A catalyst for preparing ultra-high molecular weight polyethylene oxide, its preparation method and application

Abstract

This invention discloses a catalyst for preparing ultra-high molecular weight polyethylene oxide (UHMWPE), its preparation method, and its application, relating to the field of catalyst preparation technology. The catalyst preparation method includes the following steps: S1: 1,6-hexanediamine reacts with allyl acrylate to generate intermediate 1; S2: Intermediate 1 reacts with diphenylphosphine to generate intermediate 2; S3: Intermediate 2 reacts with allyl bromide to generate intermediate 3; S4: Intermediate 3 reacts with 9-boronbicyclo[3.3.1]nonane to obtain the final product. The catalyst prepared by this invention exhibits high catalytic activity, can prepare UHMWPE, and the prepared UHMWPE has a narrow molecular weight distribution.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a catalyst for preparing ultra-high molecular weight polyethylene oxide, its preparation method, and its application. Background Technology

[0002] Polyethylene oxide (PEO) is a low-toxicity, non-irritating, and water-soluble polymer. High molecular weight PEO possesses multiple functions, including flocculation, thickening, slow release, lubrication, dispersion, retention aid, and water retention, and is widely used in numerous fields such as daily chemicals, biomedicine, papermaking, coatings, inks, textiles, building materials, steel, energy storage, and electronics. PEO is primarily synthesized from ethylene oxide through ring-opening polymerization. In this process, the catalyst plays a crucial role, effectively lowering the activation energy, increasing the polymerization rate, and controlling the molecular weight and distribution of the polymer. However, existing catalytic systems still have significant drawbacks. For example, alkali metal derivatives (such as potassium hydroxide) have insufficient and difficult-to-control catalytic activity, resulting in a lower upper limit for the molecular weight of the polymers prepared; dicyanide catalysts easily lead to polyether degradation and introduce metal residue pollution, limiting the product's application in the food and medical fields.

[0003] Chinese invention patent application CN109517157A discloses a special catalyst for the synthesis of high molecular weight polyethylene oxide and its preparation method. The catalyst is prepared from raw materials including urea, pure water, hexadecyltrimethylammonium bromide, cobalt acetate, calcium nitrate, strontium nitrate, ammonia, diethylene glycol, acetonitrile, and dichloroethylaluminum. However, the polyethylene oxide synthesized using this catalyst has a wide molecular weight distribution. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a catalyst for preparing ultra-high molecular weight polyethylene oxide, its preparation method and application.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing a catalyst for ultra-high molecular weight polyethylene oxide includes the following steps:

[0007] S1: 1,6-Hexanediamine reacts with allyl acrylate to generate intermediate 1, and the reaction equation is shown below:

[0008]

[0009] S2: Intermediate 1 reacts with diphenylphosphine to generate intermediate 2, and the reaction equation is shown below:

[0010]

[0011] S3: Intermediate 2 reacts with allyl bromide to generate intermediate 3, and the reaction equation is shown below:

[0012]

[0013] S4: Prepared by reacting intermediate 3 with 9-boronibirocyclo[3.3.1]nonane. The reaction equation is shown below:

[0014]

[0015] In step S1, the molar ratio of 1,6-hexanediamine to allyl acrylate is 1:(4.05-4.1).

[0016] In step S2, the molar ratio of intermediate 1 to diphenylphosphine is 1:(4.1-4.2).

[0017] In step S3, the molar ratio of intermediate 2 to allyl bromide is 1:(6.3-6.5).

[0018] In step S4, the molar ratio of intermediate 3 to 9-boronibirane[3.3.1]nonane is 1:(6.2-6.4).

[0019] In step S1, the reaction temperature is 50-60℃ and the reaction time is 8-10h; in step S2, the reaction temperature is 80-90℃ and the reaction time is 18-24h.

[0020] In step S3, the reaction temperature is 55-65℃ and the reaction time is 48-52h; in step S4, the reaction temperature is 55-65℃ and the reaction time is 10-14h.

[0021] The reaction solvent used in step S1 is methanol; the reaction solvent used in step S2 is anhydrous 1,4-dioxane; the reaction solvent used in step S3 is anhydrous acetonitrile; and the reaction solvent used in step S4 is tetrahydrofuran.

[0022] A catalyst for preparing ultra-high molecular weight polyethylene oxide was prepared by the above method.

[0023] Application of a catalyst in the preparation of ultra-high molecular weight polyethylene oxide.

[0024] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include:

[0025] The catalyst prepared by this invention has high catalytic activity and can prepare ultra-high molecular weight polyethylene oxide, and the molecular weight distribution of the prepared polyethylene oxide is relatively narrow. Attached Figure Description

[0026] Figure 1This is a graph showing the relationship between different catalyst dosages and the number-average molecular weight and molecular weight distribution of polyethylene oxide. Detailed Implementation

[0027] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0028] Example 1: Preparation of the catalyst:

[0029] S1: Under nitrogen protection, 300 ml of methanol, 0.1 mol of 1,6-hexanediamine, and 5 mmol of hydroquinone were added to a reaction vessel and stirred until homogeneous. The mixture was heated to 40 °C, and 0.405 mol of allyl acrylate was added dropwise over 30 min. The mixture was then heated to 50 °C and reacted for 10 h. After cooling to 40 °C, the mixture was distilled under reduced pressure for 1 h. 200 ml of cold diethyl ether was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with 100 ml of cold diethyl ether, and dried under vacuum at 50 °C for 10 h to obtain intermediate 1. Its 1H NMR spectrum data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 5.93 (ddt, J = 17.2, 11.5, 5.8 Hz, 4H), 5.37 (ddt, J = 17.0, 2.5, 1.3Hz, 4H), 5.21 (ddt, J = 11.5, 2.4, 1.6 Hz, 4H), 4.60 (dt, J = 5.7, 1.4 Hz,8H), 2.89 (t, J = 6.8 Hz, 8H), 2.55 (q, J = 6.4 Hz, 12H), 1.51 - 1.40 (m,4H), 1.31 (td, J = 6.9, 0.8 Hz, 4H);

[0030] S2: Under nitrogen protection, 500 ml of anhydrous 1,4-dioxane, 0.01 mol of copper trifluoromethanesulfonate, 0.1 mol of intermediate 1, and 0.41 mol of diphenylphosphine were added to a reaction vessel, stirred and mixed, and heated to 80 °C for 24 h. The mixture was then cooled to 50 °C, distilled under reduced pressure for 1 h, and 300 ml of cold n-hexane was added and stirred to precipitate. The precipitate was washed with 100 ml of n-hexane and dried under vacuum at 60 °C for 10 h to obtain intermediate 2. Its 1H NMR data are as follows: 1 H NMR (400 MHz, Chloroform- d) δ 7.41 - 7.25(m, 40H), 4.05 (t, J = 7.5 Hz, 8H), 2.89 (t, J = 6.8 Hz, 8H), 2.68 (t, J =9.7 Hz, 8H), 2.54 (dt, J = 12.3, 6.4 Hz, 12H), 2.04 - 1.90 (m, 8H), 1.51 -1.40 (m, 4H), 1.31 (td, J = 6.9, 0.8 Hz, 4H);

[0031] S3: Under nitrogen protection, 600 ml of anhydrous acetonitrile and 0.1 mol of intermediate 2 were added to the reaction vessel, stirred and mixed, heated to 55 °C, and 0.63 mol of allyl bromide was added dropwise over 30 min. The reaction was allowed to proceed for 52 h, then cooled to 50 °C and distilled under reduced pressure for 2 h to obtain intermediate 3; its 1H NMR spectrum data are as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 7.69 - 7.45 (m,40H), 6.01 (m, 6H), 5.71 (m, 2H), 5.41 (m, 6H), 5.28 (dt, J = 12.4, 1.7 Hz,4H), 4.54 (dt, J = 8.1, 1.4 Hz, 8H), 4.36 - 4.24 (m, 12H), 3.77 (m, 16H), 3.51 (t, J = 8.8 Hz, 4H), 2.83 (t, J = 9.3 Hz, 8H), 2.00 (m, 8H), 1.71 (m,4H), 1.51 (t, J = 12.3 Hz, 4H);

[0032] S4: Under nitrogen protection, 100 ml of anhydrous tetrahydrofuran and 0.01 mol of intermediate 3 were added to the reactor and stirred until homogeneous. Then, 124 ml of anhydrous tetrahydrofuran solution containing 0.062 mol of 9-boronbicyclo[3.3.1]nonane was added, and the mixture was heated to 40 °C and reacted for 14 h. After vacuum distillation for 1 h, the product was recrystallized using 150 ml of a mixed solution of anhydrous ethanol and ethyl acetate (volume ratio of anhydrous ethanol to ethyl acetate was 2:8), filtered, and dried under vacuum at 60 °C for 12 h to obtain the catalyst. Its 1H NMR spectrum data are as follows: 1 H NMR (400 MHz, Chloroform- d) δ 7.70 - 7.44 (m, 40H), 4.32 - 4.24 (m, 8H), 3.78 (m,16H), 3.66 - 3.58 (m, 8H), 3.49 (m, 8H), 2.84 (t, J = 9.3 Hz, 8H), 1.98 (tt,J = 9.1, 7.4 Hz, 8H), 1.77 - 1.60 (m, 8H), 1.58 - 1.27 (m, 84H), 1.18 (m,24H).

[0033] Example 2: Preparation of the catalyst:

[0034] S1: Under nitrogen protection, 300 ml of methanol, 0.1 mol of 1,6-hexanediamine, and 5 mmol of hydroquinone were added to a reaction vessel and stirred until homogeneous. The mixture was heated to 40 °C, and 0.408 mol of allyl acrylate was added dropwise over 30 min. The mixture was then heated to 55 °C and reacted for 9 h. After cooling to 40 °C, the mixture was distilled under reduced pressure for 1 h. 200 ml of cold diethyl ether was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with 100 ml of cold diethyl ether, and dried under vacuum at 50 °C for 10 h to obtain intermediate 1.

[0035] S2: Under nitrogen protection, 500 ml of anhydrous 1,4-dioxane, 0.01 mol of copper trifluoromethanesulfonate, 0.1 mol of intermediate 1 and 0.415 mol of diphenylphosphine were added to a reaction vessel, stirred and mixed, heated to 85 °C and reacted for 20 h; cooled to 50 °C, distilled under reduced pressure for 1 h, added 300 ml of cold n-hexane and stirred, precipitated, washed with 100 ml of n-hexane, and dried under vacuum at 60 °C for 10 h to obtain intermediate 2;

[0036] S3: Under nitrogen protection, 600 ml of anhydrous acetonitrile and 0.1 mol of intermediate 2 were added to the reaction vessel, stirred and mixed, heated to 50 °C, and 0.64 mol of allyl bromide was added dropwise. After the addition was completed in 30 min, the temperature was raised to 60 °C and the reaction was carried out for 50 h. The mixture was then cooled to 50 °C and distilled under reduced pressure for 2 h to obtain intermediate 3.

[0037] S4: Under nitrogen protection, 100 ml of anhydrous tetrahydrofuran and 0.01 mol of intermediate 3 were added to the reactor and stirred until well mixed. Then, 126 ml of anhydrous tetrahydrofuran solution containing 0.063 mol of 9-boronbicyclo[3.3.1]nonane was added, the temperature was raised to 40 °C, and the reaction was carried out for 12 h. The mixture was then distilled under reduced pressure for 1 h, recrystallized using a mixed solution of 150 ml of anhydrous ethanol and ethyl acetate (volume ratio of anhydrous ethanol to ethyl acetate was 2:8), filtered, and dried under vacuum at 60 °C for 12 h to obtain the catalyst.

[0038] Example 3: Preparation of the catalyst:

[0039] S1: Under nitrogen protection, 300 ml of methanol, 0.1 mol of 1,6-hexanediamine, and 5 mmol of hydroquinone were added to a reaction vessel and stirred until homogeneous. The mixture was heated to 40 °C, and 0.41 mol of allyl acrylate was added dropwise over 30 min. The mixture was then heated to 60 °C and reacted for 8 h. After cooling to 40 °C, the mixture was distilled under reduced pressure for 1 h. 200 ml of cold diethyl ether was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with 100 ml of cold diethyl ether, and dried under vacuum at 50 °C for 10 h to obtain intermediate 1.

[0040] S2: Under nitrogen protection, 500 ml of anhydrous 1,4-dioxane, 0.01 mol of copper trifluoromethanesulfonate, 0.1 mol of intermediate 1 and 0.42 mol of diphenylphosphine were added to a reaction vessel, stirred and mixed, heated to 90 °C and reacted for 18 h; cooled to 50 °C, distilled under reduced pressure for 1 h, added 300 ml of cold n-hexane and stirred, precipitated, washed with 100 ml of n-hexane, and dried under vacuum at 60 °C for 10 h to obtain intermediate 2;

[0041] S3: Under nitrogen protection, 600 ml of anhydrous acetonitrile and 0.1 mol of intermediate 2 were added to the reaction vessel, stirred and mixed, heated to 50 °C, and 0.65 mol of allyl bromide was added dropwise. After the addition was completed in 30 min, the temperature was raised to 65 °C and the reaction was carried out for 48 h. The mixture was then cooled to 50 °C and distilled under reduced pressure for 2 h to obtain intermediate 3.

[0042] S4: Under nitrogen protection, 100 ml of anhydrous tetrahydrofuran and 0.01 mol of intermediate 3 were added to the reactor and stirred until well mixed. Then, 128 ml of anhydrous tetrahydrofuran solution containing 0.064 mol of 9-boronbicyclo[3.3.1]nonane was added, the temperature was raised to 40 °C, and the reaction was carried out for 10 h. The mixture was then distilled under reduced pressure for 1 h, recrystallized using a mixed solution of 150 ml of anhydrous ethanol and ethyl acetate (volume ratio of anhydrous ethanol to ethyl acetate was 2:8), filtered, and dried under vacuum at 60 °C for 12 h to obtain the catalyst.

[0043] Example 4: Preparation of polyethylene oxide:

[0044] 500 ml of toluene and 0.1 g of catalyst (prepared in Example 1) were added to a high-pressure reactor, stirred until homogeneous, cooled to 0°C, purged with nitrogen three times, and 100 g of ethylene oxide was introduced. The reactor was then sealed, stirred, heated to 50°C, and reacted for 15 h. The mixture was then cooled to room temperature, and the reaction solution was rotary evaporated at 60°C for 1 h to obtain polyethylene oxide.

[0045] Example 5: Preparation of polyethylene oxide:

[0046] Add 500 ml of toluene and 0.1 g of catalyst (prepared in Example 2) to a high-pressure reactor, stir until homogeneous, cool to 0°C, purge with nitrogen three times, introduce 100 g of ethylene oxide, seal the reactor, stir, heat to 60°C, react for 14 h, cool to room temperature, and rotary evaporate the reaction solution at 60°C for 1 h to obtain polyethylene oxide.

[0047] Example 6 Preparation of polyethylene oxide:

[0048] Add 500 ml of toluene and 0.1 g of catalyst (prepared in Example 3) to a high-pressure reactor, stir until homogeneous, cool to 0°C, purge with nitrogen three times, introduce 100 g of ethylene oxide, seal the reactor, stir, heat to 70°C, react for 12 h, cool to room temperature, and rotary evaporate the reaction solution at 60°C for 1 h to obtain polyethylene oxide.

[0049] Figure 1 The graph shows the relationship between different catalyst dosages and the number-average molecular weight and molecular weight distribution of polyethylene oxide. The preparation method of polyethylene oxide is basically the same as in Example 5, except that the amount of catalyst added is different.

[0050] Depend on Figure 1 It can be seen that as the amount of catalyst added increases, the number-average molecular weight of the obtained polyethylene oxide gradually decreases, with little impact on the molecular weight distribution. By changing the amount of catalyst prepared in this application, polyethylene oxide with different molecular weights and narrow molecular weight distributions can be prepared.

[0051] Comparative Example 1

[0052] The preparation method of polyethylene oxide is basically the same as in Example 5, except that the catalyst is replaced with an equal weight of the catalyst prepared by the following method:

[0053] The preparation method of the catalyst is basically the same as that in Example 2, except that the 1,6-hexanediamine in step S1 is replaced with an equimolar amount of ethylenediamine.

[0054] Comparative Example 2

[0055] The preparation method of polyethylene oxide is basically the same as in Example 5, except that the catalyst is replaced with an equal weight of the catalyst prepared by the following method:

[0056] The catalyst preparation method is basically the same as in Example 2, except that the 1,6-hexanediamine in step S1 is replaced with an equimolar amount of 1,12-dodecaneamine.

[0057] Comparative Example 3

[0058] The preparation method of polyethylene oxide is basically the same as in Example 5, except that the catalyst is replaced with an equal weight of the catalyst prepared by the following method:

[0059] The preparation method of the catalyst is basically the same as that in Example 2, except that 1,6-hexanediamine in step S1 is replaced with 0.2 mol of n-hexane, the amount of diphenylphosphine added in step S2 is replaced with 0.21 mol, the amount of allyl bromide added in step S3 is replaced with 0.32 mol, and the amount of 9-boronbicyclo[3.3.1]nonane added in step S4 is replaced with 0.31 mol.

[0060] Comparative Example 4

[0061] The preparation method of polyethylene oxide is basically the same as in Example 5, except that the catalyst is replaced with an equal weight of the catalyst prepared by the following method:

[0062] The catalyst was prepared in a manner similar to that in Example 2, except that allyl bromide in step S3 was replaced with an equimolar amount of 6-bromo-1-hexene.

[0063] Comparative Example 5

[0064] The preparation method of polyethylene oxide is basically the same as in Example 5, except that the catalyst is replaced with an equal weight of the catalyst prepared by the following method:

[0065] The catalyst preparation method is basically the same as in Example 2, except that the allyl bromide in step S3 is replaced with 0.42 mol, and the 9-boronbicyclo[3.3.1]nonane in step S4 is replaced with 0.042 mol.

[0066] Comparative Example 6

[0067] The preparation method of polyethylene oxide is basically the same as that of Comparative Example 5, except that the amount of catalyst added is replaced with 0.15g.

[0068] Comparative Example 7

[0069] The preparation method of polyethylene oxide is basically the same as that of Comparative Example 5, except that the amount of catalyst added is replaced with 0.2g.

[0070] The CAS number of 9-boronibira[3.3.1]nonane used in this application is 280-64-8.

[0071] The molecular weight and molecular weight distribution of the polyethylene oxides prepared in Examples 4-6 and Comparative Examples 1-7 of this application were determined using a PL-GPC50 gel permeation chromatography instrument. The test results are shown in Table 1.

[0072] The polymerization yield is calculated using the following formula:

[0073]

[0074] Where m is the actual mass of polyethylene oxide obtained. This refers to the actual mass of ethylene oxide used.

[0075] Table 1 Performance Test Data

[0076]

[0077] As can be seen from the data in Examples 4, 5, and 6 in Table 1, the catalyst prepared in this invention has a high yield, high molecular weight, and narrow molecular weight distribution in the synthesis of polyoxyethylene from ethylene oxide.

[0078] The catalyst prepared in this application contains a boron active center, a quaternary phosphonium salt, and a quaternary ammonium salt, forming a synergistic catalytic system during ethylene oxide polymerization: the boron active center, acting as a Lewis acid, preferentially coordinates with the oxygen atoms in the ethylene oxide molecule and activates the CO bond of ethylene oxide, effectively lowering its ring-opening energy barrier; simultaneously, the cations in the quaternary phosphonium salt and quaternary ammonium salt act as nucleophilic initiators, attacking the boron-activated ethylene oxide to initiate ring-opening and form alkoxy anions; under the continuous coordination stability and regulation of the boron center, these alkoxy anions undergo highly regioselective chain growth with subsequent ethylene oxide monomers. The synergistic effect of these three components enables the ring-opening polymerization of ethylene oxide to proceed in a controllable and stable manner, thereby improving polymerization efficiency and obtaining high-yield, high-molecular-weight polyethylene oxide with a narrow molecular weight distribution.

[0079] In Comparative Example 1, the shortened linker chain length in the catalyst reduced the flexibility of the ligand / active center, increasing steric hindrance at the catalytic center and hindering monomer (ethylene oxide) from approaching the active site, leading to a decrease in yield. In Comparative Example 2, the excessively long linker chain caused the catalyst to degenerate from a compact multi-site active center to a loose structure, reducing the capture and polymerization initiation efficiency of ethylene oxide monomers and lowering overall catalytic performance. In Comparative Example 3, the lack of bifunctional linkages and multi-site synergy resulted in a decrease in local active center concentration, leading to a reduction in the molecular weight of polyethylene oxide; furthermore, the intermolecular activity differences were diffused / amplified, resulting in uneven polymerization and a wider molecular weight distribution. In Comparative Example 4, the excessively large spacing between the boron active center and the nucleophilic sites (quaternary phosphonium salt, quaternary ammonium salt) in the catalyst reduced its activation ability for ethylene oxide, leading to a decrease in yield.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A process for the preparation of a catalyst for the preparation of ultra-high molecular weight polyethylene, characterized in that Comprising the following steps: S1: 1,6-hexanediamine reacts with allyl acrylate to generate intermediate 1, S2: intermediate 1 reacts with diphenylphosphine to generate intermediate 2, S3: intermediate 2 reacts with allyl bromide to generate intermediate 3, S4: intermediate 3 reacts with 9-borabicyclo[3.3.1]nonane to generate; In step S1, the molar ratio of 1,6-hexanediamine to allyl acrylate is 1:(4.05-4.1); In step S2, the molar ratio of intermediate 1 to diphenylphosphine is 1:(4.1-4.2); In step S3, the molar ratio of intermediate 2 to allyl bromide is 1:(6.3-6.5); In step S4, the molar ratio of intermediate 3 to 9-borabicyclo[3.3.1]nonane is 1:(6.2-6.4).

2. The production method according to claim 1, characterized by, In step S1, the reaction temperature is 50-60℃, and the reaction time is 8-10h; in step S2, the reaction temperature is 80-90℃, and the reaction time is 18-24h.

3. The preparation method according to claim 1, characterized in that, In step S3, the reaction temperature is 55-65℃, and the reaction time is 48-52h; in step S4, the reaction temperature is 55-65℃, and the reaction time is 10-14h.

4. The method of claim 1, wherein, The reaction solvent used in step S1 is methanol; the reaction solvent used in step S2 is anhydrous 1,4-dioxane; the reaction solvent used in step S3 is anhydrous acetonitrile; and the reaction solvent used in step S4 is tetrahydrofuran.

5. A catalyst for the preparation of ultra-high molecular weight polyethylene, characterized in that, Prepared by the method of any one of claims 1-4.

6. Use of a catalyst prepared by the method of any one of claims 1-4 in the preparation of ultra-high molecular weight polyethylene.

Images