Phase transfer PPS fiber catalyst, preparation method and application of catalytic synthesis of triphosphazene sulfonate flame retardant

Abstract

The present invention relates to a phase transfer PPS fiber catalyst, a preparation method and an application in the catalytic synthesis of triphosphazene sulfonate flame retardants. The present invention aims to solve the problems that small molecule catalysts cannot be separated from the solution during the synthesis of triphosphazene sulfonate flame retardants, thereby causing pollution and waste of resources and energy. Preparation of polyphenylene sulfide fiber (PPS) solid-supported phase transfer catalyst: a tertiary amine is reacted with chloromethylated PPS fiber and then an iodide ion-containing PPS solid-supported phase transfer catalyst is obtained by ion exchange. The prepared solid phase transfer catalyst is used to catalyze the reaction of hexachlorotripolyphosphazene with sodium p-hydroxy sodium benzene sulfonate, and the target flame retardant is obtained by separation and purification. The present invention not only allows the catalyst to be quickly removed and recycled, but also the introduction of iodide ions can effectively promote the dehalogenation reaction, avoid the addition of dehalogenation reaction catalysts, avoid environmental and sample pollution, and reduce costs, and has good industrial application value.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardant synthesis and relates to a phase transfer PPS fiber catalyst, a preparation method and application of the catalyst in the catalytic synthesis of triphosphazene sulfonate flame retardant. Background Art

[0002] PC is a high-performance thermoplastic engineering plastic. Its excellent impact resistance, transparency, high-temperature resistance, and dielectric properties make it widely used in building materials, automotive parts, and electronic and electrical components. PC possesses a certain degree of self-extinguishing properties, with pure PC achieving a LOI of 24-26% and a UL-94 V rating in the vertical flame test. However, in areas such as building materials and electronic components, the potential for fire and resulting damage is high, necessitating higher flame retardancy requirements. Therefore, further improvements in PC's flame retardancy are being sought.

[0003] Sulfonate flame retardants are a type of halogen-free flame retardant, generally considered to be flame retardant additives specifically for PC. They have high flame retardant efficiency and require a small addition amount. Generally, only 0.05-0.1 wt% of sulfonate flame retardants are needed to greatly improve the oxygen index of polycarbonate composite materials. Due to the small addition amount, the properties of the PC matrix itself, such as tensile strength and transparency, are less affected. It is worth noting that when the sulfonate addition amount exceeds 0.1 wt%, the transparency of the material will be affected, and as the addition amount increases, the impact strength of the material decreases more significantly. Since sulfonates are organic salts, they are sensitive to water and are hygroscopic in the air. When added to PC, they will also absorb moisture due to their hygroscopicity, making the sulfonate flame-retardant PC more susceptible to hydrolysis, resulting in a decrease in the degree of polymerization and molecular weight, and affecting the performance of the material.

[0004] In recent years, more and more new sulfonate flame retardants have been developed. However, the current synthesis process of these sulfonate flame retardants mostly utilizes homogeneous small molecule catalysts. The process of separating them from the reaction system is not only complicated to operate, but also inevitably requires the use of a large amount of organic reagents, thus causing secondary pollution. In addition, some small molecule catalysts are expensive and the production process is complicated, and their disadvantage of being difficult to recycle further increases the application cost of these small molecule catalysts. In recent years, in order to reduce environmental pollution and the application cost of catalysts, more and more scholars have used different methods to immobilize small molecule catalysts on various supports to achieve the recycling of catalysts. In addition, most immobilized catalysts exist in solid form, which is more conducive to the application of industrial fixed-bed catalysis, which has more application prospects than small molecule catalysis. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention proposes a method for synthesizing triphosphazene sulfonate flame retardants by phase transfer PPS catalysis with a simple preparation process, high catalytic activity and good recycling performance, thereby solving the problems of existing small molecule catalysts being non-recyclable, polluting the environment and wasting resources in the synthesis process of triphosphazene sulfonate flame retardants.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for synthesizing a triphosphazene sulfonate flame retardant by using phase transfer PPS catalyst comprises the following steps:

[0008] Step 1: Chloromethylation of PPS fiber: Add a certain amount of PPS fiber (polyphenylene sulfide fiber), paraformaldehyde, tin tetrachloride, trimethylsilyl chloride and 1,2-dichloroethane into a hydrothermal reactor. After reacting in an oven at a certain temperature for a period of time, take out the fiber and wash it with ethanol. After drying, chloromethylated PPS fiber PPS-Cl is obtained.

[0009] Step 2: PPS immobilized with quaternary ammonium chloride: Add a certain amount of the above-mentioned PPS-Cl fiber, tertiary amine and acetonitrile into a hydrothermal reactor, react in an oven at a certain temperature for a period of time, remove the fiber and clean it with ethanol;

[0010] Step 3: PPS immobilized iodine-containing quaternary ammonium salt: the fiber obtained in step 2 was placed in a saturated sodium iodide solution and stirred at room temperature for 12-24 hours, the fiber was taken out and cleaned with distilled water, and dried to obtain PPS immobilized iodine-containing quaternary ammonium salt fiber PPS-QAI.

[0011] Furthermore, in step 1, the mass ratio of PPS fiber to reaction solution is 1:20-1:80, wherein the reaction solution is composed of the paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane, and the mass concentrations of paraformaldehyde, tin tetrachloride and trimethylchlorosilane in the reaction solution are 5-15%, 8-20% and 5-15%, respectively.

[0012] Furthermore, in step 1, the reaction temperature is 50-100° C., and the reaction time is 24-72 h.

[0013] Furthermore, in step 2, the mass ratio of the PPS-Cl fiber to the tertiary amine solution is 1:10-1:50, the tertiary amine solution is composed of the tertiary amine and acetonitrile, and the concentration of the tertiary amine solution is 3-10 mol / L.

[0014] Furthermore, in step 2, the reaction temperature is 50-100° C., and the reaction time is 12-36 h.

[0015] Furthermore, in step 2, the tertiary amine is one of triethylamine, tributylamine, N,N-dimethyl-p-toluidine, and N,N-dimethylbutylamine.

[0016] The present invention also provides a phase transfer PPS fiber catalyst prepared by the preparation method.

[0017] The present invention also provides an application of a phase transfer PPS fiber catalyst in catalytic synthesis of a triphosphazene sulfonate flame retardant. The method comprises the following steps: adding hexachlorotripolyphosphazene, sodium p-hydroxy sodium benzene sulfonate, a fiber catalyst PPS-QAI and DMF into a three-necked flask, stirring and reacting at a certain temperature for a certain time, cooling to room temperature after the reaction is completed, filtering, and concentrating the filtrate under reduced pressure. The filtrate is then directly poured into dichloromethane, and the precipitated solid is filtered and rinsed with dichloromethane. The triphosphazene sulfonate flame retardant is obtained after drying.

[0018] Furthermore, the molar ratio of hexachlorotrimer phosphazene to sodium p-hydroxybenzenesulfonate is 1:4-1:8, and the amount of the fiber catalyst PPS-QAI is 10-30 mol% calculated based on the amount of quaternary ammonium groups relative to the amount of hexachlorotrimer phosphazene.

[0019] Furthermore, the reaction temperature is 50-150° C., and the reaction time is 3-12 h.

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

[0021] (1) The PPS fiber-supported phase transfer catalyst prepared by the present invention is used to catalyze the synthesis of triphosphazene sulfonate flame retardants. The catalyst has a simple preparation process, excellent catalytic effect, easy separation, and good recycling performance. This effectively solves the problems of existing small molecule catalysts such as non-recyclability, environmental pollution, and high cost.

[0022] (2) The PPS-supported iodine-containing quaternary ammonium salt catalyst prepared by the present invention effectively promotes the dehalogenation reaction due to the introduction of iodide ions, and avoids the additional addition of a dehalogenation reaction catalyst, which is more in line with the requirements of green chemistry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the route for immobilizing iodine-containing quaternary ammonium salt on PPS fiber.

[0024] Figure 2 Example of catalytic synthesis of triphosphazene sulfonate flame retardant. DETAILED DESCRIPTION

[0025] Below in conjunction with specific embodiment, the present invention will be further described.Should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention, and those skilled in the art in this field can make some non-essential improvements and adjustments according to the content of the foregoing invention.Unindicated specific experimental steps or conditions in the embodiment, the operation or condition of the conventional experimental steps described in the document in this area can be carried out.Reagents used or instruments are not indicated by manufacturers, and are all conventional reagent products that can be obtained by commercial purchase.

[0026] A method for synthesizing a triphosphazene sulfonate flame retardant by using phase transfer PPS catalyst comprises the following steps:

[0027] Step 1: Chloromethylation of PPS fiber: Add a certain amount of PPS fiber (polyphenylene sulfide fiber), paraformaldehyde, tin tetrachloride, trimethylsilyl chloride and 1,2-dichloroethane into a hydrothermal reactor. After reacting in an oven at a certain temperature for a period of time, take out the fiber and wash it with ethanol. After drying, chloromethylated PPS fiber PPS-Cl is obtained.

[0028] Step 2: PPS immobilized with quaternary ammonium chloride: Add a certain amount of the above-mentioned PPS-Cl fiber, tertiary amine and acetonitrile into a hydrothermal reactor, react in an oven at a certain temperature for a period of time, remove the fiber and clean it with ethanol;

[0029] Step 3: PPS immobilized iodine-containing quaternary ammonium salt: the fiber obtained in step 2 was placed in a saturated sodium iodide solution and stirred at room temperature for 12-24 hours, the fiber was taken out and cleaned with distilled water, and dried to obtain PPS immobilized iodine-containing quaternary ammonium salt fiber PPS-QAI.

[0030] Example 1

[0031] The preparation method of the phase transfer PPS-supported iodine-containing quaternary ammonium salt fiber PPS-EQAI in this embodiment is as follows:

[0032] Step 1: Chloromethylation of PPS fiber: 1 g PPS fiber, 3.6 g paraformaldehyde, 5.2 g tin tetrachloride, 4.4 g trimethylsilyl chloride, and 40 mL 1,2-dichloroethane were added to a hydrothermal reactor and reacted in an oven at 60 °C for 40 h. The fiber was taken out and cleaned with ethanol, and then dried to obtain the chloromethylated PPS fiber PPS-Cl.

[0033] Step 2: PPS-supported quaternary ammonium chloride: Add 1 g PPS-Cl fiber, 10.1 g triethylamine, and 20 mL acetonitrile into a hydrothermal reactor. After reacting in an oven at 80 °C for 24 h, remove the fiber and clean it with ethanol.

[0034] Step 3: The fiber obtained by washing with ethanol in step 2 is placed in 20 mL of saturated sodium iodide solution and stirred at room temperature for 12 h. The fiber is taken out and washed with distilled water. After drying, the PPS-supported iodine-containing quaternary ammonium salt fiber PPS-EQAI is obtained.

[0035] The method for synthesizing triphosphazene sulfonate flame retardant catalyzed by PPS-EQAI, a fiber containing iodine-containing quaternary ammonium salt, is as follows:

[0036] 10 mmol of hexachlorotrimer phosphazene, 50 mmol of sodium p-hydroxybenzenesulfonate, 20 mol% of the fiber catalyst PPS-EQAI (20% of the hexachlorotrimer used), and 200 mL of DMF were added to a three-necked flask and stirred at 100°C for 5 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and poured directly into dichloromethane. The precipitated solid was filtered and rinsed with a large amount of dichloromethane. After drying, the triphosphazene sulfonate flame retardant was obtained.

[0037] Example 2

[0038] The preparation method of the phase transfer PPS-supported iodine-containing quaternary ammonium salt fiber PPS-BQAI in this embodiment is as follows:

[0039] Step 1: Same as Example 1;

[0040] Step 2: PPS-supported quaternary ammonium chloride: 1 g of PPS-Cl fiber, 27.8 g of tributylamine, and 20 mL of acetonitrile were added to a hydrothermal reactor. The mixture was reacted in an oven at 80 °C for 28 h. The fiber was then removed and cleaned with ethanol to obtain PPS-BQACl.

[0041] Step 3: The fiber obtained by washing with ethanol in step 2 is placed in 20 mL of saturated sodium iodide solution and stirred at room temperature for 12 h. The fiber is taken out and washed with distilled water. After drying, the PPS-supported iodine-containing quaternary ammonium salt fiber PPS-BQAI is obtained.

[0042] The method for synthesizing triphosphazene sulfonate flame retardant catalyzed by PPS-BQAI, a PPS-supported iodine-containing quaternary ammonium salt fiber, is as follows: the catalyst is PPS-BQAI, and the rest is the same as in Example 1.

[0043] Example 3

[0044] The preparation method of a phase transfer PPS-immobilized iodine-containing quaternary ammonium salt fiber PPS-PQAI in this embodiment is as follows:

[0045] Step 1: Same as Example 1;

[0046] Step 2: PPS-supported quaternary ammonium salt containing chloride: 1 g PPS-Cl fiber, 27 g N,N-dimethyl-p-toluidine and 20 mL acetonitrile were added to a hydrothermal reactor. After reacting in an oven at 80 °C for 36 h, the fiber was taken out and cleaned with ethanol.

[0047] Step 3: PPS-immobilized iodine-containing quaternary ammonium salt: The fiber obtained by washing with ethanol in step 2 was placed in 20 mL of saturated sodium iodide solution and stirred at room temperature for 24 h. The fiber was taken out and washed with distilled water, and dried to obtain PPS-immobilized iodine-containing quaternary ammonium salt fiber PPS-PQAI;

[0048] The method for synthesizing triphosphazene sulfonate flame retardant catalyzed by PPS-PQAI, a PPS-supported iodine-containing quaternary ammonium salt fiber, is as follows: the catalyst is PPS-PQAI, and the other parameters are the same as those in Example 1.

[0049] Example 4

[0050] The preparation method of a phase transfer PPS-immobilized iodine-containing quaternary ammonium salt fiber PPS-MQAI in this embodiment is as follows:

[0051] The method for catalytic synthesis of triphosphazene sulfonate flame retardant is as follows:

[0052] Step 1: Same as Example 1;

[0053] Step 2: PPS-supported quaternary ammonium salt containing chloride: 1 g PPS-Cl fiber, 27 g N,N-dimethylbutylamine 0.2 mol and 20 mL acetonitrile were added to a hydrothermal reactor. After reacting in an oven at 80 °C for 36 h, the fiber was taken out and cleaned with ethanol.

[0054] Step 3: PPS immobilized iodine-containing quaternary ammonium salt: The fiber obtained in step 2 was placed in 20 mL of saturated sodium iodide solution and stirred at room temperature for 24 h. The fiber was taken out and cleaned with distilled water. After drying, the PPS immobilized iodine-containing quaternary ammonium salt fiber PPS-MQAI was obtained.

[0055] The method for synthesizing triphosphazene sulfonate flame retardant catalyzed by PPS-MQAI, a PPS-supported iodine-containing quaternary ammonium salt fiber, is as follows: the catalyst is PPS-MQAI, and the other parameters are the same as those in Example 1.

[0056] The results of the above examples are shown in Table 1.

[0057] Table 1 Results of the synthesis of triphosphazene sulfonate flame retardant by phase transfer PPS catalysis

[0058] Experiment number catalyst Yield (%) 1 PPS-EQAI 74 2 PPS-BQAI 82 3 PPS-PQAI 69 4 PPS-MQAI 68 5 PPS-BQACl 41

[0059] Table 2 PPS-BQAI catalyst recycling results

[0060] Number of cycles 1 2 3 4 5 6 Yield (%) 82 80 80 81 79 75

[0061] A comparison of different catalysts reveals that PPS-BQAI has the highest catalytic activity, likely due to the larger quaternary ammonium group's enhanced phase transfer catalytic activity. Furthermore, a comparison of PPS-BQAI and PPS-BQACl reveals that when the negative ion in the quaternary ammonium group is chloride, the reaction yield is only 41%, demonstrating the significant role of iodide ions in the catalytic process. Furthermore, Table 2 shows that under the same conditions, the optimal catalyst, PPS-BQAI, maintained a reaction yield of 75% after six cycles, demonstrating the excellent recyclability of the acid-base dual-functional acrylic fiber catalyst.

[0062] The present invention not only allows for quick removal and recycling of the catalyst, but also effectively promotes the dehalogenation reaction through the introduction of iodide ions, avoiding the addition of a dehalogenation catalyst, thus preventing environmental and sample contamination while reducing costs and possessing good industrial application value. The present invention addresses the problem of the inability to separate small molecule catalysts from the solution during the synthesis of triphosphazene sulfonate flame retardants, resulting in pollution and waste of resources and energy.

[0063] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a phase transfer PPS fiber catalyst, characterized in that: The following steps are involved: Step 1: Chloromethylation of PPS fiber: PPS fiber, paraformaldehyde, tin tetrachloride, trimethylsilyl chloride and 1,2-dichloroethane were added to a hydrothermal reactor. After reacting in an oven for a period of time, the fiber was taken out and cleaned with ethanol. After drying, the chloromethylated PPS fiber PPS-Cl was obtained. Step 2: PPS immobilized with quaternary ammonium salt containing chloride: Add chloromethylated PPS fiber PPS-Cl, tertiary amine and acetonitrile into a hydrothermal reactor. After reacting in an oven for a period of time, take out the fiber and clean it with ethanol. Step 3: PPS immobilized iodine-containing quaternary ammonium salt: put the fiber obtained after washing with ethanol in step 2 into a saturated sodium iodide solution and stir at room temperature, take out the fiber and wash it with distilled water, and then dry it to obtain PPS immobilized iodine-containing quaternary ammonium salt fiber PPS-QAI, that is, phase transfer PPS fiber catalyst.

2. The method for preparing a phase transfer PPS fiber catalyst according to claim 1, wherein: In step 1, the mass ratio of PPS fiber to reaction solution is 1:20-1:80, wherein the reaction solution is composed of paraformaldehyde, tin tetrachloride, trimethylchlorosilane and 1,2-dichloroethane, and the mass concentrations of paraformaldehyde, tin tetrachloride and trimethylchlorosilane in the reaction solution are 5-15%, 8-20% and 5-15%, respectively.

3. The method for preparing the phase transfer PPS fiber catalyst according to claim 1, wherein: In the step 1, the reaction temperature is 50-100° C., and the reaction time is 24-72 h.

4. The method for preparing the phase transfer PPS fiber catalyst according to claim 1, wherein: In the step 2, the mass ratio of the chloromethylated PPS fiber PPS-Cl to the tertiary amine solution is 1:10-1:50, the tertiary amine solution is composed of the tertiary amine and acetonitrile, and the concentration of the tertiary amine solution is 3-10 mol / L; the tertiary amine is triethylamine, tributylamine, N , N -Dimethyl-p-toluidine, N , N -One of the dimethylbutylamines.

5. The method for preparing the phase transfer PPS fiber catalyst according to claim 1, wherein: In the step 2, the reaction temperature is 50-100° C., and the reaction time is 12-36 h.

6. The method for preparing the phase transfer PPS fiber catalyst according to claim 1, characterized in that: In step 3, the stirring time at room temperature is 12-24 h.

7. The phase transfer PPS fiber catalyst prepared according to the preparation method according to any one of claims 1 to 6.

8. Use of the phase transfer PPS fiber catalyst according to claim 7 in the catalytic synthesis of triphosphazene sulfonate flame retardant, characterized in that: Hexachlorotripolyphosphazene, sodium p-hydroxy sodium benzenesulfonate, phase transfer PPS fiber catalyst and DMF were added into a three-necked flask, stirred and reacted at a certain temperature for a certain time, cooled to room temperature after the reaction was completed, filtered, and the filtrate was concentrated under reduced pressure and directly poured into dichloromethane. The precipitated solid was filtered and rinsed with dichloromethane, and then dried to obtain a triphosphazene sulfonate flame retardant.

9. The use according to claim 8, characterized in that: The molar ratio of hexachlorotrimer phosphazene to sodium p-hydroxybenzenesulfonate is 1:4-1:

8. The amount of the phase transfer PPS fiber catalyst is 10-30 mol%, calculated based on the amount of quaternary ammonium groups relative to the amount of hexachlorotrimer phosphazene.

10. The use according to claim 8, characterized in that: The reaction temperature is 50-150°C, and the reaction time is 3-12h.

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