not very satisfactory, because the temperature is too low, which is not conducive to the shedding of strongly adsorbed intermediates. When the temperature is too high, it will cause the agglomeration of noble metal Pt nanoparticles and reduce the active sites.

Moreover, the above-mentioned preparation method is simple and easy to operate, and is suitable for industrial promotion and use.

Preferably, the preparation method further comprises the steps:

S3. adding the bimetallic Pt-Bi catalyst prepared by S2. to the glycerol reaction solution containing auxiliary Bi, and catalyzing oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing the bimetallic Pt-Bi catalyst; The bimetallic Pt-Bi catalyst in the reaction mixture is separated, and then calcined in an inert atmosphere at 200-300° C. to prepare the bimetallic Pt-Bi catalyst.

The prepared bimetallic Pt-Bi catalyst is added to the glycerin reaction solution containing auxiliary Bi, and steps S1. and S2. are performed again to obtain the bimetallic Pt-Bi catalyst after calcining twice;

Preferably, step S3. is performed cyclically, and the number of times that step S3. is performed is 1 to 4 times.

By cyclically performing step S3., a bimetallic Pt-Bi catalyst calcined for multiple times can be prepared.

Preferably, step S3. is performed twice.

The inert atmosphere includes Ar atmosphere and N ₂ atmosphere.

Preferably, the inert atmosphere is an argon gas atmosphere, and the flow rate of the argon gas is 10-200 mL/min. The argon atmosphere is achieved by bubbling argon.

More preferably, the flow rate of the argon gas is 20-150 mL/min.

Further preferably, the flow rate of the argon gas is 100 mL/min.

Preferably, the calcination time is 0.5-4 h.

More preferably, the calcination time is 2 h.

Preferably, Bi in the glycerol reaction solution comes from one or more of bismuth oxide, bismuth chloride or bismuth nitrate.

Preferably, the mass of the auxiliary Bi in the glycerol reaction solution is 10%-100% of the mass of Pt.

Preferably, the mass of the auxiliary agent Bi in the glycerol reaction solution is 20% to 50% of the mass of Pt.

More preferably, the mass of auxiliary Bi in the glycerol reaction solution is 20% of the mass of Pt.

Preferably, the carrier of the Pt catalyst is a nitrogen-doped carbon material.

Preferably, the nitrogen-doped carbon material is one or more of nitrogen-doped carbon nanotubes, carbon nanofibers or graphene.

Preferably, the loading of Pt in the Pt catalyst is 2˜10 wt.%.

Preferably, the loading of Pt in the Pt catalyst is 5 wt.%.

Preferably, the conditions for catalytic oxidation of glycerol to prepare 1,3-dihydroxyacetone in S1. are: the glycerol mass content of the glycerol reaction solution is 1wt.%~10wt.%, the reaction temperature is 50~80 ° C, and the O flow rate is 10~ ₂₀₀ mL /min, stirring rate 100~800 r/min, reaction time 1~10 h.

More preferably, the condition of the oxidation reaction of S1. is _: the glycerol mass content of the glycerol reaction solution is 1wt.%～10wt.%, the reaction temperature is 60～80 ℃, the O flow rate is 50～150 mL/min, and the stirring rate is 400～600 ℃. r/min, the reaction time is 2~6 h.

Further preferably, the conditions of the oxidation reaction of S1. are: the mass content of glycerol in the glycerol reaction solution is 10wt.%, the reaction temperature is 60°C, the flow rate of O ₂ is 150 mL/min, the stirring rate is 600 r/min, and the reaction time is 6h.

Preferably, the solvent of the glycerol reaction solution is water.

The present invention simultaneously protects a kind of method for producing DHA by selective catalytic oxidation of glycerol, comprising the steps:

S1. adding a Pt catalyst to the glycerol reaction solution containing auxiliary Bi, and catalyzing oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing a bimetallic Pt-Bi catalyst;

S2. Separating the bimetallic Pt-Bi catalyst in the reaction mixture, and then calcining it in an inert atmosphere at 200-300 °C to prepare a bimetallic Pt-Bi catalyst;

S3. Add the bimetallic Pt-Bi catalyst prepared in step S2. to the glycerol reaction solution containing auxiliary Bi, and catalyze the oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing the bimetallic Pt-Bi catalyst ; Then carry out step S2., prepare the bimetallic Pt-Bi catalyst again;

S4. cyclically carry out step S3., the number of times that step S3. is carried out is 1 to 5 times, and the glycerol concentration and the content of auxiliary Bi in the glycerin reaction solution are kept constant; in the process of carrying out step S1 and circulating step S3. Realize the continuous production of 1,3-dihydroxyacetone.

The production method provided by the present invention adopts an in-situ bimetallic Pt-Bi catalyst to selectively catalyze the oxidation of glycerol to produce 1,3-dihydroxyacetone. The in-situ bimetallic Pt-Bi catalyst has high catalytic activity and DHA selectivity of glycerol conversion High; the bimetallic Pt-Bi catalyst after the reaction is deactivated, the deactivated bimetallic Pt-Bi catalyst is regenerated by the above calcination method, the catalytic activity of the bimetallic Pt-Bi catalyst is recovered, and the bimetallic Pt-Bi catalyst is realized. Recycled, the glycerol concentration in the glycerol reaction solution and the content of the auxiliary Bi remain constant, and the bimetallic Pt-Bi catalyst can maintain the DHA selectivity of the initial high glycerol conversion rate, thereby realizing continuous industrial production.

Compared with the prior art, the beneficial effects of the present invention are:

The preparation method provided by the present invention can utilize the deactivated bimetallic Pt-Bi catalyst to prepare the highly active bimetallic Pt-Bi catalyst, the prepared bimetallic Pt-Bi catalyst has high catalytic activity, and can efficiently and selectively catalyze the oxidation of glycerol to produce DHA.

In addition, the method for producing 1,3-dihydroxyacetone by selective catalytic oxidation of glycerol provided by the present invention regenerates the deactivated bimetallic Pt-Bi catalyst through calcination, so as to realize the recycling of the bimetallic Pt-Bi catalyst, and the glycerol reaction solution The concentration of glycerol in the medium and the content of the auxiliary Bi are kept constant, and the bimetallic Pt-Bi catalyst can maintain the DHA selectivity of the initial high glycerol conversion rate, thereby realizing continuous industrial production.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

The raw materials in the embodiment can all be obtained commercially;

Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

In the embodiment and the comparative example, the Pt catalyst is prepared by the following method:

Pour 100 mg of nitrogen-doped carbon material into 60 ml of ethylene glycol solution to obtain a nitrogen-doped carbon material dispersion, and ultrasonically disperse for 20 min; then add 1.35 mL of H ₂ PtCl ₆ (0.02 M) solution to the nitrogen-doped carbon material. In carbon material dispersion; adjust pH to 8.5 with 0.04M KOH solution, stir and reflux at 140 °C for 2 h; filter after cooling to room temperature, rinse until the filtrate is neutral, vacuum dry at 75 °C for 24 h, grind to obtain fresh The Pt catalyst with a Pt loading of 5 wt.%.

Example 1

(1) Catalytic oxidation of glycerol to 1,3-dihydroxyacetone

To a 150 mL four-neck flask, an aqueous solution of glycerol (50 g, 10 wt.%, Bi (m _Bi /m _Pt = 0.2)) and 100 mg of Pt catalyst were added to form an in-situ bimetallic Pt-Bi catalyst with a stirring rate of 600 rpm The temperature was raised to 60 °C, and then oxygen (150 mL/min) was introduced to start the reaction; after 6 h, the reaction was stopped. The mixture of the reaction solution and the catalyst in the reactor is weighed before and after the reaction, and the liquid-solid mixture is filtered; the reaction solution is detected and analyzed by liquid chromatography.

(2) Regeneration of bimetallic Pt-Bi catalyst

The bimetallic Pt-Bi catalyst reacted in (1) was filtered, washed with water and alcohol, dried in vacuum, ground, loaded into a porcelain boat, and calcined in a horizontal high-temperature tube furnace at a temperature of 200 °C. ℃, Ar flow rate 100mL/min, calcination time 2h; the obtained catalyst is marked as Pt-Bi(200).

Example 2

The difference between this example and Example 1 is that the calcination temperature in (2) is 300°C; the other is the same as that of Example 1; the obtained catalyst is marked as Pt-Bi(300).

Example 3

The Pt-Bi(300) prepared in Example 2 was recycled once, that is, the steps (1) and (2) were repeated, and the obtained catalyst was marked as Pt-Bi(300-2).

Example 4

The Pt-Bi (300-2) prepared in Example 3 was recycled once, that is, the steps (1) and (2) were repeated, and the obtained catalyst was marked as Pt-Bi (300-3).

Example 5

The Pt-Bi (300-3) prepared in Example 4 was recycled once, that is, the steps (1) and (2) were repeated, and the obtained catalyst was marked as Pt-Bi (300-4).

Comparative Example 1

(1) Catalytic oxidation of glycerol to 1,3-dihydroxyacetone

A glycerol aqueous solution (50 g, 10 wt.%) and 100 mg Pt catalyst were added to a 150 mL four-necked flask, and the temperature was raised to 60 °C at a stirring rate of 600 rpm, and then oxygen (150 mL/min) was introduced to start the reaction; after 6 h , stop the reaction. The mixture of the reaction solution and the catalyst in the reactor is weighed before and after the reaction, and the liquid-solid mixture is filtered; the reaction solution is detected and analyzed by liquid chromatography.

(2) Separation of Pt catalyst

The Pt catalyst reacted in (1) was filtered, washed with water and alcohol, dried in vacuo, and ground, and the obtained catalyst was denoted as Pt(2).

Comparative Example 2

(1) Catalytic oxidation of glycerol to 1,3-dihydroxyacetone

To a 150 mL four-neck flask, an aqueous solution of glycerol (50 g, 10 wt.%, Bi (m _Bi /m _Pt = 0.2)) and 100 mg of Pt catalyst were added to form an in-situ bimetallic Pt-Bi catalyst with a stirring rate of 600 rpm The temperature was raised to 60 °C, and then oxygen (150 mL/min) was introduced to start the reaction; after 6 h, the reaction was stopped. The mixture of the reaction solution and the catalyst in the reactor is weighed before and after the reaction, and the liquid-solid mixture is filtered; the reaction solution is detected and analyzed by liquid chromatography.

(2) Separation of bimetallic Pt-Bi catalysts

The bimetallic Pt-Bi catalyst reacted in (1) was filtered, washed with water and alcohol, dried under vacuum, and ground, and the obtained catalyst was denoted as Pt-Bi(2).

Comparative Example 3

The difference between this comparative example and comparative example 2 is that (2) the separation steps of the bimetallic Pt-Bi catalyst are as follows: add acetone (100 mg/200 mL) to the bimetallic Pt-Bi catalyst after the reaction in (1) , stirred at 60 °C for 2 h, filtered and rinsed with 80 °C alcohol, vacuum dried, and ground; the others were the same as in Comparative Example 2;

The resulting catalyst was designated Pt-Bi (Ace.).

Comparative Example 4

The difference between this comparative example and comparative example 2 is that (2) the separation steps of the bimetallic Pt-Bi catalyst are as follows: the bimetallic Pt-Bi catalyst after the reaction in (1) is added with 1 M NaOH (100 mg/200 mL), stirred at room temperature for 2 h, and then poured the lye solution; added acetone solution (100 mg/200 mL), stirred at 60 °C for 1 h, filtered and rinsed with 80 °C alcohol, vacuum-dried, and ground; others were the same as in Comparative Example 2 ;

The resulting catalyst was designated Pt-Bi(OH).

Comparative Example 5

The difference between this comparative example and Example 1 is that the calcination temperature in (2) is 150°C; the other is the same as that of Example 1; the obtained catalyst is marked as Pt-Bi(150).

Performance Testing

The reaction solution was qualitatively and quantitatively analyzed by high performance liquid chromatography equipped with UV and differential detectors. HPX-87H (Aminex) was used as the separation column, and H ₂ SO ₄ (0.025 M) was used as the mobile phase. The wavelength of the UV detector tested was set to 210 nm, the temperature of the differential detector was 40 °C, the column temperature was 60 °C, and the mobile phase rate was 0.6 mL·min ^-1 . In this study, the qualitative analysis was carried out according to the standard samples, and the external standard method was used for quantitative analysis of the reactants and products.

The glycerol conversion and DHA selectivity of the catalyst were calculated as follows:

(1) Conversion rate of glycerol

Conversion rate of glycerol (%) = (mass of glycerol before reaction - remaining mass of glycerol after reaction) / mass of glycerol before reaction × 100 %

(2) DHA selectivity

DHA selectivity (%) = the mass of DHA produced by the reaction × 92 / [(the mass of glycerol before the reaction - the remaining mass of glycerol after the reaction) × 90] × 100 %

In Examples 1 to 5 and Comparative Examples 2 to 5, the catalyst for the initial reaction is denoted as Pt-Bi, that is, the initial in-situ bimetallic Pt-Bi catalyst;

In Comparative Example 1, the catalyst for the primary reaction is denoted as Pt, that is, the initial Pt catalyst.

The catalytic properties of the catalysts prepared in Examples 1 to 5 are shown in Table 1;

The catalytic performance of the catalysts prepared in Comparative Examples 1 to 5 is shown in Table 2.

Table 1 Catalytic performance of catalysts prepared in Examples 1 to 5

Table 2 Catalytic performance of catalysts prepared in Comparative Examples 1~5

It can be seen from Table 1 that the bimetallic Pt-Bi catalyst prepared by the preparation method provided by the present invention has high catalytic activity and can efficiently and selectively catalyze the oxidation of glycerol to produce DHA. The glycerol conversion of the catalysts obtained in Examples 1 to 5 was 25.2% to 31.1%, and the DHA selectivity was 52.9% to 62.6%, while the initial in-situ bimetallic Pt-Bi catalyst had a glycerol conversion and DHA selectivity of 18.0%. % and 44.7%, it can be seen that the catalytic performance of the bimetallic Pt-Bi catalysts prepared in Examples 1 to 5 is significantly better than the initial in-situ bimetallic Pt-Bi catalysts. Therefore, the method provided by the present invention not only restores the catalytic activity of the bimetallic Pt-Bi catalyst, but also improves the catalytic activity of the bimetallic Pt-Bi catalyst. Among them, Example 3 has the best catalytic effect, and the conversion rate of glycerol is 1.73 times that of the initial in-situ bimetallic Pt-Bi catalyst. The DHA selectivity generally decreases to a certain extent with the increase of the conversion rate. Example 3 At higher glycerol conversion, the DHA selectivity is still 1.30 times that of the initial in situ bimetallic Pt-Bi catalyst.

It can be seen from Examples 2 to 5 that the method for the selective catalytic oxidation of glycerol to prepare 1,3-dihydroxyacetone provided by the present invention is recycled through the bimetallic Pt-Bi catalyst, and the glycerol concentration and the content of the auxiliary Bi in the glycerol reaction solution are maintained. Constant, able to maintain the initial high glycerol conversion and DHA selectivity, enabling continuous production in industry. Moreover, the bimetallic Pt-Bi catalyst still has high catalytic activity after 4 times of regeneration, i.e., the 5th cycle, and can maintain the initial high glycerol conversion and DHA selectivity.

As mentioned before, the introduction of the promoter Bi into the Pt catalyst, i.e., the in-situ bimetallic Pt-Bi catalyst, can improve the glycerol conversion and DHA selectivity, as shown in Table 2.

The bimetallic Pt-Bi catalysts obtained in Comparative Examples 2 to 5 have low catalytic activity, and it is difficult to maintain the initial high glycerol conversion and DHA selectivity. The bimetallic Pt-Bi catalyst after the reaction in Comparative Example 2 was not calcined and regenerated, and the glycerol conversion and DHA selectivity were significantly reduced. Comparative Example 3 was treated with acetone, and Comparative Example 4 was treated with NaOH aqueous solution, both without calcination and regeneration, and the glycerol conversion rate and DHA selectivity were also significantly reduced. In Comparative Example 5, although the calcination regeneration was adopted, the temperature was low, and it was difficult for the regenerated bimetallic Pt-Bi catalyst to maintain the initial high glycerol conversion and DHA selectivity.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (9)

1. a preparation method of bimetallic Pt-Bi catalyst, is characterized in that, comprises the steps: S1. adding a Pt catalyst to the glycerol reaction solution containing auxiliary Bi, and catalyzing oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing a bimetallic Pt-Bi catalyst; S2. Separating the bimetallic Pt-Bi catalyst in the reaction solution mixture, and then calcining in an inert atmosphere at 200-300° C. to prepare a bimetallic Pt-Bi catalyst; The calcination time is 0.5～4h; The mass of the auxiliary Bi in the glycerol reaction solution is 20% to 50% of the mass of Pt. 2. preparation method according to claim 1, is characterized in that, described preparation method also comprises the steps: S3. adding the bimetallic Pt-Bi catalyst prepared by S2. to the glycerol reaction solution containing auxiliary Bi, and catalyzing oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing the bimetallic Pt-Bi catalyst; The bimetallic Pt-Bi catalyst in the reaction liquid mixture is separated, and then calcined in an inert atmosphere at 200-300° C. to prepare the bimetallic Pt-Bi catalyst again. 3. The preparation method according to claim 2, characterized in that, step S3. is performed cyclically, and the number of times that step S3. is performed is 1 to 4 times. 4. The preparation method according to claim 3, wherein step S3. is performed for 2 times. 5 . The preparation method according to claim 1 , wherein the inert atmosphere is an argon gas atmosphere, and the flow rate of the argon gas is 10-200 mL/min. 6 . 6 . The preparation method according to claim 5 , wherein the flow rate of the argon gas is 20-150 mL/min. 7 . 7. The preparation method according to claim 1, wherein the calcining time is 2h. 8. The method of claim 1, wherein the carrier of the Pt catalyst is a nitrogen-doped carbon material. 9. a method for selective catalytic oxidation of glycerol to prepare DHA, characterized in that, comprising the steps: S1. adding a Pt catalyst to the glycerol reaction solution containing auxiliary Bi, and catalyzing oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing a bimetallic Pt-Bi catalyst; S2. Separating the bimetallic Pt-Bi catalyst in the reaction solution mixture, and then calcining in an inert atmosphere at 200-300° C. to prepare a bimetallic Pt-Bi catalyst; S3. Add the bimetallic Pt-Bi catalyst prepared in step S2. to the glycerol reaction solution containing auxiliary Bi, and catalyze the oxidation of glycerol to prepare 1,3-dihydroxyacetone to obtain a reaction solution mixture containing the bimetallic Pt-Bi catalyst ; Then carry out step S2., prepare the bimetallic Pt-Bi catalyst again; S4. Circulate step S3., the number of times step S3. is performed is 1 to 5 times, and the glycerol concentration and the content of auxiliary Bi in the glycerin reaction solution are kept constant; in the process of performing step S1 and circulating step S3. Realize the continuous production of 1,3-dihydroxyacetone.