Preparation method and application of polyphenylene sulfide fiber immobilized FLP catalyst

Abstract

The present application relates to a kind of polyphenyl sulfide fiber immobilized FLP catalyst preparation method and application, belong to green catalysis technical field.The preparation method mainly includes the following steps: first, piperazine is reacted with chloromethylated polyphenyl sulfide fiber (PPS), so as to introduce nitrogen system hindered Lewis base (FLB) on PPS, then piperazine functionalized PPS fiber is reacted with 3-bromine propylene, then with HB (C6F5) 2, so as to introduce boron system hindered Lewis acid (FLA), on polyphenyl sulfide fiber, FLB and FLA combination form FLP.In the catalytic epoxide compound fixed carbon dioxide reaction, the excellent catalytic performance and recycling performance of the catalyst.In addition, the polyphenyl sulfide catalyst is high in flexibility, can be made into various shapes, is convenient for the filling of industrial fixed bed, has potential industrial application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of green catalysis and relates to a preparation method and application of a polyphenylene sulfide fiber-supported hindered Lewis acid-base pair (FLP) catalyst. Background Art

[0002] In 2006, Stephan first discovered and reported hindered Lewis acid-base pairs (FLPs), marking the birth of a new branch of chemical research. Over the past decade, FLPs chemistry has developed rapidly, providing a new method and new ideas for activating small molecules. Small molecules including H2, CO2, N2, THF, N2O, SO2, alkenes, alkynes, cyclic ethers, etc. can be activated using FLPs systems and participate in reactions. At the same time, most FLPs systems are metal-free systems, which are more environmentally friendly. More importantly, these discoveries have broken the conventional wisdom that small molecule activation is inseparable from transition metals and have rekindled chemists' interest in main-group elements. However, the complex preparation process, poor stability, and difficulty in recycling of homogeneous FLPs have seriously restricted their application in large-scale catalytic reactions. Therefore, the development of heterogeneous catalysts with FLPs activity has become one of the hot topics in the field of catalysis science today.

[0003] The greenhouse effect caused by a large amount of CO2 in the environment has led to a continuous rise in the global average temperature. How to reduce the CO2 content in the atmosphere has become a hot topic of concern for scientific researchers. In addition, CO2 is a cheap and abundant C1 resource. Converting CO2 into useful chemical substances through certain technical means can not only alleviate the global resource crisis but also promote the sustainable development of the ecological environment. However, the extremely high chemical bond energy of CO2 makes it difficult to be activated and converted. Therefore, how to achieve effective activation and conversion of CO2 under mild conditions has become a major difficulty in the academic community. The present invention combines the advantages of PPS fiber carriers and FLPs in the activation and conversion of CO2 to prepare a PPS-supported FLP catalyst, and uses it to catalyze the CO2 fixation reaction of epoxy compounds. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention proposes a preparation method and application of a polyphenylene sulfide fiber (PPS) immobilized hindered Lewis acid-base pair (FLP) catalyst with easily available carriers, simple catalyst preparation process, high catalytic activity and good cycle performance, which solves the problems of insufficient performance of existing CO2 chemical fixation catalyst carrier materials, complex preparation process, unsatisfactory catalytic activity, and loss of catalytic sites.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for preparing a polyphenylene sulfide fiber-supported FLP catalyst comprises the following steps:

[0007] (1) Chloromethylation of PPS fiber: A certain amount of PPS fiber, paraformaldehyde, tin tetrachloride, trimethylsilyl chloride and 1,2-dichloroethane were added to a hydrothermal reactor. After reacting in an oven at a certain temperature for a period of time, the fiber was taken out and cleaned with ethanol. After drying, the chloromethylated PPS fiber PPS-Cl was obtained.

[0008] (2) Introduction of nitrogen-based hindered Lewis base (FLB): Chloromethylated PPS fiber PPS-Cl, N-aminoethylpiperazine and distilled water were mixed in a certain proportion and refluxed for a certain time. After that, the fiber was taken out, cleaned and dried to obtain piperazine-functionalized PPS fiber PPS-P.

[0009] (3) Introduction of allyl groups: piperazine-functionalized PPS fiber PPS-P, triphenylphosphine (TPP), diisopropyl azodicarboxylate (DIAD) and THF were mixed evenly in a certain proportion, and then a certain amount of 3-bromopropylene was added. The mixture was stirred at a certain temperature for a certain time, and then the fiber was taken out, cleaned and dried to obtain allyl-functionalized polyphenylene sulfide fiber PPS-PO;

[0010] (4) Boron-based hindered Lewis acid (FLA) was introduced to prepare PPS-supported FLP catalyst: allyl-functionalized polyphenylene sulfide fiber PPS-PO was added to HB(C6F5)2 toluene solution and stirred for a certain period of time. Finally, the fiber was taken out, cleaned and dried to obtain polyphenylene sulfide fiber-supported FLP catalyst PPS-FLP.

[0011] Furthermore, in step (1), the reaction solution A is composed of paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane, the mass volume ratio of PPS fiber to the reaction solution is 1:20-1:80 g / mL, and the molar concentrations of paraformaldehyde, tin tetrachloride and trimethylchlorosilane in the reaction solution A are 0.5-1.5 mol / L, 0.25-0.75 mol / L and 0.5-1.5 mol / L, respectively.

[0012] Furthermore, in step (1), the molar ratio of paraformaldehyde, tin tetrachloride and trimethylchlorosilane is 2:1:2.

[0013] Furthermore, in step (1), the reaction temperature is 50-100° C., and the reaction time is 24-72 h.

[0014] Furthermore, in step (2), N-aminoethylpiperazine and distilled water constitute reaction solution B, wherein the volume ratio of N-aminoethylpiperazine to distilled water is 2:1-1:2, the mass volume ratio (g / mL) of chloromethylated PPS fiber PPS-Cl to the reaction solution B is 1:15-1:50, and the reflux reaction time is 4-24 hours.

[0015] Furthermore, in step (3), triphenylphosphine (TPP), diisopropyl azodicarboxylate (DIAD) and THF constitute a reaction solution C, wherein the molar ratio of TPP to DIAD is 1:1-1:3, the concentration of TPP is 50-120 mmol / L, and the mass volume ratio (g / mL) of piperazine-functionalized PPS fiber PPS-P to reaction solution C is 1:25-1:50.

[0016] Furthermore, in the step (3), the amount of 3-bromopropylene added is 1.5-3 times the amount of TPP, the reaction temperature is 20-60° C., and the reaction time is 12-72 h.

[0017] Furthermore, in step (4), the concentration of the HB(C6F5)2 toluene solution is 30-100 mmol / L, the reaction temperature is 20-80°C, and the reaction time is 8-24 h.

[0018] Furthermore, in step (4), the mass volume ratio (g / mL) of the allyl functionalized acrylic fiber PANF-PO and the toluene solution of HB(C6F5)2 is 1:25-1:50.

[0019] Furthermore, the polyphenylene sulfide fiber-supported FLP catalyst prepared by the present invention is used to catalyze the carbon dioxide fixation reaction of epoxy compounds.

[0020] After adopting the above technical solution, the present invention achieves the following beneficial effects:

[0021] (1) This invention is the first to prepare a solid FLP catalyst using polyphenylene sulfide fiber as a carrier. This catalyst has a simple preparation process, high catalytic activity, low cost, and good recyclability. It effectively solves the problems of existing FLP catalysts, such as complex preparation processes, suboptimal catalytic activity, and easy loss of catalytic sites.

[0022] (2) The polyphenylene sulfide fiber-supported FLP catalyst prepared by the present invention was applied to the catalytic carbon dioxide fixation reaction of epoxy compounds. The catalyst exhibited excellent catalytic activity, high reaction yield, and good recyclability. Furthermore, the polyphenylene sulfide catalyst is highly flexible and can be woven into various shapes, facilitating the filling of industrial fixed beds, demonstrating its potential for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1Schematic diagram of FLP catalyst immobilized on polyphenylene sulfide fiber.

[0024] Figure 2 Example of the carbon dioxide fixation reaction of epoxides.

[0025] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the polyphenylene sulfide fiber-supported FLP catalyst obtained in Example 1. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to specific examples. It should be understood that the following examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention, and that those skilled in the art may make non-essential improvements and adjustments based on the contents of the above invention.

[0027] Example 1

[0028] The preparation method of the polyphenylene sulfide fiber-supported FLP catalyst of this embodiment is as follows:

[0029] (1) 1 g of PPS fiber was added to 20 mL of a 1,2-dichloroethane solution of paraformaldehyde, tin tetrachloride, and trimethylsilyl chloride, where the molar concentrations of paraformaldehyde, tin tetrachloride, and trimethylsilyl chloride were 0.5 mol / L, 0.25 mol / L, and 0.5 mol / L, respectively. The fiber-solution mixture was added to a hydrothermal autoclave and allowed to react in an oven at 50°C for 24 h. The fiber was then removed, cleaned with ethanol, and dried to obtain the chloromethylated PPS fiber PPS-Cl.

[0030] (2) In a 100 mL round-bottom flask, 1 g of PPS-Cl fiber, 20 mL of piperazine, and 20 mL of distilled water were added and heated under reflux for 4 h under magnetic stirring. The fiber was then removed, cleaned, and dried to obtain piperazine-functionalized polyphenylene sulfide fiber PPS-P.

[0031] (3) 1 g of PPS-P fiber, 4 mmol of TPP, 8 mmol of DIAD, and 40 mL of THF were stirred evenly, and then 10 mmol of 3-bromopropylene was added. The mixture was stirred at 45 °C for 48 h. After that, the fiber was taken out, cleaned, and dried to obtain allyl-functionalized polyphenylene sulfide fiber PPS-PO.

[0032] (4) 1 g of PPS-PO fiber was added to 30 mL of 60 mmol / L HB(C6F5)2 toluene solution and stirred at 45 °C for 12 h. Finally, the fiber was taken out, cleaned and dried to obtain the polyphenylene sulfide fiber-supported FLP catalyst PPS-FLP.

[0033] Example 2

[0034] The preparation method of the polyphenylene sulfide fiber supported FLP catalyst of the present embodiment is as follows:

[0035] (1) 1 g of PPS fiber was added to 40 mL of a 1,2-dichloroethane solution of paraformaldehyde, tin tetrachloride, and trimethylchlorosilane, wherein the mass concentrations of paraformaldehyde, tin tetrachloride, and trimethylchlorosilane were 0.8 mol / L, 0.4 mol / L, and 0.8 mol / L, respectively. The above fiber and solution mixture was added to an autoclave, and after being reacted in an oven at 60°C for 40 h, the fiber was taken out and cleaned with ethanol, and after being dried, chloromethylated PPS fiber PPS-Cl was obtained.

[0036] (2) 1 g of PPS-Cl fiber, 10 mL of piperazine, and 20 mL of distilled water were added to a 100 mL round-bottom flask, and after being heated and refluxed under magnetic stirring for 12 h, the fiber was taken out, cleaned, and dried to obtain piperazine functionalized polyphenylene sulfide fiber PPS-P.

[0037] (3) 1 g of PPS-P fiber, 1.25 mmol of TPP, and 1.25 mmol of DIAD were stirred uniformly in 25 mL of THF, and after 1.875 mmol of 3-bromopropene was added, the mixture was stirred at 20°C for 12 h, and after the fiber was taken out, cleaned, and dried, allyl functionalized polyphenylene sulfide fiber PPS-PO was obtained.

[0038] (4) 1 g of PPS-PO fiber was added to 50 mL of a 100 mmol / L HB(C6F5)2 toluene solution, and after being stirred at 80°C for 24 h, the fiber was taken out, cleaned, and dried to obtain polyphenylene sulfide fiber supported FLP catalyst PPS-FLP.

[0039] Example 3

[0040] The preparation method of the polyphenylene sulfide fiber supported FLP catalyst of the present embodiment is as follows:

[0041] (1) 1 g of PPS fiber was added to 60 mL of a 1,2-dichloroethane solution of paraformaldehyde, tin tetrachloride, and trimethylchlorosilane, wherein the mass concentrations of paraformaldehyde, tin tetrachloride, and trimethylchlorosilane were 1.2 mol / L, 0.6 mol / L, and 1.2 mol / L, respectively. The above fiber and solution mixture was added to an autoclave, and after being reacted in an oven at 80°C for 56 h, the fiber was taken out and cleaned with ethanol, and after being dried, chloromethylated PPS fiber PPS-Cl was obtained.

[0042] (2) 1 g of PPS-Cl fiber, 10 mL of piperazine, and 5 mL of distilled water were added to a 100 mL round-bottom flask, and after being heated and refluxed under magnetic stirring for 18 h, the fiber was taken out, cleaned, and dried to obtain piperazine functionalized polyphenylene sulfide fiber PPS-P.

[0043] (3) 1 g of PPS-P fiber, 7.5 mmol of TPP, 22.5 mmol of DIAD, and 50 mL of THF were stirred evenly, and then 22.5 mmol of 3-bromopropylene was added. The mixture was stirred at 60 °C for 72 h. After that, the fiber was taken out, cleaned, and dried to obtain allyl-functionalized polyphenylene sulfide fiber PPS-PO.

[0044] (4) 1 g of PPS-PO fiber was added to 25 mL of 30 mmol / L HB(C6F5)2 toluene solution and stirred at 20°C for 8 h. Finally, the fiber was taken out, cleaned and dried to obtain the polyphenylene sulfide fiber-supported FLP catalyst PPS-FLP.

[0045] Example 4

[0046] The preparation method of the polyphenylene sulfide fiber-supported FLP catalyst of this embodiment is as follows:

[0047] (1) 1 g of PPS fiber was added to 80 mL of a 1,2-dichloroethane solution of paraformaldehyde, tin tetrachloride, and trimethylsilyl chloride, where the molar concentrations of paraformaldehyde, tin tetrachloride, and trimethylsilyl chloride were 1.5 mol / L, 0.75 mol / L, and 1.5 mol / L, respectively. The fiber-solution mixture was added to a hydrothermal autoclave and reacted in an oven at 100°C for 72 h. The fiber was then removed, cleaned with ethanol, and dried to obtain the chloromethylated PPS fiber PPS-Cl.

[0048] (2) In a 100 mL round-bottom flask, 1 g of PPS-Cl fiber, 20 mL of piperazine, and 30 mL of distilled water were added and heated under reflux with magnetic stirring for 24 h. The fiber was then removed, cleaned, and dried to obtain piperazine-functionalized polyphenylene sulfide fiber PPS-P.

[0049] (3) 1 g of PPS-P fiber, 2.1 mmol of TPP, 3.15 mmol of DIAD, and 30 mL of THF were stirred evenly, and then 4.2 mmol of 3-bromopropylene was added. The mixture was stirred at 35 °C for 24 h. The fiber was then removed, cleaned, and dried to obtain allyl-functionalized polyphenylene sulfide fiber PPS-PO.

[0050] (4) 1 g of PPS-PO fiber was added to 40 mL of 80 mmol / L HB(C6F5)2 toluene solution and stirred at 60 °C for 18 h. Finally, the fiber was taken out, cleaned and dried to obtain the polyphenylene sulfide fiber-supported FLP catalyst PPS-FLP.

[0051] Example 5

[0052] The polyphenylene sulfide fiber immobilized FLP catalyst prepared in the above example was applied to catalyze the reaction of fixing carbon dioxide with epichlorohydrin, and the following scheme was used:

[0053] Epichlorohydrin (50 mmol) and 5 mol% of the fiber catalyst were added into a reaction tube, which was sealed after multiple exhaust and connected with a carbon dioxide gas bag. The reaction liquid was stirred at 80°C for 12 h, and then the fiber catalyst was removed. The conversion rate of the reaction liquid was determined by gas chromatography. The fiber was washed with ethanol and water, dried, and then used for the next cycle. The experimental results are shown in Tables 1 and 2.

[0054] Comparative Example 1

[0055] B(C6F5)3 was applied to catalyze the reaction of fixing carbon dioxide with epichlorohydrin, and the following scheme was used:

[0056] Epichlorohydrin (50 mmol) and 5 mol% of B(C6F5)3 were added into a reaction tube, which was sealed after multiple exhaust and connected with a carbon dioxide gas bag. The reaction liquid was stirred at 80°C for 12 h, and then the fiber catalyst was removed. The conversion rate of the reaction liquid was determined by gas chromatography. The fiber was washed with ethanol and water, dried, and then used for the next cycle. The experimental results are shown in Table 1.

[0057] Table 1 Evaluation of the activity of polyphenylene sulfide fiber immobilized FLP catalyst in the reaction of fixing carbon dioxide

[0058] catalyst Yield (%) Example 1 99 Example 2 92 Example 3 94 Example 4 99 Comparative Example 1 52

[0059] Table 2 Evaluation of the cycle performance of the catalyst of Example 1

[0060] Number of cycles 2 4 6 8 Yield (%) 99 95 95 90

[0061] As shown in Table 1, the catalyst of the present application can efficiently catalyze the reaction of fixing carbon dioxide with epichlorohydrin, and the yield is as high as 99%. Under the optimal conditions, the catalyst of Example 1 was applied to determine the cycle performance, and the results are shown in Table 2. When the catalyst is used for 10 cycles, the reaction yield can still reach 90%, and the catalyst maintains 91% of the catalytic activity. It is shown that the catalyst has very excellent cycle performance.

[0062] It should be understood that the examples of the present application are intended to be illustrative only and not limiting in any way on the scope of the present application. Those skilled in the art can make improvements based on the above examples, and all these improvements are within the scope of protection of the appended claims of the present application.

Claims

1. A method for preparing a polyphenylene sulfide fiber-supported FLP catalyst, characterized in that: The following steps are involved: (1) Chloromethylation of PPS fiber: A certain amount of PPS fiber, paraformaldehyde, tin tetrachloride, trimethylsilyl chloride and 1,2-dichloroethane were added to a hydrothermal reactor. After reacting in an oven at a certain temperature for a period of time, the fiber was taken out and cleaned with ethanol. After drying, the chloromethylated PPS fiber PPS-Cl was obtained. (2) Introducing nitrogen-based hindered Lewis base FLB: Chloromethylated PPS fiber PPS-Cl, N -Aminoethylpiperazine and distilled water are mixed in a certain proportion and refluxed for a certain period of time, after which the fiber is taken out, cleaned and dried to obtain piperazine-functionalized PPS fiber PPS-P; (3) Introduction of allyl groups: piperazine-functionalized PPS fiber PPS-P, triphenylphosphine TPP, diisopropyl azodicarboxylate DIAD and THF were mixed evenly in a certain proportion, and then a certain amount of 3-bromopropylene was added. The mixture was stirred at a certain temperature for a certain time, and then the fiber was taken out, cleaned and dried to obtain allyl-functionalized polyphenylene sulfide fiber PPS-PO. (4) Introducing boron-based hindered Lewis acid FLA to prepare PPS-supported FLP catalyst: Allyl-functionalized polyphenylene sulfide fiber PPS-PO was added to HB(C6F5)2 toluene solution and stirred for a certain period of time. Finally, the fiber was taken out, cleaned and dried to obtain polyphenylene sulfide fiber-supported FLP catalyst PPS-FLP.

2. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In the step (1), a reaction solution A is composed of paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane, the mass volume ratio of PPS fiber to the reaction solution is 1:20-1:80 g / mL, and the molar concentrations of paraformaldehyde, tin tetrachloride and trimethylchlorosilane in the reaction solution A are 0.5-1.5 mol / L, 0.25-0.75 mol / L and 0.5-1.5 mol / L, respectively.

3. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 2, characterized in that: In the step (1), the molar ratio of paraformaldehyde, tin tetrachloride and trimethylchlorosilane is 2:1:

2.

4. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In the step (1), the reaction temperature is 50-100°C and the reaction time is 24-72 h.

5. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In the step (2), N -aminoethylpiperazine and distilled water constitute the reaction solution B, wherein N The volume ratio of -aminoethylpiperazine to distilled water is 2:1-1:2, the mass volume ratio of chloromethylated PPS fiber PPS-Cl to the reaction solution B is 1:15-1:50 g / mL, and the reflux reaction time is 4-24 h.

6. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In the step (3), triphenylphosphine TPP, diisopropyl azodicarboxylate DIAD and THF constitute a reaction solution C, wherein the molar ratio of TPP to DIAD is 1:1-1:3, the concentration of TPP is 50-120 mmol / L, and the mass volume ratio of piperazine functionalized PPS fiber PPS-P to the reaction solution C is 1:25-1:50 g / mL.

7. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In the step (3), the amount of 3-bromopropylene added is 1.5-3 times the amount of TPP, the reaction temperature is 20-60° C., and the reaction time is 12-72 h.

8. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In the step (4), the concentration of the HB(C6F5)2 toluene solution is 30-100 mmol / L, the reaction temperature is 20-80°C, and the reaction time is 8-24 h.

9. The method for preparing the polyphenylene sulfide fiber-supported FLP catalyst according to claim 1, characterized in that: In step (4), the mass volume ratio of the allyl functionalized polyphenylene sulfide fiber PPS-PO to the toluene solution of HB(C6F5)2 is 1:25-1:50 g / mL.

10. Use of the polyphenylene sulfide fiber-supported FLP catalyst prepared by the preparation method according to any one of claims 1 to 9 in catalyzing the carbon dioxide fixation reaction of epoxy compounds.

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