Catalyst for preparing diethylene glycol acid by catalytic oxidation of diethylene glycol, its preparation method and application

Abstract

The application discloses a catalyst for preparing diethylene glycol acid by catalytic oxidation of diethylene glycol, a preparation method and application thereof, and synthesizes the catalyst by an evaporation impregnation method, wherein the catalyst comprises an active component, an auxiliary agent and a carrier; the active component comprises at least one of Pt, Pd and Au, the auxiliary agent comprises at least one of Fe, Cu, Co, Mn, Sb and Ni, and the carrier is ZrO2; the loading amount of the active component is 0.1-10 wt%, and the loading amount of the auxiliary agent is 0.1-5 wt%. The catalyst can play a good catalytic role in the process of preparing diethylene glycol acid by oxidation of diethylene glycol, has good chemical stability, can realize green oxidation of diethylene glycol in an oxygen atmosphere to prepare diethylene glycol acid, and is simple in the preparation method of the diethylene glycol acid and suitable for mass production of diethylene glycol acid; moreover, the catalyst has high diethylene glycol conversion rate, which can reach more than 99%, and has high selectivity for diethylene glycol acid, which can reach more than 85%.

Description

Technical Field

[0001] This invention relates to the field of diethylene glycol preparation technology, specifically to a catalyst for the catalytic oxidation of diethylene glycol to prepare diethylene glycol, its preparation method, and its application. Background Technology

[0002] Diethylene glycol acid, with a boiling point of 167.16℃, is an important chemical raw material, mainly used as a complexing agent, in the synthesis of resins, in the manufacture of plasticizers, and in organic synthesis, with wide market applications. Currently, my country has a large demand for diethylene glycol acid, but it relies heavily on imports, with domestic production being very limited. There are three main synthetic routes for diethylene glycol acid: ① 1,4-dioxane-diketone, generated under high pressure from ethylene glycol and formaldehyde, decomposes into diethylene glycol acid under Reining nickel catalysis; ② Diethylene glycol is oxidized to diethylene glycol acid using 20% ​​nitric acid or chromium oxide as an oxidant; ③ Diethylene glycol is oxidized to diethylene glycol acid via liquid-phase catalytic oxidation using air or oxygen as an oxidant. The first two routes suffer from complex reaction processes, high energy consumption, and severe pollution, while the third route suffers from poor catalytic performance, low diethylene glycol conversion rate, and low selectivity for diethylene glycol acid. Furthermore, Chinese patent application CN109126858A discloses a method for preparing a bifunctional catalyst that simultaneously generates diethylene glycol acid and hydrogen, along with its products and applications. This method prepares a nickel-cobalt-doped CN composite catalyst, cross-linked with graphene oxide and nitrogen-doped carbon hollow spheres, used for electrolyzing alkaline diethylene glycol solutions, efficiently generating hydrogen and diethylene glycol acid at the cathode and anode, respectively. Chinese patent application CN101812699A discloses a method for simultaneously preparing tetrachloropyridine and diethylene glycol acid in an anode and cathode chamber. Using a mesh Zn-Ni alloy as the cathode and a lead electrode as the anode, it utilizes bipolar film technology to prepare 2,3,5,6-tetrachloropyridine in the cathode chamber and diethylene glycol acid in the anode chamber, exhibiting high yields of both electrode products. Both of these methods are electrolytic, making large-scale production difficult and unable to meet the huge demand for diethylene glycol acid. Therefore, this paper proposes a catalyst for the catalytic oxidation of diethylene glycol to diethylene glycol acid, along with its preparation method and applications. Summary of the Invention

[0003] One of the objectives of this invention is to provide a catalyst for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid, so as to achieve the green oxidation of diethylene glycol to diethylene glycol acid in an oxygen atmosphere and obtain a high diethylene glycol conversion rate and diethylene glycol acid selectivity.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A catalyst for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid is disclosed. The catalyst is synthesized by an evaporation impregnation method. The catalyst comprises an active component, an auxiliary agent, and a support. The active component comprises at least one of Pt, Pd, and Au. The auxiliary agent comprises at least one of Fe, Cu, Co, Mn, Sb, and Ni. The support is ZrO2.

[0006] Furthermore, calculated based on the elemental nature of the active component metal element, the loading of the active component in the catalyst is 0.1-10 wt%; calculated based on the elemental nature of the auxiliary metal element, the loading of the auxiliary in the catalyst is 0.1%-5 wt%.

[0007] Preferably, the catalyst has an active component loading of 2 wt% and an additive loading of 1 wt%.

[0008] Preferably, the catalyst is Pt-Sb-Co / ZrO2.

[0009] A second objective of this invention is to provide a method for preparing a catalyst for the catalytic oxidation of diethylene glycol to diethylene glycol acid, comprising the following steps:

[0010] (1) Prepare an active component metal salt solution, add the carrier ZrO2 to the active component metal salt solution and stir, and obtain solid powder I by evaporation, drying and grinding;

[0011] (2) Prepare an auxiliary metal salt solution, add solid powder I to the auxiliary metal salt solution and stir, and obtain solid powder II by evaporation, drying, grinding and calcination;

[0012] (3) The solid powder II was reduced under H2 atmosphere to obtain the catalyst.

[0013] Furthermore, the evaporation temperature in step (1) is 60-90℃, and the evaporation temperature in step (2) is 30-50℃.

[0014] Furthermore, in steps (1) and (2), the drying temperature is 100-120°C and the drying time is 8-12 hours.

[0015] Furthermore, in step (2), the roasting temperature is 400-550℃ and the roasting time is 2-5h.

[0016] Furthermore, in step (3), the reduction temperature is 350–450°C and the reduction time is 3–6 hours.

[0017] The third objective of this invention is to provide the application of the catalyst described above in the reaction system for the catalytic oxidation of oxygen-containing polyols to prepare carboxylic acids.

[0018] The fourth objective of this invention is to provide the application of the catalyst described above in the reaction system for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid.

[0019] Furthermore, the preparation method of diethylene glycol includes: mixing the catalyst and diethylene glycol at a molar ratio of 1:100 to 1:5000 and adding them into a reaction vessel, charging with an oxidant, and carrying out an oxidation reaction at a temperature of 80 to 140°C and a pressure of 1 to 5 MPa for 1 to 12 hours to obtain diethylene glycol.

[0020] Furthermore, the oxidant is oxygen, the reaction temperature is 100–130°C, the reaction pressure is 1–3 MPa, and the reaction time is 5–10 h.

[0021] The beneficial effects of this invention are as follows:

[0022] The catalyst prepared in this invention exhibits excellent catalytic activity and good chemical stability in the oxidation of diethylene glycol to diethylene glycol acid. It enables the catalytic oxidation of diethylene glycol to diethylene glycol acid in an alkaline environment, i.e., green oxidation to diethylene glycol acid in an oxygen atmosphere. This method of preparing diethylene glycol acid is a simple catalytic process suitable for large-scale production of diethylene glycol acid. In addition, the preparation of diethylene glycol acid using this catalyst not only achieves a high diethylene glycol conversion rate of over 99%, but also a high selectivity for diethylene glycol acid of over 85%, meaning that the diethylene glycol oxidation reaction products have a high content of diethylene glycol acid and low content of other products (such as (2-hydroxyethoxy)acetic acid and glycolic acid). Detailed Implementation

[0023] This invention provides a catalyst for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] In this invention, there are no special restrictions on the source of any raw materials; they can be commercially available.

[0025] Example 1

[0026] This embodiment describes a method for preparing a Pt-Sb-Co / ZrO2 catalyst, including the following steps:

[0027] (1) Dissolve 0.275g of chloroplatinic acid in 25ml of deionized water, stir evenly and set aside. Add 5g of carrier ZrO2 to the chloroplatinic acid solution and stir. Heat to 80℃ to completely evaporate the solvent. Then dry the evaporated solid material at 120℃ for 12h. After drying, grind to obtain Pt / ZrO2 powder with a Pt mass content of 2%.

[0028] (2) Dissolve 0.104g antimony chloride and 0.493g cobalt nitrate hexahydrate in 25ml anhydrous ethanol, stir evenly and set aside. Then, while stirring, add all the Pt / ZrO2 powder obtained in step (1), and heat to 40℃ to completely evaporate the solvent. Then, dry the evaporated solid material at 120℃ for 12h, grind it, and then calcine it in air at 400℃ for 4h to obtain unreduced catalyst powder.

[0029] (3) The unreduced catalyst powder was reduced for 4 h in an H2 atmosphere at 350 °C to obtain the Pt-Sb-Co / ZrO2 catalyst.

[0030] The catalyst contains 2% Pt by mass and 1% Sb and Co by total mass.

[0031] Example 2

[0032] The difference between Example 2 and Example 1 is that the active groups in this example are replaced with Pd and Au, respectively. Specifically, 0.216g of palladium nitrate and 0.173g of chloroauric acid are weighed and dissolved in 25ml of deionized water, and then 5g of ZrO2 is added for evaporation and impregnation. Finally, Pd-Sb-Co / ZrO2 catalyst and Au-Sb-Co / ZrO2 catalyst are prepared respectively.

[0033] In this example, all other process steps and parameters are the same as in Example 1.

[0034] Example 3

[0035] The difference between Example 3 and Example 1 is that the additives in this example are replaced with Fe, Cu, Co, Mn, Sb and Ni, respectively. Specifically, 0.360 g, 0.146 g, 0.493 g, 0.085 g, 0.104 g and 0.156 g of ferric nitrate nonahydrate, copper nitrate, cobalt nitrate hexahydrate, manganese nitrate, antimony chloride and nickel nitrate are weighed and dissolved in 25 ml of anhydrous ethanol. Then, Pt / ZrO2 powder is added while stirring, and Pt-Fe / ZrO2 catalyst, Pt-Cu / ZrO2 catalyst, Pt-Co / ZrO2 catalyst, Pt-Mn / ZrO2 catalyst, Pt-Sb / ZrO2 catalyst and Pt-Ni / ZrO2 catalyst are finally prepared.

[0036] In this example, all other process steps and parameters are the same as in Example 1.

[0037] Example 4

[0038] The difference between Example 4 and Example 1 is that the mass content of the active component is changed in this example. Specifically, 0.069 g, 0.137 g, and 0.550 g of chloroplatinic acid are weighed and dissolved in 25 ml of deionized water. After stirring evenly, 5 g of carrier ZrO2 is added to the chloroplatinic acid solution and stirred. After initial evaporation, impregnation, drying, and grinding, Pt / ZrO2 powders with Pt mass contents of 0.5%, 1%, and 4% are obtained, respectively. Then, precursor solutions of auxiliary agents Sb and Co are added and evaporated and impregnated again. After drying, calcination, grinding, and reduction, Pt(0.5)-Sb-Co / ZrO2 catalyst, Pt(1)-Sb-Co / ZrO2 catalyst, and Pt(4)-Sb-Co / ZrO2 catalyst are finally obtained.

[0039] In this example, all other process steps and parameters are the same as in Example 1.

[0040] Example 5

[0041] The difference between Example 5 and Example 1 is that the mass content of the additives is changed in this example. Specifically, 0.052g of antimony chloride and 0.247g of cobalt nitrate hexahydrate, 0.208g of antimony chloride and 0.986g of cobalt nitrate hexahydrate, and 0.416g of antimony chloride and 1.972g of cobalt nitrate hexahydrate are weighed and dissolved in 25ml of anhydrous ethanol. Then, Pt / ZrO2 powder is added while stirring, and Pt-Sb-Co(0.5) / ZrO2 catalyst, Pt-Sb-Co(2) / ZrO2 catalyst, and Pt-Sb-Co(4) / ZrO2 catalyst are finally prepared.

[0042] In this example, all other process steps and parameters are the same as in Example 1.

[0043] Example 6

[0044] Example 6 describes a method for preparing a Pt-Sb-Co / ZrO2 catalyst, including the following steps:

[0045] (1) Dissolve 0.275g of chloroplatinic acid in 25ml of deionized water, stir evenly and set aside. Add 5g of carrier ZrO2 to the chloroplatinic acid solution and stir. Heat to 60℃ to completely evaporate the solvent. Then dry the evaporated solid material at 100℃ for 10h. After drying, grind to obtain Pt / ZrO2 powder.

[0046] (2) Dissolve 0.104g antimony chloride and 0.493g cobalt nitrate hexahydrate in 25ml anhydrous ethanol, stir evenly and set aside. Then, while stirring, add Pt / ZrO2 powder and heat to 50℃ to completely evaporate the solvent. Then, dry the evaporated solid material at 120℃ for 12h and calcine it in air at 500℃ for 3h. After calcination, grind to obtain unreduced catalyst powder.

[0047] (3) The unreduced catalyst powder was reduced for 3 hours in an H2 atmosphere at 420°C to obtain the Pt-Sb-Co / ZrO2 catalyst.

[0048] Example 7

[0049] Example 7 applies the catalysts prepared in Examples 1 and 2 to the oxidation of diethylene glycol to diethylene glycol acid to determine the performance of catalysts with different active components, including the following steps:

[0050] 0.2g of the catalysts prepared in Examples 1 and 2 above and 25ml of 0.1M diethylene glycol aqueous solution were added to a batch stirred reactor, 1MPa of oxygen was introduced, the reaction temperature was set to 120℃, the stirring speed was 1000rpm, and the reaction was continued for 6h. After the reaction was stopped, the supernatant was taken for chromatographic analysis, and the results are shown in Table 1.

[0051] Table 1

[0052]

[0053] According to the data in Table 1, using Pt as the active component yields the highest diethylene glycol conversion and diethylene glycol acid selectivity.

[0054] Example 8

[0055] In Example 8, the catalysts prepared in Examples 1 and 3 were applied to the oxidation of diethylene glycol to prepare diethylene glycol acid to determine the performance of catalysts with different auxiliary components. The results are shown in Table 2. The method and parameters for the oxidation of diethylene glycol to prepare diethylene glycol acid in this example are the same as in Example 7.

[0056] Table 2

[0057]

[0058] According to the data in Tables 1 and 2, the catalyst with Pt as the active component and Sb and Co as auxiliary components supported on ZrO2 has the best performance in catalyzing the oxidation of diethylene glycol to diethylene glycol acid. The Pt-Sb-Co / ZrO2 catalyst has the highest diethylene glycol conversion rate and diethylene glycol acid selectivity, while the Pt-Co / ZrO2 catalyst and the Pt-Sb / ZrO2 catalyst have relatively high diethylene glycol conversion rate and diethylene glycol acid selectivity.

[0059] Example 9

[0060] In Example 9, the catalysts prepared in Examples 1 and 4 were applied to the oxidation of diethylene glycol to prepare diethylene glycol acid to determine the content of the active component most favorable for the formation of diethylene glycol acid. The results are shown in Table 3. The method and parameters for the oxidation of diethylene glycol to prepare diethylene glycol acid in this example are the same as in Example 7.

[0061] Table 3

[0062]

[0063] According to the data in Table 3, the Pt-Sb-Co / ZrO2 catalyst exhibits the best catalytic performance when the Pt content is 2%.

[0064] Experimental Example 10

[0065] In Example 10, the catalysts prepared in Examples 1 and 5 were applied to the oxidation of diethylene glycol to prepare diethylene glycol acid to determine the optimal content of the auxiliary component for diethylene glycol acid formation. The results are shown in Table 4. The method and parameters for the oxidation of diethylene glycol to prepare diethylene glycol acid in this example are the same as in Example 7.

[0066] Table 4

[0067]

[0068] According to the data in Table 4, the Pt-Sb-Co / ZrO2 catalyst exhibits the best catalytic performance when the total content of Sb and Co is 1%.

[0069] In summary, the Pt-Sb-Co / ZrO2 catalyst exhibits excellent performance in catalyzing the oxidation of diethylene glycol to diethylene glycol acid. When using Pt-Sb-Co / ZrO2 as a catalyst to catalyze the oxidation of diethylene glycol to diethylene glycol acid, both the diethylene glycol conversion rate and the diethylene glycol acid selectivity are very high.

[0070] Example 11

[0071] This embodiment 11 provides a method for preparing diethylene glycol acid by catalytic oxidation of diethylene glycol, including the following steps:

[0072] 0.2g of the catalyst prepared in Example 1 above and 30mL of 2M diethylene glycol aqueous solution were added to a batch stirred reactor, oxygen was introduced at 3MPa, the reaction temperature was set at 100℃, the stirring speed was 1000rpm, and the reaction was carried out for 10h to obtain the reaction products diethylene glycol acid, (2-hydroxyethoxy)acetic acid and glycolic acid.

[0073] In this embodiment, the diethylene glycol conversion rate was 99.15%, and the diethylene glycol acid selectivity was 87.19%.

[0074] Example 12

[0075] The catalytic performance of the catalyst prepared in Example 1 for the catalytic oxidation of diethylene glycol to diethylene glycol acid was tested. After the reaction, the catalyst was collected and washed with a large amount of deionized water and ethanol, dried at 120°C for 12 h, and the reaction performance was tested again without any treatment. This process was repeated multiple times to investigate the stability of the Pt-Sb-Co / ZrO2 catalyst. The results are shown in Table 5. The method for the catalytic oxidation of diethylene glycol to diethylene glycol acid in this example is the same as in Example 7.

[0076] Table 5

[0077]

[0078] The above results indicate that the Pt-Sb-Co / ZrO2 catalyst still has a high diethylene glycol conversion rate after five rounds of reaction, and the diethylene glycol acid selectivity decreases by no more than 10%, indicating that the Pt-Sb-Co / ZrO2 catalyst has good chemical stability.

[0079] Example 13

[0080] The catalyst prepared in Example 1 was used to catalytically oxidize 1,5-pentanediol and triethylene glycol to their corresponding carboxylic acids, in order to explore the ability of the Pt-Sb-Co / ZrO2 catalyst to catalyze the oxidation of other oxygen-containing alcohols with structures similar to diethylene glycol to their corresponding carboxylic acids. The results are shown in Table 6. In this example, the method and process parameters for the catalytic oxidation of 1,5-pentanediol and triethylene glycol to their corresponding carboxylic acids were the same as in Example 7.

[0081] Table 6

[0082]

[0083]

[0084] The above results indicate that the Pt-Sb-Co / ZrO2 catalyst has satisfactory performance in catalyzing the preparation of corresponding carboxylic acids (dicarboxylic acids) from oxygen-containing polyols with structures similar to diethylene glycol. The polyol conversion rate reaches over 65%, and the selectivity for the corresponding dicarboxylic acid reaches over 50%. This catalyst also has the potential to oxidize oxygen-containing polyols to prepare carboxylic acids.

[0085] It should be noted that any parts not mentioned in this invention can be achieved by using or referencing existing technologies.

[0086] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A catalyst for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid, characterized in that, The catalyst is synthesized by evaporation impregnation method. The catalyst includes an active component, an auxiliary agent, and a support. The active component includes Pt, the auxiliary agent includes Co and Sb, and the support is ZrO2.

2. The catalyst for the catalytic oxidation of diethylene glycol to diethylene glycol acid according to claim 1, characterized in that, Based on the elemental composition of the active component metal, the loading of the active component in the catalyst is 0.1-10 wt%. Based on the elemental composition of the auxiliary metal, the loading of the auxiliary in the catalyst is 0.1%-5wt%.

3. A method for preparing the catalyst according to claim 1 or 2, characterized in that, Including the following steps: (1) Prepare an active component metal salt solution, add the carrier ZrO2 to the active component metal salt solution and stir, and obtain solid powder I by evaporation, drying and grinding; (2) Prepare an auxiliary metal salt solution, add solid powder I to the auxiliary metal salt solution and stir, and obtain solid powder II by evaporation, drying, grinding and calcination; (3) The solid powder II was reduced under H2 atmosphere to obtain the catalyst.

4. The method for preparing the catalyst according to claim 3, characterized in that, The evaporation temperature in step (1) is 60~90℃, and the evaporation temperature in step (2) is 30~50℃; The drying temperature in steps (1) and (2) is 100~120℃ and the drying time is 8~12h.

5. The method for preparing the catalyst according to claim 3, characterized in that, The roasting temperature in step (2) is 400~550℃.

6. The method for preparing the catalyst according to claim 3, characterized in that, The reduction temperature in step (3) is 350~450℃.

7. The application of a catalyst in the catalytic oxidation of oxygen-containing polyols to prepare carboxylic acids, characterized in that, The catalyst is synthesized by evaporation impregnation method. The catalyst includes an active component, an auxiliary agent, and a support. The active component includes at least one of Pt, Pd, and Au. The auxiliary agent includes at least one of Fe, Cu, Co, Mn, Sb, and Ni. The support is ZrO2.

8. The application of a catalyst in the reaction system for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid, characterized in that, The catalyst is synthesized by evaporation impregnation method. The catalyst includes an active component, an auxiliary agent, and a support. The active component includes at least one of Pt, Pd, and Au. The auxiliary agent includes at least one of Fe, Cu, Co, Mn, Sb, and Ni. The support is ZrO2.

9. The application of the catalyst according to claim 8 in the reaction system for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid, characterized in that, The preparation method of diethylene glycol includes: mixing the catalyst and diethylene glycol at a molar ratio of 1:100 to 1:5000 and adding them to a reaction vessel; adding an oxidant; and carrying out an oxidation reaction at a temperature of 80 to 140°C and a pressure of 1 to 5 MPa for 1 to 12 hours to obtain diethylene glycol.

10. The application of the catalyst according to claim 9 in the reaction system for the catalytic oxidation of diethylene glycol to prepare diethylene glycol acid, characterized in that, The oxidant is oxygen, the reaction temperature is 100~130℃, the reaction pressure is 1~3MPa, and the reaction time is 5~10h.

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